Thursday, October 14, 2010

7pm, Heavy showers over S. Karnataka and central & N.central Tamilnadu... http://ow.ly/i/4yy9
7pm, "97 B".. now having a whirl to it ... http://ow.ly/i/4yy9 ... it may be named in another 12 hrs.
7pm, Heavy showers along N-E, coastal Orissa, S. Bengal and S. Bangladesh ... http://ow.ly/i/4yy9
RT @palavalli: Super heavy rain near my place. Just made it back home before it started raining in the afternoon. Whew! (6:15pm)
RT @hashbangalore: Heavy rain accompanied by gusty winds and power cut. Bangalore (6:40pm)
No North East monsoon for Tamilnadu coast till 21-Oct.
Heavy widespread showers forecast for Maharastra coast from 19-Oct... till 22-Oct.
3:30pm, Bay depression "97 B".. closing in on Orissa coast ... http://ow.ly/i/4yhI
RT @EcoPicOfTheDay: Toxic Spill, Ajka, Hungary http://bit.ly/bOelX5
Update of "97 B"... # 1 ... http://ow.ly/2TiTF
ECMWF and a couple of other models have maintained their watch for another tropical storm in the Bay on 23-Oct.. http://ow.ly/2TiTh
Heavy activity in the Bay is not allowing the seasonal anticyclone over Northwest India to extend to lower latitudes.
"97 B"... THE SYSTEM HAS SOME SIGNATURES OF A MONSOON DEPRESSION.

Bay of Bengal storm intensifies into depression

Tuesday's well-marked low-pressure area over East-central Bay of Bengal has intensified into a depression, an India Meteorological Department (IMD) said on Wednesday evening. The storm has been lying centred about 700 km east of Visakhapatnam, 550 km southeast of Gopalpur and 550 km south-southeast of Digha since the afternoon.
The system is likely to move in a west-northwesterly direction towards the South Orissa coast during the next three days. The IMD bulletin did not mention about the prospects for further intensification, though international models say enabling conditions for the eventuality have been emerging.
The sea-surface temperature over large parts of the Bay continued to be above the threshold level needed for sustaining tropical storms. Upper level divergence that sets up the window for the system to ‘breathe' through the top and moderate vertical wind shear were two variables that boosted the prospects for further strengthening.
The Joint Typhoon Warning Centre (JTWC) of the US Navy took note of flaring deep convection around a low-level circulation centre.

‘FAIR' POTENTIAL
It assessed as ‘fair' the potential for the development of a significant tropical weather system during the next 24 hours. Meanwhile, it is increasingly becoming clear that the West Pacific-South China Sea-Bay of Bengal basins would need to calm down before the northeast monsoon can unfold along India's southeast coast.
Hectic activity in the Bay is not allowing the seasonal anticyclone over Northwest India to extend to lower latitudes and preside over the simultaneous exit of southwest monsoon and entry of the northeast monsoon.

FOLLOW-UP STORM
Meanwhile, the European Centre for Medium-Range Weather Forecasts (ECMWF) and a couple of other models have maintained their watch for another tropical storm in the Bay of Bengal around October 23. The system is forecast to be lapped up by a westerly trough approaching from Northwest India and hurled over the West Bengal coast around that time. This would coincide with the formation of a very powerful system making landfall over Southwest China with implications for entire Indo-China as well.

STRONG MJO
International models point to a situation where a very strong wet phase of the Madden-Julian Oscillation (MJO) wave has ‘lit up' the South China Sea and the West Pacific.
An equally strong dry but alternating phase of the MJO has been on view over Equatorial Indian Ocean and the South Indian Peninsula over the past few days.
The dry MJO phase does not help the cause of the northeast monsoon, though active monsoons have been known to prosper despite it.
The wet phase of the MJO, an upper level disturbance that transits the regional seas periodically, is known for triggering monsoon onsets and formation of ‘low's, depressions and even cyclones.

SUPER TYPHOON
The Climate Prediction Centre of the US National Weather Services had extrapolated earlier last week of the brewing storminess in the West Pacific/South China Sea sparked by a peaking wet phase of the MJO.
As mentioned earlier, a super typhoon is in the making in the South China Sea around October 23 after a low-pressure area getting generated in the West Pacific crosses the Philippine archipelago and slides into the South China Sea.
In fact, the JTWC has already picked on a preparatory tropical depression over the West Pacific and put it under watch for intensification as a cyclone very soon.
TheECMWF sees it unleashing its fury over Southwest China, Hong Kong, Vietnam and the larger Indo-China around that date.
The Ensemble Forecast System of the US Navy's Fleet Numerical Meteorology and Oceanography centre has also supported the outlook for this super typhoon.
Since it is a westward propagating system, a remnant is expected to call in over the Bay of Bengal as well and set up a ‘low' in due course.

