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#47175 (Received by flhurricane at: 10:56 AM 20.Sep.2005) TCDAT2 HURRICANE PHILIPPE DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT TUE SEP 20 2005 THE CENTER OF PHILIPPE WAS VERY DIFFICULT TO LOCATE OVERNIGHT. EARLY MORNING SATELLITE AND MICROWAVE DATA HELPED TO DETERMINE THAT THE CENTER WAS LOCATED TO THE WEST OF THE DEEP CONVECTION. WESTERLY SHEAR HAS CONTINUED TO TAKE ITS TOLL ON THE HURRICANE...AND WITHIN THE LAST HOUR OR TWO THE LOW LEVEL CENTER HAS BECOME EXPOSED. THIS HAS RESULTED IN A RELOCATION OF THE CENTER AND A WESTWARD ADJUSTMENT TO THE TRACK FORECAST DURING THE FIRST 24-36 HOURS. CURRENT DVORAK DATA T NUMBERS SUPPORT AROUND 55 KT. HOWEVER...THE INITIAL INTENSITY FOR THIS ADVISORY WILL BE LOWERED TO 65 KT BASED A BLEND OF THE LATEST DVORAK DATA T AND CURRENT INTENSITY NUMBERS. THIS INTENSITY COULD BE A BIT GENEROUS BUT IT IS BETTER TO WAIT TO SEE IF THE WEAKENING TREND CONTINUES BEFORE DOWNGRADING PHILIPPE. THIS TRACK FORECAST CONTAINS HIGHER THAN NORMAL UNCERTAINTY AND ASSUMES THAT PHILIPPE WILL REMAIN A DEEP SYSTEM. THE FORECAST REASONING REMAINS BASICALLY UNCHANGED WITH PHILIPPE EXPECTED TO MOVE NORTHWARD INTO A WEAKNESS IN THE SUBTROPICAL RIDGE...THEN ACCELERATE NORTH THEN NORTHEASTWARD AHEAD OF A MID-LATITUDE TROUGH IN 4-5 DAYS. IF THE CURRENT WESTERLY SHEAR DOES NOT RELAX AS EXPECTED AND PHILIPPE WEAKENS...IT COULD TRACK FURTHER WESTWARD AND ADDITIONAL ADJUSTMENTS TO THE TRACK WOULD BE NEEDED. DUE TO THE CURRENT SATELLITE APPEARENCE...THE INTENSITY FORECAST WEAKENS PHILIPPE TO A TROPICAL STORM IN 12 HOURS. THE SHIPS INTENSITY MODEL CONTINUES TO RELAX THE WESTERLY SHEAR IN 12-24 HOURS AND THE OFFICIAL INTENSITY FORECAST SHOWS SLIGHT RESTRENGTHENING THEREAFTER. THE OFFICIAL FORECAST IS MUCH MORE CONSERVATIVE THAN BOTH SHIPS AND GFDL. IF PHILIPPE SURVIVES.... THE SHEAR IS FORECAST TO INCREASE AGAIN IN ABOUT 72 HOURS AND THIS SHOULD GRADUALLY WEAKEN THE CYCLONE. FORECASTER BROWN/AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 20/1500Z 18.3N 57.1W 65 KT 12HR VT 21/0000Z 18.8N 57.3W 60 KT 24HR VT 21/1200Z 20.7N 57.8W 65 KT 36HR VT 22/0000Z 22.9N 58.4W 70 KT 48HR VT 22/1200Z 25.0N 59.0W 75 KT 72HR VT 23/1200Z 30.5N 59.5W 65 KT 96HR VT 24/1200Z 35.5N 56.0W 60 KT 120HR VT 25/1200Z 40.0N 48.0W 55 KT |