Wednesday, December 27, 2017

Importance of 200 jet streams...The Initial Weather maker...the King:

As any Vagarian will agree, I have always stressed the importance of the 200 mb Jet Streams....studying the Jet Streams, one can foresee a depression coming and even the track it can take later....

Depressions are one of the most significant weather systems affecting temperate latitudes. Surprisingly, and as Vagaries mentions to all its "readers/learners",  the origin of depressions is in the upper part of the troposphere even though the effects are felt at ground level. We look at the polar front's role in creating the upper westerlies and Rossby waves which set the scene for depression formation.
 Depression begins when poleward moving warm air from the tropics meets equatorward moving cold air from the poles. The cold air from the poles is dense and forms a shallow atmospheric layer. In contrast, the warm air from the tropics is more buoyant and forms a fairly deep atmospheric layer. Where these two air masses meet (the polar front), there is a strong pressure gradient between the dense cold air and the less dense warm air. 

At ground level, this pressure gradient drives winds from the polar air into the tropical air. This should create a northerly air stream, but the spin of the earth deflects winds to the right in the northern hemisphere so a polar northeasterly wind is formed instead. At the top of the troposphere (the lowest atmospheric layer where all weather forms), the pressure gradients are reversed. 
Since the polar air is cold, dense and concentrated at ground level, there is little present in the upper troposphere so an even stronger pressure gradient exists in the opposite direction. At this height - far from the frictional drag of hills and mountains - very high windspeeds can develop. The pressure difference along the polar front therefore creates a region of high speed winds known as the upper westerlies.
The upper westerlies - and their embedded jet streams - form a series of huge meanders. In it are embedded "Divergence" and "Convergence"...Divergence being the original "Source" of a System. These help to create the depressions which form such a prominent part of  weather. The meanders vary in size and location but there are certain areas where they are very common. 
Depression source areas 
We can predict certain areas will be common "breeding grounds" for depressions from the following observations: 
1.Depressions are triggered in locations where jet streams accelerate. Depressions can form slightly aligned to the core of the Jet Streams.
2.Jet streams accelerate when the Rossby wave meander heads back towards the polar regions
3. Locating and forecasting the Divergence in the Stream.
4. Checking the core region of the Jet stream for estimating the Location of the formation of a system.

This meandering wavy pattern of the jet stream in the upper troposphere are known as Rossby waves (as shown in the second part of the picture ).
IMAGE
Now, proceeding to third and fourth picture, you will realise the invasion of some points by warmer latitudes below polar region by some cold pockets which will subsequently affect the weather of the region by causing extremities in local temperature.

Also, Rossby waves creates some areas of high pressure (at ridges) and low pressure (at troughs).



The air over a huge area of sea or land rises up to join the jet stream whilst air from thousands of square kilometres either side converges uneasily along "frontal" zones. 
By contrast, areas of decelerating jet stream result in subsiding air creating high pressure at ground level (see below).





Due to the tendency of cold wind from poles to move towards equator and warm winds vice versa towards poles, they distort the path of the jet stream travelling in a straight line and cause them to move in a wave like pattern or meander at various intervals.

Forecast of Depression formation and its location can be estimated by you...just study the 200 level jet streams. Be less dependant on Weather Models. 
 End of Article..

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Check the Latest Development in the Sub Continent Weather on Current Weather Page

Tuesday, December 26, 2017

26 Dec 2017 ..USA WEATHER ..with 3D Map

Currently ,the weather over the contiguous US is as diverse as the Indian sub-continent ; from the frigidity of the Dakotas(-29 c) to the warmth of the Florida everglades (29 c) ..


Newark/New York .. Frigid weather from the mid-west will spill to the northeast coast as max/min temps will hover around -5 c /-11 c with a mix of clouds/sun during the week .Light snowfall expected during the weekend.Wind chills can dip to a bone chilling -20 during the week.Rochester will be cloudy and experience lake snow effect with wind chills dipping to -25 (Greater Himalayas type of weather).

