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Invest 91B is now TC 04B, forecast to make landfall near Chennai/India within 6hours, 11/09utc update



INVEST 91B IS NOW TC 04B. WARNING 1 ISSUED AT 11/09UTC. CENTER LOCATED APPRX 70KM EAST SOUTHEAST OF CHENNAI AT 09/06UTC.

FORECAST REASONING.  SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.  FORECAST DISCUSSION:  TC 04B IS EXPECTED TO CONTINUE ON A WEST-NORTHWEST TRACK TOWARDS THE COAST OF INDIA AND MAKE LANDFALL NEAR CHENNAI, INDIA WITHIN THE NEXT 6 HOURS. TC 04B IS EXPECTED TO MAINTAIN CURRENT INTENSITY UNTIL IT REACHES LAND WHERE IT WILL BEGIN TO WEAKEN AND ERODE AS IT INTERACTS WITH THE TERRAIN THROUGH 12H. AFTER 12H, TC 04B WILL TRACK WESTERLY ACROSS THE INDIAN PENINSULA, RAPIDLY DISSIPATE OVER THE ROUGHER TERRAIN IN CENTRAL INDIA NEAR 24H. THE REMNANTS OF TC 04B WILL CONTINUE TRACKING  OVER INDIA AND MAY MOVE OVER THE ARABIAN SEA, HOWEVER, THERE IS LOW  PROBABILITY OF REGENERATION.
FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TC 04B IS EXPECTED TO CONTINUE ON A WEST-NORTHWEST TRACK TOWARDS THE COAST OF INDIA AND MAKE LANDFALL NEAR CHENNAI, INDIA WITHIN THE NEXT 6 HOURS. TC 04B IS EXPECTED TO MAINTAIN CURRENT INTENSITY UNTIL IT REACHES LAND WHERE IT WILL BEGIN TO WEAKEN AND ERODE AS IT INTERACTS WITH THE TERRAIN THROUGH 12H. AFTER 12H, TC 04B WILL TRACK WESTERLY ACROSS THE INDIAN PENINSULA, RAPIDLY DISSIPATE OVER THE ROUGHER TERRAIN IN CENTRAL INDIA NEAR 24H. THE REMNANTS OF TC 04B WILL CONTINUE TRACKING OVER INDIA AND MAY MOVE OVER THE ARABIAN SEA, HOWEVER, THERE IS LOW PROBABILITY OF REGENERATION.

0421110800  52N 923E  20
0421110806  61N 914E  20
0421110812  72N 901E  20
0421110818  76N 896E  20
0421110900  79N 890E  20
0421110906  86N 881E  20
0421110912  94N 873E  20
0421110918  97N 868E  20
0421111000  99N 859E  20
0421111006 104N 843E  25
0421111012 109N 832E  25
0421111018 122N 821E  30
0421111100 126N 816E  30
0421111106 130N 809E  35
NNNN

Invest 91B is now TC 04B, forecast to make landfall near Chennai/India within 6hours, 11/09utc update


SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LARGE AREA OF DEEP CONVECTION EAST AND NORTHEAST OF A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI LOOP AND A 110550Z GMI 89GHZ IMAGE. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED AND AN EARLIER 110355Z BULLSEYE METOP-B ASCAT PASS AND MULTIPLE AGENCY DVORAK ESTIMATES BETWEEN A T1.5 (25KTS) AND T2.0 (30KTS). THE ENVIRONMENT IS OVERALL MARGINALLY FAVORABLE WITH MODERATE POLEWARD OUTFLOW, WARM (28-29 CELCIUS) SEA SURFACE TEMPERATURES, ALL BEING OFFSET BY MODERATE TO STRONG VERTICAL WIND SHEAR.
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LARGE AREA OF DEEP CONVECTION EAST AND NORTHEAST OF A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI LOOP AND A 110550Z GMI 89GHZ IMAGE. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED AND AN EARLIER 110355Z BULLSEYE METOP-B ASCAT PASS AND MULTIPLE AGENCY DVORAK ESTIMATES BETWEEN A T1.5 (25KTS) AND T2.0 (30KTS). THE ENVIRONMENT IS OVERALL MARGINALLY FAVORABLE WITH MODERATE POLEWARD OUTFLOW, WARM (28-29 CELCIUS) SEA SURFACE TEMPERATURES, ALL BEING OFFSET BY MODERATE TO STRONG VERTICAL WIND SHEAR.


MODEL DISCUSSION: GUIDANCE FOR THE SHORT TRACK IS IN GENERALLY FAIR AGREEMENT, EXCEPT FOR NAVGEM AND AFUM MODEL GUIDANCE, WHICH ARE THE FAR LEFT OUTLIERS AND TURN THE TC TO THE WEST-SOUTHWEST PRIOR TO LANDFALL. THE JTWC FORECAST LIES WITHIN THE TIGHTEST GROUPING OF MODELS OF ECMWF, GFS, AND UKMET LYING JUST TO THE RIGHT OF THE CONSENSUS MEAN WITH MEDIUM CONFIDENCE. THE INTENSITY GUIDANCE IS ALSO IN FAIR AGREEMENT WITH A STEADY WEAKENING AFTER LANDFALL.
MODEL DISCUSSION: GUIDANCE FOR THE SHORT TRACK IS IN GENERALLY FAIR AGREEMENT, EXCEPT FOR NAVGEM AND AFUM MODEL GUIDANCE, WHICH ARE THE FAR LEFT OUTLIERS AND TURN THE TC TO THE WEST-SOUTHWEST PRIOR TO LANDFALL. THE JTWC FORECAST LIES WITHIN THE TIGHTEST GROUPING OF MODELS OF ECMWF, GFS, AND UKMET LYING JUST TO THE RIGHT OF THE CONSENSUS MEAN WITH MEDIUM CONFIDENCE. THE INTENSITY GUIDANCE IS ALSO IN FAIR AGREEMENT WITH A STEADY WEAKENING AFTER LANDFALL.


JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 04B.
JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 04B.

11/08UTC.
11/08UTC.
Rédigé par PATRICK HOAREAU le Thursday, November 11th 2021 à 12:37