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#4992 (Received by flhurricane at: 10:59 PM 13.Aug.2004) TCDAT3 HURRICANE CHARLEY DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT FRI AUG 13 2004 CHARLEY HAS WEAKENED SIGNIFICANTLY DURING ITS PASSAGE OVER THE FLORIDA PENINSULA. THE CENTRAL PRESSURE HAS RISEN TO AT LEAST 975 MB...WHILE SATELLITE IMAGERY HAS SHOWN A MARKED DECREASE IN THE COVERAGE AND INTENSITY OF THE CONVECTION. HOWEVER...SURFACE OBSERVATIONS SHOW THAT CHARLEY RETAINS THE TIGHT WIND CORE IT HAD AT LANDFALL...ALTHOUGH THE SMALL EYE SEEN ON RADAR AT LANDFALL IS GONE. THE INITIAL INTENSITY IS SET AT 75 KT BASED ON A COMBINATION OF SURFACE AND WSR-88D DOPPLER WIND DATA. THE INITIAL MOTION IS NOW 020/22. THERE IS NO CHANGE IN THE TRACK FORECAST PHILOSOPHY. CHARLEY IS NOW EMBEDDED IN DEEP LAYER SOUTHWESTERLIES ON THE EAST SIDE OF A UNSEASONABLY STRONG TROUGH. THE CYCLONE SHOULD MOVE GENERALLY NORTH-NORTHEASTWARD THROUGH 48 HR FOLLOWED BY A MORE NORTHEASTWARD MOTION AT HIGH LATITUDES. THIS TRACK SHOULD BRING THE CENTER OF CHARLEY ACROSS OPEN WATER FOR 12-18 HR OR SO BEFORE IT REACHES THE COAST OF SOUTH OR NORTH CAROLINA....THEN MOVE IT ALONG THE U.S. EASTERN SEABOARD. THE TRACK FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS PACKAGE AND IS ALONG THE EASTERN EDGE OF THE GUIDANCE. THE INTENSITY FORECAST IS A LITTLE PROBLEMATIC. THERE ARE A LOT OF NEGATIVE FACTORS...INCLUDING COOLER SEA SURFACE TEMPERATURES THAN CHARLEY EXPERIENCED IN THE GULF OF MEXICO...INCREASING VERTICAL WIND SHEAR...AND INCREASING PROXIMITY TO A FRONTAL ZONE. THE BIGGEST POSITIVE FACTOR IS THE CONTINUED EXISTENCE OF THE INNER CORE. BASED ON THE CORE...AND THE GFDL GUIDANCE CALLING FOR SOME INTENSIFICATION...THE INTENSITY FORECAST WILL CALL FOR SOME SLOW STRENGTHENING BEFORE THE NEXT LANDFALL. AFTER LANDFALL...CHARLEY SHOULD WEAKEN AS IT MERGES WITH THE FRONTAL ZONE AND BECOMES EXTRATROPICAL. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 14/0300Z 29.1N 81.1W 75 KT...INLAND 12HR VT 14/1200Z 32.0N 80.0W 80 KT...OVER WATER 24HR VT 15/0000Z 36.3N 77.6W 60 KT...INLAND 36HR VT 15/1200Z 41.1N 74.1W 45 KT...INLAND EXTRATROPICAL 48HR VT 16/0000Z 44.6N 70.7W 30 KT...INLAND EXTRATROPICAL 72HR VT 17/0000Z 48.5N 63.5W 30 KT...EXTRATROPICAL 96HR VT 18/0000Z...ABSORBED BY FRONTAL SYSTEM |