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#3460 (Received by flhurricane at: 4:41 AM 02.Aug.2004) TCDAT1 TROPICAL STORM ALEX DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT MON AUG 02 2004 ON THE LAST RECON FIX AT 0510 UTC...THE PRESSURE WAS DOWN TO 1005 MB BUT THE HIGHEST FLIGHT-LEVEL...850 MB...WINDS WERE 46 KT OVER THE SOUTHWEST QUADRANT. TAKING THE STANDARD REDUCTION FROM THIS LEVEL TO THE SURFACE STILL GIVES 35 KT FOR THE CURRENT INTENSITY. SUBSEQUENT SURFACE OBSERVATIONS FROM DATA BUOYS SUGGEST THAT THE CENTRAL PRESSURE MAY HAVE DROPPED A LITTLE MORE. WSR-88D DOPPLER RADAR DATA SUGGEST THAT THE STORM HAS BECOME A LITTLE BETTER ORGANIZED BUT THE CENTER IS STILL JUST TO THE NORTH OF THE AREA OF MOST INTENSE CONVECTION. WE ARE WAITING FOR THE NEXT AIRCRAFT MISSION TO SEE IF THE WINDS HAVE INCREASED. NUMERICAL GUIDANCE SUCH AS THE GFS SUGGEST THAT THE NORTHEASTERLY SHEAR OVER THE SYSTEM SHOULD BE ENDING...AND THAT THERE IS ABOUT A 24 HOUR WINDOW BEFORE INCREASING WESTERLY SHEAR AFFECTS THE TROPICAL CYCLONE. THEREFORE THE OFFICIAL FORECAST SHOWS STRENGTHENING UP TO 24 HOURS...AND THE FORECAST WIND SPEEDS ARE JUST SLIGHTLY HIGHER THAN THE LATEST SHIPS GUIDANCE. RECON...SATELLITE...AND SURFACE DATA SUGGEST LITTLE MOTION. ALEX IS STILL EMBEDDED WITHIN A WEAKNESS IN THE SUBTROPICAL RIDGE SO THE STEERING FLOW IS WEAK TO NON-EXISTENT. HOWEVER....AN APPROACHING TROUGH IN THE WESTERLIES IS SOON EXPECTED TO PROVIDE AN INCREASING SOUTHWESTERLY STEERING CURRENT...WHICH SHOULD ACCELERATE ALEX NORTHEASTWARD. EVEN THOUGH THE OFFICIAL TRACK FORECAST...LIKE THE PREVIOUS ONE...KEEPS THE STORM OFFSHORE THE PROXIMITY TO THE COAST DICTATES THAT THE TROPICAL STORM WARNINGS AND WATCHES BE MAINTAINED. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 02/0900Z 31.4N 79.5W 35 KT 12HR VT 02/1800Z 32.2N 79.0W 40 KT 24HR VT 03/0600Z 33.4N 77.3W 50 KT 36HR VT 03/1800Z 35.3N 74.3W 50 KT 48HR VT 04/0600Z 37.5N 70.5W 50 KT 72HR VT 05/0600Z 43.0N 59.0W 45 KT...BECOMING EXTRATROPICAL 96HR VT 06/0600Z 49.0N 44.0W 45 KT...EXTRATROPICAL 120HR VT 07/0600Z...ABSORBED |