Monday, May 17, 2010

Update on Bay System:
The Bay has "bounced back."  After sending negative signals throughout the last 1 month, in a rapid development, a low formed in the Bay on Sunday, and within 24hrs, now on Monday night, it is a deep depression.

A deep depression yes, but the core pressure is at 1000 mb, and the wind speed at the centre is 30 knots.

Now, the IMD forecasts it to move North-West, and deepen into a cyclonic storm, to cross the A.P. coast by the 20th.
JTWC estimates it to be a depression, and is still not declared its point of crossing the coast.
ECMRWF estimates a depression to move along the East coast, and cross the coast at Orissa.

I would personally go by that estimate. The said depression/deep depression would eventually move towards the A.P. coast till the 19th, and then graze the coast ,and cross maybe somewhere at the Orissa/ W.Bengal coast by the 23rd. That's my personal view point, and in weather, one can never be too sure or accurate. My reasoning for the system's "along the coast" movement is the W.D. moving in the Northern regions of the country. This W.D.aloft,can push the depression off course, and steer it into Orissa/ W.Bengal coast.
But things can appear and disappear in the weather mechanism within a day.
So if the W.D. vanishes.....things can be different.Therefore,alongwith paying attention to this depression, I would be focused on the W.D.s up North.
Resultantly, the Monsoon has moved into the middle Andaman regions. Now, we wait and watch for its further progress here.

For T.N. heavy rains will commence once this system approaches the coast. Then it all depends on its steering course.
For Kerala, heavy precipitation on Wednessday/Thursday, till the effect of the system is intact. Then again ...depends..? IMD may advance the Monsoon into Kerala during this period, but I would be cautious. If the system crosses into T.N.or A.P. and re-emerges into the Arabian Sea, it might just pull off the Monsoon energy Northwards or North-Westwards.
Situation is too fluid now..but will monitor, and update this blog frequently from tomorrow, at 4/6 hourly intervals.
Soon the deep depression "92B" will be named. May be before 18-May noon... http://ow.ly/1M9hy ... Keep following www.indianweatherman.com
Deep Depression "92B" .. Update #1 .. "Moved North" and conditions getting ready for Kerala coast .. http://ow.ly/1M9hy

Deep Depression "92B" .. Update #1

JTWC:
--------------

1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 11.3N 89.6E TO 14.0N 84.8E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IM-
AGERY AT 171200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.7N 88.6E. THE SYSTEM IS MOVING NORTHWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.1N
87.7E IS NOW LOCATED NEAR 11.7N 88.6E, APPROXIMATELY 495 NM EAST OF
CHENNAI, INDIA. CONVECTION CONTINUES TO ORGANIZE AROUND A DEVELOPING
LOW LEVEL CIRCULATION CENTER (LLCC). AN EARLIER 170315Z ASCAT PASS
CONFIRMS THAT A WELL-DEFINED 20 TO 25 KNOT CIRCULATION HAS FORMED.
A 171108Z SSMI MICROWAVE IMAGE INDICATES MARKED CONSOLIDATION HAS
OCCURRED WITHIN THE PAST FEW HOURS WITH DEEP CONVECTION RINGING AN
EASILY IDENTIFIABLE LLCC. SEVERAL BANDS HAVE ALSO BEGUN TO WRAP
TOWARDS THE CENTER. THE SYSTEM LIES IN CLOSE PROXIMITY TO THE UPPER
RIDGE AXIS IN A REGION OF LOW VERTICAL WIND SHEAR AND FAVORABLE
MULTIDIRECTIONAL VENTING. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS, AND MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1001 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
181500Z.

Latest Sate. shot
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JTWC : Projected path
----------------------


If this system continues its NORTH path then the South-west current will reach Kerala coast as expected on 23-May.
Already we can see heavy showers just west of Maldives Islands.

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

BOB 01/2010/02 Dated: 17.05.2010
Time of issue: 2000 hours IST

Sub: Deep Depression Over southeast Bay of Bengal and adjoining areas: Precyclone
Watch

The depression over southeast Bay of Bengal and adjoining areas moved northwestwards
, intensified into a deep depression and lay centred at 1730 hrs IST of today, the 17th May 2010
over southeast Bay of Bengal near latitude 11.00N and 88.00E, about 850 km east-southeast of
Chennai, 900 km southeast of Visakhapatnam and 1300 km south of Kolkata.

The current environmental conditions and Numerical Weather Prediction (NWP) models
suggest that the system is likely to intensify further into a cyclonic storm and move initially in a
northwesterly direction towards Andhra Pradesh coast.


