Aws Part- I Jodpur New

2

FOREWORD 1. Military aviation encompasses variety of challenging weather situations. To overcome these challenges, a great deal of progress has been made in the field of meteorology. However, keeping in mind the limitations and capabilities of aircraft with respect to weather, one needs to define a safe performance envelope for operations. Thus for all personnel directly associated with flying operations, the knowledge of weather is essential for exploiting the potential of air power accurately & effectively. 2. The new edition of Aviation Weather Summary for Jodhpur has been prepared with the aim that weather significantly impacts on the feasibility of using military force and on ensuing operations. It impacts differently on various types of forces and, in some cases, dictates the types of forces that can be employed effectively. Weather data is part of the intelligence information required by commanders and staff to plan and conduct combat operations. Air operations require continuous weather support and availability of real time information on the existing weather conditions. I am confident that the document will prove to be of immense value to the aircrew at this station and elsewhere for assessing weather over Jodhpur. 3. The effort put in by Met personnel at this base in preparing the weather summary are praiseworthy. I congratulate Wg Cdr Anupam Mehta, Senior Meteorological Officer and his team for producing this outstanding document which involved dedicated and sustained hard work over a prolonged period. 4. As this document reaches, we will be on to the New Year. I, on, behalf of all the air warriors of Air Force Station, Jodhpur take this opportunity to wish all our readers a very happy, prosperous and innovative new year. Year 2007 has a lot in store for the meteorology community all over the world, courtesy, the global warming, earthquakes, El-Nino, Tsunami, cold wave spells, floods in Rajasthan and Gujarat. 5. I conclude, by stating that victory has always gone to the side which has control of the air weather too, whether at sea or over land.

27 November 2006

(Jinendra Kumbhat) Air Commodore Air Officer Commanding

3

PREFACE 1. The meteorology, in its oneness is a multi-disciplinary complex subject and therefore needs to be taught and studied through a well focussed approach for the benefit of all concerned. I sincerely hope that Aviation Weather Summary for Aircrew, through its contents and current shape, would directly or indirectly contribute towards greater weather understanding over Jodhpur. In the scenario of constant evolution apprehending the atmospheric science and getting an insight into the origin of weather is possible only through diligent pursuit. The most important aspect about the weather is its variability. The weather often changes very quickly, sometimes in ways unexpected even on part of the most experienced and wellestablished meteorological forecasters. While scientific approach and knowledge are the basic ingredients of weather prediction, the experience and meteorological sense (personal radar) of a forecaster also play a very important role. 2. The aviation weather summary for Jodhpur airfield has been prepared with this aim. It has been crafted strictly as per the revised format issued is based on the data of last 35 years (1971-2005). The document has been prepared after a critical review of the content with suitable complement of the local weather knowledge gained by forecasters at this base. The statistics is based on data of last 35 years (1971-2005). 3.

This summary is the product of untiring efforts of all personnel of this section. Even some of the aircrew have indirectly contributed towards this document through their comprehensive weather debriefs. I gratefully acknowledge the constant encouragement I have received from AOC and COO in pursuing this goal. Gp Capt MC Joshi and Wg Cdr A Bajpayee have contributed for bringing this document in the present form by way of giving valuable suggestions and the build up of manuscript. Fg Offr Ekta Bothra has also put in efforts which are praise worthy. The acknowledgement would not be complete if I don't make mention of JWO JM Garg and JWO DK Dwivedi for their effective supervision and Sgt KP Singh and Cpl K Singh for typing the manuscript.

4.

I sincerely hope that the new edition of aviation weather summary would benefit for aviators at this base and elsewhere in IAF.

27 November 2006

(Anupam Mehta) Wing Commander Senior Meteorological Officer

4

PROLOGUE 1. The role of weather on air operations is endless but with the Indian Air Force expanding in space, its time to evaluate and address the threat of enemy’s nuclear, biological and chemical weapons. The local effectiveness of these weapons is substantially affected by weather conditions. In addition, local weather conditions have a significant effect on observability – both the ability to see an adversary as well as the ability to remain undetected. 2. Aviation weather forecasting continues to remain a challenging profession, in spite of the various advancements in the field of meteorology. These challenges are mainly on account of insufficiency of inputs available to the forecaster dealing with aviation meteorology. An accurate and timely assessment of weather is a painstaking process for the meteorologist but definitely an advantage to the aircrew. 3. In the IAF, where all of us are striving hard to create a safer flying environment by eliminating flight safety hazards, the new edition of Aviation Weather Summary of Jodhpur would definitely be valuable to the aviators. 4. I am confident that the summary will prove very useful to all air warriors concerned with flying operations. It is my pleasure and privilege to write a prologue to this unique illustrative document. I complement Wg Cdr Anupam Mehta and his staff for the excellent work done in compiling the first ever Aviation Weather Summary for aircrew. 5.

At last I am reminded of saying by Sun Tzu : “Know yourself, know your enemy; Your victory will never be endangered. Know the ground, know the weather; Your victory will then be total.”

27

November 2006

(RJ Duckworth) Group Captain Chief operations Officer

5

INDEX Sl. No.

Topic

Page No.

1.

Foreword

2

2.

Preface

3

3.

Prologue

4

4.

Index

5

5.

Geographical and Topographical Information

7

6.

Annual Cycle of Weather

12

7.

Winter Season (a) December (b) January (c) February

19 26 39 52

Pre-Monsoon season (a) March (b) April (c) May (d) June Monsoon Season (a) July (b) August (c) September Post Monsoon Season (a) October (b) November

65 72 84 97 109 123 132 145 158 171 177 191

11.

Climatological Information

202

12.

Diversionary Airfield Informations (a) Primary Diversion – Jaisalmer (b) Secondary Diversion – Uttarlai

209 210 233

13.

Additional Info

14.

FAQs

8.

9.

10.

6

CLIMATOLOGICAL DETAILS JODHPUR , JAISALMER AND UTTARLAI

Sl. No.

Tables & Figures

Page No. 203

CL1

Annual Rainfall Pattern : Jodhpur

CL2

Means and Extremes : Jodhpur (Jan – Apr)

204

Means and Extremes : Jodhpur (May – Aug)

205

Means and Extremes : Jodhpur (Sep – Dec)

206

Pentad Normal : Jodhpur (01 – 35)

207

Pentad Normal : Jodhpur (36 – 73)

208

CL3 DA_J1 to DA_J12 DA_J13 DA_J14

Summary of AWH : Jaisalmer (Jan-Dec)

211-222

Means & Extremes : Jaisalmer (Jan – Jun)

223

Means & Extremes : Jaisalmer (Jul – Dec)

224

DA_J15 Weather State for Fighters / Transports : Jaisalmer (Jan – Dec) DA _U1 to Summary of AWH : Uttarlai (Jan-Dec) DA_U12 DA_U13 Means & Extremes : Uttarlai

225 234-245 246

DA_U14 Weather State (12 Hrs block) for Fighters : Uttarlai

247

DA_U15 Weather State (12 Hrs block) for Transports : Uttarlai

248

DA_U16 Weather State (6 Hrs block) : Uttarlai

249

7

AVIATION WEATHER SUMMARY FOR AIRCREW GEOGRAPHICAL AND TOPOGRAPHICAL DETAILS 1. Jodhpur also known as ‘Suncity’ is a well known city of Raj situated in West Raj on the eastern fringes of the Thar Desert. Jodhpur has the distinction of neither being part of Thar Desert nor out of it. The Thar Desert is far to the West and North of Jodhpur; it extends from edge of Rann of Kutch beyond Luni river towards the North.The sterile, sandy and inhospitable Thar Desert in the far West and North of Jodhpur gradually improves to comparatively fertile and habitable land in the Northeast, East and Southeast. Orographic features and absence of maritime influence affect to a large extent the climate of this area. The average maximum temperatures of the order of 40 deg C in the month of Apr, May and Jun but occasionally it touches to high of 48 deg C. In the winter normal minimum temperatures are around 8 to 9 deg C except on few occasions it drops to -3 deg C in the months of Jan and Feb. The average annual rainfall is around 432 mm. Geographical Details 2.

The geographical details of Jodhpur are as follows :Latitude Longitude Elevation Magnetic Bearing Runway Orientation Runway Length Transition Level Transitional Altitude

3.

The geographical details of diversionary airfields are as under:Uttarlai Jaisalmer Nal (a) Latitude (b) Longitude (c) Elevation (d) Bearing (e) Distance (f) Runway orientation

4.

26.18º N 73.03º E 217 .00 m 45/225º 05 - 23 9000’ (2X150 ft) F/L 55 (5500 ft) 4000 ft

25.49º N 71.29º E 153 M 254º 159 KM 02 - 20

28.53º N 70.52º E 236 M 288º 224 KM 04 – 22

The geographical features of Jodhpur are depicted in Map “Q”.

28.04º N 73.12º E 213.8 M 004º 199 KM 05 - 23

8

Topographical Details 5. The only important river in the West Raj is the Luni which is a seasonal river. The river rises in the hills SE of Ajmer city, flows in NE – SW orientation passing 30 km South of Jodhpur. 6. There are few lakes in the vicinity of the town, Soorsagar and Kailana being the main lakes. Lake Kailana is the main source of water supply to entire Jodhpur town 7. The Aravalli range which is main cause of stopping the advancement of Thar Desert further east wards, runs in NE – SW orientation running from Delhi to Ahmedabad. The range is about 135 km East of Jodhpur. The Aravalli range plays a major role in influencing the precipitation characteristics at Jodhpur. 8. Effect of Topography on Local Weather. The climate of Jodhpur is tropical, arid and hot. The climate is characterised by extreme dryness, extremes of temperature and uncertain Rainfall. Jodhpur urban civilisation commences just outside the airfield and like other cities the population has increased in leaps and bounds and the city has spread its wings all around, except south of airfield. 9. Industries. Basni industrial area and railway yards which are the main source of pollution are situated approximately 08 – 10 km SSW and NW of airfield. As and when the winds become SW’ly to NW’ly due to the passage of weather system, the pollution over the city drifts over the airfield reducing visibility due to environment obscurity. 10. Layout of Air Field. details is included (Map R).

The Map/Sketch of the airfield with its topographical

11. Visibility Landmarks. The sketch of the airfield with updated visibility landmarks is included. A re-assessment of the visibility landmarks has been done before the visibility landmarks sketch is included in AWS. A number of new relevant and distinctly visible landmarks that have come up over period of time have been included. Their exact distance and bearing from the ARP has been checked. The old landmarks, those have become obscured/ masked by the growth of trees or due to urban development, have been excluded (Fig - 1).

9

Map P Nal 0040/298Km

Jaisalmer 2880/224Km

Uttarlai 2540/254Km

Map Q

10

Map R

11

VISIBILITY LAND MARKS

5000 M

Mehrangarh Fort

4000 M 3000 M Umaid Bhawan

Army W/Tank

Army Tower

2000 M DRDO

1000 M

23 End

SRE BSNL Tower

U/G ATC 05 End

107 HU 29 Sqn Hangar Hangar

Microwave Tower Water Tank

Fig – 1

Water Tank 1

Water Tank 2 Water Tank 3

12

13

ANNUAL CYCLE OF WEATHER 12. The annual cycle of weather at a place is basically guided by both climatic and seasonal variation. The cycle of weather over Jodhpur can be broadly divided in to four seasons. (a) (b) (c) (d)

Winter season Pre-monsoon Monsoon season Post Monsoon

Dec to Feb. Mar to Jun. Jul to Sep. Oct & Nov.

Winter Season (Dec – Feb) 13. The season is characterised by low temperatures, high pressure, dry winds and stable atmosphere. During the season a well marked high pressure ridge extends over the Indian sub-continent, from Iran and Afghanistan region. Cold and Dry NW'ly airmass sweeps entire NW India expect during the passage of Western Disturbance. WD moving over Northern latitudes at times induces low pressure over Central Pak and adjoining SW Raj. These low pressure areas move across Raj causing weather over the region. 14. Sub tropical jet core is seen over the region during the season. Inversion during the morning hours over the Indian sub-continent is responsible for poor visibility over Punjab, Haryana, UP, MP and Bihar. Fog/Mist also occur after passage of WD. Frequency of Rain/Thundershowers accompanied with hail progressively increases from Dec to Mar.

Pre – Monsoon Season (Mar – Jun) 15. As the Sun shifts northward, the land mass over the Indian sub-continent gets heated up resulting in rise of temperature and fall of pressure over the region. The stable atmosphere of winter progressively yields to unstable condition prior to onset of monsoon. 16. There are various synoptic features over the country which leads to violent convective activity. WD and induced low causes Andhi over NW India and Kalbaisakhi over West Bengal and Chotta Nagpur region. Most of the convective activity over southern peninsula is governed by asymptotic convergence over the region. The season is characterised by high temperatures, Dust Haze, Dust Raising winds, Dust storms and Thunderstorms generally accompanied with strong winds.

Southwest Monsoon Season (Jul – Sep) 17. The rainy season has major part to play in the economy of the country. The seasonal low which is seen over foothills gets established over NW Raj and adjoining Pakistan with gradient along West coast. The ITCZ shifts northwards and

14 gets established over Indo-Gangetic plains mostly referred as Axis of Monsoon Trough. 18. The Monsoon arrives over Kerala coast by 29 May and slowly and steadily progresses northwards. The onset of monsoon over NW India takes place by first week of July and further it establishes over the entire country by 15 Jul. Tropical Easterly jet Stream appears over southern peninsula at 9.0 km with core speed of 80-90kts. Persistent rain, low clouds and convective activity are general features of weather and also constitute major Aviation Weather Hazard during this season. The rainfall over the region is largely guided by:(a) Axis of Monsoon Trough. (b) Monsoon low / depression forming over North Bay and moving W/NW wards. (c) Intensification of seasonal LOPAR due to movement of WD across North India or merger of Monsoon low moving inland from North Bay. (d) Break Monsoon with AMT shifting northward close to foot hills and appearance of ridge along 10º N over Bay, cutting off SW Monsoon current.

Post Monsoon Season (Oct – Nov) 19. The two months of Oct and Nov give way from unstable summer Monsoon to stable winter months. This is the best season in NW India marked with comfortable temperature and weather. Weather gets affected due to formation of depression/cyclonic storm which form in the Bay of Bengal moving westward. These systems at times after crossing peninsula emerge over Arabian Sea, become more marked and move further westward. 20. This is the season for NE Monsoon over peninsular India. The pressure gradient over the country is stable with light winds prevailing in lower levels becoming westerly in higher level.

Time Series of Weather Elements 21. Variation of the frequency of occurrence of the various elements in the annual cycle from Jan to Dec is discussed. The database has the averages based on the data availability from 1971-2005. The time series of annual cycle has the graphical representation and the brief description of the trend of each of the following AWHs:(a) (b) (c)

Rainfall (Fig 2). Thunderstorms (Fig 3). Poor Visibility (i) (ii)

<1 Km. (Fig 4). < 3 Km (Fig 5).

15

TIME SERIES OF FREQUENCY OF RAINFALL (ANNUAL) FOR JODHPUR (DATABASE: 1971-2005)

10.0 8.7

9.0

8.8

NO. OF DAYS

8.0 7.0 6.0 5.0 4.0 3.0

3.5

2.2

2.0 1.0

3.9

3.5

0.8

1.3

1.2

0.6

0.5

0.

0.0 JAN

FEB

MAR

APR

MAY Fig - 2

JUN

JUL

AUG

MONTHS

TIME SERIES OF FREQUENCY OF THUNDER STORM (ANNUAL) FOR JODHPUR

SEP

OCT

NOV

DE

16 (DATABASE: 1971-2005)

8.0

7.3

7.0 5.9

NO. OF DAYS

6.0 5.0 4.0

3.6

3.0

3.7

3.6

2.6 1.7

2.0 1.0

0.3

0.5

0.7 0.1

0.1

NOV

DEC

0.0 JAN

FEB

MAR

APR

MAY Fig - 3

JUN

JUL

AUG

SEP

MONTHS

TIME SERIES OF FREQUENCY OF POOR VISIBILITY <3000M (ANNUAL) FOR JODHPUR

OCT

17 (DATABASE: 1971-2005)

10.0 8.7

9.0

8.2

NO. OF DAYS

8.0 7.0

6.3

6.0 5.0 4.0

4.5

4.1

3.6

3.1

3.0

2.4

2.1 1.6

2.0

1.1

1.0

0.7

0.0 JAN

FEB

MAR

APR

MAY Fig - 4

JUN

JUL

MONTHS

AUG

SEP

OCT

NOV

DEC

18 TIME SERIES OF FREQUENCY OF POOR VISIBILITY <1000M (ANNUAL) FOR JODHPUR (DATABASE: 1971-2005)

4.5

4.1

4.0

NO. OF DAYS

3.5

3.2

3.0 2.4

2.5 2.0

1.8

1.5 1.0

1.2

1.0

0.8

0

0.5

0.5

0.1

0.1

0.1

OCT

NOV

0.0 JAN

FEB

MAR

APR

MAY Fig – 5

JUN

JUL

MONTHS

AUG

SEP

D

20

WINTER SEASON (DEC - FEB) Introduction 22. In this season, cold dry air prevails over the country outside the peninsula region. Clear skies, fine weather, low humidity and low temperatures with large diurnal variation are some characteristics features of this season. Generally fine weather with good visibility prevails over West Rajasthan during the season most of the WDs moving across J & K, Himachal and Punjab result in partly cloudy skies with medium and high cloud over West Rajasthan. With the establishment of subtropical high over northwest India, temperatures continue to register fall during the first half of the season. The weather remains generally dry except when broken by spell of Rain / Thunder Shower under the influence of WD / Induced Low / Trough in Westerlies. With the passage of WD and induced low Fog / Mist is experienced over the region. Dust Storm / DRW are rarely experienced during the season. Surface Pressure Pattern 23. West Raj. is influenced by high pressure ridge during this season. This ridge of high pressure generally runs from Siberia to Gangetic plains. Eastward moving WDs/Induced Lows/Troughs sometimes disturb the pattern. Wind Pattern 24. Surface Wind. Position and strength of sub-tropical ridge of Central India closely affects surface wind over Jodhpur. During Dec and Jan, surface winds are generally NNE’ly < 5 kt; whereas in Feb, they become WNW’ly < 5 kt. In the wake of a W’ly system, surface winds gradually back to S’ly / SE’ly with speed 10-15 kt. 25. Upper Winds. NW’ly winds profile dominates in the lower troposphere. Winds back with height and are W’ly above 3.0 Km. The core of Sub-tropical Jet Stream generally lies between 220 N to 260 N. Speeds of the order of 130-150 kt are quite common in association with Sub-tropical Jet Stream. Surface Temperature and Humidity 26. The average Maximum and Minimum temperatures vary between 24 0 & 29 0C and 08 0 & 13 0C respectively. Pentad normals indicate that Minimum temperature reaches lowest value during first week of Jan. In the wake of an active W’ly system, the Minimum temperature often falls 4 0 to 7 0C below normal causing cold wave conditions which lasts for 2 to 4 days. 27. Relative humidity varies from 52% - 59% in the morning to 23% - 30% in the evening hours. However due to passage of active Induced Low, RH increases to > 80% for 1 to 2 days, resulting into reduction in morning visibility to a value of 1.5 Km or less in Mist/Fog.

21 Synoptic Features and Associated Weather 28. Western Disturbances. Western disturbances moving across NW India and adj Pakistan extends their influence by forming Induced Low over West Raj and adj Central Pakistan. The frequency is very less in the beginning of the season but as the systems tracks shift southward, their frequency and influence increases. The frequency of Induced Low over West Raj is about one in Dec, increasing to two in Jan and three in Feb. After the movement of the induced Low, the weather improves rapidly over West Raj. At times widespread Fog is experienced on 2nd and 3rd day over North Raj. Fog occurrence over Jodhpur is a rare phenomenon. Due to advection of cold air in the wake of WD, temperature falls rapidly and in the absence of any fresh W’ly system, cold wave conditions exists for 2-4 days. A fall of 4 0 to 50 in minimum temperatures can be experienced after passage of an active WD. Stong N’ly and NE’ly winds prevail after passage of the WD over base for 2 to 3 days. 29. The Western disturbances can be traced from the East Mediterranean Sea. Their rate of movement is about 5° longitudes per day. Occasionally an induced low may form over Rajasthan when a deep Western disturbance is moving across the Punjab. The induced lows draw moist air from Arabian Sea when they are between longitudes 70 to 80°E. 30. Seasonal Ridge/Anticyclone. The low level anticyclone generally centred over MP up to 3.0 km with southward slope is part of global sub-tropical ridge, and is the most influential factor responsible for subsidence over Raj. Besides causing clear skies over Jodhpur and adjoining airfields, its strength and proximity to Jodhpur significantly controls the visibility phenomena. 31. Westerly Trough. Apart from its role of accentuating Induced Low over West Raj, this deep amplitude W’ly trough itself causes Medium/High clouds. If trough in Westerlies in upper level is lying 50 – 70 West of the lower level induced circulation then precipitation in the form of Rain/Thunder Showers occurs over base for a day or so. Weather Pattern and Aviation Weather Hazards 32. Winter season is free from significant clouds, with generally Fine/Fair weather prevailing over the base and neighbourhood. Smoke Haze in the morning hours is the most predominant weather hazard at Jodhpur airfield. 33.

The main aviation weather hazards during this season are given below: (a) Vis < 3 Km. Visibility reduces to less than 3 Km due to Smoke Haze/Haze in the morning hours (0600-1200 Hrs) on an average of 1-3 days in the season. The highest frequency is in the month of Jan; whereas lowest in Feb. The mean duration in a day is 1-3 hours. There has been incidence when visibility remained less than 3 Km for 6-8 hours in Dec and Jan (Fig – 7). (b) Vis < 1 Km. Fog is a rare phenomena. It occurs after the passage of a well marked W’ly system, causing precipitation over West Raj. Frequency of

22 Fog is just about one day in Dec and Jan and it becomes negligible in Feb. The mean duration in a day in Dec and Jan is about 2-3 hours. The incidence of duration of more than 5 hours even has been recorded (Fig – 7). (c) Low Clouds. The spell of precipitation either at base or in the vicinity of the airfield increases with the probability of stratus clouds with base 300 m or less for a period of 1-2 hours in the morning/forenoon hours generally between 0600 to 1200 hours. However, in general the incidence of low clouds is extremely less (Fig – 7). (d) Thunder Storm/Dust Storm/Hail. Incidence of T’ Storm during the season is rare and the mean frequency is less than one day. Absolutely ‘Nil’ occurrence of D’ Storm and extremely less incidence of Hailstorm are observed during the season (Fig – 7). (e) Precipitation. During Dec, Rainfall is experienced rarely. However in Jan and Feb the mean frequency is 02 days (Fig – 7). (f) Cold Wave. Cold wave is experienced on one to two occasions in each month, some time continuing for 2 to 4 days. The temperature falls about 40 to 7 0C below normal after the passage of an active W’ly system. 34. Good, P'Good and Bad Weather State. The mean, highest and lowest frequencies have been tabulated month wise using the data from Jan 01 to Dec 05 (Table - 1). Jan is best month for flying with maximum number of good weather days and night for both transport and fighter flying.

23

STATISTICS OF GOOD, MARGINAL & BAD WEATHER STATE WINTER SEASON AIR FORCE STATION - JODHPUR

FIGHTERS / TRAINERS DAY NIGHT 0601-1200 1201-1800 1801-2400 0000-0600

DAY 0601-1200 1201-1800

NIGHT 1801-2400 0001-0600

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

Highest

29

6

2

31

2

1

31

1

1

31

1

0

30

6

1

31

2

0

31

1

0

31

1

0

Mean

27

4

0

30

1

0

31

0

0

31

0

0

27

4

0

30

1

0

31

0

0

31

0

0

Lowest

25

1

0

28

0

0

30

0

0

30

0

0

25

1

0

29

0

0

30

0

0

30

0

0

Highest

31

4

2

31

1

1

31

0

0

31

0

0

31

5

1

31

0

0

31

0

0

31

0

0

Mean

27

3

1

30

0

1

31

0

0

31

0

0

28

3

0

31

0

0

31

0

0

31

0

0

Lowest

25

0

0

29

0

0

31

0

0

31

0

0

25

0

0

31

0

0

31

0

0

31

0

0

Highest

28

2

1

28

1

1

28

1

1

28

1

1

28

2

1

28

1

0

28

0

0

28

1

0

Mean

27

1

0

27

1

0

27

0

1

28

0

0

27

1

0

28

0

0

28

0

0

28

0

0

Lowest

26

0

0

26

0

0

27

0

0

26

0

0

26

0

0

27

0

0

28

0

0

27

0

0

MONTH

DEC

JAN

FEB

DATA SET: 2001 – 05

G: GOOD

M: MARGINAL

B: BAD Table - 1

TRANSPORTS

24

50

45

Fig – 6

25

AF STATION, JODHPUR MAIN AVIATION WX HAZARDS WINTER SEASON (1991 - 2005)

4.0

MEAN FREQUENCY (NO. OF DAYS)

3.6 3.5 3.1 3.0 2.5 1.9

2.0

1.9 1.6

1.5 0.9

1.0 0.7 0.7 0.5 0.0

0.6

0.3 0.3 0.1

0.3

D'STORM

0.1

0.0 0.0

DEC

T'STORM

0.5

0.3 0.1

0.0 0.0

1.0

0.0

JAN

HAIL

PPTN

LC<300M

Fig - 7

0.1

0.1 0.1 FEB

FOG

PV<1KM

PV<3KM

SSW>30KT

0.1

26

27

DECEMBER MONTHLY WEATHER SUMMARY 35. Introduction. The winter gets established over NW India in this month. This month can be considered as the representative of winter season. The weather remains generally dry but cold over the base. On most of the days the sky remains clear. Broad Synoptic Features 36. Effects of Various Synoptic Situations on Local Weather. The ridge of high pressure in this month generally extends from Afghanistan to NW India. The anticyclone dominates over NW India upto 3.0 km giving rise to subsiding air in lower levels.In addition to this the temperature inversion at lower levels leads to Smoke Haze. The Smoke Haze lifts up as and when inversion breaks up due to heating up of land during daytime. Due to approach of active WD this anticyclone shifts SEwards and winds start backing from N’ly-NE’ly to SW’ly. The approach of WD is characterised by appearance of high clouds followed by medium/low clouds and rise in minimum temperatures. If upper level trough in Westerlies is lying 50 – 70 West of the lower level induced circulation then precipitation in the form of Rain/Thunder Showers occurs over base for a day or so. The moisture incursion from Arabian Sea with SW’ly wind flow due to approach of active WD give rise to moisture content. Generally weather remains dry and cold with state of sky being Fair / Fine mainly with Med/High clouds and occasional Smoke Haze in the morning and evening hours. 37. Behaviour of Important Parameters. The behaviour of important parameters during the month of December is as follows:(a) Pressure. The ridge of high pressure gets established over Afghanistan and N Pak which not only extends over NW India but also upto the Gangetic Plain across Central India. The ridge gets broken into cells or moves eastwards due to the approach of WD from the west. (b) Winds . The surface wind remains calm / light variable during evening and night hours. During afternoon NW’ly to NE’ly winds are experienced. The maximum surface wind ever recorded is 280/35 on 25 Dec 79. (c) Rainfall. The mean monthly Rainfall during the month is 1.6 mm. The highest Rainfall amount ever recorded during the month has been 29.6 mm in 1980. The heaviest Rainfall recorded in 24 hrs for the month is 19.8 mm on 23 Dec 80. (d) Temperature. The mean maximum temperature for the month is 0 27.4 C. The highest maximum temperature ever recorded during the month has been 33.6°C on 7 Dec 91. The mean minimum temperature for the month is 10.1 0C. The lowest ever recorded during the month has been -1.2 0 C on 14 Dec 86.

28 38. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Dec 1991 and Dec 2005 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Dec follow this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration. (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that poor visibility is the main aviation weather hazard of this month. It reduces mostly in Haze/Smoke Haze (Table – 4). 39. Time Series of Rainfall. The time series of Rainfall shows rare number of days of occurrences (Fig 14). 40. Time Series of Thunder Storms. The time series of thunder storms shows almost nil number of days occurrence (Fig – 10). 41. Time Series of PV <1Km. The time series of PV < 1 Km shows rare occurrences in last decade except in 2005 when maximum frequency of 5 days was recorded (Fig – 11). 42. Time Series of PV <3Km. The time series of PV < 3 Km shows an increase in the incidence of poor visibility since 1997(Fig – 12). 43. Time Series of Low Clouds <150m. The time series of low clouds < 150m shows an decrease in the incidence of low clouds since 2000 (Fig – 17). 44. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 18). 45. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201-1800 for fighter and transport flying (Table – 1). 46. Simultaneity of Weather. In Dec visibility < 1000m and < 3000m have 70 80% simultaneous occurrence with primary and secondary diversion during 0600 to 1000 h (Table - 5). 47. Weather over Local flying area. Weather remains dry and cold with few med / high clouds over base and neighbourhood and isolated Smoke Haze in the morning and evening hours. 48. Means of Local Upper Winds (PB Means). The local upper wind data is available up to 10000’. The analysis of the data shows that the winds up to 5000’ are

29 generally E’ly of about 10 kt whereas between 5000 to 10000’ generally Wly flow prevails with wind speeds of about 10 – 15 kt (Table 2, Table 3).

AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: DECEMBER TIME : 0000 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

6.9%

34.0%

13.5%

2.7%

1.3%

8.2%

23.6%

9.8%

mean speed

6.7

5.1

5.5

3.8

14.0

17.2

14.4

12.2

% frequency

14.5%

30.3%

34.4%

7.7%

2.7%

2.5%

5.2%

2.7%

No of observations

1000'

377

2000' 3000' 5000' 7000' 10,000'

366 17 13 10 5

447 410 434 396

mean speed

5.7

7.5

8.8

7.6

6.2

8.0

8.3

4.9

% frequency

14.1%

23.5%

28.4%

8.1%

7.4%

4.7%

10.3%

3.6%

mean speed

8.1

9.2

8.8

7.3

7.6

8.4

8.0

6.3

% frequency

22.4%

14.9%

12.9%

5.4%

5.6%

8.5%

18.8%

11.5%

mean speed

7.7

9.3

7.8

7.7

7.4

9.4

8.7

7.3

% frequency

26.7%

7.4%

4.6%

1.4%

6.0%

10.1%

27.9%

15.9%

mean speed

9.4

9.1

8.6

5.0

10.0

10.1

11.4

8.8

% frequency

18.9%

1.3%

2.3%

0.8%

3.0%

13.6%

36.1%

24.0%

mean speed

13.4

13.8

5.8

15.0

12.8

12.5

14.3

13.5

Table - 2 MEANS OF UPPER WIND AND TEMPERATURE: DECEMBER TIME : 1200 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

31.2%

34.9%

8.9%

1.7%

1.4%

6.2%

7.5%

8.2%

mean speed

4.3

4.4

4.5

1.6

3.3

5.4

4.9

4.2

% frequency

28.7%

25.7%

11.1%

1.4%

2.5%

6.5%

14.8%

9.3%

mean speed

6.4

7.0

7.2

4.3

5.3

9.6

7.1

5.3

% frequency

23.6%

27.0%

16.9%

1.2%

4.6%

6.5%

12.8%

7.5%

No of observations

1000'

292

2000' 3000' 5000' 7000' 10,000'

432 18 13 9 5

415 427 441 362

mean speed

6.2

7.1

6.9

2.4

5.8

9.6

6.6

6.1

% frequency

24.8%

15.9%

14.8%

4.7%

4.7%

7.0%

17.6%

10.5%

mean speed

7.0

7.3

6.3

4.6

5.9

10.4

7.8

6.3

% frequency

17.7%

6.8%

6.8%

2.0%

4.8%

12.2%

32.4%

17.2%

mean speed

8.7

8.3

10.0

6.2

6.3

11.0

10.5

9.5

% frequency

12.4%

2.2%

1.4%

0.3%

3.0%

14.4%

40.1%

26.2%

mean speed

14.0

8.9

8.2

0.0

13.0

17.3

16.4

14.4

Table - 3 49. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index

30 is in the comfortable zone throughout the day except between 0500 – 0900 h when it remains in uncomfortable zone (Fig – 8).