Bay area (SF,SJ) ..Mostly sunny ,fine as max/min temps will hover around 17 c / 7 c through the week till new year.Foggy mornings near the ocean and clear inland.(North Indian plains type of weather).

Phoenix ..The desert city will be sunny,crisp, dry as max/min temps will hover around 23 c / 8 c through the week till new year (Central India type of weather).

Charlotte .. The piedmont city will be cold as max/min temps will hover around 5 c / - 5 c with a mix of clouds/sun through the week till new year .Wind chills can dip to a bone chilling -15 during the week (Kashmir valley type of weather).

Seattle .. After experiencing a rare snowy festive weather , Seattle will thaw as max/min temps will hover around 8 c / 3 c with the usual winter cloudy weather/showers as the week progresses till new year (Lower Himalayas type of weather).

..Ski resorts at Cascades, Rockies, Appalachian are packed with snow.. 

Past 24 hrs .. (max / min temp in c) 
MAP LOCATION MAX MIN STATE  REGION
SF SAN FRANCISCO 14 7 CALIFORNIA BAY AREA
SJ SAN JOSE 16 4 CALIFORNIA SILICON VALLEY
Ph PHOENIX 19 6 ARIZONA SONORAN DESERT
Se SEATTLE 2 -1 WASHINGTON PUGET SOUND
Sp SPOKANE -7 -12 WASHINGTON COLOMBIA BASIN
Sc SACRAMENTO 15 1 CALIFORNIA CENTRAL VALLEY
LA LOS ANGELES 20 8 CALIFORNIA PACIFIC COAST
SD SAN DIEGO 19 7 CALIFORNIA PACIFIC COAST
Pd PALMDALE 18 2 CALIFORNIA MOJAVE DESERT
LV LAS VEGAS 17 6 NEVADA MOJAVE DESERT
SLC SALT LAKE CITY 4 -8 UTAH SALT LAKE VALLEY
Rc RAPID CITY -13 -22 SOUTH DAKOTA BLACK HILLS FOOT
De DENVER -7 -17 COLORADO ROCKIES FOOT
Om OMAHA -10 -18 NEBRASKA PLAINS
Am AMARILLO 12 -11 TEXAS HIGH PLAINS
EP EL PASO 22 2 TEXAS CHIHUAHUA DESERT
- ROCHESTER 1 -13 NEW YORK GREAT LAKES
- NEW YORK 4 -4 NEW YORK ATLANTIC COAST
- NEWARK 3 -4 NEW JERSEY ATLANTIC COAST
- CHARLOTTE 9 -1 NORTH CAROLINA PIEDMONT
- HOUSTON 12 2 TEXAS GULF COASTAL PLAIN
- MIAMI 29 18 FLORIDA EVERGLADES

A good eye over the map below, reveals the following features ..
The Bay area (SF,SJ) ,painted desert (north of Ph), the long central California valley (Sc) , Mojave desert (Pd), Basin & Range region (north of LV) , Colombia Basin (Sp) , Rockies (west of De) ,Black hills (near Rc) , mid -west plains (Om) ..




Monday, December 25, 2017

Posted 25th December Night:

Weather for the Indian Sub Continent for the next 4 days till year end.

1.  Northern Hills will see some rains/snow on 26th. Foggy weather in the Northern plains and cold air settling. As the WD (D-2) passes away, we see no rains in the Sub Continent from 27th- 31st December.

2. North Indian States of Punjab, Haryana and Delhi NCR will see moderate to dense fog on 26th/27th and 28 th . Night temperatures expected to remain constantly or around 2c lower. Delhi will be between 23/24c and 7/8c. Coolest place in the plains of India was Amritsar at 3.5c on Monday.

3. Constant East to South -East winds in Maharashtra next 4 days will see the larger variation in day-night temperatures. Days will be 28c-30c in the Interior Maharashtra regions of Madhya Mah/ Vidharbh with the nights falling to 10-12c.
Next 5 days : 
Mumbai will be between 31/32c and 16/18c. Around 15-16c variation day and Night. 
Pune will see 28/29c and 10/12c.
Aurangabad will be sunny and days will be around 30c and night cooler at 12c.

