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| #47771 (Received by flhurricane at: 4:25 PM 22.Sep.2005) TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 22 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT THU SEP 22 2005 ALTHOUGH I AM NOT CERTAIN THAT THE LOW-LEVEL VORTICITY CENTER OF PHILIPPE ACTUALLY STILL HAS A CLOSED SURFACE WIND CIRCULATION... THERE IS ENOUGH CONVECTION AND APPARENT ROTATION TO KEEP THE SYSTEM AS A NOMINAL TROPICAL CYCLONE FOR THE TIME BEING. PHILIPPE IS A SMALL TROPICAL CYCLONE EMBEDDED WITHIN A BROAD NON-TROPICAL AREA OF LOW PRESSURE. THE INITIAL INTENSITY OF 35 KT IS BASED ON AN EARLIER QUIKSCAT PASS AND A 30 KT SHIP REPORT SOUTHEAST OF THE CENTER. THE ENVIRONMENT IS CHARACTERIZED BY HIGH SHEAR AND DRY MID-LEVEL AIR SWEEPING OVER THE CYCLONE FROM THE SOUTH. A HIGHLY DIFLUENT LARGE-SCALE UPPER FLOW IS LOCATED JUST TO THE CYCLONE'S NORTH...BUT THIS PATTERN AND PHILIPPE APPEAR TO BE MOVING MORE OR LESS IN TANDEM...SO I AM NOT EXPECTING THE CYCLONE TO BE ABLE TO TAKE ADVANTAGE. SOME INCREASE IN STRENGTH IS POSSIBLE AS PHILIPPE BECOMES EXTRATROPICAL AND ACCELERATES NORTHEASTWARD BEFORE BECOMING ABSORBED WITHIN A FRONTAL ZONE AFTER ABOUT 48 HOURS. THE INITIAL MOTION IS 350/15. PHILIPPE...WHICH IS A RELATIVELY SHALLOW SYSTEM...IS EXPECTED TO ROTATE AROUND THE BROADER LOW IN WHICH IT IS EMBEDDED FOR THE NEXT 12 TO 24 HOURS. IN ABOUT 48 HOURS A FRONTAL ZONE SHOULD BE APPROACHING PHILIPPE FROM THE NORTHWEST. ALL GUIDANCE AGREES GENERALLY WITH THIS SCENARIO. HOWEVER...AS THE FRONT APPROACHES THERE ARE SIGNIFICANT DIFFERENCES AMONG THE MODELS...WITH THE NOGAPS AND UKMET ACCELERATING PHILIPPE AND/OR THE NON-TROPICAL LOW NORTHEASTWARD...WHILE THE GFS AND GFDL LEAVE PHILIPPE BEHIND OR MOVE IT NORTHEAST ONLY SLOWLY. THE OFFICIAL FORECAST LEANS TOWARD THE FASTER SOLUTION AND IS IN BEST AGREEMENT WITH THE 12Z UKMET RUN. IT IS QUITE POSSIBLE THAT PHILIPPE WILL LOSE ITS CLOSED CIRCULATION AND DISSIPATE MUCH EARLIER THAN SHOWN BELOW. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 22/2100Z 27.5N 57.7W 35 KT 12HR VT 23/0600Z 29.5N 59.2W 35 KT 24HR VT 23/1800Z 31.3N 60.2W 35 KT 36HR VT 24/0600Z 32.8N 60.2W 40 KT...EXTRATROPICAL 48HR VT 24/1800Z 35.0N 58.0W 40 KT...EXTRATROPICAL 72HR VT 25/1800Z...ABSORBED WITHIN FRONTAL ZONE |