75

Fig – 8

SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (DEC) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

YEAR(s)

FREQ

PEAK

SD

PERIOD (IST)

(a)

(b)

(c)

(d)

(e)

(k)

(f)

VIS < 3 KM

3.1

9

2003

0

1992,94,96,

09-12

2.7

VIS < 1 KM

0.7

5

2003

0

1992-96,98-02,04

06-12

1.4

CL < 300 M

0.3

5

1997

0

1991-96,98-05

09-12

1.2

CL < 150 M

0.0

0

THUNDER STORM

0.1

1

2002

0

1991-2001,03-05

20-22

0.2

DUST STORM

0.0

0

HAIL STORM

0.0

PPTN

0.3

1

1991,93,97,02,04

0

1992,94-96,98-01,03,05

00-03

0.5

FOG

0.7

5

2003

0

1992-96,98-01,04,05

06-09

1.4

>30 KTS

0.1

1

2004

0

1991-03,05

14-16

0.2

DRW

0.1

2

2004

0

1991-03,05

14-16

0.5

0.0

0

CEILING (CL)

70 0

SUR WIND

O

TEMP > 40 C

DEX

Table - 4

65

31

40

35

Fig – 9

32

TIM E S ERIES : THUNDER S TO RM (DEC) 1.2

1.0 1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0

0.0

0.0

0.0

0.0

0.0

0.0

1991

1992

1993

1994

1995

1996

1997

0.0

0.0

0.0

0.0

1998

1999

2000

2001

20 01

0.0

0.0

0.0

2002

2003

2004

2005

2002

2 00 3

2 004

2005

0.0

Fig – 10

YEARS

T IM E S ER IES : V IS IBIL IT Y < 1 K M (DEC) 6.0

5.0

NO OF DAYS

4.0

3.0

2.0

1.0

0.0 1991

19 92

1993

1994

1 995

1996

1 997

Fig – 11

1 998 YEA RS

1999

2000

33

TIM E S ERIES : V IS IBILITY < 3 KM (DEC) 10.0

9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 12

1998

1999

2000

2001

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

YEA RS

T IM E S ER IES : F O G (D EC ) 6.0

5.0

NO OF DAYS

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 13

1998 YEA RS

1999

34

TIM E S ERIES :P RECIP ITATION (DEC) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 14

1998

1999

2000

2001

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

YEARS

T IM E S ER IES :DR W (D EC ) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 15

1998 YEA RS

1999

35

TIM E S ERIES :S S W > 30 KT (DEC) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 16

1998

1999

2000

2001

2002

2003

2004

2005

2002

2003

2004

2005

YEA RS

T IM E S E R I E S : L O W C L O U D < 1 5 0 M (D E C ) 4 .5

4 .0

3 .5

NO OF DAYS

3 .0

2 .5

2 .0

1 .5

1 .0

0 .5

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig – 17

1998 Y EA RS

1999

2000

2001

36

DIURNAL VARIATION OF MAIN AWH (DECEMBER) (DATABASE: 1991-2005) 3.5 3.3

3.0 2.7 2.5

2.0

1.4

1.5

1.0

0.5 0.3

0.2 0.0

0.0 0.0 0.0

0.3

0.0 0.0

0.3 0.0

0.0 0.0

0.0

0.2

0.0 0.1

0.0

0.0 0.0 0.0

0.0

0.0 0.0 0.0 0.0 0.0

0.0 0.0 0.0 0.0 0.0

15-18

18-21

0.0

0.1

0.0 0.0 0.0

0.0 00-03

03-06

06-09

09-12

12-15

Fig - 18 T'STORM

PPTN

PV<1

PV<3

SSW>30

21-24

37

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : DECEMBER (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1 69.9 66.6

P1

0600 P2

1400 P2

0700 P2 83.6 67.9

P3 70.7 66.6

P1 75.0 70.0

0800 P2 82.3 71.7

P3 70.3 70.0

P1 87.3 70.0

0900 P2 73.7 71.7

P3 70.7 70.0

P1 86.7 66.6

1000 P2 83.4 66.6

P3 81.1 66.6

P1 81.0

1100 P2 47.0

P3 41.1

P1 69.9

1200 P2 82.2

P3 69.9

P1

1300 P2 P3

66.6

P1 74.0 66.6

P3

P1

1500 P2

P3

P1

1600 P2

P3

P1

1700 P2

P3

P1

1800 P2

P3

P1

1900 P2

P3

P1

2000 P2

P3

P1

2100 P2 P3

P3

 B&Pd P1 =   B

  X 100 

 B&Sd P2 =   B

  X 100 

 B&Pd &Sd P3 =  B 

  X100 

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 5

38

JANUARY MONTHLY WEATHER SUMMARY 50. Introduction. The weather continues to be dry and cold over the region. This is the month of peak winter, when both the maximum and minimum temperatures reach the lowest value. 2-3 spells of cold waves cause the winters even colder and more biting one. Broad Synoptic Features 51. Effects of Various Synoptic Situations on Local Weather. Low level anticyclone in the upper air well established over northwest India and cold dry continental air mass prevails over entire north and northwest India including the region of west Rajasthan. This results in prolonged spells of fine / fair weather with good visibility. Passage of WD across northwest India results in P’Cloudy / cloudy skies with medium / high clouds over west Rajasthan. Movement of upper tropospheric troughs and oscillation of sub tropical jet across west Rajasthan result in high clouds over the region.1 – 2 days of precipitation may occur during the month in association with the movement of well marked induced low / cycir across west Rajasthan. Fog / low cloud is very rare in this belt where humidity is generally low. The weather in this month is affected mainly due to mid-latitude systems. These systems cause Rain/ Thunder shower over NW Raj and WDSP Fog / Mist / Haze in the morning hours.

39 52. Behaviour of Important Parameters. The behaviour of important parameters during the month of January is as follows:(a) Pressure. The sub-tropical ridge of high pressure from Siberian High extends over the entire NW India and Indo – Gangetic Plains. It starts moving eastwards with the approach of WD. (b) Winds . The surface wind remains calm or light NW’ly / NE’ly during night and early morning hours. During daytime winds become W’ly / NW’ly. The maximum surface wind ever recorded is 340/30 on 27 Jan 99. (c) Rainfall. The mean monthly Rainfall during the month is 3.4 mm. The highest Rainfall amount ever recorded during the month has been 26.5 mm in 1992. The heaviest Rainfall recorded in 24 hrs for the month is 20.8 mm on 31 Jan 92. (d) Temperature. The mean maximum temperature for the month is 25.4 0C. The highest maximum temperature ever recorded during the month has been 32.7°C on 27 Jan 91. The mean minimum temperature for the month is 9.1 0C. The lowest ever recorded during the month has been -0.2 0 C on 28 Jan 77. 53. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Jan 1991 and Jan 2005 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Jan follow this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration. (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD is prepared in tabular form. This data indicates that visibility < 3 km occurs on 3.6 days, whereas visibility < 1 Km occurs on 1 day. The precipitation occurs on 1.9 days in the month (Table – 8). 54. Time Series of Rainfall. The time series of Rainfall shows wide fluctuation in the Rainfall amount and the number of days of occurrence with nil rainfall observed only in the year 2001 (Fig 24). 55. Time Series of Thunder Storms. The time series of thunder storms shows a rare occurrence of Thunder Storm from 1996 onwards (Fig – 20). 56. Time Series of PV <1Km. The time series of PV < 1 km shows wide fluctuation in the incidence of poor visibility <1 km occurrence in last decade (Fig – 21).

40 57. Time Series of PV <3Km. The time series of PV < 3 km shows an increase in the incidence of poor visibility < 3 km from 1999 (Fig – 22). 58. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 28). The most probable period for occurrence of PV < 3 km is 06-09 and 09-12 block. 59. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table - 1). 60. Simultaneity of Weather In Apr poor visibility (< 3000m) have 70% simultaneous occurrence with primary and 50% simultaneous occurrence with secondary diversion during 0700 to 1100 hrs. For precipitation there is 50% of occurrence at primary between 1900 – 2100 h. (Table - 9). 61. Weather over Local flying area. The good weather conditions of the winters continue to prevail over the local flying area for the first half of the month and the weather generally remains fair with scattered Haze / Smoke Haze during the morning hours. The thunderstorm activity gains momentum from the second half of the month and weather generally remains partly cloudy / cloudy during the afternoon/evening hours with isolated convective build-ups towards evening hours. Isolated Rainfalls on a few occasions associated with the convective clouds are also observed during the month.

41 62. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds up to 3000’ are generally NElies of about 05 – 10 kt whereas between 3000 – 10000’ generally Wly flow prevails with wind speeds of about 10 – 20 kt (Table – 6, Table – 7).

AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: JANUARY TIME : 0000 UTC deg C

N

No of obser-

360

vations

1000'

293

2000'

380

3000'

14

399

5000'

11

396

7000'

8

392

10,000'

3

328

DATA SET 1991-2005 (FOR TEMP 2001-2005) NE E SE S SW

% frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed

045

090

135

180

225

W

NW

270

315

I

II

III

IV

V

VI

VII

VIII

12.6% 5.2 16.1% 7.9 21.8% 7.9 20.7% 9.3 16.6% 10.9 9.5% 13.5

49.1% 5.7 23.9% 10.1 13.5% 10.2 8.6% 9.2 7.1% 9.8 0.6% 12.0

19.8% 6.7 30.8% 10.1 22.3% 9.6 6.1% 9.8 7.1% 9.5 1.8% 7.2

3.8% 5.3 7.1% 7.6 3.0% 6.5 1.5% 7.2 1.3% 10.0 1.2% 6.5

0.7% 7.5 7.1% 7.1 7.3% 9.0 4.8% 6.6 4.3% 8.2 3.4% 16.1

3.8% 5.9 4.7% 11.7 8.8% 10.3 12.9% 13.2 13.3% 13.5 14.6% 21.0

8.2% 5.8 8.2% 10.3 17.8% 9.3 26.3% 11.5 28.3% 12.1 43.9% 21.1

2.0% 5.3 2.1% 7.3 5.5% 8.4 19.2% 11.1 21.9% 12.2 25.0% 18.4

Table – 6

MEANS OF UPPER WIND AND TEMPERATURE: JANUARY TIME : 1200 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

20.3%

31.3%

8.5%

0.4%

2.5%

8.5%

13.2%

15.3%

mean speed

5.0

4.5

7.1

1.0

4.1

6.1

4.0

4.6

% frequency

26.4%

18.2%

10.8%

2.6%

2.8%

6.9%

22.6%

9.7%

mean speed

7.1

8.0

8.0

4.6

7.1

8.0

8.4

7.5

% frequency

21.6%

20.1%

15.0%

2.0%

3.8%

8.9%

17.3%

11.2%

mean speed

7.2

7.7

9.0

5.0

7.1

9.5

8.5

7.4

% frequency

16.5%

14.8%

12.0%

0.8%

4.1%

10.4%

29.5%

12.0%

mean speed

8.0

7.9

7.5

5.7

7.6

11.1

9.3

9.1

% frequency

18.2%

8.3%

9.6%

2.9%

2.7%

11.2%

35.6%

11.5%

mean speed

8.5

8.4

9.2

4.6

7.5

12.9

11.9

10.3

% frequency

7.6%

1.2%

1.5%

0.3%

3.0%

16.1%

44.1%

26.1%

mean speed

12.6

6.5

4.8

34.0

11.7

20.8

20.2

15.7

No of observations

1000'

281

2000'

390

3000'

17

393

5000'

14

393

7000'

8

374

10,000'

3

329

Table – 7

42 63. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone between 0500 – 1000 h and in partly comfortable zone between 1000 – 1200 h and again in the evening between 1800 – 2100 h (Fig – 18).

75

Fig – 18

SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (JAN) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

YEAR(s)

(a)

(b)

(c)

(d)

(e)

(k)

(f)

VIS < 3 KM

3.6

10

1999

0

1991,97,98

06-12

1.3

VIS < 1 KM

1.0

4

1999

0

1991-93,96-98,02,05

06-09

1.3

CL < 300 M

0.6

2

1992,95,2000

0

1991,93,94,96-98,01,02,05

09-12

0.8

CL < 150 M

0.0

0

THUNDER STORM

0.3

2

1996

0

1991-93,95,97-02,04,05

18-21

0.6

DUST STORM

0.0

0

HAIL STORM

0.0

0

PPTN

1.9

3

1992,99,03

0

2001

21-24

0.8

FOG

0.9

4

1999

0

1991,92,93,97,98,01,02,05

06-09

1.2

1

2003

0

1991-2002,04,05

14-16

0.2

3

1992

0

1991,93-98,2000-05

00-03

0.8

FREQ

PEAK

SD

PERIOD (IST)

CEILING (CL)

SUR WIND >30 KTS

0.1

DRW

0.3

TEMP > 40O C

0.0

70 0

Table – 8

43

40

35

Fig – 19

44

TIM E S ERIES : THUNDER S TO RM (JAN) 2.5

2.0 2.0

NO OF DAYS

1.5

1.0

1.0

1.0

0.5

0.0

0.0

0.0

1991

1992

1993

0.0

0.0

0.0

0.0

0.0

0.0

0.0

1998

1999

2000

2001

2002

2001

2002

0.0

0.0

2003

2004

2005

2003

2004

2005

0.0 1994

1995

1996

1997

Fig – 20

YEA RS

T IM E S ER IES : V IS IBIL IT Y < 1 K M (JA N) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 21

1998 YEA RS

1999

2000

45

T IM E S ER IES : V IS IB IL IT Y < 3 K M (J A N ) 1 2 .0

1 0 .0

NO OF DAYS

8 .0

6 .0

4 .0

2 .0

0 .0 1991

19 9 2

1 99 3

1 9 94

1 9 95

1996

1997

Fig – 22

1998

1999

2000

2 0 01

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

Y EA RS

TIM E S ERIES : FO G (JA N) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 23

1998 YEA RS

1999

46

T IM E S ERIES :P RECIP IT ATIO N (JAN ) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 24

1998

1999

2000

2001

2002

2003

2004

2005

2 00 0

2001

2002

2 00 3

2004

2005

YEA RS

T IM E S ER IES :DR W (JA N ) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

199 2

1993

1994

1995

1996

19 97

Fig – 25

1998 YEA RS

1999

47

TIME SERIES :SSW > 30 KT (JAN) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 26

1998

1999

2000

2001

2002

2003

2004

2005

2 00 1

20 02

20 03

20 04

2 00 5

YEARS

T IM E S ER IES : L O W C L O U D < 30 0 M (J A N ) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 1991

19 92

1 99 3

19 94

19 95

19 96

19 97

Fig – 27

1 99 8 YEA RS

199 9

200 0

48

DIURNAL VARIATION OF MAIN AWH (JANUARY) (DATABASE: 1991-2005)

49

5.0 4.4

4.5

4.4

4.0 3.5 3.0 2.5 2.0 2.0

1.7

1.7 1.5 1.1

1.1 0.9

1.0

0.7

0.6 0.5

1.0

0.9

0.3

0.2 0.0

0.7

0.7

0.2 0.0

0.0

0.2 0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.2

0.2 0.0

0.0

0.0 0.0 0.0

0.0

0

0.0 00-03

03-06

06-09

09-12

Fig - 28 T'Storm

12-15

PPTN

PV<1

15-18

PV<3

SSW>30

18-21

21

50

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : JANUARY (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1

P1

0600 P2

1400 P2 66.6

P3

P1 71.1 66.6

P3

P1

0700 P2 46.7

P3 37.8

P1 75.8 73.4

0800 P2 53.7 59.9

P3 52.4 59.9

P1 76.2 73.4

1500 P2

P3

P1

1600 P2

P3

P1

0900 P2 52.5 51.3 66.6

1700 P2

P3 43.8 28.7

P1 77.2 66.6

1000 P2 82.8 66.6

P3 45.5 66.6

P1 36.7

1100 P2 46.7

P3 36.7

P1 33.4

1200 P2 40.0

P3

P1

1800 P2

P3

P1

1900 P2

P3

P1

33.4

40.0

 B&Pd P1 =   B

  X 100 

 B&Sd P2 =   B

  X 100 

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 9

P3

P1

1300 P2

P3

2000 P2

P3

P1

2100 P2

P3

73.4

33.4

66.6

51

FEBRUARY MONTHLY WEATHER SUMMARY 64. Introduction. During this month winter continues to prevail with the same intensity, especially during night, early morning and evening hours. During the day it is comparatively warmer. The system which affect the region during January continue to affect the weather during this month also. The systems shift slightly southwards and move in easterly direction. Broad Synoptic Features 65. Effects of Various Synoptic Situations on Local Weather. Weather over base generally remains Fair / P’cloudy except for few days in the second half, when it becomes Cloudy / MOC in the presence of induced systems over Raj. Formation of induced low may cause strengthening of pressure gradient resulting in widespread DRW conditions over the region. During this period the base reports occasional low visibility. 66. Behaviour of Important Parameters. The behaviour of important parameters during the month of February is as follows:-

52 (a) Pressure. The sub-tropical ridge of high pressure continues to prevail over the N and NW parts of the country. The ridge is broken or squeezed due to the approach of WD. (b) Winds . The surface wind remains calm or light variable during night morning or evening hours. During daytime winds become N’ly / NE’ly. The maximum surface wind ever recorded is 230/45 on 14 Feb 79. (c) Rainfall. The mean monthly Rainfall during the month is 4.7 mm. The highest Rainfall amount ever recorded during the month has been 31.8 mm in 1990. The heaviest Rainfall recorded in 24 hrs for the month is 14.2 mm on7 Feb 92. (d) Temperature. The mean maximum temperature for the month is 0 28.0 C. The highest maximum temperature ever recorded during the month has been 36.6°C on 12 Feb 93. The mean minimum temperature for the month is 10.2 0C. The lowest ever recorded during the month has been -2.8 0 C on 7 Feb 74. 67. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Feb 1991 and Feb 2005 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Feb follow this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration. (b) Summary of Main Aviation Weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that the frequencies of precipitation and thunder storm are 1.9 and 0.5 days respectively (Table –12). 68. Time Series of Rainfall. The time series of rainfall shows wide fluctuation in the Rainfall amount and the number of days of occurrence over the year (Fig 34). 69. Time Series of Thunder Storms. The time series of thunder storms shows wide fluctuation in number of days occurrence of thunder storm throughout the period (Fig - 30). 70. Time Series of PV <1Km. The time series of PV <1 Km shows very rare incidence of poor visibility <1 km occurrence in last decade (Fig - 31). 71 Time Series of PV <3Km. The time series of PV <3 km shows an increase in the incidence of poor visibility <3 km during the last decade (Fig - 32).

53 72. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 40). 73. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table – 1). 74. Simultaneity of Weather For precipitation there is 40 – 60% of occurrence at primary and secondary diversion between 0900 – 1900 h (Table 13). 75. Weather over Local flying area. The good weather conditions of the winters continue to prevail over the local flying area for the first half of the month and the weather generally remains fair with scattered Haze / Smoke Haze during the morning hours. The thunderstorm activity gains momentum from the second half of the month and weather generally remains partly cloudy / cloudy during the afternoon/evening hours with isolated convective build-ups towards evening hours. Isolated Rainfall on a few occasions associated with the convective clouds are also observed during the month.

54 76. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds up to 5000’ are generally N’ly of about 5 – 10 kt whereas between 5000 to 10000’ generally Wly to NWly flow prevails with wind speeds of about 10 – 20 kt (Table 10, Table11). AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: FEBRUARY TIME : 0000 UTC deg C

N

No of observations

1000'

254

2000'

332

3000'

17

331

5000'

13

332

7000'

9

331

10,000'

4

309

% frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed

DATA SET 1991-2005 (FOR TEMP 2001-2005) NE E SE S SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

13.0% 4.6 19.3% 7.8 24.2% 8.1 23.8% 8.9 11.5% 10.3 13.0% 4.9

24.8% 5.4 12.7% 9.4 12.7% 9.2 3.0% 12.3 2.4% 10.5 24.8% 5.8

12.6% 6.3 19.3% 9.3 10.9% 9.2 6.0% 8.9 4.2% 10.4 12.6% 6.4

6.3% 4.9 3.3% 5.8 4.2% 9.9 2.1% 7.7 1.5% 13.4 6.3% 5.5

2.4% 5.7 4.8% 7.6 7.9% 5.2 6.3% 6.8 7.3% 7.4 2.4% 8.0

12.6% 5.3 9.0% 10.6 10.0% 10.7 9.9% 13.4 16.3% 15.1 12.6% 5.6

20.5% 6.9 22.6% 10.7 19.6% 11.1 31.6% 11.6 32.6% 13.4 20.5% 7.1

7.9% 5.9 9.0% 8.6 10.6% 8.3 17.2% 10.3 24.2% 11.7 7.9% 6.7

Table – 10 MEANS OF UPPER WIND AND TEMPERATURE: FEBRUARY TIME : 1200 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

18.3%

21.9%

5.8%

1.0%

3.5%

16.4%

20.3%

12.9%

mean speed

4.4

5.6

5.7

2.7

3.7

6.1

6.0

4.6

% frequency

24.9%

10.7%

7.9%

1.9%

7.1%

11.5%

24.9%

11.0%

mean speed

7.1

7.3

8.1

3.7

5.6

9.9

10.3

7.4

% frequency

18.6%

14.5%

11.6%

1.3%

5.9%

12.4%

24.0%

11.6%

No of observations

1000'

311

2000'

365

3000' 5000' 7000' 10,000'

20 14 10 4

387 390 392 312

mean speed

6.7

8.3

6.7

4.0

6.5

12.0

11.0

7.5

% frequency

19.0%

8.7%

8.7%

1.5%

5.4%

11.5%

29.0%

16.2%

mean speed

7.2

7.5

6.1

4.3

6.8

12.1

12.4

9.0

% frequency

15.1%

5.9%

4.6%

1.5%

4.8%

14.0%

35.2%

18.9%

mean speed

8.0

8.2

6.9

4.2

9.5

12.2

13.4

9.3

% frequency

7.7%

0.3%

1.9%

0.3%

2.6%

13.8%

46.5%

26.9%

mean speed

13.0

13.0

12.2

2.0

7.0

20.0

21.0

16.1

Table – 11

55 77. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the comfortable zone through out the day except between 0500-1000 h when it remains in uncomfortable zone (Fig – 28).

75

Fig – 28

SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (FEB) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

YEAR(s)

FREQ

PEAK

SD

PERIOD (IST)

(a)

(b)

(c)

(d)

(e)

(k)

(f)

VIS < 3 KM

1.6

4

2003,05

0

1993-95,97,

06-09

1.3

VIS < 1 KM

0.1

1

1992,2003

0

1991,93-02,04,05

06-09

0.3

CL < 300 M

0.3

2

1992,2003

0

1991,93-96,97-02,04,05

06-12

0.7

CL < 150 M

0.1

1

1992

0

1991,92-05

09-12

0.2

THUNDER STORM

0.5

2

1992,99,03

0

1991,94,95,97,98,00-02,04,05

21-24

0.8

DUST STORM

0.0

0

HAIL STORM

0.1

1

1999

0

1991-98,2000-05

09-12

0.2

PPTN

1.9

5

1999

0

1997,2001,04

21-24

1.5

FOG

0.1

1

1992,2003

0

1991,93-02,04,05

06-09

0.3

CEILING (CL)

70

SUR WIND 0.1

1

2003,05

0

1991-02,04

00-02

0.3

DRW

0.5

3

2005

0

1991-93,95-98,2000-02,04

00-03

1.0

TEMP > 40O C

0.0

0

INDEX

>30 KTS

Table – 12

65

56

40

35

Fig – 29

57

TIM E S ERIES : THUNDER S T O RM (F EB) 2.5

2.0

2.0

2.0

2.0

NO OF DAYS

1.5

1.0

1.0

1.0

0.5

0.0

0.0

0.0

1994

1995

0.0

0.0

0.0

0.0

0.0

2000

2001

2002

2001

2002

0.0

0.0

2003

2004

2005

2003

2004

2005

0.0 1991

1992

1993

1996

1997

Fig – 30

1998

1999

YEA RS

TIM E S ERIES : V ISIBILITY < 1 KM (FEB) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 31

1998 YEARS

1999

2000

58

TIM E S ERIES : V IS IBILITY < 3 KM (FEB) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 32

1998

1999

2000

2001

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

YEA RS

T IM E S ERIES : F O G (FEB) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 33

1998 YEA RS

1999

59

TIM E S ERIES :P R ECIP IT AT IO N (FEB) 6.0

5.0

NO OF DAYS

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 34

1998

1999

2000

2001

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

YEA RS

TIM E S ER IES :DR W (F EB ) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 35

1998 YEA RS

1999

60

TIM E S ERIES :HAIL (F EB) 1 .2

1 .0

NO OF DAYS

0 .8

0 .6

0 .4

0 .2

0 .0 19 91

19 92

1 99 3

1 99 4

1 99 5

19 9 6

19 9 7

Fig – 36

1 99 8

1 99 9

2 0 00

2 00 1

2 00 2

2 0 03

20 04

20 0 5

2001

2002

2003

2004

2005

YEA RS

T IM E S ER IES :S S W > 30 K T (F EB ) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 37

1998 YEA RS

1999

2000

61

T IM E S ERIES : L O W CL OUD < 300M (FEB) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 38

1998

1999

2000

2001

2002

2003

2004

2005

2001

20 0 2

2003

2004

2005

YEA RS

T IM E S ER IES : L O W C L O U D < 15 0M (F EB ) 1 .2

1 .0

NO OF DAYS

0 .8

0 .6

0 .4

0 .2

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig – 39

1998 Y EA RS

1999

2000

62

DIURNAL VARIATION OF MAIN AWH (FEBRUARY) (DATABASE: 1991-2005) 1.6

1.4

1.4

1.2 1.2

1.2 1.1 1.0

0.9 0.8

0.8

0.7 0.7 0.6

0.6

0.4

0.4

0.5

0.4 0.3 0.2

0.2

0.2

0.1

0.2

0.1 0.0

0.1 0.0

0.0

0.0 0.0 0.0

0.0

0.0

0.1 0.0

0.0

0.0 0.0 0.0

0.0 0.0 0.0

0.0

0.0

0.0

0.0 00-03

03-06

06-09

09-12- 40 Fig

T'STORM PPTN

12-15

PV<1

15-18

PV<3

SSW>30

18-21

21-24

0.0

63

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : FEBRUARY (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1

0600 P2

P3

P1

66.6

0700 P2

P3

P1 84.4

0800 P2

P3

66.6

P1

0900 P2

P3

P1

1000 P2

P3

P1

1100 P2

P3

P1

1200 P2

P3

P1

1300 P2

P3

33.4

33.4

33.4

33.4

33.4

33.4

66.6

66.6

66.6

66.6

66.6 66.6

66.6

33.4

66.6 33.4

33.4

P1

2000 P2

P3

P1

2100 P2

P3

P1

1400 P2

P3

P1

1500 P2

P3

P1

1600 P2

P3

P1

1700 P2

P3

P1

1800 P2

P3

P1

1900 P2

P3

33.4

33.4

33.4

66.6

73.4

66.6

44.6

66.6 28.7

22.0

33.4

16.6

16.6

66.6

40.0

33.4

33.4

66.6 66.6

33.4

 B&Pd P1 =   B

  X 100 

 B&Sd P2 =   B

  X 100 

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 13

66.6 40.0

64

65

SEASONAL WEATHER SUMMARY PRE-MONSOON SEASON

Introduction 78. In May and June the heat low over Northern India begins to get established and the pressure gradient over the semi-arid area of Rajasthan increases. This leads to gusty winds, which raise loose dust upto more than 5000 ft. Pre Monsoon is characterised by wide spread Dust Haze, very high temperatures and scanty Rainfall. Prevailing of dry weather, weak and diffused pressure pattern are the main features of this season. During this season, pressure gradient is generally weak. This is a period of steady increase of surface temperature. March is the month of least amount of Rainfall. Dust Haze is the most prominent weather hazard at this airfield. Broad Synoptic Features 79. Western Disturbance/ Induced Low. Active WDs moving across NW India & adjoining N Pak induces Low over West Raj and adj. Central Pak. The frequency of formation of such Induced Lows is more in the beginning of the season. As the tracks shift northwards with northward shift of STJ, their frequency decreases. The frequency of the Induced Low is 01 to 03. Induced system in form of a Low or UACC up to 1.5/3.0 Km, supported by W’ly trough causes Dust storm/Thunder storm activity over West Raj. If induced Low/UACC lies over SW Raj, then generally JDP, JSM and UTL experience FWSP Dust storm/Thunder Storm. In case, induced system is lying over Central/East Raj then only JDP is affected and not JSM and UTL. Prior to Dust storm/Thunder Storm activity, invariably pressure gradient steepens and West Raj experiences FWSP DRW / D’ Haze. 80. Heat Low. Heat /seasonal low shows a northward movement with the progress of season. It establishes itself over S Pakistan & adj Raj by the end of season. Whenever the Heat Low is weak, diffused pressure pattern prevails over Raj, the general weather is fair/fine. As and when pressure gradient steepens over Raj and Gujarat and Heat Low is active, FWSP DRW/Dust Haze is experienced over West Raj. 81. Westerly Trough. Westerly trough generally extending up to 25o N and lying 5o to 7o west of induced system accentuates the lows/UACCs. At times, deep amplitude trough lying around 68o E - 70o E longitude in the absence of any lower level system, causes medium/high clouds over West Raj. 82. Tropical Cyclonic Storms. Pre-Monsoon season is favourable for development of Tropical Cyclonic Storms over Bay of Bengal and Arabian Sea. Many a times, these cyclones cause rapid advancement of SW Monsoon over Indian sub continent. Generally these cyclones form over Bay of Bengal between Lat 10 o N to 15o N. They cross Tamil Nadu coast while moving in Westerly direction and enter Arabian Sea. They re-intensify there and further move in a Northerly direction and

66 some time hit Gujarat coast affecting even West Raj. These Storms of Arabian Sea are a cause of great concern as amply demonstrated by the cyclones of Jun 98 & May 99. In period of 124 years (1877 –2006), the frequency of cyclones is as mentioned below:Arabian Sea Cyclonic Storms (1877-2006) Month Mar Apr May Jun

Cyclones over Cyclones crossed Arabian Sea Gujarat coast Nil 7 29 52

Nil 01 04 19

Whenever cyclonic storm hits Gujarat Coast and follows N’ly track further, overcast skies with strong surface winds and moderate to heavy precipitation and low clouds are experienced over West Raj. The Cyclonic Storm of Jun 98 caused 96.5mm in 24 hrs and wind speed of 62 Kt over Jodhpur. Seasonal Characteristics of AWH 83.

The main aviation weather hazards during this season are given below: (a) Visibility < 3 Km. Visibility reduces to less than 3 Km in Dust Haze. The mean frequency in Mar, Apr & May is 1.7, 8.3 & 13 days respectively. Although this phenomenon can occur any time in the day but most preferred time is either in morning between 0600 - 0900 hrs or in evening between 1800 - 2100 hrs. The mean duration varies between 2 - 4 hrs. The longest duration ever recorded has been 19 hrs in the month of May (Fig – 40). (b) DRW. This phenomenon is generally experienced over West Raj in afternoon/evening between 1200 - 1800 hrs. The mean frequency of DRW over Jodhpur increases from 01.3 in Mar to 5 in Apr and 14 in May (Fig – 40). (c) Dust Storm/Thunder Storm. It is the most violent phenomenon during this season. The frequency of Dust Storm/Thunder Storm increases from less than 1 in Mar to 3 in Apr and 4 in May. The favourable direction of approach of Dust Storm/Thunder Storm is NW to NE (320-040). The favourable period of occurrence is between 1500 - 0300 hrs. Very rarely Dust Storm/Thunder Storm is experienced in early morning hrs between 0300 to 0900 hrs (Fig – 40). (d) Temperature > 40º C. High surface temperature in this season is one of the main aviation weather hazards. It not only restricts the flying operations but also affects the comfort of people. The mean frequency of this phenomenon increases from 03 days in Mar to 12 days in Apr and 26 days in May. The peak period is between 1200 - 2000hrs. There have been incidents when temperature crossed 400 C as early as 1000 hrs in the morning and remained above 40º C till 2300 hrs in the night (Fig – 40).

67 (e) Good, P'Good and Bad Weather State. The mean, highest and lowest frequencies have been tabulated month wise using the data from Jan 01 to Dec 2005 (Table - 17). March is best period with maximum no. of good weather days and night.