Based on latest analysis with NWP models and other conventional techniques,
estimated track and intensity of the system are given in the Table below:

Date/Time(IST)
Position (lat. 0N/ long. 0E)
Sustained maximum surface wind speed (kmph)
17-05-2010/1730
11.0/88.0
55-65 gusting to 75
17-05-2010/2330
11.5/87.5
55-65 gusting to 75
18-05-2010/0530
12.0/87.0
65-75 gusting to 85
18-05-2010/1130
12.5/86.5
65-75 gusting to 85
18-05-2010/1730
13.0/86.0
75-85 gusting to 95
19-05-2010/0530
14.0/85.0
75-85 gusting to 95
19-05-2010/1730
15.0/84.0
85-95 gusting to 105
20-05-2010/0530
16.0/83.0
95-105 gusting to 115
20-05-.2009/1730
17.0/82.0
95-105 gusting to 115

Under the influence of this system, coastal areas of Andhra Pradesh, are likely to
experience fairly widespread rainfall with isolated heavy to very heavy falls from 19th May 2010.
Squally wind with speed reaching 55-65 kmph likely to commence along and off Andhra Pradesh
coast from 18th evening.

Sea condition will be very rough to high along and off Andhra Pradesh coast from
18th evening. Fishermen are advised not venture into the open sea.

The system is under constant watch and concerned state Govts. are being informed
accordingly.

Next bulletin will be issued at 0230 hrs IST of 18th May 2010.
Thai. Met model .. shows the South-west monsoon onset over Kerala on 23-May.. http://ow.ly/i/1BvR
More on TMD's prediction of monsoon onset over Kerala on 23-May... http://ow.ly/1M2yE
Thailand Meteorological Department - sees the monsoon making an onset over the southwest coast (Kerala) as early as Sunday (May 23)

IMD throws open monsoon onset window in the Bay

Article dated 16-May-10
India Meteorological Department (IMD) has officially thrown open the monsoon onset window in the fast-churning Bay of Bengal, which is now home to some of the warmest tropical waters around the globe.

Sea surface temperatures (SSTs) in the south-east Bay are in the 31-32 deg Celsius-range, which is most ideal for weather systems (low-pressure areas and depressions) to prosper.

CONDITIONS FAVOURABLE

The IMD said on Sunday that conditions are favourable for onset of south-west monsoon over south Andaman Sea, Nicobar Islands and adjoining southeast Bay of Bengal during the next two days.

An upper air cyclonic circulation has already formed over southeast Bay of Bengal.

A warning valid for this period said that isolated heavy rain or thundershowers would occur over Andaman and Nicobar Islands.

The Thailand Meteorological Department (TMD) has said that an ‘active low-pressure cell' covered the Andaman Sea on Sunday.

This region is forecast to stay very cloudy with scattered thundershowers and isolated heavy rain.

Southwesterly winds are clocking variable speeds of 15 km/hr to 30 km/hr.

The Canadian Meteorological Centre (CMC) and the Global Forecasting System (GFS) model of the US National Centres for Environmental Prediction (NCEP) have hinted that a ‘low' or depression may be generated from the Bay system and travel to the east coast.

EAST COAST SYTEM

While the CMC sees the system to be active until Thursday making a landfall over the north Andhra Pradesh coast, the NCEP has suggested a slightly different trajectory positing the system into the warmer waters adjoining coastal Tamil Nadu to cross the Chennai coast by Saturday.

From here, the system might take a north-northwest course and travel all the way into northern Maharashtra and adjoining west Madhya Pradesh, the NCEP said.

Meanwhile, the IMD has said that scattered rain or thundershowers would start unfolding over Tamil Nadu, south interior Karnataka, Kerala and Lakshadweep during the first three days of this week.

In its guidance for the rest of the week, it expected to see an increase in rainfall over south peninsular India and Lakshadweep Friday onwards in clear indication that the Arabian Sea would soon get into the act to facilitate onset of rains over the Kerala coast.

Satellite imagery showed convective clouds (rain or thundershower-causing) over parts of the Northeastern States, south peninsular India, Bay Islands, south Arabian Sea, the Comorin region and east, central and south Bay of Bengal and the Andaman Sea.


The TMD sees the monsoon making an onset over the southwest coast (Kerala) as early as Sunday (May 23). This was based on the active phase of an ongoing Madden-Julian Oscillation (MJO) wave in the equatorial Indian Ocean and adjoining peninsular seas.

Meanwhile, the US Joint Typhoon Warning Centre (JTWC) has signalled building activity with separate systems in the Arabian Sea and the Bay of Bengal. The Arabian Sea system, though, was brewing far away to the west of the Indian coast, but had a ‘fair' chance of developing into a tropical storm. Exact coordinates and direction of movement would be closely monitored for implications for monsoon flows.

