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#4148 (Received by flhurricane at: 4:37 PM 10.Aug.2004) TCDAT2 TROPICAL STORM BONNIE DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT TUE AUG 10 2004 RECONNAISSANCE AND SATELLITE DATA INDICATE BONNIE HAS MAINTAINED A TIGHT INNER-CORE WIND FIELD...DESPITE THE RECENT WEAKENING OF THE CENTRAL CONVECTION. SHIP H3GQ REPORTED 40 KT SOUTHWESTERLY WINDS ABOUT 40 NMI SOUTH OF THE CENTER AT 18Z. BASED ON THIS REPORT AND A RECON REPORTED PRESSURE OF 1004 MB...THE INITIAL INTENSITY IS ONLY BEING DECREASED TO 45 KT. THE INITIAL MOTION ESTIMATE IS 005/05. THE LAST TWO RECON POSITIONS INDICATE BONNIE HAS FINALLY MADE THE LONG EXPECTED TURN TO THE NORTH THROUGH A BREAK IN THE SUBTROPICAL RIDGE. SUBSEQUENT SATELLITE DATA CONFIRMS THIS MOTION...AND POSSIBLY EVEN A SLIGHT EAST OF DUE NORTH MOTION. THIS NEW MOTION IS ALREADY TO THE RIGHT OF THE NHC MODEL GUIDANCE SUITE...SO THE OFFICIAL FORECAST TRACK IS JUST AN EXTENSION AND UPDATE OF THE PREVIOUS FORECAST TRACK. BONNIE SHOULD BEGIN TO ACCELERATE SIGNIFICANTLY TO THE NORTHEAST IN 24-30 HOURS AND MAKE LANDFALL IN THE CENTRAL PORTION OF THE FLORIDA PANHANDLE IN ABOUT 42 HOURS. AS MENTIONED IN THE PREVIOUS ADVISORIES...BONNIE IS EXPECTED TO REMAIN A SMALL TROPICAL CYCLONE THROUGHOUT THE PERIOD...WHICH CAN RESULT IN RAPID INTENSITY FLUCTUATIONS. BONNIE MAY BE GOING THROUGH ONE OF THOSE TEMPORARY FLUCTUATIONS NOW. THE INTENSITY FORECAST IS PREDICATED ON DEEP CONVECTION RETURNING WITHIN THE NEXT 6 TO 12 HOURS. ARGUMENTS FOR THUNDERSTORMS REDEVELOPING OVER THE CENTER LATER TONIGHT OR WEDNESDAY IS...THE RECENT IMPROVEMENT IN THE OUTER BANDING FEATURES NOTED IN SATELLITE IMAGERY...BONNIE EXPECTED TO MOVE INTO A WEAK OR EVEN NO SHEAR ENVIRONMENT IN 12-24 HOURS...VERY WARM SEA-SURFACE TEMPERATURES...AND THE USUAL NOCTURNAL CONVECTIVE MAXIMUM PERIOD. HOWEVER...BY 36 HOURS...SOUTHWESTERLY UPPER-LEVEL SHEAR IS EXPECTED TO BEGIN INCREASING...WHICH MAY CAP THE INTENSITY TREND PRIOR TO LANDFALL. THE OFFICIAL INTENSITY FORECAST IS THE SAME AS THE PREVIOUS INTENSITY FORECAST AND IS A BLEND OF THE SHIPS AND GFDL MODEL INTENSITY FORECASTS. WATCHES FOR PORTIONS OF THE NORTHEASTERN GULF OF MEXICO COASTAL AREAS MAY BE REQUIRED LATER TONIGHT. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 10/2100Z 24.7N 90.5W 45 KT 12HR VT 11/0600Z 25.5N 90.4W 55 KT 24HR VT 11/1800Z 26.8N 89.5W 65 KT 36HR VT 12/0600Z 28.5N 87.5W 70 KT 48HR VT 12/1800Z 31.0N 84.0W 50 KT...INLAND 72HR VT 13/1800Z 37.0N 76.5W 30 KT...EXTRATROPICAL 96HR VT 14/1800Z 53.5N 68.5W 30 KT...EXTRATROPICAL 120HR VT 15/1800Z...ABSORBED BY FRONTAL SYSTEM |