ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM HURRICANE GABRIELLE DISCUSSION NUMBER 24 NATIONAL WEATHER SERVICE MIAMI FL 11 AM EDT MON SEP 17 2001 AIR FORCE RECON HAS BEEN OUT IN THE SYSTEM THIS MORNING AND FOUND 85 KT 5000-FT FLIGHT-LEVEL WINDS IN DEEP CONVECTION...ALONG WITH A CENTRAL PRESSURE OF 983 MB. THIS INDICATES THAT GABRIELLE HAS STRENGTHENED SLIGHTLY SO THE INTENSITY HAS BEEN INCREASED TO 70 KT. THE INITIAL MOTION ESTIMATE IS 055/17. GABRIELLE HAS MADE A SLIGHT JOG TO THE LEFT OF THE PREVIOUS MOTION AND FORECAST TRACK...BUT THIS IS LIKELY JUST A SHORT TERM MOTION...POSSIBLY DUE TO RE-DEVELOPMENT OF THE LOW-LEVEL CENTER CLOSER TO THE DEEP CONVECTION LOCATED TO THE NORTHWEST. GABRIELLE IS EXPECTED TO RETURN TO THE PREVIOUS BASE COURSE OF ABOUT 060 DEGREES AS A LONG FETCH OF WESTERLY MID-TO UPPER-LEVEL WINDS OVER THE EASTERN U.S. BEGIN TO IMPINGE ON THE CYCLONE LATER TODAY. THE OFFICIAL FORECAST TRACK IS A LITTLE TO THE LEFT OF THE PREVIOUS FORECAST THROUGH 24 HOURS AND THEN RETURNS TO THE PREVIOUS TRACK BY 36 HOURS. THIS SCENARIO IS CONSISTENT WITH ALL OF THE GLOBAL MODELS...BUT IS CLOSEST TO THE AVN MODEL. THE NOGAPS MODEL APPEARS TO BE MUCH TOO FAST AND THE UKMET MODEL SEEMS TOO FAR TO THE LEFT BY TAKING THE CYCLONE ACROSS SOUTHEAST NEWFOUNDLAND IN THE FACE OF SUCH STRONG WESTERLY FLOW AT THAT LATITUDE. THE INTENSITY FORECAST IS RATHER TRICKY SINCE I AM UNCERTAIN AS TO WHEN THE SYSTEM WILL ACTUALLY MAKE THE EXTRATROPICAL TRANSITION. HOWEVER...EVEN SOME BAROCLINIC EFFECTS COULD KEEP GABRIELLE FAIRLY STRONG IN THE LATER PERIODS...SO THE SHIPS INTENSITY MODEL FORECAST WAS FOLLOWED CLOSELY. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 17/1500Z 35.8N 65.7W 70 KTS 12HR VT 18/0000Z 37.0N 62.9W 70 KTS 24HR VT 18/1200Z 38.7N 60.2W 65 KTS...BECOMING EXTRATROPICAL 36HR VT 19/0000Z 40.4N 57.8W 60 KTS...EXTRATROPICAL 48HR VT 19/1200Z 42.9N 53.7W 60 KTS...EXTRATROPICAL 72HR VT 20/1200Z 48.0N 43.5W 50 KTS...EXTRATROPICAL NNNN