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#110066 (Received by flhurricane at: 10:49 PM 10.Sep.2006) TCDAT1 HURRICANE FLORENCE DISCUSSION NUMBER 30 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062006 1100 PM EDT SUN SEP 10 2006 THE LAST RECONNAISSANCE PRESSURE WAS ABOUT THE SAME AS EARLIER TODAY... 975 MB... WITH 86 KT MAXIMUM FLIGHT-LEVEL WINDS IN THE EASTERN SEMICIRCLE OF THE CYCLONE. THIS FLIGHT-LEVEL WIND CORRESPONDS TO SUSTAINED SURFACE WINDS OF ABOUT 75-80 KT USING STANDARD WIND REDUCTION FACTORS. THE INITIAL INTENSITY WILL BE KEPT AT 80 KT BUT COULD BE A LITTLE GENEROUS GIVEN THE RECENT WEAKNESS OF THE CONVECTION OVER THE EASTERN PORTION OF THE STORM. THE SATELLITE APPEARANCE IS MORE RAGGED THAN SIX HOURS AGO AND THE LAST AIRCRAFT FIX REPORTED AN OPEN EYEWALL. STILL...THERE IS A NARROW WINDOW OF OPPORTUNITY FOR FLORENCE TO STRENGTHEN IN THE NEXT 24 HOURS BEFORE INCREASING WIND SHEAR AND COOLING SSTS HINDER ANY INTENSIFICATION. THUS... THE CYCLONE COULD BECOME A CATEGORY TWO HURRICANE OVERNIGHT BEFORE ITS CLOSEST POINT OF APPROACH TO BERMUDA EARLY MONDAY. THE INTENSITY FORECAST IS A LITTLE LOWER THAN THE PREVIOUS ONE AND IS IN BETWEEN SHIPS... WHICH PEAKS THE SYSTEM AT 87 KT... AND THE GFDL WHICH STRENGTHENS FLORENCE TO 97 KT. PHASE-SPACE DIAGRAMS FROM FSU SHOW EXTRATROPICAL TRANSITION BY THE 72 HOUR TIMEFRAME... AND THE OFFICIAL FORECAST FOLLOWS SUIT. THE HURRICANE WILL LIKELY BECOME A POWERFUL EXTRATROPICAL STORM AT HIGH LATITUDES OVER THE NORTH ATLANTIC OCEAN...AS SHOWN BY THE GLOBAL MODELS. FLORENCE APPEARS TO HAVE REACHED ITS POINT OF RECURVATURE AND IS MOVING DUE NORTHWARD... 000/12. A GRADUAL BEND TO THE NORTH- NORTHEAST IS EXPECTED AS THE STORM ENCOUNTERS THE MIDDLE-LATITUDE WESTERLIES. AS THE HURRICANE MOVES FARTHER NORTHWARD... AN ACCELERATED MOTION TOWARD THE NORTHEAST SEEMS LIKELY AHEAD OF AN UPPER-TROUGH. MODEL GUIDANCE IS STILL IN SOME DISAGREEMENT ON HOW MUCH INTERACTION FLORENCE WILL HAVE WITH THIS TROUGH. THE UKMET IS THE RIGHTMOST OUTLIER KEEPING THE SYSTEM MOSTLY SEPARATE FROM THE UPPER TROUGH WHILE MOST OF THE OTHER MODELS SHOW A TRACK CLOSER TO NEWFOUNDLAND. THE OFFICIAL FORECAST IS SHIFTED WESTWARD FROM THE PREVIOUS FORECAST... BETWEEN THE UKMET AND THE MODEL CONSENSUS... BUT STILL ON THE EASTERN EDGE OF THE GUIDANCE ENVELOPE. FORECAST POSITIONS AND MAX WINDS INITIAL 11/0300Z 31.0N 66.1W 80 KT 12HR VT 11/1200Z 32.8N 65.9W 85 KT 24HR VT 12/0000Z 35.0N 64.8W 90 KT 36HR VT 12/1200Z 37.5N 63.3W 85 KT 48HR VT 13/0000Z 40.4N 60.9W 75 KT 72HR VT 14/0000Z 46.0N 53.5W 60 KT...EXTRATROPICAL 96HR VT 15/0000Z 48.0N 43.0W 50 KT...EXTRATROPICAL 120HR VT 16/0000Z 49.0N 28.0W 40 KT...EXTRATROPICAL $$ FORECASTER BLAKE/KNABB |