As for the Bay system, the JTWC pointed to persisting area of convection, more than 1,000 km south of Kolkata. Satellite pictures revealed a broad unorganised region of convergence, deep convection and cyclonic turning.

Maximum sustained surface winds are estimated up to 28 km/hr. But JTWC assessed as ‘poor' the potential for the development of a significant tropical cyclone within the next 24 hours.

The US National Centres for Environmental Prediction (NCEP) maintained its outlook for a wave of enhanced rainfall for the India's southwest coast (Kerala) during the week ending May 23.

The entire Arabian Sea from the far west to the south-east (off Kerala) is shown to be ‘lit up' in the immediately following week (May 24 to June 1). Monsoon onset may happen mid-way through this period, which is earlier than usual. During this period, a ‘rain head' (likely storm) is shown to dig a track north-northeast from central Bay of Bengal and smash into the Thailand-Myanmar region.
Early Monsoon Onset to Aid India Cotton, Rice Sowing ... http://ow.ly/1M1sj
Chennai - Still its Max. temp. is around 37 deg C.. but today afternoon and now its very humid
Chennai - will experience extremely HUMID day & night conditions till the depression "92B" moves closer or moves away.
North Tamilnadu coast will experience extremely HUMID day & night conditions till the depression "92B" moves closer or moves away.
@sri50 @shobhawarrier .. Monsoon to kerala will set in around 24-May-10.. Follow http://ping.fm/T1BPT for more.
6pm, North states of Kashmir, Punjab and Himachal are getting cloudy due to a fresh western disturbance has moved in .. http://ow.ly/i/1Brf
6pm, Thunder cells over W. Bengal, S-W Orissa, Central Andhra, 3 more over Central and N-central Tamilnadu .. http://ow.ly/i/1Brf
Rain on 16-May.. Mayabander-8, Hut Bay-6,Nancowry, Bangalore & Port Blair-3, Chaparmukh, Carnicobar and Dibrugarh-2 CM.. http://ow.ly/i/1Bq3
IMD :: "92B" is likely to intensify further into a cyclonic storm and move initially northwesterly in a direction towards Andhra Pradesh.
RT @shuvankr: @weatherofindia There is no chance that "92B" will hit Tamilnadu coast , IMD projection track given will be right. ..???
RT @RediffNews: The much-awaited south-west monsoon on Monday brought first .. http://bit.ly/9KzAra
RT @dj_shaily: Good news! Monsoon hits Andaman, on way to Kerala http://dlvr.it/12K4X india
Conditions are favourable for further advance of monsoon over more parts of Bay of Bengal and remaining parts of Andaman Sea
4:30pm, Circulation of "92B" getting organized, while thunder storms popping over central and N-central Tamilnadu... http://ow.ly/i/1BnK
RT @INBreakingNews: Andamans receive first monsoon showers; may reach Kerala early.. http://ow.ly/17oMUA
S-W monsoon, northern limit of monsoon Lat. 5°N/Long. 80°E, Lat. 10°N/Long. 87°E, Mayabandar and Lat. 14°N/Long 98°E.. http://ow.ly/i/1Blc
On 16-May, highest maximum temperature of 47.8°C was recorded at Sri Ganganagar ( Rajasthan) ... that's Great.
RT @emkay456: @centerofright IMD announces arrival of SW Monsoon in Andamans. brace up for a cyclone on east coast of India @rajesh26
Latest GFS suggests that S-W monsoon will start over Kerala coast from 23-May .. http://ow.ly/i/1BkT
@shuvankr >>> Follow our tweets for regular weather updates, forecasts & reports from India. And visit www.indianweatherman.com
RT @shuvankr: That thing at Bay of Bengal satellite picture, is not doordarshan logo, that's 92B.
RT @shuvankr: @toralvaria Please ask your weather beat person to check up with IMD for storm systems 92B & 93A. Check my blog for latest
latest GFS model shows that the System "92B" may not intensify further but it'll touch Tamilnadu coast on 20-May .. http://ow.ly/i/1BkJ
It seems our readers are waiting and praying to god, that "92B" comes over TN coast and cools all. .. What'll happen ??
Present high level wind direction is from East to West.. this may guide the present "92B" towards Tamilnadu coast .. http://ow.ly/i/1BkA
Low pressure system "92B" .. is located 850 KM EAST-SOUTHEAST OF CHENNAI.
"92B" is upgraded to become as tropical cyclone.... http://ow.ly/1LV8U

"92B" is upgraded to become as tropical cyclone.

