Major Western disturbance to impact North India. High snow accumulations likely

METD WEATHER

Akshay Deoras

Severe Weather Forecaster,

The Western Disturbance of the year may be here! 

****** THIS IS A PARTICULARLY DANGEROUS SITUATION FOR HIGHER REGIONS OF HIMACHAL PRADESH,J&K and Uttaranchal DUE TO VERY HIGH SNOW ACCUMULATION. 

PEOPLE IN THESE AREAS MUST START PREPARING ACCORDINGLY BY STOCKING FOOD,WATER ETC BEFORE-THE SNOWFALL BEGINS ********

Attached above is the 72hr GFS 500mb ( base 00z,15th Jan). The noteworthy feature is the giant positive Vorticity region having the 500mb geopotential heights as low as 558dam! It's the western disturbance which is all set to impact North India and Nepal in the coming days. 

The lower the geopotential height as compared to other heights on the same longitude,the  more intense any storm is. 

Attached above is the precipitation expected from this system. 

Thus starting from Thursday,17th Jan very heavy snowfall is expected in J&K,Himachal Pradesh,Uttaranchal and Nepal TILL 19th Jan 2013 

Here are some expected highlights- 

* VERY HEAVY SNOWFALL WILL HAPPEN IN HIGHER REACHES OF J&K like Srinagar,Gulmarg,Sonamarg.Pahalgam,Zoji La Pass, Drass,Kargil and Leh and around in the same period 

* THERE IS A SIGNIFICANT THREAT OF AVALANCHE IN HIGH MOUNTAIN AREAS ESPECIALLY SIACHEN Glacier

* JAMMU- SRINAGAR HIGHWAY WILL BE CLOSED IN THIS TENURE. Minor flight disruptions likely at Srinagar on 18th Jan. 

* In Himachal Pradesh also very heavy snowfall will take place and also across Uttaranchal higher reaches,Nepal as well

* Heavy Rains along with an isolated threat of cloudburst across Himachal Pradesh,Uttaranchal and lower Nepal considering higher vertical vorticities.

* North Indian plains like Punjab,Haryana,Delhi-NCR, few regions in North-Western UP ( Lucknow and around) will receive thunderstorm with rains especially on 17th and 18th Jan. Considering the higher instability, hailstorm also seems likely in Punjab in this period. 

* Min temperature will rise during this period in these areas due to cloud cover

IF READERS TAKE SOME PHOTOS OF THE SNOWFALL OR THUNDERSTORM IN PLAINS, THEN PLEASE SHARE WITH METD WEATHER ON FACEBOOK OR BY MAILING TO metdweather@live.com 

As I am not well, I am unable to provide a detailed forecast.....

Sent from my iPad

Major Weather change expected in Central,Southern India

METD WEATHER
Akshay Deoras
Severe Weather Forecaster,

Nagpur recorded a minimum temperature of 6.3C on Wednesday,26th Dec 2012. However there is going to be a major weather change in the coming days in India

Bay Low Pressure system-

Attached is the 850mb GFS Map of Base 00z,28th Dec.

One can see a broad patch of anti-clockwise winds with green shading across Sri Lanka. This is the Bay low pressure system which shall pump moisture across mainland of India resulting into precipitation in the southern states-

Above is the +48hr precipitation forecast showing rainfall across Kerala,Tamil Nadu,Coastal Andhra Pradesh and some interior Karnataka.
The precipitation shall increase across Karnataka coastal areas eventually spreading into Goa on the New Year eve

If does appear that Goa may get light rain spell on 30th Dec 2012 and some on 31st Dec as well. The meteograms aren't agreeing however..

As the Bay system progresses westwards, a High Pressure system is expected to develop across Orissa at the 850mb level which shall steer the moisture and push it Northwards.

Minimum temperature in Central India will be rising nowonwards as the direction of the winds have changed.

The precipitation will spread into Southern Maharashtra with areas like Pune and subsequent interior Western Maharashtra will receive rains with rise in minimum temperature.
This shall happen on Monday,31st Dec 2012.

Pune which witnessed a min temperature around 7C shall have relatively warmer nights though a heavy rainfall event is unlikely due to the scattered precipitation tendency there..

As the moisture pumps further, it shall weaken in terms of Relative Humidity (RH) however be that much to bring cloudy skies in Nagpur and Central India.

The min temperatures will rise to around 15-17C in Nagpur taking away the winter effect in the city. Due to moisture amounts and slight unstable atmosphere, clouding shall be there in the city during ( Partial) 31st Dec and then increasing on 1st and 2nd Dec ( As of present GFS).