68

STATISTICS OF GOOD/MARGINAL/BAD WX DAYS : PREMONSOON SEASON DATA SET: 2001 – 05

MONTH

MAR

APR

MAY

JUN

G: GOOD

FIGHTERS / TRAINERS DAY NIGHT

TRANSPORTS DAY

NIGHT

0601-1200

1201-1800

1801-2400

0001-0600

0601-1200

1201-1800

1801-2400

0001-0600

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

Highest

31

2

0

31

3

4

31

1

0

31

2

0

31

2

0

31

2

0

31

0

1

31

2

0

Mean

30

1

0

29

1

1

31

0

0

31

0

0

30

1

0

31

0

0

31

0

0

31

0

0

Lowest

29

0

0

24

0

0

30

0

0

29

0

0

29

0

0

29

0

0

30

0

0

29

0

0

Highest

30

4

1

25

6

10

29

4

3

30

3

2

30

3

0

30

2

1

29

3

2

30

3

2

Mean

28

2

0

21

3

6

27

2

1

28

1

1

28

2

0

29

1

0

27

2

1

28

1

1

Lowest

25

1

0

16

1

0

24

1

0

26

0

0

27

1

0

27

0

0

25

1

0

26

0

0

Highest

31

8

1

16 13 21

26 11

4

29

7

2

31

5

2

30

7

0

29 10

2

29

9

2

Mean

27

3

1

10

6

15

23

6

2

27

3

1

29

2

0

27

4

0

25

5

1

27

3

1

Lowest

23

0

0

4

2

10

18

2

0

24

0

0

26

0

0

24

1

0

19

1

0

22

0

0

Highest

27

8

1

19

9

16

24

6

11

29

12 1

30

6

1

30

8

2

28 10

3

29

12

2

Mean

25

5

0

13

6

11

20

4

6

25

5

0

28

2

0

26

3

1

25

3

2

25

5

0

Lowest

21

2

0

9

0

5

15

2

4

18

1

0

24

0

0

21

0

0

19

0

1

18

1

0

M: MARGINAL

B: BAD Table – 14

69

AF STATION, JODHPUR MAIN AVIATION WX HAZARDS PRE-MONSOON SEASON (1991 - 2005)

9.0

8.2

MEAN FREQUENCY (NO. OF DAYS)

8.0 7.0 6.0 5.0

4.5

4.0 3.0

3.2

2.9

2.6

2.3

2.1 1.3

0.3 0.0

0.0

0.0 0.0

0.1

MAR

T'STORM

D'STORM

0.1

0.1

0.0 0.0 APR

HAIL

1.9

1.0

0.8

0.7

2.0

1.8

2.0 1.0

3.7

3.6

Fig – 41 PPTN LC<300M

0.2

0.0

MAY

FOG

PV<1KM

PV<3KM

SSW>30KT

70

500 450

Fig – 42

71

72

84. Introduction. March is the transition month from Winter to Pre-monsoon season. Sky remains generally fine / fair on most of the days and becomes cloudy with medium and high clouds under the influence of Induced Low / Cycir or southwest shift of Jet Stream. Fog, Mist, Haze / Smoke Haze continues to affect the visibility in the morning hours. Induced Low / Cycir are the main synoptic systems moving across the region and causing cloudiness. During the passage of WDs across northern parts of the country, Induced low / Cycir form and move across the region. Generally fair weather prevails throughout this month. During this month, transition takes place from winter to summer season. The rise in surface temperature is observed all over the country. Broad Synoptic Features 85. Effects of Various Synoptic Situations on Local Weather. During first week generally weather remains fine / fair as the features of winter season continue to persist except partly cloudy / cloudy on few days and isolated smoke Haze during morning hours. Fair/ partly cloudy skies with isolated convective developments and scattered D’Haze / DRW activity is observed during third and fourth week. The surface winds show a large degree of variability during daytime. 86. Behaviour of Important Parameters. The behaviour of important parameters during the month of March are as follows:(a) Pressure. As a result of rise in day temperature, the belt of high pressure extending from North Pak to NW India starts weakening and becomes a diffused one. (b) Winds. The surface wind remains light and variable during evening and night hour. The surface winds are generally light Sly during the morning hours and tend to vary between Nly to NEly thereafter. Maximum surface wind recorded for the month is 250/48 on 23 Mar 82. (c) Rainfall. The mean monthly Rainfall during the month is 1.7 mm. The highest Rainfall amount ever recorded during the month has been 16.9 mm in 1998. The heaviest Rainfall recorded in 24 hrs for the month is 8.2 mm on 20 Mar 87. (d) Temperature. The mean maximum temperature for the month is 0 33.8 C. The highest maximum temperature ever recorded during the month has been 42.0°C on 29 Mar 91. The mean minimum temperature for the month is 17.1 0C. The lowest ever recorded during the month has been 4.7 0C on 9 Mar 79. 87. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Feb 1991 and Feb 2005 is presented as follows: -

10

MARCH MONTHLY WEATHER SUMMARY

73 (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Feb follow this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration (Table – 17). (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that the frequencies of precipitation and thunder storm are 1.9 and 0.5 days respectively (Table – 16). 88. Time Series of Rainfall. The time series of Rainfall shows decrease in frequency of Rainy days after 1998 (Fig - 48).

gradual

89. Time Series of Thunder Storms. The time series of thunder storms shows a wide fluctuation in number of days of thunder storm occurrence throughout the period of 15 years (Fig - 46). 90. Time Series of Dust Storms. The time series of dust storms shows a wide fluctuation in number of days of dust storm occurrence throughout the period of 15 years (Fig - 47). 91. Time Series of PV <1Km. The time series of PV < 1 Km shows maximum occurrence in the year 2003 (Fig – 44). 92 Time Series of PV <3Km. The time series of PV < 3 Km shows wide fluctuation throughout the period but maximum occurrence period is 0200 – 0600 h and towards afternoon between 1400 – 1600 h (Fig – 45). 93. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) has been graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 51). 94. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table – 17). 95. Simultaneity of Weather. In March visibility (< 3000m) has around 70% simultaneous occurrence with primary and secondary diversion during 1400 to 1800 hrs. For precipitation there is 33% of occurrence at secondary diversion around 0800 – 0900 h and again towards evening between 1600 – 1800 h (Table - 18). 96. Weather over Local flying area. The good weather conditions of the winters continue to prevail over the local flying area for the first half of the month and the weather generally remains fair with scattered Haze / smoke Haze during the morning hours. Thunderstorm activity gains momentum from the second half of the month and weather generally remains partly cloudy / cloudy during the afternoon/evening hours with isolated convective build-ups towards evening hours. Isolated Rainfalls on a few occasions associated with the convective clouds are also observed during the month.

74

97. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds up to 10000’ are generally Wlies of about 10 – 20 throughout the day (Table – 14, Table – 15).

MEANS OF UPPER WIND & TEMPERATURE: MARCH TIME : 0000 UTC LEVEL

Temp ºC

1000' 2000' 3000' 5000' 7000' 10000'

N/A N/A 22 18 13 6

PERCENTAGE FREQUENCY AND MEAN WIND SPEED

Total No of N

observations

333 383 404 428 402 387

NE

E

SE

S

SW

W

NW

I

II

III

IV

V

VI

VII

VIII

360

045

090

135

180

225

270

315

% frequency

14.7%

30.3%

13.5%

3.0%

5.1%

11.7%

15.9%

5.7%

mean speed

4.5

6.2

9.1

5.0

4.6

7.2

7.9

5.1

% frequency

14.1%

16.2%

14.4%

5.7%

7.8%

7.6%

27.7%

6.5%

mean speed

8.1

11.3

11.1

11.8

7.5

11.8

13.5

10.9

% frequency

17.1%

10.9%

11.6%

5.0%

6.9%

11.1%

25.7%

11.6%

mean speed

9.8

12.0

10.1

8.8

8.9

12.6

13.6

12.0

% frequency

12.9%

4.2%

2.3%

1.9%

6.8%

13.8%

40.2%

18.0%

mean speed

9.8

12.0

9.2

9.0

8.1

14.2

14.2

12.4

% frequency

11.4%

1.2%

1.7%

1.7%

3.7%

15.4%

41.3%

23.4%

mean speed

11.2

6.4

7.0

8.0

11.6

15.8

15.7

13.1

% frequency

10.3%

0.5%

1.0%

0.8%

5.4%

16.8%

43.9%

21.2%

mean speed

13.9

3.0

7.5

8.3

15.6

19.4

19.6

16.2

Table – 15 TIME : 1200 UTC LEVEL

Temp ºC

1000' 2000' 3000'

N/A N/A 26

297 382 386

20

389

7000'

14

371

7

N

observations

5000'

10000'

PERCENTAGE FREQUENCY AND MEAN WIND SPEED

Total No of

390

% frequency

NE

E

SE

S

SW

W

NW

I

II

III

IV

V

VI

VII

VIII

360

045

090

135

180

225

270

315

16.8%

20.2%

7.4%

0.3%

2.4%

11.8%

20.5%

20.5%

mean speed

5.3

4.9

6.7

1.0

4.0

6.0

4.9

4.8

% frequency

18.6%

12.3%

10.2%

3.1%

3.1%

8.9%

28.8%

14.9%

mean speed

7.4

7.8

7.6

4.6

7.6

10.4

9.1

7.3

% frequency

19.4%

13.2%

10.9%

2.8%

3.9%

11.7%

25.1%

13.0%

mean speed

7.1

7.8

9.3

4.9

7.9

13.0

8.5

7.9

% frequency

15.4%

10.0%

8.0%

1.0%

4.6%

13.1%

32.6%

15.2%

mean speed

7.4

7.5

7.4

4.5

7.9

11.2

9.9

9.2

% frequency

17.0%

8.4%

8.4%

1.1%

4.0%

12.7%

35.8%

12.7%

mean speed

8.2

8.1

8.9

5.0

9.3

13.0

10.7

10.8

% frequency

6.9%

2.1%

1.3%

0.8%

3.3%

12.6%

53.6%

19.5%

mean speed

12.7

9.1

6.0

3.0

7.8

18.3

18.8

15.3

Table – 16 98. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone between 1100 – 2000 h (Fig - 42).

75

80 Fig – 43 SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (MAR) ELEMENT

78

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

YEAR(s)

FREQ

PEAK

SD

PERIOD (IST)

(a)

(b)

(c)

(d)

(e)

(f)

(g)

VIS < 3 KM

2.1

5

1995,2000

VIS < 1 KM

0.8

4

2003

0

1999,01,04

18-21

1.7

0

1993.97,98,99,01,02,04

15-18

1.0

CL < 300 M

0.0

0

CL < 150 M

0.0

0

THUNDER STORM

0.7

3

1998 1991,92,94,00,0 3

0

1991-93,99,01,02,04

21-24

0.9

DUST STORM

0.3

1

HAIL STORM

0.0

0

0

1993,95-99,01,02,04,05

15-18

0.5

PPTN

2.3

8

1997

0

1999,01,02,04

18-21

2.4

FOG

0.0

0

>30 KTS

0.1

1

1999,2000

0

1991-98,01-05

15-18

0.3

DRW

1.3

4

1998,2000

0

12-15

1.3

1.1

8

2004

0

1993,95,99,05 1991-93,96-98,0103,05

TEMP > 40O C

114-16

2.2

CEILING (CL)

76

SUR WIND

74

DEX

Table – 16

72

76

200

180 Fig – 44

30

77

T IM E S ERIES : V IS IB IL I T Y < 1 KM (M AR ) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

19 93

1 994

1995

1996

1997

Fig – 45

1998

19 99

20 00

2001

2002

20 03

2 004

200 5

2001

2 002

2003

2004

2 005

Y EA RS

T IM E S ER I ES : V IS I B IL IT Y < 3 K M (M A R ) 6.0

5.0

NO OF DAYS

4.0

3.0

2.0

1.0

0.0 19 91

199 2

1993

1994

199 5

19 96

19 97

Fig – 46

1998 YEA RS

1999

20 00

78

TIME SERIES : THUNDER STORM (MAR) 3.5

3.0 3.0

2.5

NO OF DAYS

2.0 2.0

1.5

1.0

1.0

1.0

1.0

1.0

1.0

1.0

0.5

0.0

0.0

0.0

1991

1992

1993

0.0

0.0

0.0

0.0

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

0.0 1994

1995

1996

1997

Fig – 47

1998

1999

2000

YEARS

TIM E S ERIES : D'S T O RM (M AR) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 48

1998 YEA RS

1999

2000

79

T IM E S ER IES :P REC IP IT A T IO N (M AR ) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 19 91

199 2

199 3

19 94

1995

1996

1 997

Fig – 49

19 98

199 9

200 0

20 01

200 2

200 3

2 004

20 05

2000

2001

2002

2003

2004

2005

YEA RS

T IM E S ERIES :DRW (M AR) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 50

1998 YEA RS

1999

80

T IM E S ERIES :T EM P > 40 DEG (M AR) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

1998 YEA RS

Fig – 51

1999

2000

2001

2002

2003

2004

2005

81

DIURNAL VARIATION OF MAIN AWH (MAR) (DATABASE: 1991-2005) 2.5

2.1 2.0

2.0

2.0

1.5

1.5

1.5

1.5 1.3 1.2

1.2

1.0

1.0

1.0

0.9

0.9 0.8 0.7

0.6

0.6

0.6 0.5

0.5 0.3

0.3

0.2

0.2

0.2

0.2

0.2

0.1

0.1 0.0

0.0

0.0

0.0

0.0

0.0

0.1

0.0

0.0

0.0

0.0 00-03

03-06

06-09

09-12

Fig - 52 T'STORM

12-15

PPTN

PV<1

15-18

PV<3

SSW>30

18-21

21-24

82 AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : MARCH (BASED ON DATA SET OF 1995 - 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

P1

0600 P2

P3

P1

0700 P2

P3

P1

0800 P2

P3

P1

33.4 1400 P1 P2 69.9

P3

1500 P1 P2 68.9

P3

P1 73.4

33.4

1600 P2

33.4

0900 P2

P3

66.6

P3

1700 P1 P2 23.3 40.0 33.4

33.4

P1

1000 P2

P3

P1

1100 P2

P1

P3

2000 P1 P2

P3

1800 P1 P2 20.0 46.7

33.4

P3

33.4

P1

1900 P2 40.0

44.6

Where : B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Secondary Diversion (Sd) -Uttarlai

Table – 18

 B&Pd P1 =   B

  X 100 

 B&Sd P2 =   B

  X 100 

P3

1300 P2

P3

2100 P1 P2

P3

P1 73.4

66.6

Legend:

Primary Diversion (Pd) - Jaisalmer

1200 P2

P3

 B&Pd &Sd  P3 =   X100 B  

33.4

P3

83

84 APRIL MONTHLY WEATHER SUMMARY 99. Introduction. By mid April, day temperatures increase to such an extent that it can be considered as the representative of the summer season. The weather remains generally dry and atmosphere remains unstable due to rise in day temperatures. Broad Synoptic Features 100. Effects of Various Synoptic Situations on Local Weather During the first week of the month, generally weather remains dry over Raj with P’Cloudy/ Cloudy skies mainly with high clouds except for widespread D’Haze/DRW accompanied with nil visibility and occasional Rain/T’shower. During the later part of the month, generally weather remains Fair/P’Cloudy with occasional D’Haze/DRW. However, ISOL – SCT Rain / Thunder Storm / Dust Storm associated with gale force is also experienced over Raj. 101. Behaviour of Important Parameters. The behaviour of important parameters during the month of April is as follows:(a) Pressure. As the season advances, the temperature rises and the pressure falls. The pressure pattern is totally diffused. The low over SE UP, Chattisgarh, Jharkhand and Vidharba starts getting organised and gradually shifts westwards. The pressure gradient starts building up over Saurashtra, Kutch and W Raj. (b) Winds. The surface wind remains light and variable during early morning. The surface winds pick up strength in afternoon hours and are SWly 10-20 kts. Maximum surface wind recorded for the month is 180/58 on 25 Apr 82. Subtropical Jet Stream shifts northwards and speed reduces further. Westerlies continue to dominate at upper levels but at reduced speed. (c) Rainfall. The mean monthly Rainfall during the month is 10.1 mm. The highest Rainfall amount ever recorded during the month has been 149.7 mm in 1982. The heaviest Rainfall recorded in 24 hrs for the month is 138.0 mm on 26 Apr 82. (d) Temperature. The mean maximum temperature for the month is 0 39.0 C. The highest maximum temperature ever recorded during the month has been 45.4°C on 27 Apr 79. The mean minimum temperature for the month is 22.8 0C. The lowest ever recorded during the month has been 13.4 0 C on 4 Apr 97. 102. Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that thundery activity starts its influence over the airfield in association with Dust Storm/ occasionally Precipitation. The main aviation weather hazards during the month are D’Haze / Thunder Storm and Precipitation. The surface visibility drops to less than 3 Km on 4.5 days and less

85 than 1 km on 1.8 days. The frequency of Thunder Storm and Dust Storm is 2.6 and 1.3 days respectively. The frequency of dust raising wind (DRW) increases to 2.3 days, the surface temperature crosses 40º C for almost 10 days. Gale is experienced on 2 days during the month. The role of high surface temperature become significant as it crosses 40º C during noon hours, specially in the second fortnight and thereby putting restriction on fighter flying. 103. Time Series of Rainfall. The time series of rainfall shows wide fluctuation in number of days thunder storm occurrence throughout the period (Fig - 57). 104. Time Series of Thunder Storms. The time series of thunder storms shows a wide fluctuation in number of days thunder storm occurrence throughout the period of 15 years with a fall after 1994 and further a gradual increase (Fig - 53). 105. Time Series of Dust Storms. The time series of dust storm shows a wide fluctuation in number of days of occurrence throughout the period of 15 years (Fig 56). 106. Time Series of PV <1Km. The time series of PV <1 Km shows maximum occurrence in the year 1994 (Fig – 54). 107. Time Series of PV <3Km. The time series of PV <3 Km shows wide fluctuation throughout the period with maximum occurrence in the year 1993 and 2005 (Fig – 55). 108. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 61). 109. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 for fighter and transport flying but during the period 1201 – 1800 good weather days are around 20. (Table – 17) 110. Simultaneity of Weather In April low clouds (< 300m) have 25% simultaneous occurrence with primary and secondary diversion during 0700 to 0800 hrs. For Thunderstorm the simultaneity has a percentage of 33 to 50% with primary diversion and 33 to 50% with both together during 0600 h, 1600 – 2100 h, and 0600, 1600h, and 1800 – 1900 h respectively. For precipitation there is 50% of occurrence at primary and secondary diversion at 0600 h only (Table - 22). 111. Weather over Local flying area. Generally during the first week, weather remains dry over Raj with P’Cloudy/ Cloudy skies mainly with high clouds except occasional WDSPR D’Haze/DRW activity. However, ISOL – SCT Rain / Thunder Storm / Dust Storm associated with gale force are also experienced over Raj. Low visibility is reported in association with D’Haze/DRW.

86 112. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds are generally W’lies of about 10-15 kt throughout the day (Table – 19, Table – 20). AIR FORCE STATION : JODHPUR TIME : 0000 UTC LEVEL Temp ºC

1000'

N/A

Total No of observations

339

MEANS OF UPPER WIND & TEMPERATURE: APRIL DATA SET 1991-2005 (FOR TEMP 2001-2005) PERCENTAGE FREQUENCY AND MEAN WIND SPEED N NE E SE S SW W NW 360 045 090 135 180 225 270 315 I II III IV V VI VII VIII %age frequency mean speed

2000'

N/A

366

%age frequency mean speed

3000'

25

375

%age frequency mean speed

5000'

22

373

%age frequency mean speed

7000'

16

368

%age frequency mean speed

10,000'

9

362

10.0%

16.2%

10.6%

1.8%

1.5%

28.0%

26.0%

5.9%

4.2

6.9

8.0

4.5

4.4

7.8

7.8

7.1

8.2%

7.7%

11.7%

6.0%

3.0%

16.1%

39.9%

7.4%

9.7

13.8

13.2

7.9

6.9

15.6

14.8

11.8

10.1%

5.1%

8.5%

4.5%

4.0%

14.9%

42.4%

10.4%

8.8

13.3

15.3

9.7

7.4

19.4

15.4

10.9

7.8%

4.0%

4.6%

1.3%

6.4%

15.8%

46.1%

13.9%

8.8

9.6

9.4

11.2

10.6

14.8

15.4

12.6

5.7%

1.6%

3.5%

3.0%

7.6%

14.9%

46.2%

17.4%

7.0

9.0

6.9

5.5

10.7

16.9

14.1

11.0

%age frequency

8.8%

2.2%

3.3%

0.8%

8.6%

15.2%

38.1%

22.9%

mean speed

12.3

9.9

6.9

12.3

11.0

17.6

16.0

13.7

Table – 19

AIR FORCE STATION : JODHPUR TIME : 1200 UTC LEVEL Temp ºC

1000'

N/A

Total No of observations

336

MEANS OF UPPER WIND & TEMPERATURE: APRIL DATA SET 1991-2005 (FOR TEMP 2001-2005) PERCENTAGE FREQUENCY AND MEAN WIND SPEED N NE E SE S SW W 360 045 090 135 180 225 270 I II III IV V VI VII %age frequency mean speed

2000'

N/A

373

%age frequency mean speed

3000'

31

383

%age frequency mean speed

5000'

25

371

%age frequency mean speed

7000'

19

372

%age frequency mean speed

10,000'

11

355

%age frequency mean speed

5.7%

2.4%

1.2%

0.3%

2.1%

38.7%

33.9%

NW 315 VIII 15.8%

4.2

4.6

4.8

1.0

4.4

6.9

6.5

5.5

6.4%

1.6%

1.6%

0.8%

3.2%

25.7%

49.1%

11.5%

6.4

7.5

5.5

4.0

8.3

13.4

11.3

10.0

5.2%

2.3%

1.3%

1.8%

3.4%

25.8%

49.3%

10.7%

7.0

6.8

5.6

5.7

8.5

13.4

11.2

9.7

5.9%

2.2%

1.9%

0.5%

7.3%

21.8%

49.3%

11.1%

7.2

8.1

5.7

2.5

9.0

13.8

11.8

9.5

4.8%

2.2%

2.7%

0.5%

6.2%

22.6%

49.2%

11.8%

8.8

7.5

4.9

5.0

9.0

12.3

12.2

9.4

5.6%

1.1%

1.1%

0.8%

6.8%

16.1%

51.0%

17.5%

8.8

4.3

6.8

4.7

9.1

14.0

14.9

11.3

Table – 20

87 113. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone through out the day except between 0600 – 0800 h when it remains in partly comfortable zone and between 0500 – 0600 h it’s comfortable.

85 Fig – 53 SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (APR) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

YEAR(s)

FREQ

PEAK

SD

PERIOD (IST)

(a)

(b)

(c)

(d)

(e)

(f)

(g)

VIS < 3 KM

4.5

12

1994,2005

VIS < 1 KM

1.8

7

1994

0

1997

06-09

3.7

0

1995-97,99,02

21-24

1.9

8

1994

0

1992,03

18-21

2.3

CEILING (CL)

80

CL < 300 M

0.0

0

CL < 150 M

0.0

THUNDER STORM

2.6

DUST STORM

1.3

4

2004

0

1991,9295-97,99,02

18-21

1.4

HAIL STORM

0.1

1

1994

0

1991-93,95-05

18-21

0.3

PPTN

2.9

8

1994

0

1992,99

18-21

2.2

FOG

0.0

0

1.0

4

2004

0

1991-93,97,03

18-21

1.2

0

SUR WIND >30 KTS DRW

2.3

8

2005

0

1992,93,95,99

15-18

2.5

TEMP > 40O C

10.2

20

1999

1

1995

14-16

5.6

DEX

Table – 21

75

88

200 180

Fig – 54

89

TIM E S ERIES : THUNDER S TORM (AP R) 9.0 8.0 8.0

7.0 6.0 6.0

NO OF DAYS

5.0 5.0 4.0 4.0 3.0

3.0

3.0

3.0 2.0

2.0

2.0 1.0

1.0

1.0

1.0 0.0

0.0

0.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 55

1998

1999

2000

2001

2002

2003

2004

2005

20 0 1

2 00 2

2003

2 00 4

2005

YEA RS

T I M E S ER IES : V IS IB I L IT Y < 1 K M (A P R ) 8 .0

7 .0

6 .0

NO OF DAYS

5 .0

4 .0

3 .0

2 .0

1 .0

0 .0 1 9 91

19 9 2

1993

1 99 4

1995

1996

1 9 97

Fig – 56

1 99 8 Y EA RS

1999

2 0 00

90

TIM E S ERIES : V IS IBILITY < 3 KM (AP R) 14.0

12.0

NO OF DAYS

10.0

8.0

6.0

4.0

2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 57

1998

1999

2000

2001

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

YEA RS

TIM E S ERIES : D'S TO RM (AP R) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 58

1998 YEA RS

1999

91

T IM E S ERIES :P REC IP IT AT IO N (AP R) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 59

1998

1999

2000

2001

2002

2003

2004

2005

2 000

200 1

2 00 2

2 00 3

20 0 4

20 0 5

YEA RS

T I M E S ERIES :D R W (A P R ) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 199 1

19 9 2

199 3

1 9 94

19 95

1 9 96

1 9 97

Fig – 60

1 99 8 YEA RS

1 99 9

92

TIME SERIES :TEMP >40 DEG (APR) 25.0

20.0

NO OF DAYS

15.0

10.0

5.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 61

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEARS

T IM E S ERIES :S S W > 30 KT (AP R) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 62

1998 YEARS

1999

2000

93

DIURNAL VARIATION OF MAIN AWH (APRIL) (DATABASE: 1991-2005) 3.0

2.6 2.5

2.0 2.0

1.9

1.8 1.7

1.6 1.5 1.2

1.1

0.

1.0

0.8

0.5 0.5

1.1

1.1

0.4

0.4

0.3

0.4

0.3 0.1

0.1 0.2

0.1 0.1 0.0

0.5

0.5

0.5

0.4 0.2 0.1

0.1

0.2

0.2 0.2 0.0

0.0

0.2

0.2

0.0

0.0 00-03

03-06

06-09

09-12

T'STORM PPTN Fig – 63

12-15

PV<1

15-18

PV<3

SSW>30

18-21

21-24

94

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : APRIL (BASED ON DATA SET OF 1995 - 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1

0600 P2

P3

P1

0700 P2

P3

86.1 66.6

P1

1400 P2

P3

P1

P1

0800 P2

P3

85.5 66.6

1500 P2

P3

P1

P1

0900 P2

P3

86.7 66.6

1600 P2

P3

P1

P1

1000 P2

P3

P1

1100 P2

P3

P1

1200 P2

P3

P1

1300 P2 P3

1800 P2

P3

P1

1900 P2

P3

P1

2000 P2

P3

P1

2100 P2 P3

89.9 66.6

1700 P2

76.7

P3

P1 46.7

78.9

33.4

51.1

36.7

66.6

 B&Pd P1 =   B

  X 100 

 B&Sd P2 =   B

  X 100 

 B&Pd &Sd P3 =  B 

  X100 

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table - 22

16.6 22

95

MAY MONTHLY WEATHER SUMMARY 114. Introduction. During this month, steep rise in day temperature is a common feature. There is a decrease in Dust Storm/Thunder Storm activity compared to the previous months. WD continues to affect the weather over the airfield. Broad Synoptic Features 115. Effects of Various Synoptic Situations on Local Weather Generally weather over Raj remains SCT – FWSP Dust Haze / Dust Raising Winds on most of the days during afternoon/evening hours. However during the month FWSP WDSPR Rain / Thunder Storm / Dust Storm occurred over base. 116. Behaviour of Important Parameters. The behaviour of important parameters during the month of May is as follows:(a) Pressure. Due to steep rise in day temperatures, there is fall in pressure over NW India. The seasonal heat low is seen in this month over western UP, Punjab, Haryana and N Raj. Heat low gets accentuated when WD gives rise to induced low over the region. Moderate strong pressure gradient develops over western and northwestern parts of the country.

96 (b) Winds. With the progress of the day the surface wind gets strengthened. Winds are generally SWly/Wly 10-15 kt gusting to 20-25 kt in afternoon. Steep pressure gradient results in high wind speed. Maximum surface wind recorded for the month was 320/56 on 22 May 83 and 180/56 on 22 May 99. (c) Rainfall. The mean monthly Rainfall during the month is 18.9 mm. The highest Rainfall amount ever recorded during the month has been 116.1 mm in 1982. The heaviest Rainfall recorded in 24 hrs for the month is 111.1 mm on 7 May 82. (d) Temperature. The mean maximum temperature for the month is 0 41.4 C. The highest maximum temperature ever recorded during the month has been 47.8°C on 29 May 94. The mean minimum temperature for the month is 26.9 0C. The lowest ever recorded during the month has been 17.60 C on 6 May 89. 117. Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This indicates that main aviation hazards are poor visibility due to Dust Haze /DRW for the month (Table – 25). 118. The frequency Thunder Storm/ Dust Storm is 3.6/ 2.0 and dust raising winds (DRW) 4.8 days during the month. Dust Haze is a frequent occurrence reducing visibility to less than 3 km. Gale associated with Dust Storm is experienced on 2 days. The highlight of the month is the high surface temperature during noon hours which crosses 40º C on 20 days. 119. Time Series of Rainfall. The time series of Rainfall shows wide fluctuation in the Rainfall amount and the number of days of occurrence (Fig - 67). 120. Time Series of Thunder Storms. The time series of thunder storms shows wide fluctuation in the number of days of occurrence, however, maximum occurrence was in the years 1996, 1997 and 2005 (Fig - 63). 121. Time Series of PV <1Km. The time series of PV <1 Km shows an decrease in the incidence of poor visibility <1 km occurrence in last decade (Fig - 64). 122. Time Series of PV <3Km. The time series of PV <3 Km shows an increase in the incidence of poor visibility <3 km during the last decade but (Fig – 65). 123. Time Series of SSW >30 Kt. wide fluctuation (Fig – 70).

The time series of SSW > 30 Kt shows a

124. Time Series of Temp >40 Deg. The time series of Temp > 40 Deg also shows a continuous incidences of Temp > 40 Deg C (Fig – 69). 125. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 71).

97

126. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying. (Table -17) 127. Simultaneity of Weather In this month low clouds (< 300m) have 25% simultaneous occurrence with primary and secondary diversion during 0700 to 0800 hrs. For Thunderstorm the simultaneity has a percentage of 33 to 50% with primary diversion and 33 to 50% with both together during 0600 h, 1600 – 2100 h, and 0600, 1600h, and 1800 – 1900 h respectively. For precipitation there is 50% of occurrence at primary and secondary diversion at 0600 h only (Table 26). 128. Weather over Local flying area. Generally weather over Raj remains SCT – FWSP Dust Haze / DRW on most of the days during afternoon/evening hours. However occassionally FWSP - WDSPR Rain / Thunder Storm / Dust Storm occurs. Base records low visibility in dust storm.

98 129. Means of Local Upper Winds (PB Means) The local upper wind data is available up to 10000’. The analysis of the data shows that the winds are generally Wly throughout the day (Table – 23, Table – 24).

AIR FORCE STATION : JODHPUR TIME : 0000 UTC LEVEL Temp Total No ºC of obserVations

1000'

N/A

366

2000'

N/A

392

3000'

29

384

5000'

26

371

7000' 10,000'

21 14

380 372

MEANS OF UPPER WIND & TEMPERATURE: MAY DATA SET 1991-2005 (FOR TEMP 2001-2005) PERCENTAGE FREQUENCY AND MEAN WIND SPEED N NE E SE S SW W NW 360 045 090 135 180 225 270 315 I II III IV V VI VII VIII % frequency

2.2%

4.6%

2.2%

1.4%

3.0%

53.0%

27.3%

6.3%

mean speed

5.9

6.2

5.6

6.0

9.3

8.6

8.7

8.7

% frequency

2.8%

5.1%

3.6%

1.0%

2.6%

30.9%

48.5%

5.6%

mean speed

9.6

9.0

12.3

11.2

9.6

19.0

16.8

11.6

% frequency

4.2%

1.8%

2.9%

1.8%

2.1%

26.3%

53.9%

7.0%

mean speed

9.6

11.7

13.4

8.1

14.0

22.3

17.9

10.4

% frequency

5.4%

1.6%

1.6%

1.1%

4.3%

26.4%

49.9%

9.7%

mean speed

9.8

7.7

9.0

9.8

14.2

18.5

18.0

13.7

% frequency

6.8%

2.4%

1.6%

2.1%

7.1%

15.5%

47.4%

17.1%

mean speed

9.3

7.8

6.5

6.1

9.8

16.8

15.0

13.5

% frequency

13.2%

4.0%

4.0%

2.7%

6.5%

8.1%

37.4%

24.2%

mean speed

10.7

11.7

8.4

9.0

13.1

14.3

15.4

13.2

Table – 23

TIME : 1200 UTC LEVEL Temp Total No ºC of obserVations 1000'

N/A

368

2000'

N/A

353

3000'

34

357

5000'

28

368

7000'

22

391

10,000'

15

381

AIR FORCE STATION : JODHPUR MEANS OF UPPER WIND & TEMPERATURE: MAY DATA SET 1991-2005 (FOR TEMP 2001-2005) PERCENTAGE FREQUENCY AND MEAN WIND SPEED N NE E SE S SW W NW 360 045 090 135 180 225 270 315 I II III IV V VI VII VIII % frequency 5.7% 0.3% 0.5% 0.8% 2.7% 48.9% 39.7% 1.4% mean speed 5.3 2.0 7.0 4.3 7.6 8.3 7.9 5.6 % frequency 5.4% 2.0% 0.8% 0.3% 2.5% 32.9% 49.9% 6.2% mean speed 7.6 8.6 5.7 1.0 9.1 15.6 13.9 10.4 % frequency 6.2% 0.6% 1.1% 0.8% 3.6% 30.8% 49.3% 7.6% mean speed 7.8 6.5 13.8 1.3 13.8 16.1 14.7 10.3 % frequency 6.8% 0.8% 0.8% 0.5% 4.6% 31.3% 47.8% 7.3% mean speed 6.8 10.3 21.3 2.0 12.2 15.9 15.3 11.4 % frequency 6.1% 0.8% 0.8% 1.0% 4.6% 27.6% 43.2% 15.9% mean speed 8.3 7.7 6.7 8.5 10.3 12.1 15.4 12.8 % frequency 12.6% 2.9% 2.6% 2.9% 2.4% 30.4% 36.5% 9.7% mean speed 10.5 8.2 13.2 9.5 8.9 13.4 14.6 12.2

Table – 24

99 130. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone through out the day except between 0500 – 0900 h when it remains in partly comfortable zone (Fig – 61).

90

Fig – 64

SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION – JODHPUR (MAY) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

YEAR(s)

(a)

(b)

(c)

(d)

(e)

(f)

(g)

VIS < 3 KM

8.2

18

2003

0

1999

06-09

4.1

VIS < 1 KM

3.2

8

1992

0

1999

06-09

2.1

CL < 300 M

0.2

2

1999

0

1991-98,00-02,04,05

06-10

0.5

CL < 150 M

0.0

THUNDER STORM

3.6

8

2005

0

1991,98,99

21-24

3.1

DUST STORM

2.0

5

1996

0

1991,97,99,04

21-24

1.5

HAIL STORM

0.1

1

1996

0

1991-95,97-05

18-21

0.2

PPTN

3.7

7

1994,96,97

0

1998

21-24

2.2

FOG

0.0

0

FREQ

PEAK

SD

PERIOD (IST)

CEILING (CL)

85 0

SUR WIND >30 KTS

1.9

5

2001

0

1991

18-21

1.3

DRW

4.8

14

2003

1

1991,92,94,96,99,

15-18

4.1

TEMP > 40OC

20.1

26

1993,2002

10

1997

14-16

4.1

INDEX

Table – 25

80

100

200 180

Fig – 65

101

T IM E S ERIES : TH UND ER S T O RM (M AY) 9.0 8.0

8.0

8.0

8.0 7.0 7.0 6.0 6.0

NO OF DAYS

5.0 5.0 4.0 4.0 3.0 3.0 2.0

2.0

2.0 1.0 1.0 0.0

0.0

0.0

1998

1999

0.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 66

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

TIM E S ERIES : V IS IBILITY <1 KM (M AY) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 67

1998 YEA RS

1999

2000

102

T IM E S ER IES : V IS IB IL IT Y < 3 K M (M A Y) 20.0

18.0

16.0

14.0

NO OF DAYS

12.0

10.0 8.0

6.0 4.0

2.0

0.0 1 991

1992

1 993

1994

1 995

1 996

199 7

Fig – 68

1 998

199 9

2000

2 001

200 2

2 003

20 04

2 005

2 0 01

2 00 2

20 0 3

2004

2 0 05

YEA RS

T IM E S ER IE S : D 'S T O R M (M A Y) 6 .0

5 .0

NO OF DAYS

4 .0

3 .0

2 .0

1 .0

0 .0 19 9 1

1992

1 9 93

1 99 4

19 9 5

1996

1997

Fig – 69

1 99 8 Y EA RS

1999

2000

103

TIM E S ERIES :P RECIP ITATIO N (M AY) 8.0

7.0

6.0

NO OF DAYS

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 70

1998

1999

2000

2001

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

YEA RS

TIM E S ERIES :DRW (M AY) 16.0

14.0

12.0

NO OF DAYS

10.0

8.0

6.0

4.0

2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 71

1998 YEA RS

1999

104

TIME SERIES :TEMP >40 DEG (MAY) 30.0

25.0

NO OF DAYS

20.0

15.0

10.0

5.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 72

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEARS

TIM E S ERIES :S S W > 30 KT (M AY) 6.0

5.0

NO OF DAYS

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 73

1998 YEARS

1999

2000

105

DIURNAL VARIATION OF MAIN AWH (MAY) (DATABASE: 1991-2005) 4.5 4.1 4.0

3.7

3.5 3.2 3.0

2.