Latest sat. shot
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JTWC:
----------------

(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 8.5N 57.2E,
IS NOW LOCATED NEAR 9.9N 56.5E, APPROXIMATELY 325 NM EAST-SOUTHEAST
OF CAPE GUARDAFUI, SOMALIA. RECENT ANIMATED MULTISPECTRAL IMAGERY
SHOWS WELL DEFINED LOW- AND MID-LEVEL CYCLONIC TURNING WITH DEEP
CONVECTION ASSOCIATED WITH CONVERGENCE ALONG THE WESTERN PERIPHERY.
ENVIRONMENTAL ANALYSIS SHOWS THE SYSTEM IN APPROXIMATELY 20 KNOTS OF
VERTICAL WIND SHEAR AND NEAR AN UPPER LEVEL OUTFLOW SOURCE THAT IS
PROVIDING GOOD VENTING. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS FAIR.
(2) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 8.9N 90.0E,
IS NOW LOCATED NEAR 11.1N 87.7E, APPROXIMATELY 455 NM EAST-SOUTHEAST
OF CHENNAI, INDIA. DEEP CONVECTION IS BEGINNING TO CONSTRUCTIVELY
ORGANIZE AROUND A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC).
WEAK FORMATIVE BANDING IS ESPECIALLY EVIDENT IN A 170315 METOP-A
MICROWAVE IMAGE WRAPPING TOWARDS FLARING CENTRAL CONVECTION. A
170315Z ASCAT CONFIRMS A WELL-DEFINED 20 TO 25 KNOT LLCC. THE UPPER
LEVEL ENVIRONMENT IS GENERALLY FAVORABLE AS THE DISTURBANCE SITS
NEAR THE SUBTROPICAL RIDGE AXIS IN A REGION OF LOW TO MODERATE
VERTICAL WIND SHEAR AND BROAD MULTI-DIRECTIONAL DIFFLUENCE. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 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 IS UPGRADED TO FAIR.
"93A" over Arabian sea is slightly dis-organized .. http://ow.ly/i/1BjK
3pm, Heavy Monsoon like showers crashing over S-W Srilanka... http://ow.ly/i/1BjK
3pm, Even the dead high cloud fringes of the "92B" is over Chennai and other coastal Tamilnadu .. http://ow.ly/i/1BjK
3pm, ... look at the huge cloud mass of .. "92B" over Bay... http://ow.ly/i/1BjK
3pm, Look at the HUGE circulation and it's cloud mass over entire Bay of Bengal .. http://ow.ly/i/1BjK
Bay and Arabian sea storms.. Update on "93A" and "92B"... 17-May-2010, 9:43am ... http://ow.ly/1LPYA

Update on "93A" and "92B"... 17-May-2010, 9:43am

Latest sat. shot
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JTWC
---------------------

(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 8.5N 57.2E,
IS NOW LOCATED NEAR 9.9N 56.5E, APPROXIMATELY 325 NM EAST-SOUTHEAST
OF CAPE GUARDAFUI, SOMALIA. RECENT ANIMATED MULTISPECTRAL IMAGERY
SHOWS WELL DEFINED LOW- AND MID-LEVEL CYCLONIC TURNING WITH DEEP
CONVECTION ASSOCIATED WITH CONVERGENCE ALONG THE WESTERN PERIPHERY
OF SYSTEM. ENVIRONMENTAL ANALYSIS SHOWS THE SYSTEM IN APPROXIMATELY
20KTS OF VERTICAL WIND SHEAR AND NEAR AN UPPER LEVEL OUTFLOW SOURCE
THAT IS PROVIDING GOOD VENTING. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS FAIR.
(2) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.9N 90.3E,
IS NOW LOCATED NEAR 8.9N 90.0E, APPROXIMATELY 625 NM EAST-SOUTHEAST
OF CHENNAI, INDIA. ANIMATED INFRARED IMAGERY SHOWS A BROAD REGION OF
CONVERGENCE AND MID-LEVEL CYCLONIC TURNING. RECENT MICROWAVE IMAGERY
SHOWS AN OVERALL LACK OF ORGANIZED DEEP CONVECTION. A 160009Z
WINDSAT SCATTEROMETERY PASS SHOWS BROAD TROUGHING WITH NO INDICATION
OF A CLOSED SURFACE CIRCULATION. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1008 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS POOR.
South west Monsoon breaks over extreme south Islands of Andaman.
Early morning Sat. shot shows a slightly weakened "93A" and "92B" is getting organized and building up Heavy cloud mass. http://ow.ly/i/1B7n
@piyush_veere >> Except for some pre-monsoon and Heat thunder storms, Bihar will get S-W monsoon winds only after 20-Jun-2010.