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| #4572 (Received by flhurricane at: 4:42 PM 12.Aug.2004) TCDAT3 HURRICANE CHARLEY DISCUSSION NUMBER 14 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT THU AUG 12 2004 CHARLEY CONTINUES TO STRENGTHEN AND BECOME BETTER ORGANIZED BASED ON DATA FROM RECONNAISSANCE AIRCRAFT...SATELLITE IMAGES...AND RADARS FROM CUBA. WHILE THE CENTRAL PRESSURE HAS ONLY DECREASED TO 980 MB ...THE HURRICANE IS MOVING INTO A REGION OF HIGHER THAN AVERAGE SURFACE PRESSURES FOR THIS TIME OF THE YEAR. THEREFORE...THE USUAL PRESSURE-WIND RELATIONSHIP MAY NOT BE VALID...AT THIS TIME. THE INITIAL INTENSITY OF 90 KT IS BASED ON A FLIGHT-LEVEL WIND OF 105 KT...OR A SURFACE WIND ESTIMATE OF 95 KT...AND A 92 KT DROPSONDE SURFACE WIND. A SMALL EYE HAS BECOME QUITE DISTINCT IN SATELLITE IMAGERY AND UPPER-LEVEL OUTFLOW CONTINUES TO IMPROVE AND EXPAND IN ALL QUADRANTS AS THE VERTICAL SHEAR HAS DECREASED SIGNIFICANTLY. THE INITIAL MOTION IS NOW 335/15. CHARLEY BASICALLY REMAINS ON TRACK. UNFORTUNATELY...THERE IS SOMETHING OF A QUANDARY WITH THE LATEST NHC MODEL GUIDANCE. THE NEW GFDL AND UKMET RUNS HAVE MADE A WIDE TURN 75 TO 150 NMI LEFT OF THE PREVIOUS FORECAST TRACK...AND MOST OF THE OTHER GLOBAL MODELS AND NHC MODELS HAVE ALSO MADE A WESTWARD SHIFT. HOWEVER...THE 6- AND 12-HOUR GFDL AND UKMET FORECAST POSITIONS ARE ALREADY 30 TO 60 NMI WEST OR LEFT OF THE CURRENT POSITION AND MOTION. A STRONG UPSTREAM TROUGH NOTED DIGGING SOUTHEASTWARD OVER THE NORTHWESTERN GULF OF MEXICO IN WATER VAPOR IMAGERY SHOULD HELP TO BLOCK ANY SIGNIFICANT WESTWARD MOTION. BASED ON THE DEVELOPING WESTERLY TO SOUTHWESTERLY SYNOPTIC FLOW PATTERN OVER THE GULF...AND AN APPARENT LEFT BIAS BY MOST OF THE MODEL GUIDANCE...THE OFFICIAL TRACK IS JUST AN UPDATE AND EXTENSION OF THE PREVIOUS TWO FORECAST TRACKS. THE UPPER-LOW TO THE WEST OF CHARLEY IS NO LONGER AN INHIBITING FACTOR. IN CONTRAST...CHARLEY HAS DEVELOPED WELL-DEFINED UPPER-LEVEL ANTICYCLONIC OUTFLOW THAT SHOWS SIGNS OF ONLY GETTING BETTER FOR THE NEXT 24 HOURS. GIVEN THE SMALL EYE FEATURE AND AN ABUNDANCE OF WARM WATER AHEAD OF THE HURRICANE...CHARLEY IS EXPECTED TO CONTINUE STRENGTHENING...POSSIBLY EVEN RAPIDLY INTENSIFYING...AND BECOME A MAJOR HURRICANE BEFORE MAKING LANDFALL OVER WESTERN CUBA THIS EVENING. THE TERRAIN OVER WESTERN CUBA IS NOT PARTICULARLY HIGH AND LITTLE...IF ANY...DISRUPTION OF THE CIRCULATION IS EXPECTED. GIVEN THE IMPRESSIVE OUTFLOW REGIME THAT IS FORECAST TO DEVELOP OVER THE FLORIDA PENINSULA AND EASTERN GULF BY ALL OF THE GLOBAL AND REGIONAL MODELS...MAJOR HURRICANE STRENGTH SEEMS QUITE PROBABLE OVER THE SOUTHEASTERN GULF OF MEXICO ON FRIDAY. CHARLEY COULD STRENGTHEN A LITTLE MORE BETWEEN THE 12 AND 24 HOURS TIME PERIODS...AND THEN WEAKEN SLIGHTLY BEFORE MAKING LANDFALL DUE TO INCREASING VERTICAL SHEAR AND COOLER COASTAL WATERS AROUND THE TAMPA BAY AREA. THE OFFICIAL FORECAST IS CONSISTENT WITH THE SHIPS AND GFDL INTENSITY MODELS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 12/2100Z 21.2N 81.9W 90 KT 12HR VT 13/0600Z 23.1N 82.7W 100 KT 24HR VT 13/1800Z 26.5N 83.0W 105 KT 36HR VT 14/0600Z 30.5N 82.3W 65 KT...INLAND 48HR VT 14/1800Z 34.2N 80.0W 45 KT...INLAND 72HR VT 15/1800Z 42.0N 75.0W 35 KT...INLAND EXTRATROPICAL 96HR VT 16/1800Z 48.5N 65.0W 30 KT...INLAND EXTRATROPICAL 120HR VT 17/1800Z...ABSORBED BY FRONTAL SYSTEM |
