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#288719 (Received by flhurricane at: 10:41 AM 16.Aug.2009) TCDAT4 TROPICAL DEPRESSION FOUR DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009 1100 AM EDT SUN AUG 16 2009 VISIBLE SATELLITE IMAGERY AND DATA FROM THE TAMPA WSR-88D INDICATE DEVELOPING DEEP CONVECTIVE BANDING OVER THE EAST SEMICIRCLE OF THE TROPICAL CYCLONE. IT APPEARS THAT THE WINDS ASSOCIATED WITH THE STRONGER BANDS MAY NOT YET BE MIXING DOWN TO THE SURFACE...AS NOAA BUOY 42036 LOCATED JUST TO THE NORTH-NORTHWEST OF THE CIRCULATION CENTER IS REPORTING WINDS OF LESS THAN 15 KT. AIRCRAFT RECONNAISSANCE WILL BE INVESTIGATING THE CYCLONE SHORTLY TO HELP DETERMINE IF IT HAS BECOME A TROPICAL STORM. ALTHOUGH REGIONAL UPPER-AIR SOUNDINGS AND WATER VAPOR IMAGERY SUGGEST THAT THE THERMODYNAMIC ENVIRONMENT IS ONLY MARGINALLY FAVORABLE...THE UPPER-LEVEL SOUTHERLY FLOW OVER THE DEPRESSION IS QUITE DIFFLUENT. CONSEQUENTLY...THE OFFICIAL INTENSITY FORECAST STILL REFLECTS STRENGTHENING JUST BEFORE LANDFALL. AFTER THAT TIME...WEAKENING AND DISSIPATION IS FORECAST WITHIN 48 HOURS AS THE SYSTEM MOVES INLAND OVER THE NORTHERN GULF COAST. THE INITIAL MOTION IS 330/13. THE CYCLONE IS MOVING AROUND THE PERIPHERY OF THE SUBTROPICAL RIDGE AND IS EXPECTED TO MAINTAIN THIS APPROXIMATE HEADING UNTIL LANDFALL. THE OFFICIAL FORECAST IS CLOSE TO A CONSENSUS OF A FAIRLY TIGHTLY CLUSTERED GUIDANCE SUITE. ALTHOUGH THE DEPRESSION IS VERY SMALL AND HAS A LIMITED WIND FIELD....HEAVY RAINFALL IS LIKELY NEAR THE TRACK OF THE CYCLONE ACROSS THE FLORIDA PANHANDLE...SOUTHWESTERN GEORGIA AND SOUTHERN ALABAMA. FORECAST POSITIONS AND MAX WINDS INITIAL 16/1500Z 28.7N 84.6W 30 KT 12HR VT 17/0000Z 30.2N 85.8W 50 KT 24HR VT 17/1200Z 32.1N 87.1W 35 KT...INLAND 36HR VT 18/0000Z 34.0N 88.2W 20 KT...DISSIPATING INLAND 48HR VT 18/1200Z...DISSIPATED $$ FORECASTER BRENNAN |