4. Bangalore next 5 days: Misty mornings and slight clouds in the day. Temperatures between 26//27c and 15c.
Chennai will be partly cloudy with the days around 29/30c and nights just better at 22c.
And Kolkata also dry in the range of 26/27c and 14c

5. In Sindh on Monday, Mithi was the coldest at 5.5c.
Karachi was betwee 25c and 13.5c on Monday.
 Kamra (Pak Punjab) was coolest at 1.5c.
Islamabad was lowest at 4.5c and Lahore 5c.

The 200 Jet Streams and its Importance in Weather Making....A brief explanation being compiled and in the making, shall be put up on here on Tuesday 26th Night. 

Our Vagaries Mentioned in International Press: "The Washington Post"

For the first time, Hits from US have exceeded hits from India today: USA 44.6% and India 44.4%.

Thursday, December 21, 2017

21 DEC 2017 ..CRISP WEST INDIA (MAHARASHTRA) WINTERS..

West India (Maharashtra) had sunny , crisp , fine , very dry weather..
  • The daytime humidity level throughout the state including the coastal region, was the lowest over the sub-continent (falling upto 15%).
  • The minimum temperature fell to 8 c on the Deccan plateau and to 11 c on the Konkan coastal plains .The temperatures will not breach this levels during the next 3 days .
  • The maximum heat index was a comfortable 27/29 over North /South Deccan plateau and a fine 31/32 over North/South Konkan coast (due to very low humidity , the heat index was lower by 2 points than the maximum temperatures recorded ).

MAHARASHTRA SUB-DIVISIONAL MAP (MAX/MIN TEMP IN C)..21 DEC 2017..
------------------------------------------------------------------------------------------------------------------------------------------------------------------
"Author's (Rajesh) Views added here with Image illustration:Thanks to > 70% Humidity ( In contrast to the lowest Levels dryness) in the upper air jet streams and winds at 300 and 500 levels for splashing the cloud palette from the equatorial seas over the Western India regions...The Humidity levels in the upper most air being High, it created a gradient with rising air condensing at higher levels. Thus forming first Cirrus Clouds, then changing to Alto Cirrus and then continuing with Alto Cumulus..and this picked up an excessive scattering of Red Spectrum due to high speed winds aloft."
------------------------------------------------------------------------------------------------------------------------------------------------------------------

The high clouds over the state created some great backdrops against the blue skies and provided great photographic delight during sunrise/sunset .

      
THANE DUSK (PIC : AMEYA SWAR) >

<MUMBAI SUNSET (PIC:SALIL KAWLI)

   NASIK SKIES (PIC : SHIVKUMAR) >

< BADLAPUR SKIES (PIC : ABHIJIT)

MUMBAI SKIES (PIC : ROHIT ) >

< Pavan


< Nilay

Tuesday, December 19, 2017

19 Dec 2017 .. Entire Indian sub-continent weather..
(THIS EFFORT IS BEST VIEWED ON LAPTOP / DESKTOP)


  • Most of the sub-continent (95% area) will be dry and sunny during this week.'Vagaries of the Weather' will be at the maximum with the frigidity of the Himalayas to the humid tropical weather of Lakshadweep islands.
  • Light Rain/Snow will be limited to extreme North over Kashmir & Himachal (under the influence of a weak Western Disturbance) , extreme South over Tamilnadu / Sri Lanka (shallow easterlies) & Andaman Nicobar islands ( under the influence of west moving and weakening Tropical storm 'Kai-tak')
  • Fog expected over North and East sub-continent during the morning.Night temps will drop over North towards weekend and day temps will increase over East.
  • West / Central sub-continent will be sunny,crisp and very dry; resulting in falling night temps during the week . 

Today's weather highlights over the Indian sub-continent :
  1. Some of the lowest Daytime Humidity .. Mumbai 20% , Pune/Rajkot 15 % , Jaisalmer 10% 
  2. Lowest temp over the plains .. 0.5 c (Fatehpur ..Sikar dist, Rajasthan)
  3. Highest temp .. 35.3 c (Mangalore ,Coastal Karnataka)

Indian sub-continent 3D Map 
(Location reference - W..West , S..South ..)