However, there seems to be a little problem with the initial Skew-T of that period

Above is the 1st Jan 2013 SKEW-T for Nagpur region. Its clearly visible in those indices that CAP or CIN will be greater than the CAPE ( CIN = 102 J/Kg)..
This situation depicts a non buoyant atmosphere where due to thermal inversion, buoyancy is lost thus a parcel of air ( moisture embedded) will sink as it rises due to which chance of convection and thunderstorm looks minimal now
However, the SKEW-T can change and moreover such CAP can break if there is abundant sunshine in the morning on the 1st Jan.

Situation on this rainfall event shall be more clear in the coming period

GFS shows a precipitation in Nagpur ( which then must be non convective) on 1st and 2nd Jan

Trace Amt rain can be expected on 31st Dec night ( As of 28th Dec GFS)

STAY TUNED FOR UPDATES AND FOLLOW METD WEATHER FACBOOK FOR MORE DETAILS--

Another powerful Western Disturbance all set to impact North India

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

Another powerful western disturbance is arriving towards North India. The 12z,11th Dec forecast models are indicating that the resulting precipitation (Although snowfall was reported in some stations of Himachal Pradesh today) will initiate from Wednesday,12th Dec 2012 ( a perfect 12-12-12) and will continue till around 15th Dec morning with the peak of the activity on Thursday,13th Dec 2012

Above- The GFS 700mb precipitation for 72hr (13th Dec 2012).

The change which is appearing from this simulation is that the precipitation ( in terms of snow and rain) shall be heavier towards the Himachal Pradesh,Uttarakhand side as compared to Jammu and Kashmir

Thus the snowfall shall be heavier in Himachal Pradesh than Jammu and Kashmir but it doesnt meant that J&K will not get a heavy snowfall event. Below is the expected scenario

* HEAVY SNOWFALL EXPECTED IN JAMMU AND KASHMIR,HIMACHAL PRADESH,UTTARAKHAND FROM 12TH DEC TO 14TH DEC WITH THE PEAK ON 13TH DEC

* DISRUPTIONS OF TRAFFIC POSSIBLE ON THE JAMMU-SRINAGAR HIGHWAY,SRINAGAR-LEH HIGHWAY ( ROAD ALREADY CLOSED)

*SRINAGAR CITY MAY FINALLY SEE A SNOWFALL ON 13TH DEC 2012

* GULMARG,SONAMARG,PAHALGAM TO WITNESS HEAVY SNOWFALL

* SHIMLA,MANALI AND OTHER CITIES OF HIMACHAL PRADESH TO RECEIVE VERY HEAVY SNOWFALL AND GREATER SNOW ACCUMULATIONS 

* RAINFALL EXPECTED ACROSS NORTH INDIAN PLAINS ESPECIALLY PUNJAB,HARYANA,UTTARAKHAND,HIMACHAL PRADESH

* DELHI,NCR MAY GET ISOLATED THUNDERSHOWERS DURING THE PERIOD. 

IF ANYONE WANTS TO SUBMIT THE SNOW IMAGES THEN THE IMAGES ( WITH DETAILS LIKE LOCATION,TIME OF IMAGE) MUST BE MAILED TO 

metdweather@live.com
OR 
SUBMIT ON FACEBOOK-

facebook.com/deorasakshay

THE IMAGES WILL BE PUBLISHED ON THE BLOG

Powerful Western Disturbance to impact North India bringing snowfall!

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

After a very prolonged gap, a powerful Western Disturbance will be striking North India from tomorrow onwards i.e 28th Nov 2012

Attached above is the 48hr projected base 00z,27th Nov 700mb vorticity coupled with the precipitation.. One can see that the rainfall amount will be very heavy (snowfall as well) in J&K prominently in Central,Western J&K.

With temperatures already in the freezing level, snowfall will happen on a heavy level basis in J&K and I suspect light to Moderate across Himachal Pradesh starting 28th Nov and continuing on reduced estimates on 29th Nov

Usually such western disturbances bring rains in Northern Plains like Punjab,Haryana,NCR New Delhi however with this setup, its unlikely that these regions will receive heavy rains.

On Thursday (29th Nov), I suspect some cloud cover for the Northern Plains with isolated rainfall chances (less chance though) which may not bring a much change in the weather

*** Srinagar City will also receive THE FIRST SNOWFALL OF THE SEASON ON 28TH NOV LATE PERIOD,29TH NOV. THIS SNOWFALL EVEN MAY CLOSE THE LEH-SRINAGAR HIGHWAY AROUND ZOJILA-PASS***

*** Jammu-Srinagar highway may also get traffic disruption*** 

GULMARG,SONAMARG,PAHALGAM ETC WILL BE DECORATED BY SNOW IN THIS EVENT***

RAINFALL EXPECTED IN OMAN,UAE-

Meanwhile another short wave trough shall arrive from Western regions coming over Saudi Arabia bringing rains around 29th Nov 2012 and then moving across UAE-Oman  brining rains there around 30th Nov 2012,1st Dec 2012

Thus cities like Muscat,Dubai etc will receive rains (along with parts like SE Oman) in this period

Folks from Muscat,Dubai can send the rainfall images to METD WEATHER on facebook
facebook.com/deorasakshay


STAY TUNED FOR UPDATES

Tropical Storm Nilam makes a landfall near Cuddalore

TS Nilam approaches Tamil Nadu. Landfall today afternoon

Arabian Sea system shows "signs" of life after models kill it! BOB Depression/TS to impact Tamil Nadu

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

Bay of Bengal Update- 

As was expected, the BOB system ( hence to be called as Tropical Depression) is churning in the Southern Bay of Bengal.