2.6

2.6

2.4

2.5

2.3

2.3

2.2

2.1 1.9

2.0

1.6 1.5

1.3

1.2

1.4

1.3

1.4

1.4

1.1 0.9

1.0 0.6

0.6

0.6

0.5 0.0

0.4 0.4

0.3

0.2 0.3 0.0

0.0

0.1

0.0

0.3

0.3

0.1

0.0

0.0

0.0 00-03

03-06

06-09

09-12

Fig – 74 T'STORM PPTN

12-15

PV<1

15-18

PV<3

SSW>30

18-21

21-24

106 AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : MAY (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1 76.6

0600 P2 74.9

P3

P1

0700 P2

P3

P1

71.6

73.9

79

72.7

71.6

0800 P2 74.9

P3

P1

0900 P2

P3

P1

69.9

73.3

84.4

73.3

77.7

1000 P2

P1

1100 P2

P3

P1

1200 P2

P3

P1

1300 P2

P3

46.7

77.7

75.5

75.5

44.4

74.4

41.2

45.1

41.7

39.9

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

33.4

33.4

P3

66.6

P1 78.7

1400 P2 83.7

66.6

66.6

66.6

66.6

P3

P1

1500 P2

P3

P1

72.3

76.2

82.8

71.6

33.4 66.6

 B&Pd P1 =   B

  X 100 

1600 P2

P3

P1

56.1

86.8

55

52.5

87.2 33.4

16.6 33.4

16.6

16.6 33.4

16.6 33.4

 B&Sd P2 =   B

1700 P2

P3

P1

51.6

55.6

44.6 66.6

  X 100 

66.6

66.6

P3

P1

71 33.4

30.2

78.9

88.1 66.6

33.4

33.4

33.4 66.6

16.6 66.6

1800 P2

1900 P2

P3

P1

2000 P2

P3

P1

67.7

63.6 22

75.1 66.6

42.9 22

54.4 33.4

16.6 33.4

16.6

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 26

22 66.6

2100 P2 31.1 33.4

P3 27 33.4

107

JUNE MONTHLY WEATHER SUMMARY 131. Introduction. The month is the driest and the hottest of the premonsoon months. The visibility remains poor due to FWSP D’Haze/DRW over the region. Broad Synoptic Features 132. Effects of Various Synoptic Situations on Local Weather Due to steep pressure gradient strong wind prevails over Raj and D’Haze / DRW activity is experienced over base and N’hood. Under the influence of WD base reports T’Showers / Dust Storm with light Rain. 133. Behaviour of Important Parameters. The behaviour of important parameters during the month of June is as follows:(a) Pressure. The extended heat Low over NW India shifts further westward and gradually deepens and becomes more marked in this month. The heat low establishes over Central Pak and Baluchistan and a trough runs along Indo – Gangetic plains from this low.

108 (b) Winds. Strong Wly/SWly wind continue to dominate the region for most period of the time. The STJ is not seen over the Indian sub continent. The highest wind speed recorded was 010/90 on 29 Jun 98. (c) Rainfall. The mean monthly Rainfall during the month is 41.0 mm. The highest Rainfall amount ever recorded during the month has been 185.0 mm in 1996. The heaviest Rainfall recorded in 24 hrs for the month is 94.0 mm on 3 Jun 75. (d) Temperature. The mean maximum temperature for the month is 0 35.7 C. The highest maximum temperature ever recorded during the month has been 48.0°C on 4 Jun 91. The mean minimum temperature for the month is 28.1 0C. The lowest ever recorded during the month has been 17.2 0 C on 3 Jun 97. 134. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Jun 1991 and Jun 2000 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean condition of statistical data of aviation weather hazards for Jun follows this summary. It contains the information about the highest and the lowest duration of a particular threehour block in addition to mean duration. (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This indicates that main aviation hazard is poor visibility due to Dust Haze /DRW/Dust Storm for the month. The frequencies of Thunderstorm and precipitation are 5.7 and 6.8 days respectively (Table – 29). 135. Time Series of Rainfall. The time series of Rainfall shows wide fluctuation in the Rainfall number of days of occurrence. However, there is a decrease in the frequency since 1997 (Fig - 77). 136. Time Series of Thunder Storms. The time series of thunder storms shows wide fluctuation in number of days occurrence of thunder storm days. Maximum frequency was observed in the year 1993 (Fig – 73). 137. Time Series of Dust Storms. The time series of dust storms shows wide fluctuation in number of days occurrence of dust storm days. Maximum frequency was observed in the year 2005 (Fig – 76). 138. Time Series of PV <1Km. The time series of PV <1 Km shows wide fluctuation in the incidence of poor visibility <1 km occurrence in last decade (Fig – 74). 139. Time Series of PV <3Km. The time series of PV <3 Km also shows wide fluctuation in the incidence of poor visibility <3 km during the last decade (Fig – 75).

109

140. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written. 141. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table – 17). 142. Simultaneity of Weather In this month low clouds (< 300m) have 25% simultaneous occurrence with primary and secondary diversion during 0700 to 0800 hrs. For Thunderstorm the simultaneity has a percentage of 33 to 50% with primary diversion and 33 to 50% with both together during 0600 h, 1600 – 2100 h, and 0600, 1600h, and 1800 – 1900 h respectively. For precipitation there is 50% of occurrence at primary and secondary diversion at 0600 h only (Table 30).

110 143. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds are generally SWly to Wly flow prevails with wind speeds of about 10 – 20 kt (Table – 27, Table – 28). AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: JUNE TIME : 0000 UTC deg C

N

of observations

1000'

330

2000'

349

3000'

27

353

5000'

24

322

7000'

20

346

10,000'

14

376

% frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed

DATA SET 1991-2005 (FOR TEMP 2001-2005) NE E SE S SW

W

NW

360

045

090

135

180

225

270

315

I 3.3% 3.4 2.3% 12.8 3.4% 8.0 4.3% 11.1 8.4% 10.3 16.2% 11.0

II 3.3% 4.7 2.3% 6.4 1.7% 7.8 3.1% 10.0 4.6% 10.8 11.2% 11.8

III 1.5% 9.4 3.4% 10.8 4.8% 10.3 7.1% 11.5 10.1% 9.9 17.6% 11.7

IV 1.5% 4.2 1.1% 9.5 0.3% 11.0 3.1% 9.8 4.3% 11.5 4.8% 10.0

V 3.3% 7.4 4.0% 12.3 5.1% 10.9 9.6% 11.3 14.5% 11.0 9.0% 9.3

VI 58.5% 8.4 29.8% 17.1 28.9% 21.6 19.9% 18.7 22.3% 14.8 6.4% 15.3

VII 25.2% 9.0 52.1% 15.8 52.7% 17.0 46.3% 15.9 28.0% 13.9 25.8% 14.7

VIII 3.3% 5.9 4.9% 7.9 3.1% 7.2 6.5% 11.1 7.8% 10.2 9.0% 11.4

Table – 27

MEANS OF UPPER WIND AND TEMPERATURE: JUNE TIME : 1200 UTC deg C

N

of observations

1000'

323

2000'

353

3000'

32

346

5000'

27

318

7000'

22

346

10,000'

15

317

% frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed

DATA SET 1991-2005 (FOR TEMP 2001-2005) NE E SE S SW

W

NW

360

045

090

135

180

225

270

315

I 6.2% 6.0 4.5% 10.2 4.3% 9.2 5.0% 9.4 8.1% 9.9 15.1% 9.3

II 2.8% 4.3 3.4% 10.5 4.3% 10.5 5.0% 11.1 4.0% 9.0 12.0% 10.3

III 1.9% 8.7 2.5% 10.3 4.9% 9.4 4.4% 9.0 6.6% 11.6 10.1% 11.8

IV 1.9% 6.3 3.1% 9.0 2.0% 10.1 2.2% 7.6 2.6% 9.1 5.4% 7.9

V 3.4% 7.7 4.5% 9.1 4.3% 9.5 5.7% 9.1 7.2% 8.7 6.6% 11.2

VI 53.9% 8.0 36.3% 14.3 36.7% 16.0 34.9% 15.3 25.1% 12.4 8.5% 11.4

VII 26.9% 7.1 43.6% 12.8 39.6% 11.9 38.4% 12.0 38.7% 12.3 26.8% 12.8

VIII 3.1% 5.2 2.0% 10.7 3.8% 6.8 4.4% 11.0 7.5% 8.7 15.5% 10.4

Table –28 144. Weather over Local flying area. Due to steep pressure gradient during strong wind prevails over Raj during the month and results in D’Haze / DRW activity over base and N’hood. Under the influence of WD light Rain is also experienced.

111 145. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone through out the day (Fig – 71).

88 Fig –75 SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (JUN) MEAN FREQ

VIS < 3 KM VIS < 1 KM CEILING (CL) CL < 300 M CL < 150 M THUNDER STORM DUST STORM HAIL STORM PPTN FOG SUR WIND >30 KTS DRW TEMP > 40O C

8.7 4.1

INDEX

ELEMENT

1.3 0.3 5.7 3.0 0.0 6.8 0.0 3.3 6.3 15.5

HIGHEST FREQ

YEAR(s)

LOWEST FREQ

YEAR(s)

18 10

1992 2005

1 0

8 3 11 8 0 11

1996 1996 1993 2005

9 18 24

86

84

82

1997 1997

PEAK PERIOD (IST) 18-21 18-21

4.5 2.6

0 0 2 0

1992-95,00,01,04 1991-95,97,99-05 1991,99,00 1997

06-09 03-06 18-21 18-21

1.3 0.8 2.7 1.9

1997

3

1991,92,99,00

15-21

2005 2003 2002

0 1 5

1994,96, 1996 2001

00-06 18-21 15-18

Table –29

SD

UNC 2.9

2.6 4.9 6.2

112

200 180 Fig – 76

113

TIM E S ERIES : THUNDER S TORM (JUN) 12.0 11.0

10.0 9.0 8.0

8.0

8.0

NO OF DAYS

7.0

7.0

7.0 6.0

6.0

6.0

4.0 4.0 3.0

3.0

2.0

2.0

2.0

1999

2000

2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –77

1998

2001

2002

2003

2004

2005

20 01

20 02

200 3

2 00 4

2 005

YEA RS

T IM E S ER IES : V IS IBIL IT Y < 1 K M (JU N) 1 2.0

1 0.0

NO OF DAYS

8.0

6.0

4.0

2.0

0.0 1 99 1

1 99 2

1 993

19 94

19 95

19 96

199 7

Fig –78

1 99 8 YEA RS

1 999

20 00

114

T IM E S ERIES : V IS IBIL ITY < 3 KM (JUN) 20.0

18.0

16.0

14.0

NO OF DAYS

12.0

10.0

8.0

6.0

4.0

2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –79

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

T IM E S ER IES : D 'S T O RM (JU N ) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –80

199 8 YEA RS

1999

2000

115

TIM E S ERIES :P RECIP ITATIO N (JUN) 12.0

10.0

NO OF DAYS

8.0

6.0

4.0

2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –81

1998

1999

2000

2001

2002

2003

2004

2005

2 0 00

2 00 1

2 00 2

2 00 3

20 0 4

20 0 5

YEA RS

T IM E S ER IES :DR W (JU N ) 20 .0

18 .0

16 .0

14 .0

NO OF DAYS

12 .0

10 .0

8 .0

6 .0

4 .0

2 .0

0 .0 1 9 91

1 9 92

1 99 3

1 99 4

1 99 5

199 6

19 9 7

Fig –82

19 9 8 Y EA RS

19 99

116

TIM E S ERIES :TEM P > 40 DEG (JUN) 30.0

25.0

NO OF DAYS

20.0

15.0

10.0

5.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –83

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEARS

TIM E S ERIES :S S W > 30 KT (JUN) 10.0

9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 84

1998 YEA RS

1999

2000

117

TIM E S ER IES : L O W CL O UD < 300M (JU N) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 85

1998

1999

2000

2001

2002

2003

2004

2005

2002

2003

2004

2005

YEA RS

T I M E S E R I E S : L O W C L O U D < 1 5 0 M (J U N ) 3 .5

3 .0

2 .5

NO OF DAYS

2 .0

1 .5

1 .0

0 .5

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig – 86

1998 Y EA RS

1999

2000

2001

118

DIURNAL VARIATION OF MAIN AWH (MAY) (DATABASE: 1991-2005) 6.0

5.0

5.0

4.0 3.3

3.3 3.0

3.0 2.5

2.6

2.5

2.6

2.6 2.0

2.0

3.

3.2

1.8

1.8

1.6

1.5

1.4

1.3

1.4

1.2

1.3

1.0 0.4

0.4

0.6 0.4

0.5 0.2

0.4

0.3 0.1

0.0

0.0

0.9

0.7

0.6

0.3 0.0

0.3

0.0

0.0 00-03

03-06

06-09

09-12 T'STORM PPTN PV <1

12-15 PV <3

SSW>30

15-18

18-21

21-24

119 Fig – 87

120

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : JUNE (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

0600 P2

P3

P1 53.3

16.6

36.7

16.6

22 40

46.2

P1

1400 P2

P1 36.7

0700 P2

P3

P1 91.2

0800 P2

P3

P1 94.4

16.6

23.4

16.6

22

40

35.7

P3

P1

1500 P2

33.4

40

33.4

33.4

69.9

69.9

P3

P1 73.7

1600 P2 79.2

66.6

69.9

73.4

 B&Pd P1 =   B

69.9

33.4

  X 100 

0900 P2 94.4

P3 94.4

P1

1000 P2

66.6 68.9

66.6

66.6

66.6

66.6

46.2

71

46.2

33.4

36.7

33.4

P3 72.9

P1 48.7

1700 P2 45.1

P3 38.1

P1 72.7

1800 P2 78.3

P3 72.7

33.4

46.7 22

66.6 16.6 28.7

11.4

33.4 50

16.6 40

16.6

 B&Sd  P2 =   X 100  B 

1100 P2

P3

P1

1200 P2

P3

P1

1300 P2

P3

33.4

23.3

16.6

33.4

36.7

33.4

33.4

40

33.4

P1 60.3

1900 P2 75

P3 50.9

2000 P2 56.9

P3 45.9

P1 78.2

2100 P2 78.3

P3 71.5

66.6

66.6

33.4

P1 56.2 66.6 66.6

33.4

33.4

66.6

66.6

66.6

24.3 66.6

13.6 27.5

22

26.7 33.4

15.6 43.3

13.3 26.7

33.4 30.1

16.6 43.3

30.1

P1

66.6

66.6

36.7

P3

44.6 56.6

31.4 16.7

16.7

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 30

121

122 MONSOON SEASON (JUL-SEP) Introduction 146. The period from mid Jun to Sep constitutes Monsoon Season. The onset of monsoon takes place usually by end of first week of July over the region. During this season, a Heat Low develops over Central Pakistan region. Steep pressure gradient is generally seen over Raj region. Most of the annual Rainfall occurs during this season. The base experiences the maximum SW monsoon activity in July and August. During the period, Rain/Thunder showers and low clouds are generally experienced by the airfield.

Surface Pressure Pattern 147. The seasonal Heat Low establishes over Baluchistan & adjoining West Raj/Gujarat. Axis of Monsoon trough (AMT) extends from the centre of Heat Low to Head Bay through Gangetic Plains. Its position fluctuates North-South on day to day basis. Normal position of AMT is from Ganganagar (Raj) to Kolkata (WB), which is well North of Jodhpur. The pressure gradient becomes steep over North Raj and Gujarat under following conditions:(a) Western end of the AMT shifts to foothills under influence of a Westerly System. (b) Break Monsoon conditions. (c) Close proximity of Monsoon Low/Depression.

Wind Pattern 148. Surface Wind. Surface wind is mainly SW’ly 06-15 Kt. It undergoes changes due to oscillation of AMT. Whenever AMT passes close to JDP, surface wind direction changes to S'ly to SSE'ly. When AMT shift south of JDP, surface wind further changes to SE’ly to E’ly. During Break Monsoon conditions, surface winds are of the order of 15 to 20 Kt from SW’ly direction. 149. Upper Wind. The lower tropospheric upper wind pattern is identical to the surface pressure pattern. Strong W’lys prevail in the lower tropospheric levels. Above 3.0 Km, the region comes under the sway of anticyclone centred over South Pak and adj. West Raj, resulting in NE/E’ly flow. During this season, STJ withdraws from the region.

Surface Temperature and Humidity 150. The average Maximum & Minimum temperatures vary between 34 o C & 27 o C respectively. Pentad normal indicates that Minimum is lowest (23.3o C) in

123 the last week of September and highest (27.4o C) in the first week of July. The Maximum temperature is lowest (33.6o C) in first and third week of Aug and highest (37.4o C) in the first week of July. 151. Relative Humidity is highest in this season. In morning hours the RH is above 71 % with highest being in Aug (79%) and in the evening hours it is above 52% with highest being in August (58%). 152. The discomfort graphs of this season indicates that in the month of Jul, Aug & Sep, the period between 1000 hrs & 1800 hrs falls in the zone of “uncomfortable” due to the combination of high humidity and high temperatures.

Synoptic Features and Associated Weather 153. Monsoon Low/Depression. On an average about 2-3 lows /depressions form over Head /Northwest Bay of Bengal during each month of Monsoon Season. A few of them even reach upto the intensity of Deep Depression. Formation of Monsoon Low/Depression over Northwest Bay and their Northwest Movement inland along Axis of Monsoon trough (AMT) is most significant feature of this season. Most of these systems weaken and fill up by the time they reach West MP. At times they maintain their intensity while moving in W/NW'ly direction or even intensify over East/West Raj. Under such situations JDP and adj area do experience FWDSPR / heavy PPTN. It takes about 2.5 to 3 days for a Monsoon Low to affect the base in terms of active weather after it crosses GWB/Orissa coast. Mid- Latitude Systems and their Interaction with Monsoon Systems 154. During SW Monsoon, mid latitude W’ly systems exercise considerable influence on the weather activity over Raj and adj states. Their effects are as follows: (a) Intensifying or developing lower tropospheric cyclonic circulation/troughs. (b) Enhancing Rainfall in pre existing systems. (c) Causing recurvature of depressions and lows. (d) Leading to onset of break Monsoon conditions. Middle Latitude systems affect the Monsoon activities over Raj mainly by interacting with the Monsoon systems over East Raj and adj West MP. Such situations result in heavy Rainfall over Jodhpur and adj areas. Axis of Monsoon Trough (AMT) 155. The axis of Monsoon trough runs at sea level from Ganganagar to Kolkotta passing through Allahabad with W'ly to SW'ly winds to the South and E’lies to the

124 North of the trough line. AMT oscillates on day to day basis and has a vital bearing on the Monsoon Rainfall. No other semi-permanent feature has such a control on the Monsoon activity. AMT close to Jodhpur in the absence of any other significant system controls the weather over Jodhpur and neighbourhood. AMT within 2 to 3 degree North/South of Jodhpur causes Rain/Thunder Shower over the region. During break Monsoon conditions when AMT lies close to foothills of Himalayas, strong SW'ly wind profile on surface/lower levels dominates over West Raj. Under such situations possibility of Dust Haze and DRW can not be ruled out. Onset and withdrawal of SW Monsoon 156. Onset of Monsoon. Although there is no fix date for the onset but generally SW Monsoon sets in over Jodhpur by the end of first week of July. At times Tropical Cyclonic Storm over North Arabian Sea in the month of Jun pulls up the monsoon current up to the West Raj thereby leading to an early onset of Monsoon over Jodhpur. Tropical Cyclones of Jun 1998 and Jun 1996 are two recent examples for causing early onset over Jodhpur. 157. Withdrawal of SW Monsoon. SW Monsoon normally withdraws from West Raj by 10 Sep. Quite often if there is break in Monsoon towards last week of August, the revival does not take place at all. Weather Pattern & Aviation Weather Hazards 158. West Raj receives principal amount of its annual Rainfall (75 to 80%) during SW Monsoon season. There is considerable variation of Monsoon activity and Rainfall from year to year. It is well known that the largest variation in the country is over West Raj. The coefficient of variation of Rainfall is more than 80%. July & August are the two Rainiest months, each accounting individually to about 30% of the annual Rainfall. However, there are high frequencies of drought & equally high frequencies of excessive Rainfall (floods). It would be worth highlighting the topic of drought and excessive Rainfall over West Raj. 159. Drought. Meteorologically, Drought is defined as a situation when annual Rainfall over the area or place is less than 75% of the normal. It is further classified as moderate Drought if Rainfall deficit is between 25 to 50% and severe Drought if it is more than 50%. Drought conditions as they prevailed over Jodhpur during the 33 yrs period from 1968 to 2000 are described below . (a) Jodhpur became victim of Drought on 13 years during last 33 yrs. These thirteen years with the annual amount of Rainfall within the bracket are - 1968 (153.4mm), 1969(145.4), 1971 (295.9mm), 1974 (296.0mm), 1980(246.6), 1981(260.9), 1984 (296.3mm), 1985 (212.6mm), 1986 (276.8mm), 1987(135.1), 1991 (231.9mm), 1999 (318.2mm) & 2000 (275mm). (b) The severest Drought occurred in 1987 when Jodhpur’s annual Rainfall was only 135.1mm against the normal of 432.6mm. During this year the Monsoon Rainfall was 44.7mm against the normal of 335.5mm.

125

(c) Out of 13 Drought years, 04 years are classified as severe Drought and 09 moderate Drought years. 160. Excessive Rainfall. It may generally be said that Rainfall, sufficiently in excess of the normal, is a pre dominant factor for occurrence of floods. For the present description annual Rainfall of 125% or more above the normal is considered as excessive Rain. The following highlights about this phenomenon over Jodhpur: (a) In last 33 years i.e. from 1968 to 2000, only one year had excessive Rainfall. In year 1975, Jodhpur recorded 169.5% above the normal Rainfall. The actual Rainfall recorded was 1165.5 mm against the normal of 432.5mm. In the Monsoon season( Jun – Sep ), 924.3 mm was recorded against the normal of 335.5 mm. (b) In 1990, Jodhpur recorded Rainfall close to “excessive Rain”. 121.6% above the normal Rainfall was recorded in this year. The annual Rainfall was 958.3 mm against the normal of 432.5 mm and Monsoon Rainfall recorded was 892.5 mm against the normal of 335.5 mm. Aviation Weather Hazards 161.

The main aviation weather hazards during this season are given below:(a) Low Clouds. The presence of low clouds at 300 m or less can be a serious limitation for air operations. The frequency of low clouds with base 300 m or less during July, Aug and Sep is 7.1,4.9 & 1.8 respectively. The preferred period of occurrence is half an hour after sunrise and they last for generally 2 to 3 hours. The base of low clouds initially may be as low as 200 m but it gradually lifts up as the day progresses. The movement is generally SW/S to NE/N wards and amount varies from 2 to 6 octas (Fig – 84). (b) Rain/Thunder Showers. The Rainfall activity over Jodhpur is controlled by the oscillation of western end of axis of Monsoon trough and its close proximity to Jodhpur. On an average, there are 5.5 days of thunderstorms with preferred timings between 1800 & 2100. Thunderstorms, at times are associated with gale having wind speed of 50 to 60 Kt, occurring during evening hours. Visibility normally reduces to 1-3 Kms in Rain. Low clouds in the morning hours between 0600 & 1000 hrs followed by passing spells of showers around Noon and latter a spell of T’ Showers in the evening is the general trend (Fig – 84). (c) Heavy Precipitation. Jodhpur experiences spells of moderate to heavy precipitation in the month of July & August. In one day (24 hrs) the airfield has recorded Rainfall as high as 172.2 mm. These spells are generally experienced during the following synoptic situations: (i) Monsoon system lying over West MP and adj East Raj as a Low or as a Depression/Deep Depression over Central MP (800 East to 85 0 East Longitude) and adj region.

126

(ii)

Intensification of weak Monsoon Low over West Raj, under the influence of a WD/ Deep Upper Tropospheric trough

162. The South West Monsoon model for Jodhpur is reflected in a tabular form. 163. Good, P'Good and Bad Weather State. The Mean, highest and lowest frequencies have been tabulated month wise using the data from Jan 01 to Dec 2005 (Table – 31).

127

STATISTICS OF GOOD, MARGINAL & BAD WEATHER STATE MONSOON SEASON DATA SET: 2001 – 05 FIGHTERS / TRAINERS DAY NIGHT 0601-1200 1201-1800 1801-2400 0001-0600

0601-1200

1201-1800

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

Highest

28

6

10

31

6

8

29

4

6

30

5

2

30

4

6

31

4

3

31

3

2

29

7

2

Mean

22

4

5

26

2

3

26

2

3

28

2

1

26

2

3

28

2

1

29

1

1

28

3

0

Lowest

17

3

0

18

0

0

23

1

1

25

1

0

21

1

0

24

0

0

26

0

0

24

2

0

Highest

30

7

7

30

4

4

31

3

4

31

2

1

30

3

6

31

4

3

31

3

1

31

1

1

Mean

26

3

2

27

2

2

27

2

2

29

1

1

27

2

2

28

2

1

28

2

1

30

0

1

Lowest

18

1

0

23

0

1

26

0

0

28

0

0

23

1

0

26

0

0

27

0

0

29

0

0

Highest

30

2

0

30

1

6

29

5

4

30

1

0

30

0

0

30

3

1

29

4

1

30

1

0

Mean

29

1

0

28

0

2

26

2

2

30

0

0

30

0

0

29

1

0

26

3

1

30

0

0

Lowest

28

0

0

23

0

0

23

0

0

29

0

0

30

0

0

26

0

0

25

1

0

29

0

0

MONTH

JUL

AUG

SEP

G: GOOD

M: MARGINAL

B: BAD

Table –31

TRANSPORTS DAY

NIGHT 1801-2400 0001-0600

128

1000 950 900

Fig – 88

129

AF STATION JODHPUR MAIN AVIATION WX HAZARDS MONSOON SEASON (1991 - 2005)

16.0

14.8

MEAN FREQUENCY (NO. OF DAYS)

14.0 11.7

12.0

10.0 8.7 8.0 6.8 6.0

7.8

7.3

6.3

6.3

5.9

5.7

5.1 4.1

4.0

4.1

3.0

2.4 2.0

0.0

3.7

3.3

1.3 0.0

0.0

JUN

0.0

0.0 0.0

JUL

D'STORM

HAIL

1.4

1.2

0.8 0.0

T'STORM

2.4

1.9

PPTN

Fig – 89

LC<300M

0.0

0.4

0.1 0.0

AUG

FOG

PV<1KM

0.0 SEP

PV<3KM

SSW>30KT

0.5

0.7

130

131 JULY MONTHLY WEATHER SUMMARY 164. Introduction. The pre-monsoon activity with D,storm and D’Haze continues to prevail over the airfield till SW monsoon sets over the base. The SW monsoon over JDP sets in by middle of the month. There is a marked improvement in the visibility conditions. Clouding and Rainfall are mostly in association of convective activity. Broad Synoptic Features 165. Effects of Various Synoptic Situations on Local Weather During first fortnight generally cloudy to MOC skies with ISOL to SCT Rain / T’ Showers / Dust Storm activities in the afternoon / night. Due to steep pressure gradient strong surface wind prevails over Raj and SCT to WDSP Dust Haze / DRW activity is experienced over base and N’hood. During second fortnight generally weather over base and N’hood remains P’cloudy to cloudy. However, with the southward shift of AMT and UACC over South Raj, ISOL – SCT Rainfall activity occurs over the region. Cloudy / MOC skies are reported throughout the period. 167. Behaviour of Important Parameters. The behaviour of important parameters during the month of June is as follows:(a) Pressure. The heat low over Central Pakistan, Baluchistan and S Afghanistan remains intense throughout the month. It frequently oscillates northwards and southwards. The AMT gets firmly established over IndoGangetic plains. The pressure gradient is generally steep. (b) Winds. Strong Wly/SWly wind continue to dominate the region for most period of the time. The highest wind speed recorded was 090/60 on 18 Jul 99. (c) Rainfall. The mean monthly Rainfall during the month is 150.4 mm. The highest Rainfall amount ever recorded during the month has been 570.9 mm in 1990. The heaviest Rainfall recorded in 24 hrs for the month is 172.2 mm on 3 Jul 90. (d) Temperature. The mean maximum temperature for the month is 35.7 0C. The highest maximum temperature ever recorded during the month has been 42.8°C on 3 Jul 68. The mean minimum temperature for the month is 26.7 0C. The lowest ever recorded during the month has been 20.0 0 C on 29 Jul 86. 168. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Jul 1991 and Jul 2005 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Jul follows this summary. It

132 contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration. (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that precipitation with or without Thunderstorm are main aviation weather hazards. These are generally associated with low clouds and reduce the visibility simultaneously (Table – 34). 169. Time Series of Rainfall. The time series of Rainfall shows wide fluctuation in the Rainfall number of days of occurrence. Maximum frequency is seen in the year 2001 (Fig - 91). 170. Time Series of Thunder Storms. The time series of thunder storms shows wide fluctuation in number of days of occurrence of thunder storms (Fig – 87). 171. Time Series of PV <1Km. The time series of PV <1 Km shows a decrease in the incidence of poor visibility <1 km occurrence in last decade. Maximum frequency was seen in the year 2003 (Fig - 88). 172. Time Series of PV <3Km. The time series of PV <3 Km shows wide fluctuation in the incidence of poor visibility <3 km during the last decade. Maximum frequency is observed in the year 2003 (Fig – 89). 173. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hrly) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 97). 174. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table -31). 175. Simultaneity of Weather In Jul low clouds (< 300m) have 50% simultaneous occurrence with secondary diversion and 30% with primary during 0600 to 0900 hrs. For Thunderstorm the simultaneity has a percentage of 60% with primary diversion during 1500 – 1600 h respectively. For precipitation there is 20% of occurrence at primary between 1400 – 1600 h and at secondary diversion 40% throughout the day (Table - 35). 176. Weather over Local flying area. Generally cloudy to MOC skies with ISOL to SCT Rain / T’ Showers / Dust Storm activities in the afternoon / night is observed. Due to steep pressure gradient strong surface wind prevails over Raj and SCT to WDSPR Dust Haze / DWR activity is experienced over base and N’hood However, with the southward shift of AMT and UACC over South Raj, ISOL – SCT Rainfall activity occurs over the region. Cloudy / MOC skies are reported throughout the period. 177. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds are generally

133 SWly to Wly with wind speeds of about 10 – 20 kt throughout the day (table – 32, Table – 33).

AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: JULY TIME : 0000 UTC deg C

N

No of obser-

360

vations

1000'

318

2000'

375

3000'

24

360

5000'

21

354

7000'

18

324

10,000'

14

305

DATA SET 1991-2005 (FOR TEMP 2001-2005) NE E SE S SW

% frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed

045

090

135

180

225

W

NW

270

315

I

II

III

IV

V

VI

VII

VIII

1.3% 4.8 1.1% 6.0 2.5% 8.7 3.7% 10.5 11.1% 8.6 14.4% 9.7

3.1% 6.6 1.9% 8.1 1.7% 9.5 3.7% 7.0 8.6% 10.8 21.0% 12.1

1.3% 3.5 1.1% 10.5 2.2% 8.9 4.2% 9.0 15.1% 9.2 20.0% 10.6

0.3% 6.0 1.9% 7.1 1.4% 7.4 3.4% 7.8 9.3% 8.1 9.8% 9.5

6.0% 8.8 4.0% 13.6 5.0% 10.3 10.2% 11.4 13.3% 10.7 10.2% 8.7

68.6% 7.8 46.1% 19.3 42.2% 22.0 37.3% 20.2 17.0% 15.2 3.9% 12.6

17.3% 8.5 41.6% 15.8 43.1% 17.3 31.6% 15.8 18.8% 11.8 8.9% 11.0

2.2% 7.3 2.4% 8.8 1.9% 11.4 5.9% 10.7 6.8% 10.3 11.8% 10.3

Table –32 MEANS OF UPPER WIND AND TEMPERATURE: JULY TIME : 1200 UTC deg C

N

No of obser-

360

vations

1000'

344

2000' 3000' 5000' 7000' 10,000'

376 29 24 20 15

384 370 359 261

DATA SET 1991-2005 (FOR TEMP 2001-2005) NE E SE S SW

% frequency

045

090

135

180

225

W

NW

270

315

I

II

III

IV

V

VI

VII

VIII

3.2%

2.6%

2.3%

2.6%

5.8%

66.9%

14.5%

2.0%

mean speed

5.5

6.4

3.1

6.2

6.7

7.1

7.2

4.7

% frequency

4.5%

1.9%

2.7%

2.4%

9.3%

58.2%

19.7%

1.3%

mean speed

8.5

8.7

9.4

6.9

9.7

14.1

19.0

7.2

% frequency

2.9%

3.4%

3.9%

2.3%

9.4%

54.9%

19.8%

3.4%

mean speed

8.0

9.2

10.1

6.3

9.9

14.6

10.3

7.1

% frequency

3.8%

3.8%

6.2%

1.4%

9.7%

45.9%

21.4%

7.8%

mean speed

10.2

12.7

11.7

9.6

12.8

14.0

11.9

9.0

% frequency

10.0%

11.1%

10.3%

3.6%

14.5%

20.3%

22.6%

7.5%

mean speed

10.0

11.3

10.8

9.1

9.6

12.1

10.3

9.9

% frequency

19.2%

21.1%

11.1%

6.9%

8.0%

5.7%

16.1%

11.9%

mean speed

11.3

11.6

12.0

10.9

9.0

14.1

10.6

10.6

Table –33

134 178. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone through out the day except between 0500 – 0800 h when it remains in partly comfortable zone (Fig – 85).

