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#461750 (Received by flhurricane at: 4:35 AM 25.Sep.2011) TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011 500 AM AST SUN SEP 25 2011 PHILIPPE HAS BECOME A LITTLE BETTER ORGANIZED DURING THE PAST SEVERAL HOURS. THE CURVED BAND OVER THE WESTERN SEMICIRCLE HAS WIDENED AND THE CENTRAL CONVECTION HAS EXPANDED AND DEEPENED. SUBJECTIVE AND OBJECTIVE DVORAK CLASSIFICATIONS HAVE INCREASED AND NOW SUPPORT AN INITIAL INTENSITY OF 40 KT. ADDITIONAL STRENGTHENING OF THE CYCLONE IS LIKELY DURING THE NEXT COUPLE OF DAYS AS PHILIPPE REMAINS IN FAVORABLE ATMOSPHERIC AND OCEANIC CONDITIONS...AND THE OFFICIAL FORECAST BRINGS PHILIPPE TO HURRICANE STRENGTH BY 48 HOURS. AFTER THAT...THE CYCLONE WILL BE ENCOUNTERING AN INCREASE IN SOUTHWESTERLY SHEAR AS IT MOVES OVER COOLER WATERS. THIS LESS CONDUCIVE ENVIRONMENT SHOULD CAUSE SOME WEAKENING BY THE END OF THE FORECAST PERIOD. THE OFFICIAL FORECAST IS ABOVE THE SHIPS AND LGEM GUIDANCE BUT BELOW THE AGGRESSIVE GFDL MODEL. THE TROPICAL STORM IS MOVING WEST-NORTHWESTWARD AT ABOUT 11 KT TO THE SOUTH OF A NARROW RIDGE. THE MODELS ARE IN RELATIVELY GOOD AGREEMENT IN SHOWING THE RIDGE WEAKEN IN RESPONSE TO A SERIES OF SHORTWAVE TROUGHS MOVING ACROSS THE SUBTROPICAL EASTERN ATLANTIC. THIS PATTERN WILL CAUSE PHILIPPE TO GRADUALLY TURN NORTHWARD OVER THE EASTERN ATLANTIC IN THREE TO FOUR DAYS. THE OFFICIAL FORECAST IS CLOSE TO THE MULTI-MODEL CONSENSUS AND WAS NUDGED WESTWARD AT THE END OF THE FORECAST PERIOD...TRENDING TOWARD THE GFS AND ECMWF MODELS. FORECAST POSITIONS AND MAX WINDS INIT 25/0900Z 12.0N 29.8W 40 KT 45 MPH 12H 25/1800Z 12.8N 31.4W 45 KT 50 MPH 24H 26/0600Z 13.9N 33.2W 55 KT 65 MPH 36H 26/1800Z 14.9N 34.6W 60 KT 70 MPH 48H 27/0600Z 16.2N 35.6W 65 KT 75 MPH 72H 28/0600Z 18.5N 37.5W 60 KT 70 MPH 96H 29/0600Z 22.0N 38.5W 60 KT 70 MPH 120H 30/0600Z 25.0N 38.5W 55 KT 65 MPH $$ FORECASTER CANGIALOSI |