The above morning IR-BD imagery shows the exposed LLCC centred somewhere in the 9.5N,83.5E which is ~ 530km SE of Chennai.
So far the max sustained winds are around 55km/hr with MSLP ~ 1002mb.

The system has intensified since the last post due to favoured conditions. The model analysis suggests that the system is moving in a region of 30kt upper air divergence and around 15kt low level convergence with the V wind shear to be around 10kt.

Based on the models and observations, it appears that the system which at present is a Tropical Depression will INTENSIFY to a marginal Tropical Storm status ( With max sustained winds of around 65kt )

As a Tropical Storm, it shall head for a landfall in a region

 Between Ammapatam to Cuddalore ( Tamil Nadu) 

    ON Tuesday,Oct 30 2012 night period to Oct 31 2012 Wednesday early   morning hours- 

(10PM IST- 0400hrs IST) 

IMPACTS- 

* ROUGH SEA WILL CONTINUE NEAR THE TAMIL NADU COAST TILL 1ST NOV 2012 

* STRONG GUSTY WINDS WILL BE WITNESSED in ENTIRE TAMIL NADU, PONDICHERRY ( PUDUCHERRY),COASTAL BORDERING ANDHRA PRADESH BEGINNING TONIGHT AND ENDING AFTER THE SYSTEM PASSES

* HEAVY RAINS  ARE LIKELY IN THE AREAS IN CYCLONE's PATH AND ADJOINING AREAS AS SHOWN IN THE MAP AND THEN STRETCHING AS NORTH AS HYDERABAD on 31st Oct 2012 AS THE SYSTEM MOVES. MODERATE RAINS IN KARNATAKA AS WELL. 

* CHENNAI ALSO WILL WITNESS HEAVY RAINS,WINDS IN THE PERIOD 

* Flooding Potential across INTERIOR TAMIL NADU 

After the landfall, the depression will move inland and will be steered by the upper air winds which will move the system North-North East wards on Oct 31 due to which the rainfall shall spread into Karnataka,Andhra Pradesh,Maharashtra and the entire Eastern coastal states on 1-2nd Nov 2012. 

The rainfall then shall spread further reaching Northern Maharashtra-Central MP latitude by Nov 2-3 2012 due to which Nagpur will get rainfall in a period between 1-4th Nov 2012 with cloud skies. ( For exact details refer METD WEATHER FACEBOOK PAGE) with highest chances of rains on Nov 2-3. 

II- Arabian System- 

The recent GFS models have turned a lot since the last post and now they aren't showing any chance of Arabian System to form or it merging with the Bay Storm/Depression. 

Infact as was reported on METD WEATHER Facebook, the system faced a lot of problems on Oct 28th i.e yesterday as there was no proper low level convergence to grip the convection. 

However things changed today and lets have a look-

Animation- 

http://rammb.cira.colostate.edu/products/tc_realtime/loop.asp?product=4kmirimg&storm_identifier=IO962012&starting_image=2012IO96_4KMIRIMG_201210282200.GIF

Above- 

The top most image is of 28th Oct 0730GMT where the system faced a lot of problems due to lack of LL convergence. The below image is of Oct 29 0730GMT showing that the system has organised a lot since last 24hr given the developing Low level convergence of around 10kt. 

The system continues to remain in an excellent poleward outflow ( associated with the Bay system) of around 30kt and favoured SST to support robust convection. The wind shears are also relaxed (vertical). 

Here is a look at the latest precipitation embedded in the system- 

One can observe that outer rain bands have formed and there seems to be a developing LLCC with more banding from the Southern periphery of the system

Thus, I do expect that the Arabian Sea system will intensify further given the excellent conditions available. However, there is a decreasing confidence at the moment whether the system will head towards Gujarat or not. 

Considering the model runs and vicinity of the Bay system, it appears that the Arabian Sea system shall head NE gradually and move inland somewhere in Karnataka when the Bay system will be present. So in such a case, the chance of Arabian System forming into a Tropical Cyclone is very very less. However it can get converted into a Tropical Depression, move NE and move inwards in the Western Coast of India

As a result, the warnings issued previously for Gujarat STAND CANCELLED