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

TROPICAL CYCLONE/DEPRESSION ALERTS FOR INDIA

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

"THE TROPICAL CYCLONE/DEPRESSION ACTIVITY BOTH IN THE ARBIAN SEA AND BAY OF BENGAL IS EXPECTED. STORM TRACKS CAN THREATEN INDIA"

"" FOR THE LATEST UPDATES, FOLLOW METD WEATHER ON FACEBOOK"""

The flattened 2012 North Indian Ocean Cyclone Season has revived with two candidates. BOB 01 and Tropical Storm Murjan. As METD WEATHER doesn't consider it, lets not discuss those past systems.

I- Bay of Bengal ( BOB)

The above DUNDEE imagery ( IR) spectrum shows massive CB clouds in the Central BOB with cloud tops around -30C at the moment. The imagery is of 0530PM IST. 

Animation (IR) here shows how the system has evolved robustly. 

http://rammb.cira.colostate.edu/products/tc_realtime/loop.asp?product=4kmirimg&storm_identifier=WP932012&starting_image=2012WP93_4KMIRIMG_201210270900.GIF

The above imagery shows that the system has organised much as seen from its symmetrical geometry. The system is encountering a building ~10kt convergence at the lower levels with extremely favorable thermodynamic conditions. The system continues to have 20kt upper air divergence with relaxed wind shears (vertical of 05-10kt barely) to support cyclogenesis in the 28-30C SST in the region.

Considering the favoured conditions, it appears that the system is very likely to strengthen further in the next 48hrs before it approaches the Indian SE and Sri-Lanka coast. 

The system can advance further and get a "Tropical Storm" status in the next 48hrs...

Where will it head? 

As per the 12z model which has been consistent, the system will be heading West and will make a landfall in a region between Cuddalore,Tamil Nadu and Northern Sri Lanka region. The area is purposively being kept large to settle the landfall uncertainties.  

The landfall seems to be happening on Oct 30 2012 in the morning - afternoon time ***
*** time may change***

Potential Impacts-

* Rough Seas offshore Tamil Nadu will initiate within 48hrs and will increase as the system approaches. 

* Heavy Rains with strong winds shall initiate in the Eastern Tamil Nadu region from 29th Oct and increasing ( VERY HEAVY) during the landfall. 

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

II- ARABIAN SEA

The above DUNDEE imagery showing a wedge region of convection in the Southern Arabian Sea. So far the region hasn't shown any significant convergence and hence the system continues to remain widespread in the Arabian Sea. 

However, as the Bay System ( Possibly will be named Tropical Storm Nilam) will interact with the Arabian System and due to this, the moisture amounts of the Arabian System will increase. 

As the Arabian System moves as per the estimated NW track due to the upper air wind pattern, it seems that system will intensify robustly ( Its having around 15kt lower convergence, 10kt upper air divergence, around 5-10kt vertical wind shear, favoured SST), 

This system has a very high chance of getting converted to a Tropical Storm and due to its path, Western India will face some rainfall events. 

At present, at the upper level a shortwave trough is digging through India and as the trough exits which eventually co-incides with the system's northerly approach, the system will be steered by the jet streams which will start the system turning NE towards India-Sindh region

Model uncertainty exists at the moment however considering the consistency and the upper air pattern, it appears that the system will make a landfall somewhere near NW Gujarat-Sindh border 

on Saturday,Nov 3 2012 *** 

*** timings will vary*** 

The region of landfall is purposively kept wide to avoid uncertainties of the models 

The probable landfall areas ( will be modified suitably)

Entire West Coastal Gujarat,Sindh coast. 

IMPACTS-

Rainfall shall happen across Western Coast of India ( excluding Kerala) with more amounts towards Goa,Western Maharashtra,NW Maharashtra, Central Maharashtra and vicinity. 

LAKSHADWEEP ALSO WILL GET  RAINS AS THE SYSTEM WILL APPROACH VERY CLOSE TO IT

Mumbai,Pune etc will get rains around 3-4th Nov period *** 

The landfall impacts shall vary with the storm's intensity hence it shall be notified later on. 

Rough seas shall persists near the Indian coasts

STAY TUNED FOR UPDATES