Bay of Bengal: Severe Cyclonic Storm AILA (02B)

[Grifforzer]

BOB02-2009
Dated: 24. 05. 2009
Time of issue: 1130 hours IST

Subject: Deep Depression over west central, adjoining east central and northwest Bay of Bengal and cyclone alert for West Bengal coast.

Under its influence, rainfall at most places with heavy to very heavy falls at a few places and isolated extremely heavy falls (≥ 25 cm) is likely over Gangetic West Bengal and north coastal Orissa during next 48 hours.

Gale wind speed reaching 65-75 kmph gusting to 85 kmph are likely to commence along and off West Bengal coast from today, the 24th May 2009 evening. Squally winds speed reaching 45-55 kmph gusting to 65 kmph are likely to commence along and off north Orissa coasts from today, the 24th May evening.

Sea condition will be high along and off West Bengal coast and rough to very rough along and off Orissa coast. Fishermen are advised not to venture into the sea along and off these coasts.

Next bulletin will be issued at 1430 hrs IST of today, the 24th May 2009.

[Grifforzer]

IMD STILL has this at 25KT

no eye means no upgrade to deep depression for them

That is kind of harsh. I for one believe that the India Meteorological Department forecasters are starting to get their act together with monitoring and identifying cyclones.

[Chacor]

The 06z:

BOB 02/2009/06 Dated: 24. 05. 2009

Time of issue: 1330 hours IST

Sub: Deep Depression over west central, adjoining east central and northwest Bay of Bengal and cyclone alert for West Bengal coast.

The deep depression over west central & adjoining east central and north west Bay of Bengal remained practically stationary and lay centred at 1130 hours IST of today, the 24th May 2009 near lat. 18.00 N and long. 88.50 E, about 350 km southeast of Paradip, 400 km south-southeast of Sagar Island and 470 km south-southwest of Khepupara (Bangladesh). The system is likely to intensify further into a cyclonic storm and move in a near northerly direction and cross west Bengal-Bangladesh coast near latitude 890 E (100 km east of Sagar Island) around 25th May 2009 evening.

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


Under its influence, rainfall at most places with heavy to very heavy falls at a few places and isolated extremely heavy falls (≥ 25 cm) is likely over Gangetic West Bengal and north coastal Orissa during next 48 hours.

Squally winds speed reaching 50-60 kmph gusting to 70 kmph are likely to commence along and off north Orissa and West Bengal coasts from today, the 24th May evening. It is likely become gale wind speed reaching 75-85 kmph gusting to 95 kmph along and off West Bengal coast during landfall period. Sea condition will be high to very high along and off West Bengal coast and very rough along and off Orissa coast. Fishermen are advised not to venture into the sea along and off these coasts.

Next bulletin will be issued at 1930 hrs IST of today, the 24th May 2009.

[Derek Ortt]

Looks like the expected RI has begun

http://www.ssd.noaa.gov/mtsat/flt/t1/loop-vis.html

[Derek Ortt]

so JT is also ignorning the QS? Not sure why when there are so many unflagged 45-55KT vectors

The nature of the BoB leads to Monsoon Depressions being formed from the SW monsoon flow around Indochina. Often times this flow is rather strong and it will induce a warm-core cyclone in the region on the poleward side of the flow. When the high winds are still only on one side of the system, the winds are generally a result of the monsoon and the system isn't self sufficient. Once you see higher winds wrapping all the way around the LLCC then you know it's an independent system and not an eddy vortex.

I'm almost positive that's what the delay has been. Yes, India is known to be late on systems that are not hitting India, but for both JTWC and DEMS to be "slow" tells me that even though there are high monsoonal winds, the system isn't (wasn't) fully developed. If that is the case, it's probably not going to have the extreme low pressures and convection (hence low Dvorak values) that you would expect.

fair point. However, there were winds higher than 35KT north of the center on QS yesterday... closer to 45KT. I just believe there is far too much emphasis placed on the Dvorak technique at the expense of other data (in the Atlantic, the intensity is often QS based... if available... if there is no recon)

[HurricaneRobert]

It still looks like it was cut in half with most of the convection in the southern portion.