86 Fig –90 SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (JUL) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

(a) VIS < 3 KM

6.3

VIS < 1 KM

2.4

84

YEAR(s)

LOWEST

YEAR(s)

FREQ

PEAK

SD

PERIOD (IST)

(b)

(c)

(d)

(e)

(f)

(g)

14

2003

0

1998

18-21

3.8

6

2003

0

1998,02

18-21

1.7

CEILING (CL)

UNC

CL < 300 M

7.8

19

1994

0

2005

06-09

5.4

CL < 150 M

1.2

5

1993

0

1991,96-98,01,02,04,05

09-12

1.7

THUNDER STORM

7.3

13

2003

0

2002

18-21

3.3

DUST STORM

0.8

3

2000

0

1992,94,96-98,01,02

15-18

0.9

HAIL STORM

0.0

PPTN

14.8

23

2001

3

2002

18-21

5.8

FOG

0.0 5

82

2005

0

1993,94,97,98,01,02

12-15

1.9

7

2004

0

1992,95,96,98,01

21-24

2.2

7

1991

0

1993,94,96,01,02,05

15-18

1.9

SUR WIND >30 KTS

1.9

DRW

2.2 O

INDEX

TEMP > 40 C

1.5

Table –34

135

600

550 Fig –91

136

TIM E S ERIES : THUNDER S TO RM (JUL) 14.0 13.0

13.0

12.0 11.0

10.0 9.0

9.0

NO OF DAYS

8.0 8.0 7.0

7.0 6.0

6.0

6.0

6.0 5.0

5.0 4.0

4.0

2.0

0.0 0.0 1991

1992

1993

1994

1995

1996

1997

Fig –92

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

TIM E S ERIES : V IS IBILIT Y < 1 KM (JUL) 7.0

6.0

NO OF DAYS

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –93

1998 YEARS

1999

2000

137

T IM E S ERIES : V IS IB IL ITY < 3 KM (JUL ) 1 6 .0

1 4 .0

1 2 .0

NO OF DAYS

1 0 .0

8 .0

6 .0

4 .0

2 .0

0 .0 1991

19 9 2

1 99 3

1 9 94

1 9 95

1996

1997

Fig –94

1998

1999

20 0 0

2 0 01

2002

2003

2004

2005

2001

2002

2003

2004

2005

Y EA RS

TIM E S ERIES : D'S T O RM (JUL ) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –95

1998 YEA RS

1999

2000

138

TIM E S ERIES :P RECIP ITATION (JUL) 25.0

20.0

NO OF DAYS

15.0

10.0

5.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 96

1998

1999

2000

2001

2002

2003

2004

2005

2000

2001

2002

2003

2004

2005

YEA RS

TIM E S ERIES :DRW (JUL) 8.0

7.0

6.0

NO OF DAYS

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 97

1998 YEA RS

1999

139

T IM E S ERIES :T EM P > 40 DEG (JUL ) 8.0

7.0

6.0

NO OF DAYS

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 98

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

T IM E S ER IES :S S W > 30 KT (JUL ) 6.0

5.0

NO OF DAYS

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 99

1998 YEA RS

1999

2000

140

T IM E S ERIES : L O W CLO UD < 300M (JUL) 20.0

18.0 16.0

14.0

NO OF DAYS

12.0

10.0

8.0 6.0

4.0 2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 100

1998

1999

2000

2001

2002

2003

2004

2005

2002

2003

2004

2005

YEA RS

T IM E S E R IES : L O W C L O U D < 1 5 0 M (J U L ) 6 .0

5 .0

NO OF DAYS

4 .0

3 .0

2 .0

1 .0

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig – 101

1998 Y EA RS

1999

2000

2001

141

DIURNAL VARIATION OF MAIN AWH (JUL) (DATABASE: 1991-2005) 8.0

6.9

7.0

6.5 6.2

6.0 5.4 5.0

5.3

4.7 4.1

4.1

4.0

4.0 3.2 3.0

2.7 2.4

2.2

2.0 1.3

1.2

1.4

1.3

1.3 1.0

1.0

0.7 0.4 0.0

0.4 0.1

0.0

0.4 0.0

0.2

0.3

0.5

0.5 0.2

0.0

0.6

0.6

0.9 0.4

0.3

0.3

0.0 00-03

03-06

06-09

09-12

Fig - 102

T'STORM

PPTN

12-15 PV<1

PV <3

15-18 SSW>30

18-21

21-24

0.5

142

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : JULY (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1

0600 P2

P3

P1

0700 P2

P3

P1

51.3 70.9

49.4

23.9

25.9

28.6

16.6

59.4

16.6

50.8

40.2

P1

18.9

1400 P2

36.7

 B&Pd P1 =   B

P3

P1

1500 P2

P3

P1

16.6

66.6 30.0

32.9

28.6

11.4

  X 100 

0800 P2

P3

46.9

P1

0900 P2

P3

P1

20.9

31.5

15.8

37.3

45.4 1600 P2

27.4

P3

18.6

P3

P1

P1

1700 P2

P3

P1

17.9

37.7

17.9

27.0 10.0

  X 100 

1800 P2

27.0 23.2

1100 P2

34.0

P3

P1 66.6 66.6

1200 P2

P3

P1

1300 P2

P3

27.0 8.3

42.3 15.3

13.9

26.4

12.5

14.4

25.7

12.3

2000 P2

P3

P1

2100 P2

P3

17.0

18.3 35.0

11.4

1900 P2

P3

P1

18.8

18.8

21.1

 B&Pd &Sd  P3 =   X100 B  

B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Secondary Diversion (Sd) -Uttarlai

Table –35

P1

68.0

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR.

Primary Diversion (Pd) - Jaisalmer

P3

17.5

29.3

11.4

 B&Sd P2 =   B

1000 P2

28.9

143

AUGUST MONTHLY WEATHER SUMMARY

144

179. Introduction. SW monsoon current continues to cause weather over the base. Though the Rainy days are less in this month, the sky on most of the days remains P’cloudy / cloudy. During break / weak monsoon conditions, P’cloudy weather prevails over the base. During prolonged break monsoon conditions, D’Haze / DRW may be experienced over the area. Broad Synoptic Features 180. Effects of Various Synoptic Situations on Local Weather. Weather remains Mainly Overcast to Cloudy. SCT Rain and Low Clouds in the morning / evening hrs and ISOL Thunderstorm activities in the night occur on few days. Rain / T’Shower occurs on most of the days due to low pressure area over Raj and AMT close to base. Rain fall activity continues upto end of the month 181. Behaviour of Important Parameters. The behaviour of important parameters during the month of August is as follows:(a) Pressure. There is no appreciable change in the pressure pattern. The seasonal heat low continues to emain over Central Pak and Baluchistan. The LOPAR in the month also swings north and southwards. (b) Winds. The surface wind depends on the position of the AMT. If it is north of the base then surface wind is SW’ly and if it is to south of base then winds are E’ly / SE’ly. The maximum surface wind ever recorded is 040/50 on 28 Aug 75. (c) Rainfall. The mean monthly Rainfall during the month is 122.8 mm. The highest Rainfall amount ever recorded during the month has been 424.1 mm in 1973. The heaviest Rainfall recorded in 24 hrs for the month is 110.8 mm on 7 Aug 79. (d) Temperature. The mean maximum temperature for the month is 34.0 0C. The highest maximum temperature ever recorded during the month has been 41.6°C on 25 Aug 72. The mean minimum temperature for the month is 25.5 0C. The lowest ever recorded during the month has been 19.90 C on 25 Aug 72. 182. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Aug 1991 and Aug 2005 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Aug follows this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration. (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that

145 precipitation with or without Thunderstorm are main aviation weather hazards (Table – 38). 183. Time Series of Rainfall. The time series of Rainfall shows wide fluctuation in the Rainfall number of days of occurrence but generally a declination is seen after 1994. (Fig - 102) 184. Time Series of Thunder Storms. The time series of thunder storms shows a decreased number of days occurrence of thunder storms from 1996, however, maximum occurrence is seen in the year 2004 (Fig – 99). 185. Time Series of PV <1Km. The time series of PV <1 Km shows a decrease in the incidence of poor visibility <1 km occurrence in last decade (Fig – 100). 186. Time Series of PV <3Km. The time series of PV <3 Km shows a wide fluctuation in the incidence of poor visibility <3 km during the last decade (Fig – 101). 187. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - 108). 188. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table - 31). 189. Simultaneity of Weather In Apr low clouds (< 300m) have 30 – 50% simultaneous occurrence with primary and secondary diversion during 0600 – 1400 h. For Thunderstorm the simultaneity has a percentage of 33 to 50% with both together during 0600 – 0700 h. For precipitation there is 30 – 50% of occurrence at primary and at secondary diversion 50 – 60% throughout the day (Table 40). 190. Weather over Local flying area. During first week weather remains MOC to Cloudy. SCT Rain and low clouds in the morning / evening hrs and ISOL thunderstorm activity in the night is observed on few days. Rain / T’Shower occurs on most of the days due to low pressure area over Raj and AMT close to base. Cloudy to MOC skies reported throughout the later part of the month. Low clouds in early morning hours are a general phenomenon throughout the period.

146 191. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds up to 5000’ are generally SWlies of about 10 – 20 kt whereas between 5000 to 10000’ generally Nly to NEly flow prevails with wind speeds of about 10 kt (table – 36, Table – 37). AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: AUGUST TIME : 0000 UTC deg C

N

No of obser-

360

vations

1000'

319

2000'

393

3000'

23

362

5000'

21

381

7000'

18

359

10,000'

13

334

DATA SET 1991-2005 (FOR TEMP 2001-2005) NE E SE S SW

% frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed % frequency mean speed

045

090

135

180

225

W

NW

270

315

I

II

III

IV

V

VI

VII

VIII

1.9% 5.5 1.3% 4.2 3.6% 7.8 8.7% 9.9 14.8% 10.8 17.4% 10.9

2.2% 4.9 2.0% 7.8 2.8% 9.8 5.8% 9.2 12.5% 12.3 25.4% 11.1

1.6% 7.4 3.3% 11.2 3.3% 10.3 5.2% 9.2 14.5% 9.4 20.1% 10.6

0.3% 11.0 0.5% 11.0 1.4% 10.0 1.6% 6.7 8.9% 7.4 7.2% 8.8

1.3% 8.8 1.8% 6.4 0.8% 7.7 10.5% 9.0 16.7% 9.0 5.4% 9.3

69.3% 7.3 38.2% 16.9 42.3% 19.4 39.9% 16.5 12.8% 16.7 6.6% 13.3

20.4% 9.5 47.6% 15.7 40.6% 16.4 20.5% 16.3 13.9% 10.7 9.9% 11.7

3.1% 7.3 5.3% 9.2 5.2% 12.4 7.9% 10.1 5.8% 10.4 8.1% 12.2

Table – 36 MEANS OF UPPER WIND AND TEMPERATURE: AUGUST TIME : 1200 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

1.7%

3.4%

4.0%

1.1%

6.5%

71.6%

9.9%

1.7%

mean speed

5.3

4.3

6.2

4.8

7.8

6.7

6.7

5.8

% frequency

2.5%

4.7%

3.0%

0.8%

5.8%

61.3%

18.0%

3.9%

mean speed

7.4

9.3

6.8

17.3

11.6

12.7

13.0

9.7

% frequency

3.3%

5.3%

4.3%

0.8%

6.8%

53.3%

22.7%

3.5%

No of observations

1000'

352

2000'

362

3000' 5000' 7000' 10,000'

28 23 19 14

396 391 368 344

mean speed

8.1

10.7

13.6

10.7

11.0

14.0

11.8

11.5

% frequency

5.6%

5.4%

7.4%

1.3%

10.7%

43.0%

21.5%

5.1%

mean speed

9.2

10.1

8.8

6.2

10.9

13.2

11.2

12.4

% frequency

19.8%

9.0%

9.0%

4.1%

10.9%

22.8%

15.8%

8.7%

mean speed

11.6

11.2

10.6

5.1

8.0

10.7

12.3

9.0

% frequency

32.6%

22.7%

10.8%

3.5%

3.8%

5.8%

9.3%

11.6%

mean speed

11.1

11.3

11.2

6.9

8.7

9.6

9.9

11.7

Table – 37

147 192. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone through out the day except between 0500 – 0800 h when it remains in partly comfortable zone.

84 Fig – 103 SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (AUG) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

(a)

(b)

(c)

(d)

VIS < 3 KM

4.1

8

2004

VIS < 1 KM

1.2

3

1997

21

1994

3

1996

12

YEAR(s)

FREQ

PEAK

SD

PERIOD (IST)

CEILING (CL) CL < 300 M

6.3

CL < 150 M

0.6

THUNDER STORM

5.9

DUST STORM

0.0

82

(e)

(f)

(g)

0

2000,02

06-09

2.7

0

1991,93,98,00,02,05

06-09

1.2

0

1998

06-09

5.5

0

1991-93,95,98,00,01,04,05

09-12

1.0

2004

0

1999

18-21

3.2

0

UNC

HAIL STORM

0.0

0

PPTN

11.7

26

1994

3

1993

18-21

5.1

FOG

0.0

SUR WIND >30 KTS

0.4

2

1998

0

1991-94,97,00,02,04,05

03-06

0.6

DRW

0.2

2

1998

0

1991-97,99-01,03-05

03-06

0.5

TEMP > 40O C

0.2

2

2002

0

1991-97,99-01,03-05

15-18

0.5

Table – 38

80

148

600 550 Fig – 104

149

TIM E S ERIES : THUNDER S TO RM (AUG) 14.0

12.0 12.0

10.0

10.0

10.0

NO OF DAYS

9.0

8.0 7.0

7.0

6.0 5.0

5.0

5.0

5.0

5.0

4.0

4.0

4.0

2.0 1.0 0.0 0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 105

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

TIM E S ERIES : V IS IBILITY <1 KM (AUG) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 106

1998 YEA RS

1999

2000

150

TIM E S ERIES : V IS IBILITY < 3 KM (AUG ) 9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 107

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

T IM E S ERIES :P RECIP IT AT IO N (AUG ) 30.0

25.0

NO OF DAYS

20.0

15.0

10.0

5.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 108

1998 YEA RS

1999

2000

151

T IM E S ERIES :D RW (AU G ) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig – 109

1998

1999

2000

2001

2002

2003

2004

2005

2 001

2 002

20 03

20 04

2005

YEA RS

T IM E S ER IES :T EM P > 40 D EG (A U G ) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 1991

19 92

1993

199 4

199 5

1996

1997

Fig – 110

1 998 YEA RS

1 999

2000

152

TIM E S ERIES :SS W >30 KT (AUG) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –111

1998

1999

2000

2001

2002

2003

2004

2005

2002

2003

2004

2005

YEA RS

T I M E S E R IE S : L O W C L O U D < 3 0 0 M (A U G ) 2 5 .0

2 0 .0

NO OF DAYS

1 5 .0

1 0 .0

5 .0

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig –112

1998 Y EA RS

1999

2000

2001

153

TIM E S ERIES : LOW CLO UD < 150M (AUG) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –113

1998 YEA RS

1999

2000

2001

2002

2003

2004

2005

154

DIURNAL VARIATION OF MAIN AWH (AUG) (DATABASE: 1991-2005)

8.0

6.9

7.0

6.5 6.2

6.0 5.4 5.0

5.3

4.7 4.1

4.1

4.0

4.0 3.2 3.0

2.7 2.4

2.2

2.0 1.3

1.2

1.4

1.3

1.3 1.0

1.0

0.7 0.4 0.0

0.4 0.1

0.0

0.4 0.0

0.2

0.3

0.5

0.5 0.2

0.0

0.6

0.6

0.9 0.4

0.3

0.3

0.0 00-03

03-06

06-09

09-12

Fig - 114

T'STORM

12-15

PPTN

PV<1

15-18

PV<3

SSW>30

18-21

21-24

0

155

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : AUGUST (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1

0600 P2

P3

P1

69.5

35.3

34.3

66.6 36.7

66.6 63.7

66.6 35.0

62.2 76.7 33.4 26.0

P3

P1

P1

1400 P2

24.6

22.0

22.0

66.6

33.4

55.5

33.4

15.5

 B&Pd P1 =   B

  X 100 

0700 P2 33.4

P3

P1 33.4

18.9

17.7

42.9 73.6

33.4 54.7

33.4 24.7

28.6

1500 P2

P3

P1

0800 P2

0900 P2

P3

P1

32.7 34.2

15.8

15.8

28.9 23.7

28.6

40.2

64.0

40.2

30.3

P3

P1

1700 P2

P3

P1

P3

P1

35.3

34.3

61.9 1600 P2

66.6

21.2

13.3

24.2 20.0

69.9

31.3

16.6

 B&Sd P2 =   B

45.1 26.7

25.0 20.1

13.3

1000 P2

P3

P1

1100 P2

P3

P1

28.9

26.7

46.9 38.4

46.9 38.4

44.6 36.7

60.7

28.6

35.7

35.6

P3

P1

1900 P2

66.6

22.0

38.4 31.0

41.7 30.0

1800 P2

44.1

22.0

33.2 31.1

52.4 33.3

  X 100 

29.9 20.0

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 39

1200 P2

P3

P1

1300 P2

P3

33.4 71.7

18.9

16.6

44.6 71.0

24.2

22.0

33.4

33.4

61.1

33.4

22.0

43.4

22.0

P3

P1

2000 P2

P3

P1

2100 P2

P3

26.0 25.0

32.9

16.6 31.3

28.0

22.0 25.3 22.0

9.2 50.0

156

SEPTEMBER MONTHLY WEATHER SUMMARY 193. Introduction. There is sudden improvement in the weather over the region with the withdrawal of SW monsoon. However when the withdrawal of SW monsoon is in progress, the base gets occasional Dust Storm / Thunder Storm activity in the evening hours. By the later part of the month the weather becomes absolutely fair/fine. Broad Synoptic Features 194. Effects of Various Synoptic Situations on Local Weather. Weather remains P’Cloudy / Cloudy during day and Fair / Fine during night with OCNL Haze / S’ Haze during morning hours for short period. Under the influence of the prevailing systems base experiences Thunder Storm activity in late afternoon/evening hours and also precipitation and low clouds. 195. Behaviour of Important Parameters. The behaviour of important parameters during the month of August is as follows:(a) Pressure. The pressure pattern over NW India starts getting diffused. The heat low over Baluchistan also becomes less important.

157 (b) Winds . the surface winds during night and early morning hours are light and variable. During afternoon / early night hours surface winds are SW’ly. The maximum surface wind ever recorded is 040/45 on 29 Sep 93. (c) Rainfall. The mean monthly Rainfall during the month is 49.3 mm. The highest Rainfall amount ever recorded during the month has been 369.6 mm in 1992. The heaviest Rainfall recorded in 24 hrs for the month is 84.4 mm on 9 Sep 76. (d) Temperature. The mean maximum temperature for the month is 35.5 0C. The highest maximum temperature ever recorded during the month has been 42.6°C on 6 Sep 05. The mean minimum temperature for the month is 25.4 0C. The lowest ever recorded during the month has been 15.40 C on 30 Sep 94. 196. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Sep 1991 and Sep 2005 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Sep follows this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration. (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that in this month, all the main aviation weather hazards become less severe comparing to previous Monsoon months (Table – 43). 197. Time Series of Rainfall. The time series of Rainfall shows a declination in the Rainfall number of days of occurrences since 1994 (Fig - 114). 198. Time Series of Thunder Storms. The time series of thunder storms shows an decreased number of days occurrence of thunder storm from 1998 (Fig – 110). 199. Time Series of PV <1Km. The time series of PV <1 Km shows almost NIL incidences of poor visibility <1 km occurrence after 1999 (Fig – 111). 200. Time Series of PV <3Km. The time series of PV <3 Km shows a decrease in the incidence of poor visibility <3 km after 1994 (Fig – 112). 201. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hrly) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - ).

158

202. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table - 31). 203. Simultaneity of Weather In Sep for thunderstorm the simultaneity has a percentage of 30% with primary diversion 1700 – 1900 h. For precipitation there is 60% of occurrence at primary and secondary diversion at 1200 h only (Table 44). 204. Weather over Local flying area. During the first fortnight, weather remains P’Cloudy / Cloudy during day and Fair / Fine during night with OCNL Haze / S’ Haze during morning hours for short period. Base experiences Thunder Storm activity in late afternoon/evening hours and precipitation and low clouds on few occassions. During the second fortnight, generally weather remained Fair / P’Cloudy with ISOL Rain / T’ Storm / Dust Storm mainly in the evening / night.

159 205. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the winds up to 5000’ are generally Wlies of about 10-15 kt whereas between 5000 to 10000’ generally Nly to NEly flow prevails with wind speeds of about 10 kt (Table – 41, Table – 42).

AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: SEPTEMBER TIME : 0000 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

4.7%

17.4%

4.1%

1.2%

2.1%

36.9%

29.2%

4.4%

mean speed

4.6

5.5

6.9

3.5

5.3

6.2

8.9

5.3

% frequency

2.3%

3.1%

4.5%

2.8%

8.2%

24.4%

47.6%

7.1%

No of observations

1000'

339

2000'

353

3000'

25

387

5000'

21

402

7000' 10,000'

17 12

377 410

mean speed

5.8

10.2

7.4

8.3

10.7

14.7

14.1

10.3

% frequency

4.1%

3.4%

6.2%

2.8%

7.0%

22.7%

44.7%

9.0%

mean speed

8.8

8.9

10.2

10.6

8.5

15.3

14.2

10.5

% frequency

7.7%

7.0%

6.7%

5.7%

15.4%

18.2%

27.9%

11.4%

mean speed

9.4

8.8

9.3

8.4

8.9

14.2

13.0

9.9

% frequency

20.2%

16.4%

15.1%

9.3%

13.3%

8.2%

10.1%

7.4%

mean speed

9.6

11.1

10.5

9.6

8.9

10.7

10.3

8.2

% frequency

23.4%

24.1%

15.6%

8.3%

5.9%

1.5%

14.4%

6.8%

mean speed

10.9

11.8

9.8

10.7

12.4

6.7

14.1

6.5

Table – 40 MEANS OF UPPER WIND AND TEMPERATURE: SEPTEMBER TIME : 1200 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

5.0%

8.8%

6.6%

3.8%

6.3%

35.8%

27.7%

6.0%

mean speed

5.4

5.8

6.0

4.4

7.7

6.0

7.3

4.1

% frequency

9.5%

5.0%

6.9%

2.4%

7.4%

34.9%

28.8%

5.0%

No of observations

1000'

318

2000'

378

3000'

29

387

5000'

23

408

7000'

18

390

10,000'

12

355

mean speed

7.4

9.5

8.8

5.7

9.1

10.7

9.1

7.6

% frequency

10.3%

7.0%

6.7%

2.3%

7.0%

30.0%

29.5%

7.2%

mean speed

8.1

9.0

8.2

8.7

10.4

10.9

9.2

6.7

% frequency

13.2%

9.1%

5.4%

4.2%

13.5%

23.0%

22.1%

9.6%

mean speed

9.6

9.3

8.7

6.7

10.1

12.2

9.5

8.1

% frequency

20.5%

11.3%

6.4%

5.4%

13.1%

12.8%

16.9%

13.6%

mean speed

9.0

9.3

9.6

7.2

8.3

9.3

9.6

9.3

% frequency

32.7%

15.8%

13.0%

4.5%

5.4%

3.9%

11.0%

13.8%

mean speed

11.0

11.1

9.1

14.3

10.8

8.9

9.5

13.1

Table – 41

160 206. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the uncomfortable zone through out the day except between 0500 – 1000 h when it remains in partly comfortable zone (Fig – 108).

86 Fig –115 SUMMARY OF MAIN AVIATION WEATHER HAZARDS(1991-2005) AIR FORCE STATION - JODHPUR (SEP) ELEMENT

MEAN

HIGHEST

FREQ

FREQ

YEAR(s)

LOWEST

YEAR(s)

(a)

(b)

(c)

(d)

(e)

(f)

(g)

VIS < 3 KM

2.8

7

1994

0

1995,00,01

15-18

2.5

VIS < 1 KM

0.5

3

1992

0

1991,94-96,00-06

12-15

0.8

FREQ

PEAK

SD

PERIOD (IST)

CL < 300 M

1.7

84 7

1994

0

1996,98-04

06-09

2.3

CL < 150 M

0.4

4

1992

0

1991,93-96,98-05

09-12

1.1

THUNDER STORM

3.7

9

2005

0

2001,02

18-21

2.9

DUST STORM

0.1

1

1998

0

1991-97,99-05

15-18

0.2

HAIL STORM

0.0

0

PPTN

5.1

11

1994

0

2002

12-15

3.2

FOG

0.1

1

1998

0

1991-97,99-05)

06-09

0.2

>30 KTS

0.7

3

2005

0

1991,92,95,97,00-03

18-21

0.9

DRW

0.7

2

2004

0

1991,92,94,95,97,00-03

15-21

0.8

TEMP > 40O C

1.7

12

2002

0

1991-98,03

15-18

3.3

CEILING (CL)

SUR WIND

82

Table – 42

UNC

161

600 550 Fig –116

500

162

T IM E S ERIES : T HUNDER S TO RM (S EP ) 10.0 9.0 9.0

8.0 7.0

7.0

7.0

7.0 6.0 NO OF DAYS

6.0 5.0

5.0

5.0

4.0 3.0

3.0

3.0

2.0 1.0

1.0

1.0

1.0

1.0 0.0

0.0

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –117

1998

1999

2000

YEA RS

TIM E S ERIES : V IS IBILIT Y < 1 KM (S EP ) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –118

1998 YEA RS

1999

2000

163

T IM E S E R IES : V IS IB IL IT Y < 3 K M (S E P ) 8 .0

7 .0

6 .0

NO OF DAYS

5 .0

4 .0

3 .0

2 .0

1 .0

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig –119

1998

19 9 9

2 00 0

2001

2002

2003

2004

2005

200 1

200 2

2 0 03

20 0 4

2005

Y EA RS

T IM E S ER IES :P R EC IP IT AT IO N (S EP ) 12 .0

10 .0

NO OF DAYS

8 .0

6 .0

4 .0

2 .0

0 .0 1991

1 9 92

19 9 3

1 9 94

19 9 5

1 9 96

1 99 7

Fig –120

1 998 Y EA RS

19 9 9

2000

164

TIM E S ERIES :DRW (S EP ) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –121

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

TIM E S ERIES :TEMP >40 DEG (S EP ) 14.0

12.0

NO OF DAYS

10.0

8.0

6.0

4.0

2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –122

1998 YEA RS

1999

2000

165

T IM E S ERIES :S S W > 30 KT (S EP ) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –123

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

T IM E S ER IES : L O W C L O UD < 300M (S EP ) 8.0

7.0

6.0

NO OF DAYS

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –124

1998 YEA RS

1999

2000

166

T I M E S E R I E S : L O W C L O U D < 1 5 0 M (S E P ) 4 .5

4 .0

3 .5

NO OF DAYS

3 .0

2 .5

2 .0

1 .5

1 .0

0 .5

0 .0 1991

1992

1993

1994

1995

1996

1997

1998 Y EA R S

Fig –125

1999

2000

2001

2002

2003

2004

2005

167

DIURNAL VARIATION OF MAIN AWH (SEP) (DATABASE: 1991-2005) 3.5

3.0 3.0

2.5

2.3 2.1

2.0

2.0 1.8

1.6

1.6

1.6

1.4

1.5

1.2 1.0

0.8 0.6

0.5 0.5

0.3 0.0

0.1

0.2 0.0

0.0

0.1

0.0

0.1

0.2 0.0

0.0

0.4

0.3 0.0

0.1

0.0

0.0

0.1

0.2

0.2 0.0

0.0

0.1

0.0

0.1 0.1

0.0 00-03

03-06

06-09

09-12

Fig –127 T'STORM PPTN

12-15 PV<1

PV<3

15-18 SSW>30

18-21

21-24

168

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : SEPTEMBER (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1

P1

0600 P2

1400 P2

P3

P3

P1

0700 P2

P3

66.6

66.6

66.6

P1

1500 P2

P3

P1

P1

0800 P2

1600 P2

P3

P3

33.4

 B&Pd P1 =   B

  X 100 

P1

P1

0900 P2

1700 P2

P3

P3

P1

P1

33.4

 B&Sd P2 =   B

1000 P2

1800 P2

P3

P3

P1

P1

1100 P2

1900 P2

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Secondary Diversion (Sd) -Uttarlai

Table – 43

P3

21.1 33.4

  X 100 

Primary Diversion (Pd) - Jaisalmer

P3

P1

1200 P2

P3

66.6

66.6

66.6

P1

2000 P2

P3

21.1 22.2

P1

1300 P2

P3

P1

2100 P2

P3

19.9

169

170

POST MONSOON SEASON (OCT – NOV) Introduction 207. The SW monsoon starts withdrawing from NE India and the peninsula. The withdrawal proceeds in stages eastwards and southwards. There is a transitional period when SW monsoon pattern of pressure and winds undergo steady modification prior to establishment of winter pattern. Surface Pressure Pattern 208. The seasonal Low gradually shifts to Central Bay and adjoining SW Bay and High pressure area establishes over NW India. The pressure gradient gets totally diffused and one or two isobars are marked over the entire country. SW Monsoon withdraws from the major parts of the country. AMT shifts to 13 o N in Oct and further South as the season progresses. Weak and diffused pressure pattern over Raj is the main feature of this season. Pressure gradient over Raj steepens either under the influence of active WD or a Tropical Cyclone in Arabian Sea, approaching towards Gujarat. The main characteristics of pressure pattern during this season are rapid rise in surface pressure and equally rapid decrease in surface temperature. Wind Pattern 209. Surface Wind. Surface wind pattern is largely governed by low level wind profile up to 0.9 Km. The position of low level anticyclone over Central parts of the country is the deciding factor of wind pattern. The surface winds are mainly WSW'ly / WNW'ly 03 kt in Oct and NE'ly 02 kt in Nov. During this season, Gale wind speed of the order of 40 – 45 Kt associated with CB clouds have been observed. 210. Upper Wind. Weak wind field prevails over Raj in lower troposphere. Winds below 3.0 Km are W/NW'ly 04 – 07 Kt. The middle and upper tropospheric Westerly wind profile strengthens gradually.

Synoptic Features and Associated Weather 211. Western Disturbance/Induced Low. Active WD moving across NW India and adjoining N Pakistan induces Low over West Raj and adjoining Central Pakistan. The frequency of such systems is quite less and they seldom affect the weather over West Raj. In the event of a well marked induced Low over West Raj and adjoining Central Pakistan, cloudy weather prevails for 1-2 days followed by isolated Rain/thunder storm. 212. Westerly Trough. Westerly trough, a rare feature of this season, extending up to 25o N and lying 5o to 7o West of induced system, accentuates these Low/UACCs. At times Raj & adjoining region experiences SCT/FWSP Medium/High clouds under the influence of deep amplitude trough lying between 68o E & 70o E longitude, in the absence of any low level system.

171 213. Tropical Cyclonic Storms. Post Monsoon season is a favourable period for the development of Tropical Storms over Bay of Bengal and Arabian Sea. Generally Tropical Cyclones/Depressions, which form over Bay of Bengal, move westwards crossing TamilNadu coast and enter SE Arabian Sea. Most of these disturbances continue to move in a W'ly/WNW'ly direction. However, one odd cyclonic storm recurves and moves in a Northerly direction, hit Gujarat coast and even affect West Raj. These Storms of Arabian sea are a cause of great concern as amply demonstrated by the Cyclone of Nov 1981. In the period of last 30 years, the frequency of cyclones is mentioned below. 214. Whenever cyclonic storm hits Gujarat coast and follows N'ly track, then overcast/cloudy sky with strong surface winds, moderate precipitation and low clouds are experienced over West Raj. The cyclonic storm of Nov 1981 caused 45.5 mm Rain in 48 hours (15.7 mm on 02 Nov and 29.8 on 03 Nov 1981) and wind speed of 36 Kt from NW'ly direction over Jodhpur Weather Pattern and Aviation Weather Hazards 215. Generally fair to fine weather prevails over Raj during this season. This is one of the best seasons for flying due to least aviation weather hazards. 216.

The main aviation weather hazards during this season are given below: (a) Visibility < 3 Km. With the gradual drop in night temperature, smoke Haze is experienced in the morning and night. In smoke Haze, visibility is generally between 3 and 5 Km. Very rarely visibility drops below 3 Km. The frequency is just 1.1 in Oct and 0.7 in Nov (Fig – 121). (b) Rain / Thunderstorm. Rain / Thunderstorms occur on one or two days in a month. The frequency of Thunder storm / precipitation in Oct is 1.7 / 2.5 and Nov is 0.1 / 0.9. The peak period of occurrence is 1800 to 2100 hrs IST. However, under the influence of Tropical Cyclone, Rainfall may be continuous with spells of moderate to heavy precipitation for one or two days (Fig – 121). (c) Temperature > 40 oC. High surface temperature in the month of Oct is one of the important aviation weather hazards as far as flying in daytime in concerned, although it is not a usual or prolonged feature. The frequency is very less just 0.8 with mean duration of about 70 minutes. The peak period is 1500 to 1800 hrs IST (Fig – 121).

