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#464051 (Received by flhurricane at: 10:50 AM 04.Oct.2011) TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 42 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011 1100 AM AST TUE OCT 04 2011 SINCE THE PREVIOUS ADVISORY...A COUPLE MORE MICROWAVE IMAGES ARRIVED AND INDICATE THAT THE INNER CORE STRUCTURE OF PHILIPPE REMAINED WELL ORGANIZED THROUGH 1000 UTC. THE IMAGES REVEALED A LOW- AND MID-LEVEL EYE FEATURE THAT WAS VERTICALLY ALIGNED. THIS DATA ALONG WITH DVORAK AND AMSU INTENSITY ESTIMATES SUGGEST THAT PHILIPPE WAS POSSIBLY NEAR HURRICANE STRENGTH OVERNIGHT. SINCE THAT TIME...THE CLOUD PATTERN IN VISIBLE IMAGERY APPEARS SLIGHTLY LESS IMPRESSIVE WITH THE CENTER NEAR THE NORTHERN EDGE OF THE SMALL CONVECTIVE MASS. BASED ON A CONSENSUS OF THE LATEST DVORAK INTENSITY ESTIMATES THE INITIAL WIND SPEED IS SET AT 55 KT. ACCORDING TO A SHEAR ANALYSIS FROM UW-CIMSS...PHILIPPE REMAINS UNDER ABOUT 20 KT OF NORTHERLY SHEAR. AS THE CYCLONE CONTINUES WESTWARD DURING THE NEXT DAY OR SO IT IS EXPECTED TO MOVE CLOSER TO A NARROW UPPER-LEVEL RIDGE THAT SHOULD PROVIDE A SLIGHTLY MORE FAVORABLE UPPER-LEVEL ENVIRONMENT. AS A RESULT...THE OFFICIAL FORECAST CALLS FOR SOME MODEST STRENGTHENING AND MAKES PHILLIPE A HURRICANE IN A DAY OR SO. AFTER 48 HOURS...STRONG WESTERLY UPPER-LEVEL WINDS ASSOCIATED WITH A MID-LATITUDE TROUGH MOVING OFF THE EAST COAST OF THE UNITED STATES ARE FORECAST TO IMPINGE UPON THE CYCLONE AND SHOULD CAUSE WEAKENING. PHILIPPE IS ALSO EXPECTED TO INTERACT WITH A FRONT WITHIN 4 OR 5 DAYS...AND THE NEW FORECAST SHOWS PHILIPPE AS AN EXTRATROPICAL CYCLONE AT 120 HOURS. PHILIPPE IS MOVING WESTWARD AT ABOUT 10 KT. THE CYCLONE IS NEARING THE SOUTHWESTERN PORTION OF A MID/UPPER-LEVEL RIDGE OVER THE CENTRAL ATLANTIC AND SHOULD TURN WEST-NORTHWESTWARD VERY SOON. THE LARGE AFOREMENTIONED TROUGH MOVING OFF THE COAST OF THE UNITED STATES SHOULD CAUSE PHILIPPE TO RECURVE IN A COUPLE OF DAYS. AFTER THAT THE CYCLONE IS FORECAST TO ACCELERATE NORTHEASTWARD IN DEEP SOUTHWESTERLY FLOW OVER THE CENTRAL ATLANTIC. THE GFS HAS TRENDED FASTER AFTER 48 HOURS...AND THE OFFICIAL FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION. THE ECMWF MODEL CONTINUES TO DISSIPATE THE CYCLONE IN A COUPLE OF DAYS...HOWEVER GIVEN ITS TENACITY PHILIPPE IS MAINTAINED AS A CYCLONE THROUGHOUT THE FORECAST PERIOD. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 23.9N 59.4W 55 KT 65 MPH 12H 05/0000Z 24.0N 60.7W 55 KT 65 MPH 24H 05/1200Z 24.5N 61.8W 60 KT 70 MPH 36H 06/0000Z 25.4N 62.2W 65 KT 75 MPH 48H 06/1200Z 26.5N 62.0W 65 KT 75 MPH 72H 07/1200Z 28.5N 58.5W 60 KT 70 MPH 96H 08/1200Z 31.0N 53.0W 50 KT 60 MPH 120H 09/1200Z 36.0N 47.0W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ FORECASTER BROWN |