Tropical Storm Thane update

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The Precipitable Water imagery shows rich moisture ( brown to orange color around cyclonic spin i.e Thane Storm. The Dark blue or purple shows very very low PW or moisture content )

METD WEATHER

Akshay Deoras

Severe Weather Forecaster

1130PM IST,28th Nov 2011

Tropical Storm Thane update 

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The latest IR satellite imagery indicates that TS Thane has exposed convection with cloud tops around -80C. The convection cycle is peaking now due to favored conditions at 15N,68.2E where SST is 29C.
The IR-NHC clearly indicates that horizontal shearing to the North and North-West of LLC has affected the compactness of the system and it has started disintegrating in that region.

Though the persisting 30kt poleward outflow and some 10kt low level convergence is assisting the central convection,

IT IS NOTED THAT THE PATH OF TS THANE HAS BEEN CHANGED THAN WHAT WAS BEING EXPECTED. THE EARLIER PATH COMPRISED OF A CLOSE ENCOUNTER WITH WEST COAST OF INDIA AND LANDFALL IN SINDH.

"BUT THE 12Z RUNS ALONG WITH PAST FEW TIMES HAVE BEEN CLEAR THAT THERE IS A STRONG POSSIBILITY OF DEVELOPMENT OF A HIGH PRESSURE ( ANTICYCLONE) AT LOW LEVELS OVER GUJARAT IN NEXT 48HRS.

SO THANE WILL MOVE NORTH WEST INSTEAD OF NORTH.

THE TOTAL PRECIPITABLE WATER OR MICROWAVE IMAGERY OF THE ARABIAN SEA INDICATES THAT THERE IS A PRESENCE OF COOLER SST AND ABSENCE OF MOISTURE IN CENTRAL REGION. THE ATTACHED IMAGE IS OF THE PW WHICH SHOWS LACK OF MOISTURE AFTER 24HRS FOR SYSTEM

CONSIDERING ABOVE TWO CASES,
TS THANE WILL BEGIN TO WEAKEN CONSIDERABLY AFTER 24HRS DUE TO
HIGHLY SHEARED ENV,DECREASING MOISTURE AND SST

ITS TRACK IS VIRTUALLY TOWARDS OMAN BUT IT WILL DIE BEFORE VIRTUALLY REACHING OMAN.

SO PEOPLE OF OMAN
NOT A SINGLE THREAT!

METD WEATHER FORECAST ( VALID +24HRS)
DEVELOPMENT STRENGTH - MODERATE
CAT 1 CYCLONE FORMATION - VERY POOR

Significant Chance of Tropical Cyclone Formation in Arabian Sea

METD WEATHER
AKSHAY DEORAS
SEVERE WEATHER FORECASTER

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AS MENTIONED IN THE LAST POST, THE POSSIBILITY OF FORMATION OF A TROPICAL STORM/CYCLONE IN THE ARABIAN SEA HAS SIGNIFICANTLY INCREASED


The Visible and Infrared observations indicate presence of wedge area of flaring convection in the Indian Ocean near Sri Lanka given the latest peak -50C cloud tops in the region especially in the region north of MALE.
Model forecast guidance has improved a lot and is in consistent agreement that persisting area of low pressure  at 4.9N,78.3E has robust potential for organizing into a good tropical depression system.

GFS guidance form CIMSS suggests that the area of flaring convection near the low level circulation center in in the sea having SST of 30C. The IR-BD and IR-NHC spectrum imagery implies that a wide area of convection is organizing North-West of MALE given the favored themal condition.
The system is facing very good upper air divergence of 40kt peak and low level convergence of 5-10kt in relaxed sheared environment. The persisting upper air conditions has helped the system's convection to gain momentum and the developing LLC will enable in the improvement of geometry of the system.

A note from the Joint Typhoon Warning Center indicates presence of 25-30kt wind near the LLCC and MSLP of 1001mb.