172

AIR FORCE STATION : JODHPUR STATISTICS OF GOOD, MARGINAL & BAD WEATHER STATE POST MONSOON SEASON DATA SET: 2001 – 05 FIGHTERS / TRAINERS MONTH

OCT

NOV

DAY

TRANSPORTS

NIGHT

DAY

NIGHT

0601-1200

1201-1800

1801-2400

0000-0600

0601-1200

1201-1800 1801-2400

0001-0600

G

M

B

G

M

B

G

M

B

G

M

B

G

M

B

G

M B

G

M

B

G

M

B

Highest

31

3

1

31

2

2

31

1

0

31

2

1

31

3

1

31

4

0

31

1

0

31

2

1

Mean

30

1

0

30

0

1

31

0

0

30

0

1

30

1

0

30

1

0

31

0

0

30

0

1

Lowest

28

0

0

27

0

0

30

0

0

29

0

0

28

0

0

27

0

0

30

0

0

29

0

0

Highest

30

2

0

30

0

1

30

0

0

30

0

0

30

1

0

30

0

0

30

0

0

30

0

0

Mean

29

1

0

30

0

0

30

0

0

30

0

0

28

1

1

30

0

0

30

0

0

30

0

0

Lowest

28

0

0

29

0

0

30

0

0

30

0

0

29

0

0

30

0

0

30

0

0

30

0

0

G: GOOD

M: MARGINAL

B: BAD Table – 44

173

100

90 Fig –127

174

AF ST AT ION, JODHPUR M AIN AVIAT ION WX HAZARDS POST M ONSOON SEASON (1991 - 2005)

3

2.5

MEAN FREQUENCY (NO. OF DAYS)

2.5

2 1.7 1.5 1.1 1

0.9 0.7

0.5

0

0.0

0.0

0.1

0.1

0.1

0.2

0.1

0.0

OCT

T'STORM

D'STORM

0.1

0.0

0.0

0.1

NOV

HAIL

Fig –128 PPTN LC<300M

FOG

PV<1KM

PV<3KM

SSW>30KT

0.1

175

176 OCTOBER MONTHLY WEATHER SUMMARY 217. Introduction. The sky remains practically cloudless and visibility remains good on most of the days over the airfield. The weather over Raj remains fine with cool and pleasant nights. Broad Synoptic Features 218. Effects of Various Synoptic Situations on Local Weather. The weather remains generally fine / fair with isolated Haze / Smoke Haze in morning and evening hours. 219. Behaviour of Important Parameters. The behaviour of important parameters during the month of October is as follows:(a) Pressure. The thermal low weakens and shifts southwards and gets established over WC Bay off Tamil Nadu coast. An ill-defined and diffused pressure pattern is the main feature of this month. (b) Winds . The surface winds during night and early morning hours are light and variable with tendency of NE’ly / SE’ly and W’ly / NW’ly in afternoon and evening hours. The maximum surface wind ever recorded is 180/45 on 1 Oct 99. (c) Rainfall. The mean monthly Rainfall during the month is 8.5 mm. The highest Rainfall amount ever recorded during the month has been 67.7 mm in 1975. The heaviest Rainfall recorded in 24 hrs for the month is 35.4 mm on 24 Oct 75. (d) Temperature. The mean maximum temperature for the month is 3602 0C. The highest maximum temperature ever recorded during the month has been 41.2°C on 2 Oct 68. The mean minimum temperature for the month is 19.9 0C. The lowest ever recorded during the month has been 11.6 0 C on 25 Oct 73. 220. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Oct 1991 and Oct 2000 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Oct follow this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration. (b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that

177 this month has fairly good weather. Visibility generally remains good (Table – 48). 221. Time Series of Rainfall. The time series of Rainfall shows deterioration in the Rainfall number of days of occurrences after 1997. (Fig - 128) 222. Time Series of Thunder Storms. The time series of thunder storms shows an increased number of days occurrence of T’St from 1999 (Fig – 124). 223. Time Series of PV <1Km. The time series of PV <1 Km shows almost NIL incidence of poor visibility <1 km occurrence (Fig – 125). 224. Time Series of PV <3Km. The time series of PV <3 Km shows a wide fluctuation in the incidence of poor visibility <3 km during the last decade (Fig – 126). 225. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written. 226. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table - 45). 227. Simultaneity of Weather In Apr low clouds (< 300m) have 60% simultaneous occurrence with primary and secondary diversion during 1400 to 2100 hrs. For Thunderstorm the simultaneity has a percentage of 33 to 50% with primary diversion and 33 to 50% with secondary 1600 – 1800 h. For precipitation there is 60% of occurrence at primary and secondary diversion after 1400 – 2000 h only (Table - 49). 228. Weather over Local flying area. The good weather conditions prevails over the base with fine / fair weather with isolated Haze / Smoke Haze in morning and evening hours.

178 229. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that the generally Nly to NEly wind flow prevails with wind speeds of about 10 kt (Table – 46, Table – 47). AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: OCTOBER TIME : 0000 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

11.6%

44.2%

13.0%

2.5%

2.5%

8.0%

14.1%

4.0%

mean speed

4.7

5.1

6.3

5.0

3.9

6.5

6.8

5.8

% frequency

7.8%

13.3%

20.4%

7.5%

7.3%

11.1%

25.6%

7.0%

mean speed

7.9

9.7

8.4

8.4

6.9

9.3

10.4

8.6

% frequency

9.9%

12.9%

18.1%

6.9%

8.4%

12.4%

19.8%

11.6%

mean speed

7.3

8.3

7.8

8.4

8.0

9.9

10.8

8.4

% frequency

18.5%

11.3%

10.8%

5.3%

8.0%

9.3%

22.3%

14.5%

No of observations

1000'

276

2000'

398

3000' 5000'

25 21

404 399

7000'

15

399

10,000'

8

454

mean speed

8.1

7.2

7.3

6.0

6.3

9.5

9.5

8.2

% frequency

22.1%

15.0%

10.5%

3.3%

7.0%

8.5%

17.0%

16.5%

mean speed

8.1

8.0

5.8

5.2

6.4

10.0

10.8

9.0

% frequency

26.7%

13.7%

7.5%

2.2%

1.8%

5.5%

28.6%

14.1%

mean speed

12.1

9.9

8.3

6.9

8.6

11.7

12.4

9.0

Table – 45 MEANS OF UPPER WIND AND TEMPERATURE: OCTOBER TIME : 1200 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

24.1%

18.7%

10.4%

1.2%

0.8%

13.7%

19.9%

11.2%

mean speed

4.3

5.9

6.8

5.3

4.0

5.1

5.3

5.0

% frequency

23.9%

13.9%

8.3%

1.8%

3.5%

11.6%

25.2%

11.8%

mean speed

7.2

7.3

6.5

5.0

7.3

7.5

7.4

5.3

% frequency

25.6%

14.9%

9.7%

1.6%

3.4%

10.2%

23.5%

11.2%

mean speed

7.1

7.8

6.9

2.0

6.6

8.4

7.1

5.3

% frequency

39.5%

15.2%

5.1%

1.6%

2.8%

6.5%

19.2%

10.0%

mean speed

7.5

8.1

7.9

2.3

7.3

9.7

8.8

6.5

% frequency

28.5%

18.3%

5.9%

4.1%

3.3%

4.6%

19.0%

16.2%

mean speed

8.3

7.5

6.5

6.3

8.2

13.0

9.3

7.7

% frequency

31.1%

14.1%

6.1%

4.0%

1.9%

6.9%

18.9%

17.0%

mean speed

9.1

8.6

8.8

7.7

8.6

13.6

10.3

10.6

No of observations

1000'

241

2000'

3000'

5000'

7000'

10,000'

397

28

22

17

9

383

428

389

376

Table –46

179 230. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the partly comfortable zone through out the day except upto 0700 h when it remains in the comfortable zone (Fig – 122).

85

Fig –129

AIR FORCE STATION : JODHPUR

SUMMARY OF MAIN AVIATION WEATHER HAZARDS

ELEMENT

MEAN FREQ

HIGHEST FREQ

OCTOBER (1991 - 2005) LOWEST YEAR(s) FREQ

YEAR(s)

PEAK PERIOD (IST)

SD

(a)

(b)

(c)

(d)

(e)

(f)

(g)

VIS < 3 KM

1.1

5

2004

0

1992,94,96,2000,01

21-24

1.3

VIS < 1 KM

0.1

1

1998,99

0

1991-97,2000-05

09-12

0.1

CL < 300 M

0.1

2

1998

0

1991-97,99-05

09-12

0.5

CL < 150 M

0.1

2

1998

1991-97,99-05

09-12

0.5

THUNDER STORM

1.7

9

1997

0

1991,92,94,96,01,02,05

18-21

2.3

DUST STORM

0.0

0

HAIL STORM

0.0

0

PPTN

2.5

9

1997

0

1991,94,01,02,05

18-21

2.5

FOG

0.1

1

1998

0

1991-97,99-05

06-09

0.2

CEILING (CL)

SUR WIND

80

>30 KTS

0.2

2

1999

0

1991-97,98,2000-05

15-18

0.5

DRW

0.3

2

2004

0

1991-96,98,2000-03,05

15-18

0.6

0.8

12

2002

0

1991-2001,03,04,05

15-18

3.0

O

TEMP > 40 C

Table – 47

180

100

90 Fig –130

181

T IM E S ERIES : T H UNDER S T O RM (O CT ) 10.0 9.0 9.0

8.0

7.0

NO OF DAYS

6.0

5.0 4.0 4.0 3.0 3.0 2.0

2.0

2.0

2.0

2.0 1.0 1.0 0.0

0.0

1991

1992

0.0

0.0

0.0

0.0

0.0

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

0.0 1993

1994

1995

1996

1997

Fig –131

1998

1999

2000

YEA RS

T IM E S ERIES : V IS IBIL IT Y < 1 KM (O CT ) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1 997

Fig –132

1998 YEA RS

1999

2000

182

T IM E S E R IES : V IS IB IL IT Y < 3 K M (O C T ) 6 .0

5 .0

NO OF DAYS

4 .0

3 .0

2 .0

1 .0

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig –133

1998

19 9 9

2 00 0

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

Y EA RS

T IM E S ERIES :P RECIP IT ATION (O CT) 10.0

9.0

8.0

7.0

NO OF DAYS

6.0

5.0

4.0

3.0

2.0

1.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –134

1998 YEARS

1999

2000

183

T IM E S ER I ES :D R W (O C T ) 2.5

2.0

NO OF DAYS

1.5

1.0

0.5

0.0 19 9 1

19 9 2

19 9 3

1 9 94

19 95

1 9 96

1 9 97

Fig –135

1 99 8

1 99 9

2 00 0

2 00 1

2 00 2

2 00 3

20 0 4

20 0 5

2001

2002

2003

2004

2005

Y EA RS

TIM E S ERIES :TEM P > 40 DEG (O CT) 14.0

12.0

NO OF DAYS

10.0

8.0

6.0

4.0

2.0

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –136

1998 YEA RS

1999

2000

184

T IM E S ER IES :S S W > 30 K T (O C T ) 2 .5

2 .0

NO OF DAYS

1 .5

1 .0

0 .5

0 .0 1991

19 9 2

1 99 3

1 9 94

1995

1996

19 9 7

Fig –137

1 99 8

1 9 99

2 0 00

2001

2002

20 0 3

2 00 4

2 0 05

2 00 1

2 0 02

2003

2 00 4

2005

YEA RS

T IM E S ER IES : L O W C L O UD < 300M (O C T ) 2 .5

2 .0

NO OF DAYS

1 .5

1 .0

0 .5

0 .0 1 99 1

19 9 2

1 99 3

1994

1995

19 9 6

1997

Fig –138

1998 Y EA RS

19 9 9

2 00 0

185

T I M E S E R I E S : L O W C L O U D < 1 5 0 M (O C T ) 2 .5

2 .0

NO OF DAYS

1 .5

1 .0

0 .5

0 .0 1991

1992

1993

1994

1995

1996

1997

Fig –139

1998 Y EA R S

1999

2000

2001

2002

2003

2004

2005

186

DIURNAL VARIATION OF MAIN AWH (OCT) (DATABASE: 1991-2005) 1.6

1.5

1.5 1.4

1.4

1.2

1.2

1.1

1.0

0.9

0.9

0.9

0.8 0.7

0.7 0.6

0.6

0.5

0.4

0.2

0.3

0.3 0.2

0.2

0.1

0.3

0.4

0.3

0.3

0.2

0.1 0.0 0.0 0.0

0.0 0.0 0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0 00-03

03-06

06-09

09-12 T'STORM

PPTN

12-15 PV<1

PV<3

15-18 SSW>30

18-21

21-24

0.0

187 Fig –140 AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : OCTOBER (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1

0600 P2

P3

P1

1400 P2

P3

P1 66.6

0700 P2

P3

P1

1500 P2

P3

P1 66.6

0800 P2

P3

P1

0900 P2

P3

P1

1000 P2

P3

P1

1100 P2

P3

P1

1200 P2

P3

P1

1300 P2

P3

1600 P2

P3

P1

1700 P2

P3

P1

1800 P2

P3

P1

1900 P2

P3

P1

2000 P2

P3

P1

2100 P2

P3

66.6

66.6

66.6

66.6

66.6 50.0

16.6

16.6

66.6

66.6

P1

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

66.6

33.4

33.4

16.6 36.7

50.0 33.4

16.6 16.6

33.4 44.6

73.4 44.6

33.4 22.0

18.0 44.6

 B&Pd P1 =   B

  X 100 

 B&Sd P2 =   B

  X 100 

66.6 56.7 51.4

16.6 44.6

22.0 40.0

22.0 13.3

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 48

22.0 13.3

33.4

188

189 NOVEMBER MONTHLY WEATHER SUMMARY 230. Introduction. This month marks the beginning of wintry and associated weather. Clear skies, fine weather, low humidity and low temperature are the normal features. The dry spells are broken at intervals by migratory lows which move across Northern India and clouding with or without precipittion over Raj. The surface temperature drops considerably in this month. Broad Synoptic Features 231. Effects of Various Synoptic Situations on Local Weather. Generally weather remains dry over base and diversion with ISOL - SCT S’ Haze in morning and night hours. Weather under the influence of WD remains P’Cloudy / Cloudy with med / high clouds. Minimum temperature starts dropping in night. 232. Behaviour of Important Parameters. The behaviour of important parameters during the month of October is as follows:(a) Pressure. In this month pressure pattern of winter starts getting established over the Indian sub-continent. The ridge of high pressure over NW India gets established, stretching from Afghanistan to NW India across N Pak. On the approach of WD, the ridge of high pressure starts getting squeezed and moves eastwards. The high pressure values are overtaken by low pressure values over NW India. (b) Winds . The anticyclonic circulation gets established over Gujarat and adj SE Raj upto 3.1 Km. When an active WD / induced low moves eastwards the circulation shifts further SE wards. The maximum surface wind ever recorded is 330/36 on 3 Nov 81. (c) Rainfall. The mean monthly Rainfall during the month is 4.1 mm. The highest Rainfall amount ever recorded during the month has been 59.2 mm in 1976. The heaviest Rainfall recorded in 24 hrs for the month is 30.9 mm on 21 Nov 76. (d) Temperature. The mean maximum temperature for the month is 31.8 0C. The highest maximum temperature ever recorded during the month has been 38.7°C on 6 Nov 69. The mean minimum temperature for the month is 14.4 0C. The lowest ever recorded during the month has been 5.20 C on 27 Nov 78. 233. Aviation Weather Hazards. Detailed summary of Main Aviation Weather Hazards has been prepared with its frequency, time of occurrence with peak period and SD values. The data between Nov 1991 and Nov 2000 is presented as follows: (a) Detailed Aviation Weather Hazards. The mean conditions of statistical data of aviation weather hazards for Nov follow this summary. It contains the information about the highest and the lowest duration of a particular three-hour block in addition to mean duration.

190

(b) Summary of Main Aviation weather Hazards. Summary of main aviation weather hazards with their frequency, time of occurrence, peak period and SD has been prepared in the tabular form. This data indicates that this month is having extremely good weather (Table – 52). 234. Time Series of Rainfall. The time series of Rainfall shows wide fluctuation in the Rainfall number of days of occurrences (Fig - 139). 235. Time Series of Thunder Storms. The time series of thunder storms shows a rare number of days occurrence of thunder storms throughout the period (Fig – 136). 236. Time Series of PV <1Km. The time series of PV <1 Km shows a NIL incidence of poor visibility <1 km occurrence in last decade (Fig – 137). 237. Time Series of PV <3Km. The time series of PV <3 Km shows an increase in the incidence of poor visibility <3 km during the last decade (Fig – 138). 238. Diurnal Variation of AWH. Diurnal Variation of main AWH blockwise (03 hr) is graphically represented. The inferences of the most probable and least probable period of occurrence of particular AWH are written (Fig - ). 239. Good / Marginal / Bad Weather days (Transport and Fighter). Generally the weather remains good during the period 0600-1200 and 1201 to 1800 for fighter and transport flying (Table - 45). 240. Simultaneity of Weather In Nov. for poor visibility <3000m 30 – 40 % of occurrences for both the diversions between 0600 – 0900 h and for precipitation there is 60% of occurrence secondary diversion between 0900 – 1100 h only (Table - 53). 241. Weather over Local flying area. Weather remains dry over base and diversion with ISOL - SCT S’ Haze in morning and night hours. Weather under the influence of WD remains P’Cloudy / Cloudy with med / high clouds. Minimum temperature starts dropping in night.

191 242. Means of Local Upper Winds (PB Means) the local upper wind data is available up to 10000’. The analysis of the data shows that generally Nly to NEly flow prevails with wind speeds of about 10 kt (Table – 50, Table – 51).

AIR FORCE STATION, JODHPUR MEANS OF UPPER WIND AND TEMPERATURE: NOVEMBER TIME : 0000 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) No of observations

1000' 2000' 3000' 5000'

% frequency

275 367 21 16

384 389

7000'

12

384

10,000'

7

381

N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

10.2%

48.0%

19.6%

4.0%

3.6%

4.4%

5.1%

5.1%

mean speed

5.8

6.2

5.9

5.8

3.5

6.4

6.2

4.6

% frequency

11.2%

24.3%

33.2%

9.5%

4.1%

4.9%

8.4%

4.4%

mean speed

7.9

9.9

9.5

7.5

5.7

7.7

7.9

5.5

% frequency

11.2%

18.2%

23.7%

11.2%

7.3%

7.6%

13.3%

7.6%

mean speed

7.1

8.6

8.5

7.8

7.1

9.3

7.2

6.2

% frequency

19.5%

14.1%

10.3%

6.2%

6.7%

13.4%

19.3%

10.5%

mean speed

7.7

8.2

8.0

7.2

6.9

8.3

8.5

7.7

% frequency

20.1%

10.2%

4.7%

2.3%

7.0%

15.9%

26.6%

13.3%

mean speed

9.2

9.9

8.2

8.8

5.7

10.2

9.4

8.5

% frequency

19.2%

7.9%

5.2%

2.4%

4.2%

8.9%

32.5%

19.7%

mean speed

11.5

10.2

7.8

6.9

9.2

14.9

13.0

11.2

Table – 49 MEANS OF UPPER WIND AND TEMPERATURE: NOVEMBER TIME : 1200 UTC deg C

DATA SET 1991-2005 (FOR TEMP 2001-2005) N

NE

E

SE

S

SW

W

NW

360

045

090

135

180

225

270

315

I

II

III

IV

V

VI

VII

VIII

% frequency

25.0%

24.1%

9.4%

1.3%

4.0%

12.1%

14.3%

9.8%

mean speed

4.7

3.96

4.14

5.00

3.00

4.59

5.41

3.27

% frequency

35.9%

15.4%

10.4%

1.8%

2.3%

9.6%

13.5%

10.9%

mean speed

6.7

7.24

6.48

4.29

3.44

6.68

6.60

5.83

% frequency

30.8%

17.6%

11.1%

2.6%

3.7%

7.9%

15.3%

11.1%

mean speed

7.1

7.46

7.00

4.90

5.79

8.20

5.98

5.67

% frequency

28.6%

19.5%

12.6%

2.2%

2.7%

7.1%

17.6%

9.6%

No of observations

1000'

224

2000'

384

3000' 5000' 7000' 10,000'

24 17 13 7

380 364 365 361

mean speed

7.4

7.35

8.26

8.00

5.80

8.00

7.09

6.31

% frequency

19.5%

14.0%

9.3%

4.1%

6.8%

13.4%

19.7%

13.2%

mean speed

8.4

8.88

7.76

6.33

5.44

9.18

10.67

9.50

% frequency

13.3%

7.8%

2.8%

2.5%

6.6%

12.2%

34.9%

19.9%

mean speed

11.6

8.07

5.10

5.78

7.79

12.30

13.08

11.35

Table – 50

192 243. Discomfort Index. The comfort index calculated on the basis of average value of temperatures and humidity variation during the day indicates that the index is in the partly comfortable zone through out the day except between 0900 – 1100 h and again after 1900 h when it remains in comfortable zone.

78

Fig –141

AIR FORCE STATION : JODHPUR

SUMMARY OF MAIN AVIATION WEATHER HAZARDS HIGHEST FREQ

NOVEMBER (1991 - 2005) LOWEST YEAR(s) FREQ

(a)

(b)

(c)

(d)

(e)

PEAK PERIOD (IST) (f)

VIS < 3 KM

0.7

3

1997

0

1991,92,93-96,98,99,01

06-09

0.9

VIS < 1 KM

0.1

1

1997

0

1991-96,98-05

06-09

0.1

1

1997

0

1991-96,98-05

09-12

0.2

2002

0

1991-2001,03-05

18-21

0.3

1997

0

1992,94-95,99,01,03-05

00-03

1.3

2002

0

1991-2001,03-05

00-03

0.2

ELEMENT

MEAN FREQ

CEILING (CL)

76

CL < 300 M

0.1

CL < 150 M

0.0

THUNDER STORM

0.1

1

DUST STORM

0.0

0

HAIL STORM

0.0

0

PPTN

0.9

4

FOG

0.0

0

>30 KTS

0.1

1

DRW

0.0

TEMP > 40O C

0.0

YEAR(s)

SD (g)

0

SUR WIND

74 0 0

Table – 51

193

100 90 Fig –142

194

T IM E S ERIES : T H UND ER S T O RM (NO V ) 1.2

1.0

1.0

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0

0.0

0.0

0.0

0.0

0.0

1992

1993

1994

1995

1996

1997

0.0

0.0

0.0

0.0

1998

1999

2000

2001

2001

0.0

0.0

0.0

2002

2003

2004

2005

2002

2003

2004

2005

0.0 1991

Fig –143

YEA RS

TIM E S ERIES : V IS IBIL IT Y < 1 KM (NO V ) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1 997

Fig –144

1998 YEA RS

1999

2000

195

T IM E S ERIES : V IS IBIL ITY < 3 KM (NO V ) 3.5

3.0

NO OF DAYS

2.5

2.0

1.5

1.0

0.5

0.0 1 991

19 92

1 99 3

1 99 4

1 99 5

19 96

19 97

Fig –145

19 98

19 99

2 00 0

200 1

20 02

20 03

20 04

20 05

20 01

200 2

2 003

200 4

2005

YEA RS

T I M E S ER IES :P R E C IP IT A T IO N (N O V ) 4.5

4.0

3.5

NO OF DAYS

3.0

2.5

2.0

1.5

1.0

0.5

0.0 19 91

1992

1 993

1994

1 995

19 96

1997

Fig –146

1 998 Y EA RS

199 9

2000

196

TIM E S ERIES :S S W > 30 KT (NO V ) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –147

1998

1999

2000

2001

2002

2003

2004

2005

2001

2002

2003

2004

2005

YEA RS

T IM E S ER IES : L O W C L O UD < 300M (NO V ) 1.2

1.0

NO OF DAYS

0.8

0.6

0.4

0.2

0.0 1991

1992

1993

1994

1995

1996

1997

Fig –148

1998 YEA RS

1999

2000

197

DIURNAL VARIATION OF MAIN AWH (NOV) (DATABASE: 1991-2005) 0.8

0.7

0.7

0.7

0.6 0.6

0.5

0.5

0.5

0.5

0.4 0.3 0.3

0.2 0.2

0.2 0.1 0.1

0.1

0.1 0.0

0.0 0.0 0.0

0.0

0.0 0.0 0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0 0.0 0.0

0.0

0.0 0.0 0.0

0.1 0.0

0.0

0.0

0.0 0.0 0.0

0.0 00-03

03-06

06-09

09-12

Fig –148 T'STORM PPTN

12-15 PV<1

PV<3

15-18 SSW>30

18-21

21-24

198

AIR FORCE STATION: JODHPUR SIMULTANEITY OF WEATHER : NOVEMBER (BASED ON DATA SET OF 1995 – 2005) WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation WEATHER ELEMENT VIS < 3000 M VIS < 1000 M Cloud Ceiling < 300 M Cloud Ceiling < 150 M Thunder Storm Precipitation

Legend: Where :

P1 33.4

0600 P2 33.4

P3

P1 44.1

0700 P2 44.1

P3 44.1

P1 16.6

0800 P2 33.4 66.6

P3 16.6

P1 33.4

0900 P2 33.4

P3 33.4

P1

66.6

P1

1400 P2

P3

P1

1500 P2

P3

P1

1600 P2

P3

P1

1700 P2

1000 P2

P3

P1

66.6

P3

P1

1800 P2

1100 P2

P3

P1

1200 P2

P3

66.6

66.6

66.6

P1

2000 P2

P3

  X 100 

 B&Sd P2 =   B

  X 100 

P3

P1

1900 P2

P3

 B&Pd &Sd  P3 =   X100 B  

B&Pd &Sd signifies the frequency of simultaneous occurrence weather at Base and both Diversions in the same METAR. B&Pd signifies the frequency of simultaneous occurrence at the Base and Primary diversion in the same METAR. B&Sd is the frequency of simultaneous occurrence at the Base and Secondary diversion. B is the frequency of occurrence at the Base Primary Diversion (Pd) - Jaisalmer

Secondary Diversion (Sd) -Uttarlai

Table – 52

1300 P2

P3

P1

2100 P2

P3

33.4

66.6

 B&Pd P1 =   B

P1

66.6

199

1200 1150

201 Fig – CL 1

202 MEANS AND EXTREMES : JODHPUR (DATA: JAN 1991 – DEC 2005) QFF (hPa) 03 UTC

Highest

1026.9

Mean

1017.4

Lowest

1005.1

DRY BULB TEMPºC 12 UTC

03 UTC

Highest

FEB

MAR

APR

Mean

1015.4

Lowest

1005.5

SD

3.2

Highest

1021.2

Mean

1012.1

Lowest

1003.3

SD

3.2

Highest

1018.7

Mean

998.7

SD

2.9

12 UTC

03 UTC

12 UTC

MAX

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Year

Year

Year

Year

Year

Year

Year

Year

Year

17(95)

14(02) 26(03)

18(95)

1023.3 1013.7

18.0 11.5

15(96)

1002.8

24(03)

2.8 6(81)

1018.9

1(93)

1000.8

1018.4

17(90)

998.2

1(98)

1014.4

24(02)

988.2 3.0

28.6

10.8

1(78)

32.8

20(05)

18.0 1.8

34.6

16.0

21(04)

40.2

26(00)

14.4

03(03)

44.4

16,20, 21(04)

18.0 2.8

18.2

2.2

19.0

01(82)

5.0

27(03)

23.6

20(05)

10.0 2.2

17(99)

22.0

5.0

21(05) 30(03)

32.1

26(02)

7.2

08(86)

29.2

23(96)

100

21

78

09(79)

6

94

7

94

11(01)

3

28(80) 16,24 (01)

82

24(90)

0

28(72)

100

31(76)

36.6

18.2

01(82)

42.0

11(93)

21.3

19(90)

45.4

28(77)

21.6

-2.8

30(77)

30.4

27(03)

4.7

7(74)

30.4

26.5

92

3.1

71,72 74,75 77-80 84-86 91,98 00-02 04,05

0.0

31.8

0.0 8.0

31(91)

16.9 1.7

9(79)

3.4

27(79)

Year

4.7

17.1 1(95)

Monthly

6.1

3.6

3.5

25(82)

-0.2

11.5

33.8 03(03)

31(03)

2.8

3.5

9.0

29(05)

15.7

19.0 9.2

28.0

17 03(03)

13(90)

2.7

11.6 11(05)

32.7 25.4

23

12.2

24(86)

29(92)

11.8 01(03) 08(05)

34

0.0 3.7

29(87)

In 24 hr

(KT) Date/

Date/

Year

Year 340/30

20.8

31/92 27/99

90 72,74 81,84 85,88 91,94 95,97 01,02 04

230/45 14.2

07/92 14/79

98 72-75 76-80 83-86 88,90, 91, 93-96, 99-02, 04,05

149.7

82

10.1

73-75 79,80 86,87 89,90 92,95 99,03

250/48 8.2

20/87 23/82

180/58 20.2

10,11 (05)

18(01)

14.8

2.3 29(01) 30 (01, 05)

19

100 28

49

17.4 04(03)

23(04)

14.7

2.5

17.5 25(82)

6.5

100 55

14.9

2.2

30(02)

08(70)

2.4

13.6

37.5 10(05)

23(01)

2.4

3.2

21(05)

2.2

31.0 13.7

9.9

32.4 04(03)

15(02)

1.9

3.2

27.7 8(85)

15(95)

26.5

1.7

1003.2 28(01)

28(03)

22.0

3.3

19(83)

5.8

13.6

16.8 7.6

2.7

2.2

1007.8 25(02)

23 (01,05)

15.0

3.2 6(1971)

24.0

28(91)

23.4

1.8

1011.3 29(80) 17(93)

6.6

33.0

Max Wind

RAINFALL (MM)

MIN

Date/

1007.8

Lowest

03 UTC

TEMPºC

Year

3.0 1023.3

12 UTC

RH (%)

Date/

JAN

SD

WET BULB TEMPºC

13.0 2.1

32 14(95)

10 11.5

16 04(01)

1 9.2

39.0 02,28 (02)

23.8 2.9

22.8 15(83)

13.4 3.1

4(97)

0.0 25.9

138.0

26/82 25/82

203 QFF (hPa) 03 UTC

Highest

1012.6

Mean

1003.8

Lowest

988.9

SD

2.8

DRY BULB TEMPºC 12 UTC

03 UTC

WET BULB TEMPºC

12 UTC

03 UTC

RH (%)

12 UTC

03 UTC

12 UTC

1008.1

Mean

1000.0

Lowest

987.6

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Year

Year

Year

Year

Year

Year

Year

Year

Year

Year

11(87)

1009.6

28(92)

999.2

35.0

11(03)

30.5

46.2

19(98)

40.0

26.4

16(02)

21.9

31.8

11(90)

22.8

77

22(01

46

100

22(02)

989.5

20(02)

2.9 3(97)

1006.9

22.4

03(05)

1.7 16(81)

995.4

35.6

20.0

06(82)

2.8 01(05)

30.7

46.8

12.4

03(03)

2.1 02(91)

38.6

27.2

2.4

11(01)

2.1 15(01)

24.6

35.0

6

20 11(03)

13.8 24(72)

25.2

93

Highest

JUL

Mean

AUG

2.8

1005.6

985.8

SD

2.5

1010.1

Mean

1001.4

Lowest

992.3

SD

2.7

979.4

4(93)

3.1

6(92) 4(96)

999.3

Lowest

Highest

10(98)

1003.5

974.3

12(88)

1006.0

23(71)

988.8 2.6

02(03)

25.2

28(79)

31.8

24.8 1.0

42.4

21.6

02(02)

41.4

11(91)

23.4 2.9

09(05)

2

19(03)

96

27.4

10(91)

22.2

18(03)

27.8

14(02)

22.2 0.9

34.0

7.0

05(04)

35.6

04(87)

20.4 1.3

01(05)

98

27(72)

53

23(01) 10(03)

100

14(02) 24(04)

52 8.7

100

4

28(03)

100

01(76) 03(82) 04(84) 09(86)

17 16.1

8(82)

46.8

11(98)

4(79) 7(89) 20(01)

116.1

82

In 24 hr

42.8

2(00)

Date/

Year

Year 320/56 22/83

0.0

77,79,84 88,89,91 98,03,04

111.1

07/82 180/56 22/99

26.2 18(03)

185.0

96 010/90

47.3

17.2

3(97)

2.4

31.8

0.0

03/75

85 29/98

47.4

1(91)

570.9

90 090/60

25.6

26.7 29(86)

41.6

20.0

150.4 2(96)

1.7

17(87)

30.5

0.0

172.2

03/90

02 18/99

116.0

10(87)

424.1

72 040/50

34.0 10(90)

35.0

Year

94.0 26.6

3.0 10(70) 16(72) 17,18(73) 22(91) 25,28(95) 07(97)

17.6

Monthly

(KT) Date/

18.9

28.2

35.7 28(74) 31(00)

18(02)

2.6 20(92) 6(94) 5(95)

2.8 23(78) 17(79) 04(90) 12(92) 24(94,95)

58 01,02 (02)

23.6

33.6 26.9

40.0

17.5

77 19(86)

21(96) 20(99)

52

10.9

20(93)

8

30(94)

2.6

11.7

74

25.8 22(01)

20

23(81) 05(96)

32

9.1

1.2

24.7 16(72)

