#chennai - temp. now 10:34pm is 25 deg C and going down slowly. City can expect a cloudy morning with medium high cloud cover & DRY.
Sunday, November 18, 2012
"03B" - Becoming DRY and Weakening now, crawling S-W
"03B" - Becoming DRY and Weakening now.
A dry Deep Depression, crawling S-W and showing signs of weakening.
9pm Satellite IR shows convection along E,S-E and N-E.. almost nothing over the rest of the system.
Medium level clouding seen over S-W periphery may reach Chennai, S.Andhra coast by early morning tomorrow.
Latest position plot on map.
JTWC warning at 8:30pm
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A dry Deep Depression, crawling S-W and showing signs of weakening.
9pm Satellite IR shows convection along E,S-E and N-E.. almost nothing over the rest of the system.
Medium level clouding seen over S-W periphery may reach Chennai, S.Andhra coast by early morning tomorrow.
Latest position plot on map.
JTWC warning at 8:30pm
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TROPICAL CYCLONE (TC) 03B LOCATED APPROXIMATELY 465 NM EAST- NORTHEAST OF CHENNAI, INDIA HAS TRACKED SOUTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE DEEP CENTRAL CONVECTION HAS NEARLY BEEN COMPLETELY SHEARED FROM THE NOW FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). AN OLDER 180628Z OSCAT PASS SHOWED A SIGNIFICANT REGION OF 35 KNOT WINDS WITHIN THE NORTHEASTERN QUADRANT OF THE LLCC. THE SOUTHWESTERN QUADRANT INDICATED MUCH LIGHTER WINDS BETWEEN 15 TO 20 KNOTS. ANIMATED TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE DRY AIR CONTINUES TO WRAP TOWARDS THE CENTER OF THE SYSTEM AND HAS STEADILY DIMINISHED THE INFLOW OF THE WARMER MOIST TROPICAL AIR MASS IN THE SOUTHEASTERN QUADRANT. UPPER LEVEL ANALYSIS INDICATES TC 03B IS LOCATED TO THE NORTH OF A SUBTROPICAL RIDGE (STR) AXIS. OVER THE PAST FEW HOURS THE VERTICAL WIND SHEAR (VWS) HAS INCREASED TO MODERATELY HIGH LEVELS (20 TO 30 KNOTS) WHICH IS RESPONSIBLE FOR THE OBSERVED SHEARING OF THE CONVECTION TO THE NORTHEAST OF THE LLCC. DVORAK ESTIMATES FROM PGTW INDICATE A NOTICEABLE WEAKENING TREND OVER THE PAST 12 HOURS. INTENSITY HAS BEEN MAINTAINED AT 35 KNOTS BASED ON THE PREVIOUSLY MENTIONED OSCAT PASS AND THE OBSERVED STRUCTURE OF THE LLCC IN MSI. MODEL GUIDANCE HAS BEEN STEADY OVER THE PAST 12 HOURS WITH THE WEST-SOUTHWEST TRACK, EXCLUDING WBAR WHICH CONTINUES TO SHOW A NORTHWARD TRACK. BASED ON THE INCREASE IN VWS, THE FORECASTED INTENSITY HAS BEEN DECREASED OVER THE NEXT 24 HOURS TO A STEADY STATE FORECAST, WITH DISSIPATION BY TAU 48. BASED ON CONSISTENT MODEL GUIDANCE AND THE RECENT INCREASE IN TRACK SPEED TO THE SOUTHWEST, THERE IS NOW HIGH CONFIDENCE IN THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 181200Z IS 14 FEET.
Colourful forecasts and very frequent changes in track forecasts have cast a shadow on the reliability and accuracy of model forecasts. True, all models go as per their computers, fed with the current parameters, but all including popular US model computers are in no position to accurately estimate the possible changes in the parameters they depend on. All judge from the possible computed estimates of wind shear, SST, pressure ridges, winds aloft and surrounding conditions.
4:30pm, Latest satellite IR shows that convective activity around "03B" is getting less.. A Dry Depression !!.. http://ow.ly/i/18NHE
"98B" is now "03B" - Deep Depression now! Moving S-W
"98B" is now "03B" - Deep Depression now! Moving S-W
As expected by GFS models the system is now moving S-W. Still a deep depression.
Pressure at 996mb.
Winds upto 60km/hr.
1:30pm, latest satellite.
Latest position plot on map.
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IMD warning at 1pm.
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The deep depression over eastcentral Bay of Bengal moved westwards and lay centred at 1130 hrs IST of
JTWC warning at 2:30pm
--------------------------------------------
As expected by GFS models the system is now moving S-W. Still a deep depression.
Pressure at 996mb.
Winds upto 60km/hr.
1:30pm, latest satellite.
Latest position plot on map.
------------------------------------------
IMD warning at 1pm.
------------------------------------------
The deep depression over eastcentral Bay of Bengal moved westwards and lay centred at 1130 hrs IST of
today 18
th
November 2012 near latitude 16.0
0
N and longitude 88.0
0
E, about 900 km east-northeast of Chennai, 550
km east-southeast of Visakhapatnam and 500 km southeast of Paradip. The system would intensify further into a
cyclonic storm and move slowly westwards during next 12 hrs and west-southwestwards towards south Andhra
Pradesh and north Tamil Nadu coasts during subsequent 72 hrs.