What's going on in the Arabian Sea? That system has been persistent for days.

[Derek Ortt]

looks like a 55KT storm on sat imagery now

[Ed Mahmoud]

looks like a 55KT storm on sat imagery now

Maybe more...

[Derek Ortt]

I want a high-res microwave pass from the last 2 hours. I wouldn't be surprised if an eye is forming

[P.K.]

Well RSMC New Delhi now have this listed as a T2.5 so they will name this shortly. JTWC at T3.0 and the SAB also at T3.0.

[HURAKAN]

WTIO31 PGTW 241500
SUBJ: TROPICAL CYCLONE 02B (TWO) WARNING NR 003
1. TROPICAL CYCLONE 02B (TWO) WARNING NR 003
01 ACTIVE TROPICAL CYCLONE IN NORTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
241200Z --- NEAR 18.3N 88.4E
MOVEMENT PAST SIX HOURS - 360 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
REPEAT POSIT: 18.3N 88.4E
---
FORECASTS:
12 HRS, VALID AT:
250000Z --- 19.8N 88.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 005 DEG/ 08 KTS
---
24 HRS, VALID AT:
251200Z --- 21.4N 88.6E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 005 DEG/ 09 KTS
---
36 HRS, VALID AT:
260000Z --- 23.1N 88.8E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 48 HR POSIT: 010 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
261200Z --- 24.8N 89.1E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
241500Z POSITION NEAR 18.7N 88.4E.
TROPICAL CYCLONE (TC) 02B (TWO), LOCATED APPROXIMATELY 255 NM SOUTH
OF KOLKATA, INDIA, HAS TRACKED NORTHWARD AT 03 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 241153Z
AMSU IMAGE INDICATE TIGHTLY-CURVED BANDING AND AN IMPROVED, MORE
DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). THEREFORE, THERE IS
INCREASED CONFIDENCE IN THE CURRENT POSITION AS WELL AS THE 6-HOUR
MOTION. THE SYSTEM IS FORECAST TO ACCELERATE NORTHWARD AND SHOULD
MAKE LANDFALL NEAR TAU 24. THE AVAILABLE MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH THIS TRACK WITH A TIGHT CLUSTER OF MODELS THROUGH
TAU 48. TC 02B IS LOCATED WITHIN A FAVORABLE ENVIRONMENT WITH GOOD
RADIAL OUTFLOW AND IS EXPECTED TO INTENSIFY TO A PEAK INTENSITY OF
60-65 KNOTS PRIOR TO LANDFALL, AND WILL DISSIPATE OVER NORTHERN
BANGLADESH BY TAU 48. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 241200Z
IS 18 FEET. NEXT WARNINGS AT 242100Z, 250300Z, 250900Z AND
251500Z.//
NNNN

[HURAKAN]

[Derek Ortt]

eye hasnt formed yet, but it looks like a banding eye will form very soon

[Derek Ortt]

I HOPE I am not seeing a third outflow jet... there is one SW, one north, and looks like one SE

[Derek Ortt]

has been named Aila

http://www.imd.ernet.in/section/nhac/dynamic/rsmc.htm

[Chacor]

Cyclonic storm, not TS.

[senorpepr]

Cyclonic storm, not TS.

My apologies on that. The header on the RSMC bulletin had tropical storm and I wasn't thinking.

[KWT]

24hrs for this system to strengthen, which is plenty of time for this system to ramp up quite a bit more, though the inner core still isn't totally evolved.

[Derek Ortt]

might have picked up a little more speed than expected... would be very good news

[CrazyC83]

From the looks of it, I would say 60 kt based on trends from QuikSCAT yesterday.