01(77)

25.9

0.9

17(87)

2.2

47.8 41.4

10.0

60

1.6

24.9

32.4 01(04)

20.0

1.0

3.4

27.6 13(75)

18(03)

34.2 16(01) 23(01,03) 30(03)

1.3

997.9 18(73) 26(97)

33.4

23.8

3.2

28.5

2.6

29(79)

19(03)

1.5

995.6 15(93)

22.4

06(82)

Max Wind

RAINFALL (MM)

MIN

Date/

JUN

SD

MAX

Date/

MAY

Highest

TEMPºC

22.4 2.6

25.5 30(73)

19.9 1.5

264.0

122.8 25(72)

4.4 100.2

05/96

93 28/75

204 QFF (hPa) 03 UTC

Highest

1014.2

Mean

1006.1

Lowest

992.6

SD

2.7

Highest

1019.2

DRY BULB TEMPºC 12 UTC

03 UTC

WET BULB TEMPºC

12 UTC

03 UTC

RH (%)

12 UTC

03 UTC

TEMPºC 12 UTC

MAX

MIN

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Date/

Year

Year

Year

Year

Year

Year

Year

Year

Year

Year

22(94)

1010.6

23(94)

34.6

07(05)

41.8

06(05)

26.4

19(05)

34.6

02(85)

92

17(05)

100

03,15(84),07(92)

42.6

7(05)

30.8

7(05)

Max Wind

RAINFALL (MM)

Monthly

Year

369.6

74

In 24 hr

(KT) Date/

Date/

Year

Year

040/45 1002.2

27.8

33.8

22.7

24.2

64

45

35.5

24.2

49.3

SEP

84.4

Mean

1011.4

Lowest

999.2

SD

2.9

Highest

1023.4

8(92)

989.6

6(73)

2.8 24(79)

1016.6

25.0

15(02)

1.2 24(79)

1007.4

29.8

23.0

08(76)

2.8 06,11 (01)

24.3

40.0

16.2

29(01)

1.4 09(02)

33.8

24.6

18.6

13(74)

1.6 03(01) 04(02)

17.2

29.6

31 10.1

01(79)

20.7

88

Mean

1015.8

Lowest

1006.3

SD

2.5

Highest

1025.8

Mean

1018.0

Lowest

1008.3

SD

2.6

998.2

4(96)

2.9 30(89)

1019.4

18.2

31(05)

1.7 30(89)

1011.8

26.0

18.4

23(80)

2.4 06(02)

19.1

37.6

11.6

29(05)

1.9 27(93)

28.9

16.4

15.0

31(95)

2.1 02(01)

12.0

24.2

21

12(01)

17.3

78

13(74)

100

27(01) 23(03)

1

02(90)

38

98

12(89)

41.2

29(96)

20.5

9(02)

27

38.7

30(94)

28.0

18(98)

11.6

12(01)

31.8

22.8

67.7 8.5

31(96)

3.0 29(02)

0.0

0.0 14.9

21(91)

14.4

59.2 4.0

NOV 3(81)

1003.6

27(02)

2.4 21(86)

1021.8

13.0

30(05)

1.4 20(86)

18.4

18.0

20(76)

2.2 18(04)

31.6

7.6

26(03)

1.5 16(02)

14.4

10.4

30(05)

1.9 11(01)

24.0

20

25(02)

9.3 25(73)

100

4

17(74)

12.3 16(03)

88

21.0

18(76)

2.7 03(88)

35.8

5.2

27(78)

3.1 1(02)

21.6

09/76

86,87 29/93

77.1

19.9

2.4 20(76),12(78)

15.4 2.0

36.2

13.5 13(02)

25.4 2.6

27

10.9 16(91)

7 15.8

44

OCT 5(96)

29(01)

0.0 12.6

2(02)

74 72,73 76-78 80,84 87,89 91,93 02,03 05

180/45 35.4

24/75 01/99

75 70-75 77,8390 92,9496 98,99,01 03-05

29.6

80

1.6

70-73 75-79 81,83,84 86,88,89 92-01 03,05

330/36 30.9

21/76 03/81

280/35 1014.2

13.9

24.7

8.9

DEC 32(04)

1005.1 2.5

23(80)

7.2 1.8

16(03)

14.4 2.3

22(80)

4.6 2.0

14.8 27(04) 24(05)

5.4 2.1

48 30(87)

21

29 03(02) 05,12(05)

13.0

Table – CL 2

5 10.4

27.4 12(86)

17.4 2.8

10.2 27(80)

-1.2 2.7

15(86)

0.0 5.4

19.8

23/80 25/79

205

PENTAD NUMBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

PENTAD NORMALS : AF JODHPUR (QFF , MAX AND MIN) BASED ON DATA OF 1970 – 2005 PERIOD PRESSURE (QFF) TEMPERATURE FROM TO 0300Z SD 1200Z SD MAX SD MIN 01-Jan 05-Jan 1018.3 2.69 1014.7 2.50 25.5 2.81 8.7 06-Jan 10-Jan 1017.9 2.66 1014.2 2.33 25.3 2.44 9.1 11-Jan 15-Jan 1017.1 3.14 1013.4 3.01 25.4 2.53 9.3 16-Jan 20-Jan 1017.4 3.07 1013.8 2.97 25.1 2.72 8.7 21-Jan 25-Jan 1016.8 3.00 1013.3 2.89 25.3 2.63 9.4 26-Jan 30-Jan 1016.7 2.98 1013.1 2.72 25.8 2.94 9.6 31-Jan 04-Feb 1016.9 3.17 1012.8 3.09 25.7 2.80 9.6 05-Feb 09-Feb 1016.3 3.06 1012.1 2.89 26.8 3.17 9.6 10-Feb 14-Feb 1015.7 2.82 1011.6 2.84 28.0 3.24 11.2 15-Feb 19-Feb 1014.4 3.22 1010.4 3.20 28.3 3.27 11.9 20-Feb 24-Feb 1015.0 2.84 1010.8 2.90 28.9 3.62 12.7 25-Feb 01-Mar 1014.3 3.08 1010.0 3.24 30.1 3.23 14.2 02-Mar 06-Mar 1014.1 2.91 1010.1 2.93 31.6 3.25 14.7 07-Mar 11-Mar 1013.1 2.91 1008.9 2.84 32.8 2.98 15.6 12-Mar 16-Mar 1012.8 3.04 1008.5 2.99 33.3 3.19 16.6 17-Mar 21-Mar 1011.2 2.42 1006.8 2.67 34.7 2.83 17.9 22-Mar 26-Mar 1010.5 2.66 1006.3 2.97 35.2 3.11 18.7 27-Mar 31-Mar 1010.1 2.61 1005.9 2.80 36.1 3.30 19.5 01-Apr 05-Apr 1009.5 2.40 1005.0 2.58 37.0 2.70 20.4 06-Apr 10-Apr 1008.6 2.67 1004.2 2.82 37.6 2.76 21.1 11-Apr 15-Apr 1008.2 2.70 1003.6 2.73 38.8 2.98 22.3 16-Apr 20-Apr 1007.7 3.04 1002.9 3.09 39.2 2.83 23.3 21-Apr 25-Apr 1007.0 2.55 1002.2 2.50 40.1 2.26 24.4 26-Apr 30-Apr 1005.7 2.42 1001.1 2.42 41.0 2.17 25.3 01-May 05-May 1005.3 2.47 1000.7 2.61 40.7 2.69 25.6 06-May 10-May 1004.8 2.33 1000.0 2.61 41.1 3.05 26.4 11-May 15-May 1003.7 2.73 999.2 2.88 41.9 2.46 27.2 16-May 20-May 1003.2 3.00 998.5 2.97 41.8 2.33 27.2 21-May 25-May 1003.1 2.73 998.4 2.51 41.4 2.44 27.4 26-May 30-May 1002.8 2.81 998.0 3.21 41.3 2.38 27.5 31-May 04-Jun 1002.6 2.46 997.8 3.23 41.0 2.35 28.0 05-Jun 09-Jun 1000.9 2.34 996.1 2.88 41.2 2.42 28.6 10-Jun 14-Jun 1000.6 2.39 995.7 2.51 40.3 3.12 28.1 15-Jun 19-Jun 998.9 2.67 994.1 3.17 40.3 2.66 28.5 20-Jun 24-Jun 999.1 2.63 994.6 2.61 39.2 2.66 28.1 CL – 3

SD 2.77 2.76 2.73 2.87 2.92 3.04 2.56 3.41 3.28 3.31 3.58 3.79 2.67 3.14 3.18 2.84 3.10 2.94 2.63 2.78 2.59 2.95 2.13 2.14 2.58 2.59 2.24 2.72 2.47 2.47 2.79 2.46 2.77 2.31 1.96

206 PENTAD NORMALS : AF JODHPUR (Cont…..) PENTAD NUMBER 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73

PERIOD FROM TO 25-Jun 29-Jun 30-Jun 04-Jul 05-Jul 09-Jul 10-Jul 14-Jul 15-Jul 19-Jul 20-Jul 24-Jul 25-Jul 29-Jul 30-Jul 03-Aug 04-Aug 08-Aug 09-Aug 13-Aug 14-Aug 18-Aug 19-Aug 23-Aug 24-Aug 28-Aug 29-Aug 02-Sep 03-Sep 07-Sep 08-Sep 12-Sep 13-Sep 17-Sep 18-Sep 22-Sep 23-Sep 27-Sep 28-Sep 02-Oct 03-Oct 07-Oct 08-Oct 12-Oct 13-Oct 17-Oct 18-Oct 22-Oct 23-Oct 27-Oct 28-Oct 01-Nov 02-Nov 06-Nov 07-Nov 11-Nov 12-Nov 16-Nov 17-Nov 21-Nov 22-Nov 26-Nov 27-Nov 01-Dec 02-Dec 06-Dec 07-Dec 11-Dec 12-Dec 16-Dec 17-Dec 21-Dec 22-Dec 26-Dec 27-Dec 31-Dec

PRESSURE (QFF) 0300Z SD 1200Z 998.9 2.71 994.6 998.9 2.54 995.0 999.4 2.52 995.1 999.0 2.59 995.4 999.2 2.29 995.4 999.9 2.38 996.3 999.4 2.42 996.2 999.8 2.44 996.6 1000.4 2.55 997.1 1000.6 2.54 997.1 1001.2 2.41 997.9 1002.0 1.82 998.4 1002.6 2.65 999.0 1003.3 2.72 999.7 1004.1 2.19 1000.4 1005.4 2.32 1001.6 1006.3 2.31 1002.6 1007.3 2.31 1003.1 1007.3 2.57 1003.3 1008.3 2.45 1004.3 1009.2 2.18 1005.1 1010.1 2.25 1006.1 1011.1 2.44 1007.0 1012.1 2.62 1008.2 1013.5 2.26 1009.5 1014.1 2.38 1010.1 1014.7 2.33 1010.6 1014.8 2.18 1010.7 1015.9 1.94 1011.7 1016.0 2.22 1012.0 1016.7 2.52 1012.8 1017.1 2.76 1013.4 1018.2 2.63 1014.4 1017.7 2.21 1013.9 1017.9 2.34 1014.1 1018.2 2.82 1014.3 1018.0 2.68 1014.2 1018.2 2.94 1014.5 Table – CL 3

SD 2.89 2.64 2.54 2.69 2.25 2.84 2.36 2.47 2.50 2.61 2.43 1.98 2.50 2.64 2.51 2.34 2.53 2.50 2.66 2.62 2.04 2.31 2.44 2.58 2.17 2.31 2.11 2.02 1.94 2.08 2.38 2.71 2.42 2.26 2.24 2.91 2.53 2.58

MAX 38.8 37.3 37.1 36.3 35.1 34.7 34.3 34.4 33.8 34.0 33.6 34.1 34.1 34.5 34.5 34.6 35.3 36.1 36.6 37.2 37.1 37.0 36.4 36.0 35.0 34.8 33.9 33.0 32.2 31.4 30.3 29.2 28.5 28.4 27.9 27.4 26.2 25.6

TEMPERATURE SD MIN 2.59 27.8 2.91 27.5 2.65 27.5 2.70 27.0 3.22 26.5 2.82 26.3 2.74 26.1 3.10 25.9 2.53 25.6 2.58 25.7 2.84 25.4 2.43 25.3 2.43 24.9 2.10 25.1 2.38 24.6 2.68 24.3 2.62 24.4 2.55 23.7 2.43 23.3 2.04 22.9 2.16 21.9 2.07 20.9 2.53 19.9 2.03 18.9 2.46 18.0 2.06 16.8 2.15 15.8 1.81 15.0 2.00 14.6 2.43 13.9 2.29 12.7 2.68 11.5 2.28 10.9 2.64 10.1 2.52 10.1 2.82 9.9 2.50 10.0 2.47 9.1

SD 1.97 1.74 1.65 1.66 1.66 1.50 1.54 1.52 1.42 1.64 1.47 1.44 1.67 1.22 1.41 1.50 1.77 2.08 2.48 2.53 2.36 2.49 2.65 2.61 2.19 2.38 2.63 2.58 2.63 3.14 2.88 2.61 2.04 2.68 2.90 2.84 2.48 2.88

207

208

209

210 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: JANAUARY

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

5.5

12

1 (99)

0

1 (96)

3.9

0600-0900

Vis < 1.0km

1.9

8

1 (99)

0

4 (91,93,96,97)

2.42

0600-0900

5

1 (99)

0

5 (91,94,96,98,03)

1.56

0900-1200

ELEMENT

Ceiling (CL) CL < 300m

1.5

CL < 150m

0

0

0

0

0

0

0

Thunderstorm

0.2

2

01 (03)

0

8 (91,92,94,95, 97-00)

0.4

2100-2400

Duststorm

0

0

0

0

0

0

0

Hail Storm

0

0

0

0

0

0

0

PPTN

2.3

5

1 (92)

0

3 (00-02)

2.3

1800-2100

Sur Wind >30Kts

0

0

0

0

0

0

0

DRW

0.3

2

1 (92)

0

14 (91, 93 - 05)

0.64

1800-2100

Temp>40 º C

0

0

0

0

0

0

0

Table – DA J1

211 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: FEBRUARY

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

2.5

6

02 (92,05)

0

01 (95)

1.68

0600-0900

Vis < 1.0km

0.9

4

01 (05)

0

07 (91,93,95,97,01,02,04)

0.87

0600-0900

1

8

01 (05)

0

05 (94, 95,96,01,02)

0.6

0600-0900

CL < 150m

0

0

0

0

0

0

0

Thunderstorm

0.5

2

01 (03)

0

08 (93,94,96,97, 0002,04)

0.5

1500-1800

Duststorm

0.2

2

01 (03)

0

13 (91, 93 -0002,04,05)

0.3

1500-1800

Hail Storm

0.1

1

01 (92)

0

09 (91, 93 -00)

0.3

1500-1800

PPTN

1.9

5

02 (95,99)

0

05 (94, 96, 97,00,04)

1.97

1500-1800

Sur Wind >30Kts

0

0

0

0

0

0

0

DRW

1

4

01 (92)

0

07 (91,93,95,96, 99,00,04)

1.41

1500-1800

Temp>40 º C

0

0

0

0

0

0

0

ELEMENT

Ceiling (CL) CL < 300m

Table – DA J2

212 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: MARCH

Mean

tHighes

Year(s)

Lowest

Year(s)

SD

Peak Period

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(g)

2.3

6

01 (91)

0

03 (95,98,99)

1.9

1500-1800

0.8

3

01 (97)

0

06 (93,95,96,98, 99,00,01-05)

0.8

1500-1800

0.1

0

0

0

0

0

0

0

0

0

0

0

0

Thunderstor m

1

5

01 (97)

0

0.8

2100-2400

Duststorm

0.5

3

01 (97)

0

0.5

1500-1800 2100-2400

Hail Storm

0

0

0

0 05 (91,92,93,98, 99) 06 (93,95,96,98, 99,00) 0

0

0

PPTN

2.7

11

0

01 (95)

0.5

1500-1800

0

08 (91,92,93,95, 96,98, 99,00)

0.4

1500-1800 2100-2400

0

2 (95,99)

1.4

1500-1800

0

09 (91-98,00)

2.7

1500-1800

ELEMENT

Vis < 3km Vis<1.0km Ceiling (CL) CL< 300m CL < 150m

Sur Wind >30Kts

0.3

3

DRW

1.8

4

Temp>40 º C

0.7

3

0 01 (97) 01 (97) 01 (96) 01 (99)

Table – DA J3

213 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: APRIL

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

6.7

12

02 (91,92)

1

01 (99)

1.7

1800-2100

Vis<1.0km

3.1

7

01 (99)

0

01 (99)

2

1800-2100

Ceiling (CL) CL< 300m

0.6

2

01 (97)

0

05 (91,95, 96,98, 99)

0.2

0600-0900

CL < 150m

0

0

0

0

0

Thunderstorm

2.7

7

01 (94)

0

02 (92,99)

1.5

1800-2100

Duststorm

2.2

5

01 (94)

0

01 (99)

1.6

1800-2100

Hail Storm

0.9

1

01 (95)

0

09 (91-94 & 96-00)

PPTN

2.3

5

01 (97)

0

01 (99)

1.4

1800-2100

Sur Wind >30Kts

0.9

3

01 (97)

0

04 (92,93,98,00)

1.1

0000-0300

DRW

3.7

5

01 (98)

0

01 (93)

1.0

1500-1800

Temp>40 º C

8.9

20

01 (00)

0

04 (91,92,93,95)

3.8

1500-1800

ELEMENT

Table – DA J4

0

1800-2100

214

SUMMARY OF MAIN AVIATION WEATHER HAZARDS: MAY

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

9.7

16

01 (02)

2

02 (99)

3.8

1500-1800

Vis<1.0km

4.5

9

01 (92)

1

02 (95,00)

1.5

0600-0900

1.1

5

01 (99)

0

03 (92,94,98,0105)

0

0600-0900

CL < 150m

0.2

1

02 (97, 99)

0

04 (91,96,98,0005)

0

0900-1200

Thunderstorm

3.5

8

02 (96, 97)

0

01 (91,04)

2.9

2100-2400

Duststorm

3.1

8

01 (96)

0

01 (99,04)

2.1

1800-2100

Hail Storm

0.2

2

01 (97)

0

08 (91-96 & 98-05)

0

1800-2100

PPTN

3.1

7

02 (96, 97)

0

01 (91)

2.4

2100-2400

Sur Wind >30Kts

2.5

9

01 (96)

0

01 (91)

1.3

0900-1200

DRW

8.7

18

02 (00,02)

2

01 (92)

3.7

1500-1800

Temp>40 º C

17.4

27

01 (02)

0

03 (91,92,93)

2.9

1500-1800

ELEMENT

Ceiling (CL) CL< 300m

Table – DA J5

215 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: JUNE

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

11.7

21

01 (92)

3

01 (93)

2.97

1200-1500

Vis < 1.0km

5.3

13

01 (92)

1

01 (92)

1.2

1800-2400

CL < 300m

4.3

10

02 (96, 97)

1

03 (91, 92, 94)

1.79

0600-0900

CL < 150m

0.1

1

01 (96)

0

9(91-95

0.3

0900-1200

ELEMENT

97-00) Thunderstorm

4.4

11

01 (97)

1

01 (94)

2.06

1800-2100

Duststorm

3.6

8

01 (98)

1

02 (99,00)

1.36

1800-2100

Hail Storm

0

0

0

0

0

0

0

PPTN

3.9

10

02 (97, 98)

0

01 (00)

1.47

0000-0300

Sur Wind >30Kts

2.8

8

01 (02)

0

02 (93,96)

2.58

0900-1500

DRW

10.8

18

02 (03,04)

3

02 (93,99)

3.01

1200-1500

Temp>40ºC

17.7

28

01 (05)

4

01 (99)

7.63

1500-1800

Table – DA J6

216

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

SUMMARY OF MAIN AVIATION WEATHER HAZARDS: JULY AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

11.7

21

01 (92)

3

01 (93)

2.97

1200-1500

Vis < 1.0km

5.3

13

01 (92)

1

01 (92)

1.2

1800-2400

CL < 300m

4.3

10

02 (96, 97)

1

03 (91, 92, 94)

1.79

0600-0900

CL < 150m

0.1

1

01 (96)

0

9(91-95

0.3

0900-1200

ELEMENT

97-00) Thunderstorm

4.4

11

01 (97)

1

01 (94)

2.06

1800-2100

Duststorm

3.6

8

01 (98)

1

02 (99,00)

1.36

1800-2100

Hail Storm

0

0

0

0

0

0

0

PPTN Sur Wind >30Kts DRW

3.9

10

02 (97, 98)

0

01 (00)

1.47

0000-0300

2.8

8

01 (02)

0

02 (93,96)

2.58

0900-1500

10.8

18

02 (03,04)

3

02 (93,99)

3.01

1200-1500

Temp>40ºC

17.7

28

01 (05)

4

01 (99)

7.63

1500-1800

Table – DA J7

217

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

SUMMARY OF MAIN AVIATION WEATHER HAZARDS: AUGUST AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

4.5

9

03 (91, 92, 99)

1

1 (00)

1.36

1500-1800

Vis < 1.0km

1.7

5

01 (98)

0

04(93,00,01,05)

1.1

1500-1800

CL < 300m

9.8

23

01 (94)

6

01 (93)

4.6

0600-0900

CL < 150m

0.7

3

01 (99)

0

7(9194,97,98,00)

1.1

0600-0900

Thunderstorm

5.1

10

01 (03)

0

01 (02)

3.77

1800-2100

Duststorm

1.4

6

01 (98)

0

06 (93, 97, 99, 00,01,05)

1.1

1500-1800

Hail Storm

0

0

0

0

0

0

0

PPTN

6.3

20

01 (94)

1

01 (93)

3.88

1800-2100

Sur Wind >30Kts

0.6

3

02 (95, 98)

0

07 (91-94, 97, 99, 00,03-05)

0.49

1500-1800

DRW

3.5

9

01 (98)

0

01 (99)

2.04

1500-1800

Temp>40 º C

2.7

14

01 (98)

0

05 (93, 94, 99,01,03)

2.87

1500-1800

ELEMENT

Table – DA J8

218 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: SEPTEMBER

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

2.7

7

01 (94)

0

04 (95,00,01,03)

2.23

1500-1800

Vis < 1.0km

0.9

4

01 (92)

0

07 (91,95, 96,00,01,03-04)

0.98

1500-1800

5.3

14

01 (94)

0

01 (99)

1.79

0600-0900

CL < 150m

0.1

1

01 (93)

0

09 (91,92, 94-00)

0.3

1800-2100

Thunderstorm

3.1

7

01 (94)

0

05 (91,99, 00,01,03)

2.5

1800-2100

Duststorm

0.9

3

02 (93,05)

0

07 (91,94, 96,00,01,03,04)

1.26

1500-1800

Hail Storm

0

0

0

0

0

0

0

PPTN

3.2

8

02 (98,05)

0

05 (91,99, 00,01,03)

2.99

1800-2100

Sur Wind 30Kts

0.3

2

01 (02)

0

12 (91,92, 9400,01,03-04)

0.8

1500-1800

DRW

1.1

5

01 (05)

0

07 (91,93, 94,96, 97, 00,03)

1.72

1200-1500

Temp>40 º C

3.4

11

01 (93)

0

04 (91,94, 96,03)

2.8

1500-1800

ELEMENT

Ceiling (CL) CL < 300m

Table – DA J9

219

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

SUMMARY OF MAIN AVIATION WEATHER HAZARDS: OCTOBER AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

2.1

15

01 (04)

0

07 (93,94, 96,99, 00,01,03)

1.22

0600-0900

Vis < 1.0km

0.5

3

01 (04)

0

0.45

1500-1800

0.5

3

02 (97,98)

0

1.18

0600-0900

CL < 150m

0

0

0

0

0

0

Thunderstorm

1.1

5

01 (97)

0

1.49

1500-1800

Duststorm

0.2

2

01 (97)

0

13(91-96, 98-00,0103,05)

0.6

1500-1800

Hail Storm

0

0

0

0

0

0

0

PPTN

1.1

6

01 (97)

0

1.8

1800-2100

Sur Wind >30Kts

0.1

2

01 (97)

0

0.6

1500-1800

DRW

0.3

2

02(02,04)

0

12 (91-97, 9900,01,03,05)

0.3

0600-0700

Temp>40 º C

2.1

11

01 (00)

0

09 (91-95, 97,99,04,05)

3.34

1500-1800

ELEMENT

Ceiling (CL) CL < 300m

07 (91-94, 96, 99,0001,03,05) 07 (9196,99,01,0305) 0 06 (91,96,0103,05)

08 (91,93, 95,96,0103,05) 14 (91-96, 98-00,0105)

Table – DA J10

220

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak Period

SUMMARY OF MAIN AVIATION WEATHER HAZARDS: NOVEMBER AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

0.7

3

02 (97,02)

0

07 (91-93,95, 98,99,01)

1.07

0600-0900

Vis < 1.0km

0.2

2

01 (96)

0

13 (91-95, 97-03,05)

0.6

0600-0900

0.2

2

01 (96)

0

13 (91-95, 98-05)

0.69

0600-0900

CL < 150m

0.3

2

01 (96)

0

08 (91-95, 98-00)

0.64

0600-0900

Thunderstorm

0.3

2

01 (02)

0

12 (91,93-96, 9801,03-05)

0.4

0600-0900

Duststorm

0

0

0

0

0

0

0

Hail Storm

0

0

0

0

0

0

0

PPTN

0.7

4

01 (02)

0

11 (92,94-96, 9801,03-05)

1.01

2100-2400

Sur Wind >30Kts

0

0

0

0

0

0

0

DRW

0.7

1

01(02)

0

14(91-01,03-05)

0

0

Temp>40 º C

0

0

0

0

0

0

0

ELEMENT

Ceiling (CL) CL < 300m

Table – DA J11

221 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: DECEMBER

Mean

Highest

Year(s)

Lowest

Year(s)

SD

Peak

AF JAISALMER (DATA 1991- 2005)

Fqy (a)

Fqy (b)

(c )

Fqy (d)

(e)

(f)

(k)

Vis < 3km

2.5

6

02 (92,05)

0

01 (95)

1.68

0600-0900

Vis < 1.0km

0.9

4

01 (05)

0

07 (91,93,95,97,01,02,04)

0.87

0600-0900

1

8

01 (05)

0

05 (94, 95,96,01,02)

0.6

0600-0900

CL < 150m

0

0

0

0

0

0

0

Thunderstorm

0.5

2

01 (03)

0

08 (93,94,96,97, 0002,04)

0.5

1500-1800

Duststorm

0.2

2

01 (03)

0

13 (91, 93 -00-02,04,05)

0.3

1500-1800

Hail Storm

0.1

1

01 (92)

0

09 (91, 93 -00)

0.3

1500-1800

PPTN

1.9

5

02 (95,99)

0

05 (94, 96, 97,00,04)

1.97

1500-1800

Sur Wind >30Kts

0

0

0

0

0

0

0

DRW

1

4

01 (92)

0

07 (91,93,95,96, 99,00,04)

1.41

1500-1800

Temp>40 º C

0

0

0

0

0

0

0

ELEMENT

Ceiling (CL) CL < 300m

Table – DA J12

222

MEANS AND EXTREMES : AIR FORCE JAISALMER (DATA: JAN 1973 – DEC 2005)

MONTH JAN

FEB

MAR

APR

MAY

JUN

QFF(hPa) 0300 1200 UTC UTC

DRY BULB TEMP 0 C 0300 1200 UTC UTC

WET BULB TEMP 0 C 0300 1200 UTC UTC

RH % 0300 1200 UTC UTC

MAX TEMP 0 C

MIN TEMP 0 C

RAIN FALL (MM) 24 MONTHLY HRS 21.7 14.1

HIGHEST

1026.3

1023.9

18.6

31.0

16.8

21.4

100

97

32.2

16.4

MEAN

1017.6

1014.3

9.4

22.4

6.2

13.5

61.6

31.9

24.0

7.0

2.0

LOWEST

1007.9

1003.6

1.4

12.0

-2.5

7.2

20

2

13.5

-2.5

0.0

HIGHEST

1023.6

1020.5

23.2

25.4

18.0

23.0

100

96

37.3

21.5

24.8

MEAN

1015.4

1011.7

12.8

25.5

8.9

15.3

56.5

28.7

26.9

10.1

4.1

LOWEST

1004.7

1000.2

1.4

8.8

-2.0

5.4

10

1

17.0

-1.3

0.0

HIGHEST

1011.1

1007.2

37.8

46.2

29.4

31.6

100

100

48.2

34

132.1

MEAN

1002.9

998.6

29.4

40.5

22.9

23.9

55.6

22.3

42.1

25.4

14.4

LOWEST

994.1

990.6

22.6

23.4

11.6

8.4

9

1

25.6

16

0

HIGHEST

1021.4

1016.9

29.8

40.6

22

28.2

100

85

43.0

25.8

17.8

MEAN

1011.5

1007.7

20.2

31.5

14.2

18.5

47.7

24.5

32.8

15.7

1.8

LOWEST

1002.8

998.3

9.6

17

4.4

9.6

6

1

13.6

2.4

0

HIGHEST

1018.2

1014.3

37

44.8

26

31.2

91

75

46.6

28.8

27.4

MEAN

1007.3

1003

25.6

34.6

18.9

21.7

45.9

22.2

38.6

21.9

4.4

LOWEST

998.0

992.7

16.4

21

8.4

11.6

7

1

24.7

10.4

HIGHEST

1008.4

1005.0

39.8

48.0

28.8

33.5

100

100

49.7

34.0

0 115.2

MEAN

998.0

994.1

30.0

40.0

25.0

25.8

66.7

30.7

41.4

26.9

26.3

LOWEST

989.6

982.1

23.6

25.4

17.6

19.4

13

3

28.8

17.9

0.0

Table – DA J13

MAX SUR WIND DATE/YEAR

24033 21.2 25040 111.3 340/58 15.0 270/60 19.8 220/58 76.6 320/55

223 MEANS AND EXTREMES : AIR FORCE JAISALMER (DATA: JAN 1973 – DEC 2005)

MONTH HIGHEST JUL MEAN LOWEST HIGHEST AUG MEAN LOWEST HIGHEST SEP MEAN LOWEST HIGHEST OCT MEAN LOWEST HIGHEST NOV MEAN LOWEST HIGHEST DEC MEAN LOWEST

QFF(hPa) 0300 1200 UTC UTC 1004.5 1002.4 998.1 994.3 989.5 986.6 1009.6 1004.8 1000.3 996.8 992.1 988.9 1013.0 1010.5 1005.4 1001.5 996.8 992.3 1020.7 1019.0 1011.0 1007.2 1003.1 997.9 1023.0 1020.5 1015.5 1011.8 1009.0 1005.5 1025.7 1022.2 1018.4 1014.7 1007.0 1004.1

DRY BULB TEMP 0 C 0300 1200 UTC UTC 35.2 43.8 29.4 36.2 24.6 25.0 35.2 42.8 27.6 34.6 24.0 24.0 32.2 41.2 27.1 35.4 16.0 26.6 31.4 40.4 24.7 33.9 17.4 19.0 26.2 36.6 17.5 28.5 9.4 15.4 19.0 30.4 11.0 23.8 1.6 11.4

WET BULB TEMP 0C 0300 1200 UTC UTC 29.4 33.6 25.4 26.5 22.4 22.0 28.6 32.0 24.9 26.3 21.2 22.6 27.8 31.4 23.4 24.7 14.4 19.0 27.6 30.0 18.6 21.3 11.2 14.4 23.0 27.4 12.5 17.8 4.0 10.4 18.0 21.4 7.4 14.4 -3.0 5.0

RH % 0300 1200 UTC UTC 100 100 75.5 45.7 31 20 100 100 79.1 50.0 41 25 100 100 75.3 40.4 23 9 95.0 98.0 54.9 28.2 10.0 3.0 100.0 100.0 51.5 29.4 22.0 5.0 100 100 58.3 30.9 12 1

Table – DA J14

MAX TEMP 0 C 44.4 37.7 27.0 45.4 36.5 25.4 42.4 37.1 27.5 42.0 36.8 20.4 38.0 31.5 19.6 34.6 26.3 14.4

MIN TEMP 0 C 31.4 26.2 20.6 31.2 25.4 22.0 29.5 24.1 18.6 28.8 20.4 11.2 24.0 13.4 3.0 16.2 8.0 -0.8

RAIN FALL (MM) 24 MONTHLY HRS 195.3 77.2 TRACE 331.3 188.8 68.1 TRACE 158.9 52.6 24.1 0.0 78.6 45.8 6.0 0.0 47.6 44.4 2.6 0.0 35.7 33.2 1.9 0.0

MAX SUR WIND DATE/YEAR

200/50,090/50

050/50

020/38

330/61

050/25

25035

224 GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: JANUARY DAY April

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BA D

Highest Mean

28 26

5 4

3 1

31 31

1 0

0 0

31 30

2 1

0 0

31 31

1 0

0 0

Lowest

24

2

0

30

0

0

29

0

0

30

0

0

GOOD

MARGINAL

BAD

37

TRANSPORT: JANAUARY DAY

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

April Highest Mean

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

28

7

3

31

0

0

31

2

0

31

1

0

26

4

1

31

0

0

31

0

0

31

0

0

Lowest

23

1

0

28

0

0

29

0

0

30

0

0

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: FEBRUARY DAY April

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BA D

Highest Mean

28 26

3 1

4 1

29 28

1 0

1 0

28 27

2 1

1 0

29 28

2 0

0 0

Lowest

21

0

0

26

0

0

25

0

0

26

0

0

GOOD

MARGINAL

BAD

37

225 TRANSPORT: FEBRUARY DAY April Highest Mean Lowest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

28

3

2

29

1

0

29

1

1

29

2

0

26

2

0

28

0

0

28

0

0

28

0

0

24

0

0

27

0

0

26

0

0

26

0

0

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: MARCH DAY March Highes t Mean Lowest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

