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| #47475 (Received by flhurricane at: 10:46 AM 21.Sep.2005) TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT WED SEP 21 2005 WESTERLY SHEAR FROM THE LARGE UPPER-TROPOSPHERIC CYCLONE NEAR 23N 61W CONTINUES TO TAKE ITS TOLL ON PHILIPPE. THE TROPICAL CYCLONE REMAINS DISORGANIZED WITH AN EXPOSED LOW LEVEL CLOUD CENTER IN MORNING VISIBLE SATELLITE IMAGERY. OVERNIGHT POSITION ESTIMATES WERE NOT BAD AND ONLY A SLIGHT EASTWARD ADJUSTMENT NEEDED TO BE MADE TO THE INITIAL POSITION. DVORAK INTENSITY ESTIMATES ARE BETWEEN 45 AND 55 KT. A 0922 UTC QUIKSCAT PASS DID NOT DETECT ANY BELIEVABLE 50 KT WIND VECTORS AND THEREFORE THE INITIAL INTENSITY WILL BE LOWERED TO 45 KT FOR THIS ADVISORY. THE INITIAL MOTION IS ESTIMATED AT 360/5. THE FORECAST REASONING THROUGH 72 HOURS REMAINS UNCHANGED...WITH PHILIPPE EXPECTED TO MOVE SLOWLY NORTH TO NORTH-NORTHWESTWARD INTO A WEAKNESS IN THE SUBTROPICAL RIDGE. THE MAIN MODEL DIFFERENCES OCCUR IN THE EXTENDED PERIODS. THE GFS...NOGAPS...AND ECMWF NOW SUGGEST THAT THE CYCLONE MAY NOT GET PICKED UP BY A LARGE EXTRATROPICAL CYCLONE OVER THE NORTH ATLANTIC. HOWEVER...THE UKMET AND GFDL CONTINUE TO FORECAST A NORTHEASTWARD ACCELERATION AND EVENTUAL ABSORPTION. THE OFFICIAL FORECAST WILL BACK OFF ON ABSORPTION AND ONCE AGAIN PROVIDE A 5 DAY FORECAST POINT. IF MODEL TRENDS CONTINUE IN THAT SOLUTION...THE 5 DAY FORECAST POINT MAY HAVE TO BE ADJUSTED WESTWARD IN SUBSEQUENT FORECASTS. DESPITE THE CURRENT SHEARED CONDITION OF PHILIPPE...AND WITH NO DECREASE IN SHEAR LIKELY...IT IS A LITTLE HARD TO UNDERSTAND WHY BOTH THE SHIPS AND GFDL MODELS RE-INTENSIFY PHILIPPE. OUT OF DEFERENCE TO THIS GUIDANCE THE OFFICIAL FORECAST WILL SHOW A LITTLE RESTRENGTHENING...BUT CONTINUED WEAKENING SEEMS JUST AS LIKELY. THE WIND RADII WERE ADJUSTED BASED ON THE QUIKSCAT DATA. FORECASTER BROWN/FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 21/1500Z 20.2N 57.2W 45 KT 12HR VT 22/0000Z 21.5N 57.4W 45 KT 24HR VT 22/1200Z 23.8N 58.0W 55 KT 36HR VT 23/0000Z 26.0N 58.6W 55 KT 48HR VT 23/1200Z 28.5N 59.0W 55 KT 72HR VT 24/1200Z 34.5N 57.5W 50 KT 96HR VT 25/1200Z 38.5N 50.0W 45 KT 120HR VT 26/1200Z 41.5N 44.0W 45 KT |
