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| #214348 (Received by flhurricane at: 10:55 PM 06.Sep.2008) TCDAT3 TROPICAL STORM HANNA DISCUSSION NUMBER 41 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008 1100 PM EDT SAT SEP 06 2008 THE CENTER OF HANNA IS MOVING OVER THE WEST-CENTRAL PORTION OF LONG ISLAND. THE INITIAL MOTION ESTIMATE IS 050/26...AND HANNA IS RIGHT ON TRACK. GRADUAL ACCELERATION IS FORECAST DURING THE NEXT 48 HOURS AS HANNA GETS CAUGHT UP IN THE FAST UPPER-LEVEL WESTERLIE...AND THE NEW NHC MODEL GUIDANCE IS TIGHTLY CLUSTERED ABOUT THE PREVIOUS FORECAST TRACK. THEREFORE...NO SIGNIFICANT CHANGES HAVE BEEN MADE AND HANNA IS EXPECTED TO CLEAR THE U.S. COASTLINE AROUND CAPE COD MASSACHUSETTS BY 07/0900Z. HANNA'S FAST FORWARD MOTION HAS LIKELY CONTRIBUTED TO SOME OF INCREASE IN OBSERVED SURFACE WINDS OBTAINED FROM SHIPS AND BUOYS SOUTH OF LONG ISLAND. TWO UNCONFIRMED SHIP REPORTS OF 64 KT AND 60 KT HAVE BEEN RECEIVED DURING THE PAST COUPLE OF HOURS...ONE OF WHICH OCCURRED IN A RAIN BAND. HOWEVER...THESE COULD HAVE BEEN ISOLATED GUSTS AND THE RAIN BANDS HAVE SINCE DISSIPATED. THEREFORE...THE INITIAL INTENSITY WILL BE 50 KT FOR THIS ADVISORY BASED ON EARLIER DOPPLER VELOCITY VALUES OF 70 KT AT 5000 TO 7000 FT THAT COVERED A SIGNIFICANT PORTION OF THE SOUTHEASTERN QUADRANT OF HANNA IN SEVERAL RAIN BANDS. LITTLE CHANGE IN STRENGTH IS EXPECTED THROUGHOUT THE FORECAST PERIOD...AND HANNA COULD EASILY BE AN EXTRATROPICAL STORM WITH 50-KT SUSTAINED WINDS AT ANY OF THE FORECAST TIMES. FORECAST POSITIONS AND MAX WINDS INITIAL 07/0300Z 40.5N 73.4W 50 KT...BECOMING EXTRATROPICAL 12HR VT 07/1200Z 43.0N 68.8W 50 KT...EXTRATROPICAL 24HR VT 08/0000Z 46.4N 61.1W 45 KT...EXTRATROPICAL 36HR VT 08/1200Z 48.8N 53.2W 45 KT...EXTRATROPICAL 48HR VT 09/0000Z 50.0N 45.0W 45 KT...EXTRATROPICAL 72HR VT 10/0000Z 52.5N 28.3W 45 KT...EXTRATROPICAL 96HR VT 11/0000Z 56.5N 15.5W 45 KT...EXTRATROPICAL 120HR VT 12/0000Z 61.5N 11.5W 45 KT...EXTRATROPICAL $$ FORECASTER STEWART |