31

01/93

00

31

01/91

01/03

31

04/93

03/04

31

01/96

02/05

29

2

0

28

2

1

30

1

0

30

1

0

30

00

00

29

00

00

27

00

00

29

00

00

FOR TRANSPORT: MARCH

19

DAY

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

March Highest Mean

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

31

01/03

00

31

01/03

01/03

31

04/93

02/97

31

01/96

02/05

30

1

0

30

1

0

30

1

0

30

1

0

Lowest

30

00

00

29

00

00

28

00

00

29

00

00

226

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: APRIL DAY April Highest Mean Lowest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD 30

MARGINAL 01/05

BAD 00

GOOD 30

MARGINAL 03/97

BAD 02/04

GOOD 30

MARGINAL 02/02

BAD 05/05

GOOD 30

MARGINAL 02/94

BAD 02/04

27

2

1

22

2

6

27

1

2

28

1

1

29

00

00

26

00

00

24

00

00

28

00

00

37

FOR TRANSPORT: APRIL DAY April Highest Mean Lowest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

30

1/96

00

30

3/97

02/05

30

03/05

4/92

30

2/04

1/02

26

3

1

28

3

4

28

1

1

28

1

1

29

00

00

27

00

00

25

00

00

00

00

00

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: MAY DAY May GOOD

0600- 1200 h MARGINAL

BAD

NIGHT 1200- 1800 h GOOD MARGINAL

BAD

1800- 2400 h GOOD MARGINAL

BAD

GOOD

0000- 0600 h MARGINAL

BAD

Highest

31

03/04

3/99

31

02/04

3/03

31

04/95

4/99

30

03/02

2/04

Mean Lowest

25 28

5 00

1 00

13 26

3 00

5 00

25 25

4 00

2 00

25 00

5 00

1 00

227 FOR TRANSPORT: MAY DAY May Highest Mean Lowest

0600- 1200 h GOOD MARGINAL 31

01/2000

25

5

BAD 03/9 9 1

28

00

00

NIGHT

1200- 1800 h GOOD MARGINAL 31

02/91

20

4

BAD 01/0 3 7

29

00

00

1800- 2400 h GOOD MARGINAL 31

04/95

26

4

BAD 04/9 9 1

25

00

00

0000- 0600 h GOOD MARGINAL 31

03/02

25

6

BAD 02/9 9 0

28

00

00

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: JUNE DAY April

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

Highest Mean

30

12

6

22

8

19

26

9

BA D 5

25

3

2

16

3

11

24

4

Lowest

15

0

0

7

0

0

20

0

GOOD

MARGINAL

BAD

29

11

1

2

27

3

0

0

1

0

0

37

FOR TRANSPORT: JUNE DAY April Highest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

30

9

2

27

9

18

26

8

5

29

10

1

Mean

26

3

1

21

5

4

25

4

1

27

3

0

Lowest

19

0

0

12

0

0

22

0

0

20

0

0

228

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: JULY DAY April Highest Mean Lowest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

30 24 16

7 2 0

8 5 1

27 25 20

5 3 0

10 3 0

28 24 19

5 3 0

0000- 0600 h BA D 8 4 0

GOOD

MARGINAL

BAD

30 28 24

3 2 0

6 1 0

37

FOR TRANSPORT: JULY DAY April Highest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

30

0

6

27

7

2

28

6

5

30

3

3

Mean

26

2

3

26

4

1

24

5

2

28

2

1

Lowest

21

3

0

22

1

0

20

2

0

25

1

0

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: AUGUST DAY April

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BA D

Highest

31

3

7

29

2

3

30

3

7

31

2

1

Mean

28

1

2

28

2

1

27

1

3

30

1

0

Lowest

22

0

0

27

1

0

24

0

0

29

0

0

GOOD

MARGINAL

BAD

229

37

FOR TRANSPORT: AUGUST DAY April Highest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

31

1

6

30

2

3

30

3

3

31

2

1

Mean

29

0

2

29

1

1

28

2

1

30

0

0

Lowest

24

0

0

27

1

0

26

0

0

29

0

0

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: SEPTEMBER DAY April

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

Highest Mean

29

2

3

30

2

4

30

1

BA D 3

28

1

1

28

1

1

28

0

Lowest

26

0

0

27

0

0

26

0

GOOD

MARGINAL

BAD

30

0

2

2

29

0

1

0

28

0

0

37

FOR TRANSPORT: SEPTEMBER DAY April Highest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

30

1

2

30

2

3

30

0

2

30

1

1

Mean

29

0

1

29

0

1

29

0

1

30

0

0

Lowest

28

0

0

28

0

0

28

0

0

29

0

0

230 GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: OCTOBER DAY April Highest Mean Lowest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

31

6

1

31

2

0

31

2

BA D 1

29

2

0

31

0

0

30

1

24

0

0

29

0

0

29

0

GOOD

MARGINAL

BAD

31

2

0

0

31

0

0

0

29

0

0

37

FOR TRANSPORT: OCTOBER DAY April

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

Highest Mean

31

4

1

31

2

0

31

2

1

31

2

0

30

1

0

31

0

0

30

1

0

31

0

0

Lowest

26

0

0

29

0

0

29

0

0

29

0

0

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: NOVEMBER DAY April Highest Mean Lowest

NIGHT

GOOD

0600- 1200 h MARGINAL

1200- 1800 h MARGINAL

BAD

GOOD

30

2

1

30

0

1

30

29

1

0

30

0

0

28

0

0

29

0

0

BAD

1800- 2400 h GOOD MARGINAL

0000- 0600 h MARGINAL

BAD

GOOD

BAD

0

0

30

0

0

30

0

0

30

0

0

30

0

0

30

0

0

231

37

FOR TRANSPORT: NOVEMBER DAY April Highest Mean Lowest

NIGHT

0600- 1200 h GOOD 30 29 28

MARGINAL 2 1 0

1200- 1800 h BAD 0 0 0

GOOD 30 30 29

MARGINAL 0 0 0

1800- 2400 h BAD 1 0 0

GOOD 30 30 30

MARGINAL 0 0 0

0000- 0600 h BAD 0 0 0

GOOD 30 30 30

MARGINAL 0 0 0

BAD 0 0 0

GOOD /MARGINAL/BAD WEATHER DAYS FOR FIGHTER: DECEBER DAY April Highest Mean Lowest

NIGHT

0600- 1200 h

1200- 1800 h

1800- 2400 h

0000- 0600 h

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BAD

GOOD

MARGINAL

BA D

29 26 22

9 4 0

4 1 0

31 29 25

6 2 0

1 0 0

31 30 26

5 1 0

0 0 0

GOOD

MARGINAL

BAD

31 30 26

5 1 0

0 0 0

NIGHT

GOOD

0600- 1200 h MARGINAL

BAD

GOOD

Highest

30

9

1

31

4

1

31

Mean Lowest

27 22

4 1

0 0

29 27

2 0

0 0

30 26

April

37

FOR TRANSPORT: DECEBER DAY 1200- 1800 h MARGINAL

BAD

Table – DA J14

1800- 2400 h GOOD MARGINAL

BAD

GOOD

0000- 0600 h MARGINAL

BAD

5

0

31

5

0

1 0

0 0

30 26

1 0

0 0

232

233 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: JANUARY AF STN UTTARLAI (DATA : 1991- 2005) Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e) 1991, 96, 98, 2001 -03 & 05

(f)

(g)

Vis <1 Km

1.3

05

2000

00

2.1

0600- 0900

Vis < 3 Km

3.2

08

1999

00

1991, 1998

4.1

0600 – 1200

Ceiling < 300 m

0.9

03

2004

00

1991, 96, 98, 2001, 03 & 05

1.3

0600- 1200

Thunder Storm

0.3

01

1994, 1995

00

1991 – 93, 96 - 2005

0.4

0900 – 1800

Dust Storm

0.1

01

1992

00

1991, 1993 -2005

0.3

1500 – 2100

Precipitation

1.5

04

1992

00

1996, 97, 2000 - 02

2.0

0900 – 1200

D'Haze

1.2

06

2003

00

1991, 95 – 99, 2001

2.1

1200 – 1500

S/Wind > 30 Kts

00

00

1991 2005

00

1991- 2005

0.0

-

DRW

0.2

01

1992, 1994

00

91,93,95 05

0.4

1200 – 1500

Fog

1.2

05

2000

00

1991, 96, 98, 2001 -03 & 05

2.0

0600 – 0900

Mist

2.1

06

1999 & 2000, 04

00

1991, 96, 98 & 2005

2.9

0600 - 0900

Elements

Table – DA U1

234 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: FEBRUARY AF STN UTTARLAI (DATA : 1991- 2005)

Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

0.6

02

2000 & 05

00

1991, 95 -98, 2002 & 04

1.0

0600 – 0900

Vis < 3 Km

2.2

06

2003 & 05

00

1991, 95 - 97 & 2004

2.9

0600 – 0900

Ceiling < 300 m

0.3

02

2003

00

1991, 93 -2002 & 04

0.6

0600 – 0900

Thunder Storm

0.4

02

1999

00

1991, 93 -95, 97-98, 200002 & 04

0.9

1500 – 2100

Dust Storm

0.1

01

1999

00

1991-98, 2000-05

0.3

1500 – 1800

Precipitation

1.3

03

1998, 2003

00

1994, 96-97, 2001 & 04

1.7

1500 – 1800

D'Haze

3.6

11

2001

00

1995

4.6

1200 – 1500

S/Wind > 30 Kts

0.2

02

2005

00

1991, 932004

0.6

1800 – 2100

DRW

0.6

02

00

1991, 93, 9597, 2000-02 & 04

1.0

1500 – 1800

Fog

0.4

01

00

1991, 952002 & 04

0.6

0600 – 0900

00

1991, 93, 95-2002 & 04

0.5

0600 – 0900

Elements

Mist

0.3

01

1998, 2003 & 05 1992-94, 2003 & 05

1992, 94, 2003 & 05

Table – DA U2

235 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: MARCH AF STN UTTARLAI (DATA : 1991- 2005)

Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

0.7

02

1992, 2000, 02 & 03

00

1.1

1500 – 1800

Vis < 3 Km

1.8

07

2003

00

2.5

1500 – 1800

Ceiling < 300 m

0.1

01

1993

00

0.3

0600 – 0900

Thunder Storm

0.7

02

1996, 1998

00

0.9

1800- 2100

Dust Storm

0.3

01

1995, 97, 2000 & 01

00

0.5

1500 – 1800

Precipitation

1.6

08

1997

00

2.6

1800- 2100

D'Haze

5.5

17

2003

00

1997

6.6

0900 – 1200,

S/Wind > 30 Kts

0.2

02

1997

00

1991-96, 982001 & 03 -05

0.6

1500 – 1800

DRW

1.2

04

1997

00

1994, 99, 2002 & 04

1.5

1500 – 1800

Temp > 40°C

2.3

10

2004

00

1992-93, 95, 97, 2001 & 05

3.6

1500 - 1800

Fog

00

00

1991 2005

00

1991- 2005

0.0

-

Mist

00

00

1991 2005

00

1991- 2005

0.0

-

Elements

1991, 93-94, 96, 98-99, 2004 & 05 1996, 99, 2004 & 05 1991, 92, 94-2005 1991 – 94, 2000, 03 & 04 1991- 94, 96, 98, 99, 2002 - 05 1991, 93, 94, 2000, 01, 03 & 05

Table – DA U3

236 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: APRIL AF STN UTTARLAI (DATA : 1991- 2005) Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

1.5

4.0

2001

0.0

92,93, 96 & 99

1.9

1800-2100

Vis < 3 Km

3.8

8.0

2001

0.0

92 & 96

4.5

2100-2400

Ceiling < 300 m

0.0

0.0

91-2005

0.0

91-2005

0.0

-

Ceiling < 150 m

0.0

0.0

91-2005

0.0

91-2005

0.0

-

Thunder Storm

1.9

5.0

2001

0.0

91,92,99, 00&02

2.5

1800-2100

Dust Storm

1.1

4.0

2001

0.0

91-93, 95, 96 &99

1.5

1800-2100

Hail Storm

0.1

1.0

1997

0.0

91-96 & 98-2005

0.3

1200-1500

Precipitation

1.4

5.0

2001

0.0

99, 00 & 02

1.9

2100-2400

D'Haze

8.8

19.0

2003

2.0

1993

10.1

0900-1800

S/Wind > 30 Kts

0.6

2.0

2005

0.0

91, 92, 94, 95, 96, 99, 00 & 02

0.8

1800-2100

DRW

2.3

6.0

1997

0.0

92, 93, 95 & 99

2.9

1500-1800

Temp > 40°C

14.5

26.0

1999

6.0

1992

15.3

1500-1800

Elements

Table – DA U4

237 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: MAY AF STN UTTARLAI (DATA : 1991- 2005)

Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

2.7

6.0

97 & 01

1.0

95, 98, 02 & 04

3.1

1800-2100

Vis < 3 Km

6.7

20.0

2003

1.0

1998

8.2

2100-2400

Ceiling < 300 m

0.5

2.0

95 & 99

0.0

91,92,94, 96,98, 00, & 02-05

0.8

0600-0900

Ceiling < 150 m

0.2

2.0

1999

0.0

91- 98 & 00-05

0.5

0900-1200

Thunder Storm

2.1

7.0

2005

0.0

91, 93, 98, 03 & 04

2.9

1800-2100

Dust Storm

1.4

4.0

97 & 01

0.0

91, 00, 03 & 04

1.8

1800-2100

Hail Storm

0.0

0.0

91-2005

0.0

91-2005

0.0

-

Precipitation

2.2

5.0

94, 97 & 05

0.0

91 & 03

2.7

1800-2100

D'Haze

15.2

29.0

2003

3.0

91 & 96

16.9

1500-2100

S/Wind > 30 Kts

0.9

3.0

1997

0.0

91, 93, 98, 03 & 04

1.3

1200-2100

DRW

4.4

11.0

2003

0.0

91 & 99

5.4

1500-1800

Temp > 40°C

26.2

31.0

1993

20.0

1997

25.5

1200- 2000

Elements

Table – DA U5

238 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: JUNE AF STN UTTARLAI (DATA : 1991- 2005)

Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

3.5

9.0

1992

0.0

2001

4.1

1800-2100

Vis < 3 Km

8.1

21.0

2003

1.0

1995

9.7

2100-2400

Ceiling < 300 m

1.1

7.0

1996

0.0

91, 92, 95, 98, 00, 02, 04 & 05

2.0

0600-0900

Ceiling < 150 m

0.0

0.0

91-2005

0.0

91-2005

0.0

-

Thunder Storm

3.1

7.0

1996

0.0

95 & 03

3.6

1800-2400

Dust Storm

2.1

5.0

2002

0.0

01 & 03

2.5

1800-2100

Hail Storm

0.0

0.0

91-2005

0.0

91-2005

0.0

-

Precipitation

4.3

8.0

96, 97 & 04

1.0

1995

4.8

1800-2100

D'Haze

14.5

26.0

2005

3.0

1997

15.5

1800-2100

S/Wind > 30 Kts

1.1

3.0

2002

0.0

91, 94, & 01

1.4

1800-2100

DRW

5.8

17.0

2004

0.0

1995

7.3

1500-1800

Temp > 40°C

19.3

28.0

1993

6.0

97 & 01

20.0

1500-1800

Elements

Table – DA U6

239 MAIN AVIATION WEATHER HAZARDS: JULY AF STN UTTARLAI (DATA : 1991- 2005) Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

1.3

7

2003

0

1996-99, 2002, 05

2.1

1200-2100

Vis < 3 Km

4.2

14

2003

0

1998

5.7

1800-2100

Ceiling < 300 m

5.7

15

1994, 2001

0

1991, 2004

7.4

0600-0900

Ceiling < 150 m

0.5

2

1994, 2001

0

1991-93, 95-2000, 02-05

0.7

0900-1200

Thunder Storm

5.7

15

2003

0

1991, 2002

6.7

1800-2100

0

1994-99, 2001-02, 04

1.1

1800-2100

Elements

Dust Storm

0.6

2

199293, 2000, 03

Hail Storm

0.0

0

19912005

0

1991-2005

0.0

-

Precipitation

10

22

2003

2

2002

11.0

0600-0900 1800-2100

D'Haze

7.8

22

2005

1

1996, 97

9.5

1500-1800

S/Wind > 30 Kts

0.8

3

1992

0

1995, 98, 99, 2002, 04

1.1

1800-2100

DRW

2.3

7

2002

0

1991, 93, 94, 96, 98

3.0

1500-1800

Temp > 40°C

4.3

12

1991

0

1994, 2001, 02

5.4

1500-1800

Table – DA U7

240 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: AUGUST AF STN UTTARLAI (DATA : 1991- 2005)

Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

0.7

3

2003

0

1991-93, 95, 96, 99, 2001, 02, 05

1.1

1800-2100

Vis < 3 Km

2.2

7

1994

0

1991, 93

2.9

1800-2100

Ceiling < 300 m

4.9

21

1994

0

1991, 2004, 05

7.0

0600-0900

Ceiling < 150 m

0.0

0

19912005

0

1991-2005

0.0

-

Thunder Storm

4.7

9

1994, 2003

0

1993, 99

5.3

1800-2100

Dust Storm

0.2

2

2004

0

1991-97, 992003, 05

0.6

1500-1800

Hail Storm

0.0

0

19912005

0

1991-2005

0.0

-

Precipitation

9.7

23

1994

1

1993

10.6

0900-1200

D'Haze

2.2

7

2004

0

1994-97

3.1

1800-2100

S/Wind > 30 Kts

0.2

3

2004

0

1991-2003, 05

0.8

1800-2100

DRW

0.8

3

2004, 05

0

1991, 92, 9497, 99, 200, 01

1.2

1200-1500

Temp > 40°C

0.4

3

1998

0

1991-97, 992001, 03-05

0.8

1500-1800

Elements

Table – DA U8

241 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: SEPTEMBER AF STN UTTARLAI (DATA : 1991- 2005)

Mean Freq

Highest Freq

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(a)

(b)

(c )

(d)

(e)

(f)

(g)

Vis <1 Km

0.6

2

1992, 94, 2005

0

1991, 95-97, 99-2003

1.0

0600-0900

Vis < 3 Km

1.9

4

1994, 2002, 04, 05

0

1991, 95, 2000, 01, 03

2.4

1500-2100

Ceiling < 300 m

1.8

11

1994

0

1991, 95-97, 99-2004

3.5

0600-0900

Ceiling < 150 m

0.0

0

19912005

0

1991-2005

0.0

-

Thunder Storm

3.5

10

2005

0

1991, 2001, 03

4.2

1800-2100

Dust Storm

0.2

1

1992, 2004

0

1991, 932003, 05

0.6

1500-1800

Hail Storm

0.0

0

19912005

0

1991-2005

0.0

-

Precipitation

3.7

10

1998, 2005

0

1995, 2001, 03

5.1

1800-2100

D'Haze

2.2

8

2004

0

1992, 94-97, 2001

3.0

1800-2100

S/Wind > 30 Kts

0.5

2

2004

0

1991, 94-96, 98-2003, 05

0.7

1500-1800

DRW

1.1

6

2002

0

1991, 93-97, 99, 2001, 03

2.0

1500-1800

Temp > 40°C

3.8

9

2000, 01

0

1992-94, 97, 2003

5.0

1500-1800

Elements

Table – DA U9

242 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: OCTOBER AF STN UTTARLAI (DATA : 1991- 2005)

(a)

High est Freq (b)

Vis <1 Km

0.2

02

2002

00

Vis < 3 Km

0.7

04

2004

00

Ceiling < 300 m

0.4

02

1998

00

Ceiling < 150 m

0.0

00

91- 05

00

Thunder Storm

1.9

06

1999

00

Dust Storm

0.1

01

2002

00

Hail Storm

0.0

00

91 - 05

00

Precipitation

2.0

05

97, 99

00

D'Haze

1.5

12

2004

00

S/Wind > 30 Kts

0.0

00

91- 05

00

1991-2005

0.0

DRW

0.1

01

1995

00

1991-1994, 1996-2005

0.3

1200-1500

Temp > 40°C

3.5

14

2002

00

91, 92, 94, 97, 03, 05

5.6

1500-1800

Fog

0.0

00

91- 05

00

1991-2005

0.0

Mist

0.0

00

91- 05

00

1991-2005

0.0

Squall

0.1

01

1997

00

1991-1996, 1998-2005

0.3

Elements

Mean Freq

Year(s)

Lowest Freq

(c )

(d)

Year(s)

SD

(e) 1991-2001, 03 - 05 1992, 94, 96, 97, 99, 00, 03, 05 1991, 9397, 01-05

(f)

Peak Period (IST) (g)

0.5

2100-0600

1.5

0600-0900

0.6

0600-1200

1991-2005 1991, 96, 02, 03, 05 1991-2001, 2003-2005 1991-2005 1991, 96, 02, 03, 05 1992, 93, 94, 96, 97, 00, 01, 03

Table – DA U10

0.0 2.7

1500-1800

0.3

2100-2400

0.0 2.7

1500-1800

3.3

0300-0900

1800-2100

243 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: NOVEMBER AF STN UTTARLAI (DATA : 1991- 2005)

Mean Freq

High est Freq

(a)

(b)

Vis <1 Km

0.4

02

Vis < 3 Km

0.7

Ceiling < 300 m

Elements

Year(s)

Lowest Freq

Year(s)

SD

Peak Period (IST)

(e) 92 - 96, 98 –01, 03, 04

(f)

(g)

0.8

0600-0900

(c ) 1997, 2005

(d)

04

2002

00

92 -96, 98 01, 03

1.3

0600-0900, 1500-1800

0.4

02

1996

00

91, 92, 94, 95, 98 - 05

0.6

0600-0900

Ceiling < 150 m

0.0

00

91 - 05

00

91 - 05

0.0

Thunder Storm

0.4

02

2002

00

Dust Storm

0.2

01

1991, 2002

00

Hail Storm

0.0

00

91 - 05

00

91 - 05

0.0

Precipitation

0.8

04

2002

00

1992, 95, 96, 98, 99, 01, 03, 05

1.4

0600-0900 1500-1800

D'Haze

0.6

07

2002

00

1991-2001, 03, 05

1. 8

0900-1500

S/Wind > 30 Kts

0.1

01

2002

00

1991-2001, 03 - 05

0.3

1800-2100

DRW

0.1

01

2002

00

1991-2001, 03 - 05

0.3

1800-2100

Temp > 40°C

0.0

00

91 - 05

00

91 - 05

0.0

0.0

Fog

0.3

02

1997

00

1991-1996, 98- 05

0.5

0600-0900

Mist

0.4

02

1997

00

1991-1996, 98- 03, 05

0.5

0600-0900

00

91 - 93, 95, 96, 98 - 01, 03 - 05 92 - 01, 03 - 05

Table – DA U11

0.6

1500-1800

0.4

1500-1800

244 SUMMARY OF MAIN AVIATION WEATHER HAZARDS: DECEMBER AF STN UTTARLAI (DATA : 1991- 2005) Mean Freq

Highest Freq

Year(s)

Lowest Freq

(a)

(b)

(c )

(d)

Vis <1 Km

0.7

04

2003

00

Vis < 3 Km

2.4

08

2003

00

Ceiling < 300 m

0.4

02

1998

00

Thunder Storm

00

00

1991 2005

00

Dust Storm

00

00

1991 2005

00

Precipitation

0.2

01

2002 & 04

00

D'Haze

0.7

05

2004

00

S/Wind > 30 Kts

0.1

01

2004

00

DRW

0.1

01

2004

00

Elements

Fog

0.6

04

2003

00

Mist

1.0

06

2003

00

Year(s)

SD

Peak Period (IST)

(e) 1991-93, 95-96, 982001 & 05 1992, 95 & 99 1992-96, 99-2001, 04 & 05

(f)

(g)

1.3

0600 – 0900

3.4

0600 – 0900

0.7

0900 – 1200

1991- 2005

0.0

-

1991- 2005

0.0

-

0.4

0600 – 0900 1500 – 2100

1.6

1200 – 1500

1991-2003 & 05

0.3

1200 – 1500

1991-2003 & 05

0.3

1200 – 2100

1.1

0600 – 0900

2.1

0600 - 0900

1991-2001, 03 & 05 1992-98, 2000-01, 03 & 05

1991-93, 95-96, 982001, 04 & 05 1991-96, 99, 2001 & 05

Table – DA U12

245 MEANS AND EXTREMES AIR FORCE STATION : UTARLAI DATA SET : (Jan 1974 - Dec 2005)

DEC JAN FEB MAR

APR

Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest

MAX TEMP (°C) 34.8 27.8 17.0 34.3 25.8 14.8 38.0 28.6 18.0 43.4 34.6 21.8

Highest Mean

47.2 39.8

Lowest MAY

JUN

Highest Mean Lowest Highest Mean Lowest

JUL AUG SEP

OCT

NOV

Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest

26.2 48.7 42.5 27.0 49.4 41.2 26.0 44.0 37.1 27.6 43.2 35.4 25.6 43.4 36.8 26.8 42.6 37.1 20.4 39.6 32.4 21.6

WINTER SEASON RH ( %) RAINFALL MMS MIN TEMP 0300 1200 24 MONTHLY (°C) UTC UTC HRS 15.8 100 096 06.8 06.8 6.4 057 033 0.5 22/80 -05.2 022 005 0.0 18.2 100 100 14.3 14.3 5.5 059 031 01.8 09/82 -05.0 016 004 0.0 21.2 100 090 16.2 15.2 8.6 055 027 3.2 18/03 -05.0 012 005 0.0 26.4 096 086 12.2 9.2 14.8 048 023 01.1 21/81 -00.5 011 002 0.0 PRE – MONSOON SEASON 29.0 091 089 32.0 19.0 20.9 046 021 3.2 26/82 7.4 012 001 0.0 32.5 100 097 72.4 70.2 25.4 058 024 14.1 22/99 14.8 010 003 0.0 34.0 096 092 102.5 85.0 27.4 067 034 25.3 30/94 17.5 028 009 0.0 SW – MONSOON SEASON 31.0 100 100 387.5 226.0 26.6 078 051 107.3 16/75 20.8 050 023 0.0 30.0 100 100 557.8 263.6 25.4 081 057 81.7 07/90 21.2 050 022 0.0 31.5 100 100 197.3 93.6 23.9 077 047 33.3 26/81 15.4 029 012 0.0 POST – MONSOON SEASON 27.6 100 100 53.5 49.7 18.5 061 033 08.8 09/83 6.5 021 008 0.0 22.0 100 094 47.5 47.5 11.5 057 034 03.5 12/78 01.6 024 009 0.0 Table – DA U13

MAX SURFACE WIND 200/33 31/04 050/40 30/76 270/55 16/78 230/40 20/81 160 / 50 11 / 01 290/50 01/78 270 / 75 27&28 / 79 180/70 26/02 020/70 03/75 050/60 16/79 050/60 28/78 090/50 25/74

090/40 18/74 240/48 05/02

246 AIR FORCE STATION UTARLAI STATISTICS OF GOOD, MARGINAL AND BAD: WEATHER STATE FOR FIGHTER 12 HOURLY BLOCK (Data Set Jan 2001 – Dec 2005) WINTER SEASON

MONTH DEC JAN

FEB MAR

APR

MAY

JUN

JUL AUG

SEP

OCT NOV

Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest Highest Mean Lowest

DAY(12h)(0601-1800) NIGHT(12h)(1801-0600) Good Marginal Bad Good Marginal Bad 31 05 00 31 03 00 29 02 00 30 01 00 26 00 00 28 00 00 31 04 00 31 00 00 30 01 00 31 00 00 27 00 00 31 00 00 28/29 02 00 28/29 03 00 27 01 00 27 01 00 26 00 00 25 00 00 31 05 00 31 03 00 29 02 00 30 01 00 26 00 00 28 00 00 PRE-MONSOON SEASON 25 13 02 30 04 01 21 09 00* 28 02 00* 17 05 00 26 00 00 21 24 04 31 08 00 13 16 02 26 05 00 05 10 00 23 00 00 21 18 01 30 14 00 18 12 00* 23 07 00 11 08 00 16 00 00 MONSOON SEASON 30 10 04 31 06 01 24 05 02 28 03 00* 17 01 00 25 00 00 30 07 04 31 05 01 27 03 01 29 02 00* 20 01 00 26 00 00 30 05 01 30 02 00 28 02 00* 29 01 00 25 00 00 28 00 00 POST MONSOON SEASON 31 12 00 31 02 00 28 03 00 30 01 00 19 00 00 29 00 00 30 01 00 30 00 00 30 00* 00 30 00 00 29 00 00 30 00 00

Table – DA U14 AIR FORCE STATION UTARLAI STATISTICS OF GOOD, MARGINAL AND BAD WEATHER STATE FOR TRANSPORT 12 HOURLY BLOCK (Data Set Jan 2001 – Dec 2005)

MONTH DEC JAN FEB MAR

APR MAY JUN

JUL AUG SEP

OCT NOV

247 WINTER SEASON DAY(12h)(0601-1800) NIGHT(12h)(1801-0600) Good Marginal Bad Good Marginal Bad Highest 31 05 00 31 03 00 Mean 29 02 00 30 01 00 Lowest 26 00 00 28 00 00 Highest 31 03 00 31 00 00 Mean 30 01 00 31 00 00 Lowest 28 00 00 31 00 00 Highest 28/29 02 00 28/29 03 00 Mean 27 01 00 27 01 00 Lowest 26 00 00 25 00 00 Highest 31 05 00 31 03 00 Mean 30 01 00 30 01 00 Lowest 26 00 00 28 00 00 PRE-MONSOON SEASON Highest 25 13 02 30 04 01 Mean 21 09 00* 28 02 00* Lowest 17 05 00 26 00 00 Highest 21 24 04 31 08 00 Mean 13 16 02 26 05 00 Lowest 05 10 00 23 00 00 Highest 24 17 01 30 14 00 Mean 19 11 00* 24 06 00 Lowest 12 06 00 16 00 00 MONSOON SEASON Highest 31 08 02 31 05 01 Mean 27 03 01 29 02 00* Lowest 21 00 00 26 00 00 Highest 31 04 01 31 05 00 Mean 29 02 00* 29 02 00 Lowest 26 00 00 26 05 00 Highest 30 05 00 30 02 00 Mean 29 01 00 29 01 00 Lowest 25 00 00 28 00 00 POST MONSOON SEASON Highest 31 12 00 30 02 00 Mean 28 03 00 30 01 00 Lowest 19 00 00 29 00 00 Highest 30 00 00 30 00 00 Mean 30 00 00 30 00 00 Lowest 30 00 00 30 00 00

Table – DA U15 AIR FORCE STATION UTARLAI STATISTICS OF GOOD, MARGINAL AND BAD WEATHER STATE 06 HOURLY BLOCK (Data Set Jan 2001 – Dec 2005) WINTER SEASON

MONT H

DAY(12h) 06h(0601-1200) 06h(12011800)

NIGHT(12h) 06h(1801-0000) 06h(0001-0600)

DEC

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

Highes t Mean Lowest Highes t Mean Lowest Highes t Mean Lowest Highes t Mean Lowest

Bad Goo d 1 31

248 Mar B g ad 2 1

Go od 28

Mar g 5

Goo Mar d g 31 3

Ba d 0

Goo d 31

27 25 29

4 3 4

0 0 1

30 28 31

1 0 2

0 0 0

30 28 31

28 26 28

3 2 4

0 0 1

30 29 28

1 0 3

0 0 1

26 23 31

2 0 2

0 0 0

26 25 31

2 0 5

0 0 8

30 29

1 0

Mar g 4

Ba d 0

1 0 0

0 0 0

30 27 31

1 0 0

0 0 0

31 31 28

0 0 3

0 0 0

31 31 28

0 0 1

0 0 0

27 25 31

1 0 3

0 0 1

28 27 31

0 0 3

0 0 0

1 0

0 0

30 28

1 0

0 0

Highes t Mean Lowest Highes t Mean Lowest Highes t Mean Lowest

30

3

0 27 2 2 30 0 23 0 0 28 PRE-MONSOON SEASON 0 22 7 14 27

28 27 29

2 0 17

0 0 1

16 11 9

4 2 6

10 4 25

26 25 25

3 2 14

1 0 4

29 27 31

1 0 6

0 0 0

24 13 27

7 2 10

0 0 1

5 0 20

4 1 7

22 18 22

20 15 25

9 4 15

2 0 10

28 25 30

3 0 11

0 0 0

24 19

5 1

1 0

8 4

4 1

26 19

4 0

0 0

Highes t Mean Lowest Highes t Mean Lowest Highes t Mean Lowest

30

7

8 5 17 18 4 2 6 11 MONSOON SEASON 11 29 6 8 29

8

3

31

4

1

23 14 27

4 1 9

4 0 7

24 17 30

4 2 3

3 0 4

25 20 31

4 0 2

2 0 3

29 26 31

1 0 5

1 0 1

24 20 30

5 3 3

2 0 2

27 24 30

2 0 3

2 0 7

28 26 30

1 0 4

2 0 1

29 26 30

2 0 0

0 0 0

28 25

1 0

1 0

30 30

0 0

0 0

Highes t Mean Lowest Highes t

31

4

1 25 2 3 28 1 0 22 0 0 25 0 POST MONSOON SEASON 0 31 4 12 31 2

1

31

2

1

30 27 30

1 0 0

0 0 1

0 0 0

30 29 30

1 0 1

0 0 0

26 15 30

2 0 1

3 0 0

30 29 30

3

2

30

3

0

1 0 0

Mean Lowest

30 29

0 0

0 0

30 29

249 0 0

0 0

30 30

0 0

0 0

30 29

0 0

0 0