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#388349 (Received by flhurricane at: 9:44 AM 07.Nov.2010) TCDAT1 TROPICAL STORM TOMAS DISCUSSION NUMBER 39 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL212010 1100 AM AST SUN NOV 07 2010 TOMAS HAS WEAKENED RAPIDLY DURING THE LAST SEVERAL HOURS. DEEP CONVECTION HAS WITHERED AWAY...DUE TO ABOUT 35 KT OF WESTERLY SHEAR...WITH ONLY A VERY SMALL AREA OF THUNDERSTORMS REMAINING NEAR THE CENTER. THE INITIAL INTENSITY IS ESTIMATED TO BE 50 KT...BASED ON A BLEND OF OBJECTIVE AND SUBJECTIVE SATELLITE INTENSITY ESTIMATES AND WIND REPORTS FROM BUOY 41047. TOMAS ALSO APPEARS TO BE GRADUALLY LOSING ITS TROPICAL CHARACTERISTICS. SATELLITE IMAGES SHOW COLD AIR STRATOCUMULUS CLOUDS WRAPPING AROUND THE WESTERN AND SOUTHERN PORTIONS OF THE CIRCULATION...AND SHIP REPORTS SUGGEST THAT THE SYSTEM COULD BE DEVELOPING FRONTAL BOUNDARIES. THE GFS-BASED SHIPS MODEL SHOWS THE SHEAR INCREASING FURTHER...TO NEAR 50 KT IN 12 HOURS. THIS...COMBINED WITH MID-LEVEL RELATIVE HUMIDITIES BELOW 40 PERCENT...AND COOL WATERS SHOULD CAUSE TOMAS TO BECOME POST-TROPICAL LATER TODAY OR TONIGHT. AN 0624 UTC AMSU OVERPASS AND A 1014 UTC SSMIS IMAGE INDICATE THAT THE LOW-LEVEL CENTER IS LOCATED ABOUT 50 N MI WEST OF THE PREVIOUS ESTIMATE. THESE DATA ALSO SUGGEST THAT TOMAS HAS SLOWED DOWN SUBSTANTIALLY AND TURNED NORTHWARD DURING THE PAST 12-18 HOURS... RESULTING IN AN INITIAL MOTION ESTIMATE OF 005/5. THE CYCLONE IS EXPECTED TO MOVE IN A MOTION BETWEEN NORTHEAST AND EAST-NORTHEAST WITH A GRADUAL INCREASE IN FORWARD SPEED...TO THE SOUTH AND SOUTHEAST OF A STRENGTHENING LARGE BAROCLINIC LOW OVER THE NORTH ATLANTIC. THIS MUCH LARGER LOW SHOULD ABSORB WHATEVER IS LEFT OF TOMAS IN ABOUT 4 DAYS. FORECAST POSITIONS AND MAX WINDS INITIAL 07/1500Z 26.0N 69.6W 50 KT 12HR VT 08/0000Z 26.4N 68.7W 45 KT...POST-TROPICAL 24HR VT 08/1200Z 26.9N 66.5W 35 KT...POST-TROPICAL 36HR VT 09/0000Z 27.9N 63.9W 30 KT...POST-TROP/REMNT LOW 48HR VT 09/1200Z 30.0N 61.0W 25 KT...POST-TROP/REMNT LOW 72HR VT 10/1200Z 36.0N 57.0W 25 KT...POST-TROP/REMNT LOW 96HR VT 11/1200Z...DISSIPATED $$ FORECASTER CANGIALOSI |