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| #4180 (Received by flhurricane at: 10:50 PM 10.Aug.2004) TCDAT3 TROPICAL STORM CHARLEY DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT TUE AUG 10 2004 BACK NEAR 20Z...THE AIR FORCE RESERVE HURRICANE HUNTER FOUND A TIGHT CENTER WITH CENTRAL PRESSURE OF 999 MB AND MAXIMUM FLIGHT LEVEL WINDS OF 72 KT JUST TO THE NORTHEAST. SINCE THEN...A PERSISTENT CONVECTIVE BURST HAS FORMED OVER OR JUST EAST TO THE CENTER. THE INITIAL INTENSITY IS 55 KT BASED ON THE AIRCRAFT DATA AND A 55 KT INTENSITY ESTIMATE FROM TAFB. IT SHOULD BE NOTED THAT FAST FORWARD MOTION IS LIKELY ENHANCING THE WINDS IN THE NORTHEASTERN SEMICIRCLE BEYOND THAT WHICH WOULD NORMALLY BE SUPPORTED BY A 999 MB STORM. THE INITIAL MOTION IS 295/22...AND THE SHORT-TERM MOTION MAY BE JUST A LITTLE TO THE LEFT OF THAT. CHARLEY IS ON THE SOUTHWEST SIDE OF THE SUBTROPICAL RIDGE...WHILE TROPICAL STORM BONNIE IS OVER THE CENTRAL GULF OF MEXICO AND A DEVELOPING DEEP-LAYER TROUGH OVER THE CENTRAL UNITED STATES. THIS COMBINATION SHOULD MOVE CHARLEY WEST-NORTHWESTWARD FOR 24 HR OR SO...FOLLOWED BY RECURVATURE TO THE NORTH AND NORTHEAST. THE BIG QUESTION IS WHERE WILL THIS HAPPEN. THE VARIOUS MODELS ARE NOW TIGHTLY CLUSTERED FOR THE FIRST 72 HR... CALLING FOR CHARLEY TO TRACK ACROSS JAMAICA...THE CAYMAN ISLANDS... AND WESTERN CUBA ON ITS WAY TO THE SOUTHEASTERN GULF OF MEXICO. THE CLUSTERING HAS BECOME EVEN TIGHTER THAN 6 HR AGO SINCE THE GFS AND GFDL HAVE SHIFTED WESTWARD...WHILE THE NOGAPS HAS SHIFTED EASTWARD. THE FIRST 72 HR OF THE FORECAST TRACK IS NUDGE JUST A LITTLE TO THE EAST OF THE PREVIOUS PACKAGE. AFTER 72 HR...WHILE THERE IS GOOD AGREEMENT ON THE DIRECTION...THERE IS SIGNIFICANT DISAGREEMENT ON THE SPEED BETWEEN THE FASTEST NOGAPS...THE INTERMEDIATE GFDL...GFS...AND NHC98...AND THE SLOWER BAMS. THE FORECAST WILL COMPROMISE ON THE SPEED...CALLING FOR CHARLEY TO MOVE INLAND ALONG THE WESTERN GULF COAST OF FLORIDA AND ACCELERATE TO THE NORTHEAST. THE 72-120 HR PART OF THE FORECAST IS CONSIDERABLY FASTER THAN THE PREVIOUS FORECAST BASED ON THE STRENGTH OF THE TROUGH SHOWN IN THE MODELS. CHARLEY IS IN A GENERALLY FAVORABLE ENVIRONMENT...ALTHOUGH THERE ARE SOME SIGNS THAT UPPER-LEVEL WESTERLY FLOW FROM A CYCLONE WEST OF THE STORM IS UNDERCUTTING THE OTHERWISE IMPRESSIVE OUTLOW AT THIS TIME. OTHER THAN THAT...THERE IS NO OBVIOUS REASON OTHER THAN HITTING LAND THAT CHARLEY SHOULD NOT STRENGTHEN. THE GFDL AND SHIPS BOTH CALL FOR 95-100 KT WINDS IN THE SOUTHEASTERN GULF OF MEXICO. THE INTENSITY FORECAST WILL NOT GO QUITE THAT HIGH JUST YET...BUT WILL CALL FOR CHARLEY TO BECOME A CATEGORY 2 HURRICANE OVER THE GULF. AFTER RECURVATURE...PASSAGE OVER LAND AND THE START OF EXTRATROPICAL TRANSITION SHOULD CAUSE STEADY WEAKENING. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 11/0300Z 16.0N 72.8W 55 KT 12HR VT 11/1200Z 17.1N 75.7W 60 KT 24HR VT 12/0000Z 18.8N 78.8W 65 KT 36HR VT 12/1200Z 20.7N 81.1W 70 KT 48HR VT 13/0000Z 22.9N 82.3W 75 KT...INLAND 72HR VT 14/0000Z 26.5N 83.0W 85 KT...OVER WATER 96HR VT 15/0000Z 31.0N 82.0W 65 KT...INLAND 120HR VT 16/0000Z 37.5N 77.0W 35 KT...INLAND |