I will not be surprised to find REMARKABLE IMPROVEMENT IN THE STRENGTHENING OF THIS SYSTEM IN NEXT 24HRS CONSIDERING THE FAVORED CONDITIONS


Extremely Active Phase of MJO-

As seen from the above EWP map of Climate Prediction Center,a very active "WET PHASE" of MJO is landing in the Indian Subcontinent. Its very obvious that under the influence of this favored phase, the low pressure region mentioned above shall intensify. 




Intensity,Track and Effects


The Model guidance is fluctuating in the intensity of the system but considering the assistance from MJO, it does appear that the system will get converted to a Tropical Storm or Category 1 Cyclone. 
It shall be too early to go with Cat 1 Cyclone however the probability of it can't be ruled out. 


The Track of the system shall be in the Arabian Sea initially (26th Nov) passing close to Kerala. 
The system will move OFFSHORE WESTERN COAST OF INDIA BUT IS EXPECTED TO BE AT A SAFE DISTANCE FROM THE SHORE thus limiting the rainfall totals in the continent. 
Due to the less resistance from coastal dry air, the system shall intensify on its way reaching in the North Arabian Sea offshore Gujarat this month end. 
The upper air winds ( Jet Streams) will then curve the path of this system which will bend it over North Gujarat or so. However we must wait till more details arrive




The possible effects will be 
Rough Seas in Eastern Arabian Sea offshore the West Coast of India
Strong Winds and GALE at the coasts ( West India)
Moderate Rainfall at the coastal regions 


( ALERT MAP SHALL BE PUT ON SOON)


WINTER BLOW OFF!
If this system happens to bend towards India, then it will deflect the North,North Western winds and due to its influence the winds shall be westerly to SW. This will lead to rise of night temperature in Western India and Central India also...


STAY TUNED FOR UPDATES

Weather expected to TAKE A TURN IN INDIA.

METD WEATHER
AKSHAY DEORAS
SEVERE WEATHER FORECASTER

The overall 2011 Winter is in a smooth stage with temperatures making a sharp dip at minimum near the west coast of Maharashtra and interiors like Pune and settling around 15C at min here in Nagpur.
This year's November has been overall DRY as compared to the last year when it was remarkably wet due to a coupled effect of La Nina and enhanced phase of Madden Jullian Oscillation.

This month, the MJO phase turned down to DRY or INACTIVE phase which assisted in the cool air incursion and spread in India. However the GFS models are continuing to predict a "STORMY OUTLOOK THIS MONTH END"

The Empirical Wave Propogation from Climate Prediction Center is indicating an arriving ENHANCED or WET phase of MJO by 27th Nov 2011.

At the same time, the GFS forecast models are indicating "A JUST FORMED LOW PRESSURE AROUND 5N,80E" IN THE INDIAN OCEAN" will cross Sri Lanka and enter the Arabian Sea around 25-26th Nov 2011. The Long Range models continue to predict that it will reach intensification stage offshore the West Coast of India due to conducive environment.

If it comes true, then Western India will experience HEAVY RAINS STARTING FROM 26-27TH NOV 2011. THE RAINS WILL BECOME HEAVY WITH GALE CONDITIONS AND STORM SURGES WHICH WILL PURELY DEPEND ON THE INTENSITY OF THE LOW

INCREASED MOISTURE ENVIRONMENT FOR CENTRAL INDIA
IF THE PATH OF THE SYSTEM REMAINS THE SAME AS MENTIONED ABOVE, THEN THERE WILL BE A REMARKABLE CHANGE IN THE WEATHER STARTING FROM THIS MONTH END AND WHICH MAY CONTINUE TO AROUND MID DECEMBER


THERE WILL BE INCREASE IN THE MOISTURE LEVEL IN MAHARASHTRA. 
THE WINDS ALSO WILL RE-DIRECT FROM SOUTH-EAST TO SOUTH FOR NAGPUR AND ENTIRE MAHARASHTRA


THIS ALSO WILL TRIGGER RAINFALL IN NAGPUR AND SOME PARTS OF MAHARASHTRA AND TOTALLY BLOW AWAY THE WINTER FOR SOME DAYS


STAY TUNED FOR UPDATES RELATING TO IT