(INDIAN SUB-CONTINENT -Current Weather.. Max / Min temp in celcius during past 24 hrs):

MAP LOCATION
(WEST)
MAX  MIN  MAP LOCATION
(SOUTH/CENTRAL)
MAX  MIN 
W1 MUMBAI 32 20 S1 CHENNAI 29 21
W2 PUNE 28 12 S2 BENGALURU 27 15
W3 NORTH GOA 34 18 S3 KOCHI 34 19
W4 RAJKOT 29 17 S4 COLOMBO 32 23
W5 KARACHI 27 15 C1 NAGPUR 28 9
W6 JAISALMER 25 10 C2 INDORE 27 11


MAP LOCATION
(NORTH)
MAX  MIN  MAP LOCATION
(EAST)
MAX  MIN 
N1 DELHI 23 9  E1 KOLKATA 22 16
N2 JAIPUR 26 10  E2 DHAKA 21 17
N3 LUCKNOW 21 7  E3 BHUBANESHWAR 28 12
N4 LEH 3 -13  E4 KATHMANDU 20 5
N5 BHATINDA 22 5  E5 TAWANG 9 -1

Friday, December 15, 2017

IT'S MID -DECEMBER & NORTH KONKAN WAS COOLER THAN MOST OF INTERIOR MAHARASHTRA  during past couple of days..

Refer the 'sub-divisional Maharashtra map' below .. ( 14 Dec 2017 , MAX / MIN TEMP in C) 

The Konkan coast will get warmer than Interior Maharashtra from tomorrow ..

Sunday, December 10, 2017

Monitoring Mumbai's Mangroves: See Article on Mumbai Page

Posted Sunday Night:

Weather System of the Day: Western Disturbance D-1.....over North India with Induced Low over Punjab/North Rajasthan on Monday.
Rain expected from this system in J&K, H.P, Punjab, Haryana, Delhi, West U.P. And North Rajashthan . The WD is not of extreme nature and moderate rains/snow expected on 11th Monday, 12th Tuesday and 13th Wednesday. 

City weather for 11th/12th and 13th December:
Mumbai: Next 3 days will be clear and prevailing W/NW winds. Likely to clear the fog and smog seen in Mumbai for the last 2 days. Night temperatures likely to fall from Wednesday morning. 
Pune: With clear skies, the nights are expected to get colder, dropping to around 11/12c by Wednesday morning.


Srinagar: Rains expected on Monday and turning to snow on Tuesday 12rh and Wednesday. cold temperatures with days below 7c.
DelhiNCR: Light/Medium rainfall in many parts will realise in a rise in the night temperature minimums. Days will get cooler at 23/24c.
Colder days next week in Delhi, Haryana, Punjab and Rajasthan.


Bangalore: Next 3 days will be misty in the morning, and the day-night temperature range will be between 29c-16c.
Kolkata: With the rains clearing, the days wil  get warmer to 27c, and mornings will be foggy.

Thursday, December 07, 2017

Posted Thursday Night:

BB-19, depression at estimated core pressure now at 998 mb, and located at 12.7N and 88.7E Thursday evening. Divergence in the upper winds and Low wind shear is favourable for poleward outflow and further strengthening. 
Likely to track towards Odisha/West Bengal coast.

Heavy showers likely in Bhubaneshwar on Friday and Saturday.
Moderately heavy showers expected in Kolkata on Friday/Saturday.
No effect on Chennai or T.N. from system.

Western Disturbance D-1 will approach North India on 11th as expected. Rain/Snow likely in Kashmir/H.P and rains in Punjab, Haryana, N.Rajasthan and West U.P. 
Snowfall liikely in Gulmarg, Pahalgam and Srinagar on around 12th December.
---------------------------------------------------------------------------------------------------------------------
U.A.E.
During this weekend, Friday/Sat/Sunday, cool NW winds will blow in the U.A.E. and Muscat.
Very light rain in some parts is likely in Abu Dhabi on Friday, otherwise clear skies.
Abu Dhabi will be in the range of 24c-14c and Muscat around 25c - 14c.

