000 WTNT42 KNHC 050236 TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 44 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011 1100 PM AST TUE OCT 04 2011 THE STRUCTURE OF PHILIPPE HAS AGAIN CHANGED LITTLE SINCE THE LAST ADVISORY. CONVENTIONAL AND MICROWAVE SATELLITE DATA SHOW THAT THE LOW-LEVEL CENTER IS LOCATED NEAR THE NORTHWESTERN EDGE OF THE CONVECTION...WITH THE MICROWAVE IMAGERY SUGGESTING A MID-LEVEL EYE IS SOUTHEAST OF THE SURFACE CENTER. SATELLITE INTENSITY ESTIMATES ARE 55 KT FROM TAFB AND 45 KT FROM SAB...AND...BASED ON THIS AND THE LACK OF CHANGE IN ORGANIZATION...THE INITIAL INTENSITY REMAINS 55 KT. PHILIPPE HAS BEGUN ITS FORECAST NORTHWARD TURN WITH THE INITIAL MOTION NOW 300/6. THE CYCLONE IS NEAR THE WESTERN END OF THE SUBTROPICAL RIDGE...WITH WATER VAPOR AND INFRARED IMAGERY SHOWING A DEEP-LAYER TROUGH AND ASSOCIATED SURFACE COLD FRONT TO THE NORTHWEST. ALL GUIDANCE AGREES THAT PHILIPPE SHOULD RECURVE ON THE EASTERN SIDE OF THE TROUGH DURING THE NEXT 48-72 HOURS. HOWEVER... THERE IS A SIGNIFICANT SPREAD IN THE TRACK GUIDANCE BASED ON THE MODEL FORECASTS OF THE EVENTUAL FATE OF PHILIPPE. THE GFS... CANADIAN...NOGAPS...GFDL...AND HWRF MODELS SHOW THE CYCLONE REMAINING STRONG THROUGH EXTRATROPICAL TRANSITION AND FORECAST A NORTHWARD OR EVEN WEST OF NORTH MOTION BY 120 HOURS AS PHILIPPE MERGES WITH THE TROUGH. THE ECMWF AND UKMET SHOW A MUCH WEAKER PHILIPPE MOVING EASTWARD AHEAD OF THE COLD FRONT THAT EVENTUALLY ABSORBS THE TROPICAL CYCLONE. THE OFFICIAL FORECAST FOLLOWS THE EXTRATROPICAL TRANSITION SCENARIO AND SHOWS PHILIPPE TURNING NORTHWARD BY 120 HOURS. THE NEW FORECAST IS FASTER THAN THE PREVIOUS FORECAST...BUT IS SLOWER THAN THE MODEL CONSENSUS. WHILE PHILIPPE REMAINS UNDER NORTHERLY VERTICAL WIND SHEAR... ANALYSES FROM THE SHIPS MODEL AND CIMSS AT THE UNIVERSITY OF WISCONSIN SUGGEST THE SHEAR IS GRADUALLY DECREASING. THE DYNAMICAL MODELS SUGGESTS THERE WILL BE A 36-48 HOUR WINDOW OF MORE FAVORABLE CONDITIONS AS THE CYCLONE PASSES THROUGH AN UPPER-LEVEL RIDGE...AND MOST OF THE INTENSITY GUIDANCE RESPONDS TO THIS BY FORECASTING INTENSIFICATION. AFTER 48 HOURS...THE SHEAR SHOULD INCREASE AGAIN...WITH EXTRATROPICAL TRANSITION FORECAST TO START AT AROUND 96 HOURS AND FINISH BY 120 HOURS. THE NEW INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS ADVISORY AND IS IN BEST AGREEMENT WITH THE SHIPS AND LGEM MODELS. IT SHOULD BE NOTED THAT THE GFDL AND HWRF MODELS FORECAST A HIGHER PEAK INTENSITY THAN SHIPS AND LGEM...SO IT CANNOT BE RULED OUT THAT PHILIPPE COULD BE STRONGER THAN CURRENTLY FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 24.6N 60.4W 55 KT 65 MPH 12H 05/1200Z 25.3N 61.1W 55 KT 65 MPH 24H 06/0000Z 26.1N 61.5W 60 KT 70 MPH 36H 06/1200Z 27.2N 60.9W 65 KT 75 MPH 48H 07/0000Z 28.4N 59.6W 65 KT 75 MPH 72H 08/0000Z 30.5N 54.5W 60 KT 70 MPH 96H 09/0000Z 35.0N 48.0W 55 KT 65 MPH 120H 10/0000Z 40.5N 45.5W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ FORECASTER BEVEN