JTWC warning at 2:30pm
--------------------------------------------
TROPICAL CYCLONE (TC) 03B LOCATED APPROXIMATELY 385 NM SOUTH OF KOLKATA, INDIA HAS TRACKED WEST-SOUTHWESTWARD AT 02 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE DEEP CENTRAL CONVECTION HAS DIMINISHED SLIGHTLY SINCE THE PREVIOUS FORECAST, WITH THE LOW LEVEL CIRCULATION CENTER (LLCC) SHOWING A SMALL AMOUNT OF ELONGATION IN THE NORTHWESTERN QUADRANT. ANIMATED TOTAL PRECIPITABLE WATER SHOWS THE DRY AIR ALONG THE WESTERN HALF OF THE SYSTEM CONTINUES TO WRAP TOWARD THE CENTER OF THE SYSTEM. THE DRY AIR HAS ALMOST COMPLETELY ISOLATED THE LLCC FROM THE INFLOW OF THE WARMER MOIST TROPICAL AIR MASS IN THE SOUTHEASTERN QUADRANT. THIS WEAKENING OBSERVED IN THE CONVECTION IS LIKELY DUE IN GREAT PART TO THIS INFLUX OF DRY AIR. UPPER LEVEL ANALYSIS INDICATES TC 03B IS LOCATED UNDER THE AXIS OF A SUBTROPICAL RIDGE (STR) AND IS IN THE DIVERGENT QUADRANT OF A SUBTROPICAL JET MAX TO THE NORTHEAST, WHICH IS PROVIDING AMPLE POLEWARD OUTFLOW. THE VERY FAVORABLE OUTFLOW IN ASSOCIATION WITH CONSOLIDATION OF THE LLCC WITHIN THE NEXT 36 HOURS WILL CAUSE A WEAK INTENSIFICATION, BUT WILL QUICKLY BE OVERCOME BY INCREASING VERTICAL WIND SHEAR AND DRY AIR ENTRAINMENT. WITH THE EXCEPTION OF WBAR, MODEL GUIDANCE HAS COME INTO GOOD ALIGNMENT INDICATING A WEST TO WEST-SOUTHWEST TRACK. TC 03B IS CURRENTLY TRACKING SLOWLY IN A WEAK STEERING ENVIRONMENT, BUT AS A STR LOCATED OVER INDIA BUILDS, THE SYSTEM IS EXPECTED TO TRACK MORE QUICKLY TO THE WEST-SOUTHWEST. EVEN WITH THE INCREASED CONSOLIDATION OF MODEL GUIDANCE, THE SYSTEM BEING IN A POOR STEERING ENVIRONMENT LENDS TO LOW CONFIDENCE IN THE FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 180600Z IS 14 FEET.
"98B" - New path prediction ! Amazing !
At present "98B" is slowly crawling N-W.
Latest COLA GFS model has come up with a new path prediction for "98B" .
The system is expected to move N-W for next 12hrs and then start drifting S-W and end up near Chennai, S.Andhra coast on 21/22-Nov.
And IMD warning at 8pm was somewhat based on this model.
Here's the IMD warning at 8pm...
The depression over eastcentral Bay of Bengal moved west-nothwestwards, intensified into a deep
depression and lay centred at 1730 hrs IST of today, the 17th November 2012 over eastcentral Bay of Bengal near latitude 16.00N and longitude 89.00E, about 1000 km east-northeast of Chennai, 650 km east-southeast of Visakhapatnam and 550 km southeast of Paradip. The system would intensify further into a cyclonic storm and move slowly west-northwestwards during next 12 hrs. It would move west/west-southwestwards towards south Andhra Pradesh and north Tamil Nadu coasts during subsequent 72 hrs.
Opinion #1 --> This S-W drift may not be the case, because the 200hpa Jet is from S-W or S above 13th parallel. This will steer the system North, N-W or N-E.
Opinion #2 --> COLA model expects a Anti-cyclone is expected to move in from Myanmar into N-E Bay during next 3 days.. so this may make the present system "98B" to drift S-W.
Latest COLA GFS model has come up with a new path prediction for "98B" .
The system is expected to move N-W for next 12hrs and then start drifting S-W and end up near Chennai, S.Andhra coast on 21/22-Nov.
Here's the IMD warning at 8pm...
The depression over eastcentral Bay of Bengal moved west-nothwestwards, intensified into a deep
depression and lay centred at 1730 hrs IST of today, the 17th November 2012 over eastcentral Bay of Bengal near latitude 16.00N and longitude 89.00E, about 1000 km east-northeast of Chennai, 650 km east-southeast of Visakhapatnam and 550 km southeast of Paradip. The system would intensify further into a cyclonic storm and move slowly west-northwestwards during next 12 hrs. It would move west/west-southwestwards towards south Andhra Pradesh and north Tamil Nadu coasts during subsequent 72 hrs.
Opinion #1 --> This S-W drift may not be the case, because the 200hpa Jet is from S-W or S above 13th parallel. This will steer the system North, N-W or N-E.
Opinion #2 --> COLA model expects a Anti-cyclone is expected to move in from Myanmar into N-E Bay during next 3 days.. so this may make the present system "98B" to drift S-W.
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