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#45592 (Received by flhurricane at: 10:49 PM 12.Sep.2005) TCDAT1 TROPICAL STORM OPHELIA DISCUSSION NUMBER 27 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT MON SEP 12 2005 THE STRUCTURE OF OPHELIA HAS CHANGED LITTLE OVER THE PAST SEVERAL HOURS...ALTHOUGH THE CONVECTIVE TOPS ARE A LITTLE COOLER THAN THEY WERE EARLIER. A NOAA AIRCRAFT MEASURED SURFACE WINDS OF 60 KT NORTH OF THE CENTER WITH THE STEPPED FREQUENCY MICROWAVE RADIOMETER AROUND 2238Z...AND AN AIR FORCE AIRCRAFT MEASURED 700 MB WINDS OF 72 KT. BASED ON THESE DATA...THE INITIAL INTENSITY REMAINS JUST BELOW HURRICANE STRENGTH. WHILE THE STRUCTURE OF OPHELIA...WITH A RADIUS OF MAXIMUM WIND OF 45-60 NMI...AS WELL AS MARGINAL WATER TEMPERATURES...ARGUES AGAINST ANY RAPID OR LARGE INTENSITY INCREASES...IT WOULD TAKE VERY LITTLE FOR OPHELIA TO REGAIN HURRICANE STATUS. WITH BOTH THE SHIPS AND GFDL GUIDANCE INDICATING SUCH...A HURRICANE WARNING AT THIS TIME IS THE PRUDENT COURSE OF ACTION. THE MOTION REMAINS SLOW AND ERRATIC...WITH AN INITIAL MOTION ESTIMATED AT 290/3. RAOB DATA AT 0Z SUGGEST THAT HIGH PRESSURE TO THE NORTHWEST OF OPHELIA IS WEAKENING WITH THE APPROACH A MID-LEVEL TROUGH. MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT THAT THE INFLUENCE OF THE HIGH WILL SHORTLY DIMINISH AND OPHELIA WILL BEGIN TO TURN NORTHWARD AND THEN NORTHEASTWARD OVER THE NEXT 48 HOURS...ALTHOUGH WITH VERY LITTLE ACCELERATION. THIS COULD RESULT IN A VERY SLOW PROGRESSION OF THE SYSTEM ACROSS THE HURRICANE WARNING AREA. GIVEN THE SIZE OF THE WIND FIELD...WINDS AT OR NEAR HURRICANE STRENGTH COULD BE A PROLONGED EXPERIENCE IN MANY LOCATIONS. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 13/0300Z 31.8N 77.9W 60 KT 12HR VT 13/1200Z 32.4N 78.1W 65 KT 24HR VT 14/0000Z 32.9N 78.1W 65 KT 36HR VT 14/1200Z 33.7N 77.8W 65 KT 48HR VT 15/0000Z 34.6N 77.2W 65 KT 72HR VT 16/0000Z 36.0N 75.5W 55 KT 96HR VT 17/0000Z 38.0N 72.0W 50 KT 120HR VT 18/0000Z 42.0N 66.0W 40 KT...EXTRATROPICAL |