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#373432 (Received by flhurricane at: 10:46 AM 03.Sep.2010) TCDAT3 TROPICAL STORM FIONA DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082010 1100 AM AST FRI SEP 03 2010 AIRCRAFT DATA FROM THIS MORNING SHOWED PEAK SFMR WINDS OF 39 KT AND FLIGHT-LEVEL WINDS OF 48 KT...SUPPORTING AN INITIAL WIND SPEED OF ABOUT 40 KT. SATELLITE IMAGES SHOW THAT CONVECTION HAS BECOME RATHER THIN NEAR THE CENTER...WITH THE CIRCULATION OF FIONA ALSO TAKING ON AN ELONGATED APPEARANCE. SLOW WEAKENING SEEMS LIKELY GIVEN THE PERSISTENT NORTHERLY SHEAR AND MODEL GUIDANCE IS ON GOOD AGREEMENT WITH THIS SCENARIO. THE NHC FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ADVISORY. ALL MODELS WEAKEN THE SYSTEM DRAMATICALLY IN A COUPLE OF DAYS...AND DISSIPATION IS EXPECTED AFTER THAT TIME. GIVEN THE LATEST SATELLITE PRESENTATION...IT WOULD NOT BE A SURPRISE IF FIONA DECAYED FASTER THAN THE FORECAST BELOW. FIONA HAS TURNED TO THE NORTH-NORTHEAST AND IS MOVING 020/11 KT. THE MODELS ARE WELL CLUSTERED NOW ON BRINGING THE CENTER NEAR BERMUDA IN ABOUT 18 HOURS. THEREAFTER...SOME ACCELERATION IS ANTICIPATED AS THE STORM ENCOUNTERS INCREASING SOUTHWESTERLY FLOW. THE NHC FORECAST IS VERY CLOSE TO THE PREVIOUS ONE AND THE DYNAMICAL MODEL CONSENSUS. THE INITIAL WIND RADII HAVE BEEN REDUCED BASED ON AIRCRAFT DATA...AND STILL MIGHT BE A LITTLE GENEROUS. FORECAST POSITIONS AND MAX WINDS INITIAL 03/1500Z 29.0N 66.4W 40 KT 12HR VT 04/0000Z 30.6N 65.7W 35 KT 24HR VT 04/1200Z 32.7N 64.6W 35 KT 36HR VT 05/0000Z 35.2N 63.1W 30 KT 48HR VT 05/1200Z 38.1N 61.2W 25 KT 72HR VT 06/1200Z...DISSIPATED $$ FORECASTER BLAKE |