Update of "97 B"... # 1

IMD warning
-------------------------

BOB 03/2010/05                                                                   Dated: 14.10.2010
Time of issue: 1130 hours IST

            The depression over eastcentral and adjoining northwest and westcentral Bay of Bengal remained practically stationary and lay centred at 0830 hrs IST of today, the14th October 2010 over the same areas near latitude 18.00N and longitude 88.50E, about 550 km east of Visakhapatnam (Andhra Pradesh), 430 km southeast ofGopalpur (Orissa) and 400 km south-southeast of Digha (West Bengal).
            The current environmental condition and numerical weather prediction (NWP) models suggest that the system would intensify further into a deep depression and move west-northwestward and cross Orissa coast between Gopalpur and Paradip by 15th October 2010 evening.
            Under the influence of this system, widespread rainfall with heavy to very falls at a few places would occur over coastal Orissa and isolated heavy to very falls over interior Orissa, coastal areas of West Bengal and north coastal Andhra Pradesh during next 48 hours.
            Squally winds with speed reaching 45-55 kmph would occur along and off north Andhra Pradesh, Orissa and West Bengal coasts during next 48 hours.
            Sea condition will be rough to very rough along and off these coasts during this period. Fishermen are advised not to venture into the sea off these coasts.
            The system is under constant watch and concerned state Govts are being informed accordingly.


JTWC
--------------------

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 18.2N 
90.1E, IS NOW LOCATED NEAR 20.6N 90.16E, APPROXIMATELY 410 NM SOUTH-
SOUTHEAST OF KOLKATA, INDIA. THE SYSTEM HAS SOME SIGNATURES OF A 
MONSOON DEPRESSION IN THAT THE AREA OF CONVECTION AND HIGHEST WINDS 
IS DISPLACED FROM THE CENTER, BUT CONVECTION IS CONFINED TO THE 
WESTERN QUADRANT RATHER THAN ITS SOUTHERN FLANK. ANIMATED INFRARED 
IMAGERY SHOWS THAT ALTHOUGH THERE HAS BEEN SOME RECENT CONSOLDIATION 
IN THE LOW LEVELS THE CONVECTION REMAINS DIRUNAL AND LIMITED 
PRIMARILY TO THE AREA OF CONVERGENCE ON THE SYSTEM'S WESTERN FLANK. 
AN UPPER LEVEL ANTICYCLONE OVER SOUTHEASTERN CHINA IS DRIVING 
30-35 KNOT EASTERLIES OVER THE BASIN AND RAPIDLY SHEARING THE 
CONVECTION.  A 131458Z 89HZ MICROWAVE IMAGE SHOWS THE POOR 
ORGANIZATION OF THE CONVECTION. SURFACE OBSERVATIONS IN THE VICINITY 
VERIFY A BROAD CYCLONIC CIRCULATION WITH PEAK REPORTED WINDS AT 25 
KNOTS, WHILE A 1458Z ASCAT IMAGE SHOWS A FIELD OF 30 KNOT 
NORTHEASTERLIES EXTENDING OVER THE NORTHWEST REGION OF THE SYSTEM. 
WESTERLIES EQUATORWARD OF THE SYSTEM ARE BEING ENHANCED BY A WANING 
WEST WIND BURST THAT HAS PEAKED OVER THE INDIAN OCEAN AND IS NOW 
TRANSLATING DOWNSTREAM INTO THE PACIFIC BASIN. ALTHOUGH SEA SURFACE 
TEMPERATURES IN THE BASIN ARE FAVORABLE FOR DEVELOPMENT, MODERATE 
VERTICAL WINDSHEAR COUPLED WITH THE LOOSE ORGANIZATION AT THE 
BOUNDARY LEVEL ARE CURRENTLY OPPOSING DEVELOPMENT OF THE SYSTEM. 
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. 
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE 
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE 
WITHIN THE NEXT 24 HOURS REMAINS FAIR.
Satellite shot
-----------------

Report of depression "97 B".. @10 am ... http://ow.ly/2ThL3
RT @JenDelgadoCNN: 1.5 million people have been hit by floods in central & west Africa. 377 killed. Nigeria, Cameroon & Benin hardest hit.
Report of depression @10 a.m.
The depression is now situated at 20.6N and 90.1E, that is approx. off the Orissa coast, south east of Kolkata. Almost stationary since last 12 hrs.
The core pressure is at 1002 mb, and will now fall after the 14th. as anticipated earlier. Winds are at an average speed of 25-30 knots, but gusts in the north-west quadrant are at 30 knots.
The major clouding is in the western quadrant. And the eastern quadrant shows minimum clouding. This is because of easterly winds blowing along the trough axis line, that is "shearing " that quadrant. In fact, it is these easterlies that is going against the deepening of the system.
Anyway,it should strengthen now, and by 16th, become a depression at 996/998 and cross into Indian coast thru Orissa.
I think we can still assume it to track west/northwest after crossing inland and weaken rapidly.
Rains will be skirting the Vidharbha region from the 16th. while moving into east M.P. Added moisture is likely to precipitate some showers in interior Mah. and north Konkan Thursday thru Monday.