Wednesday, December 06, 2017

Posted Wednesday 6th Night:

BB-19: A depression currently located at 10.2N and 88.2E. Wind speeds estimated at 40 kmph with estimated core pressure at 1004 mb.
Showing sparse convection at centre and more cloud bands in Northern periphery.
Very good divergence in upper winds will strengthen it rapidly.Track will now be NW maybe becoming N/NW after 36  hrs.

A Major WD ( D-1) will approach and precipitate rain/snow over North Pakistan on 10th and over NW India on around 11th December....

Mumbai: Partly cloudy skies with drop in Night temperatures next few nights. Possibility of light rains again in Mumbai on around 11th ...more later

Maximum Temperatures dropped in Gujarat on 6th as a medium cloud cover of incursion moisture covered the region:
V.V. Nagar 18.1c, Surat 18.4c, Idar 18.8c, Ahmadabad/Vadodra 19.0c, Gandhinagar 19.8c, Amreli 20.0c. 


OCKHI Rainfall in Maharashtra ..Map prepared by Vagarian Tejas and Data from Vagarian Abhijit












Tuesday, December 05, 2017

Posted Tuesday 5th December Night:

The erstwhile "Ockhi" has almost dissipated and with a "bald" centre, is located at 19.1 N and 71.5E. Massive dry air encirclement and cold waters almost decayed the system within 12-18 hrs.Difficult without cloud imagery to get exact core pressure and wind speeds, but approximately average pressure should be 993 mb and 30-40 kmph winds.

As expected much earlier by Vagaries, dry air encirclement and cold waters with wind shear almost finished off the system.
Let us move to BB-19 now....
Dry day tomorrow for Gujarat and North Konkan. Day Temperatures rising in Gujarat.

Mumbai: The maximum rain spell is over. With not much rain now, Wednesday will be devoid of rains, and in fact bright.

Andheri received 29 mms of rain, dadar 28 mms, Goregaon 32 mms, 
Colaba IMD managed 70.3 mms in 12 hrs till 8.30 pm. This is the highest 24 hr and overall December rain for Colaba. Previous December record was 51.1 mms in the month in 1962 with same day (5th Dec) heaviest 24 hr fall of 47.8 mms/
 Today, Scruz recorded 36 mms in the same 12 hrs period of time. Scruz also breaks its own December record which was 55.7 in 1967 and heaviest fall was 31.4 mms on 12 Dec 1967. Total this year in December is 58 mms till 8.30 pm 5th Dec.
Maximum temperatures on 5th December: Colaba 23.2c and Scruz 23.3c.

Cool day in Gujarat on 5th December:Max temperatures; 

Gandhinagar 19.0c, Ahmadabad 19.1c, V.V. Nagar 20.1c, Surat 20.6c, Idar 21.0c, Bhavnagar 21.6c, 
---------------------------------------------------------------------------------
Posted Tuesday 5th Dec Morning:

Mumbai: Heavy rains currently lashing Mumbai. As the depleted storm moves past and skirts Mumbai, 5.30 am at 18N and 70.6E, just about 250-260 kms west/South West off Mumbai.Estimated pressure 990 mb at core.
 But the main convection area is now around Mumbai, East of the centre. And apparently the Centre, seen thru convection clouds as they weaken just  200-220 kms West off Mumbai. Extra thick and convection clouds seen around and on Mumbai .Image of 9.30 am.

Mumbai rainfall expected to decrease substantially post noon or evening.









Mumbai rains till 11.30 am Tuesday from 8.30 am: CST Station 21 mms, Dadar (Salil) 22 mms, Vagaries Club 21 mms
Current Temp at Vagaries 22.4c at 11.30 am

Posted Monday 15th January: Very Unusual Weather for January in the Sub Continent.... North-East Monsoon has Ceased and is withdrawn fro...