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#462871 (Received by flhurricane at: 4:47 AM 29.Sep.2011) TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 21 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011 500 AM AST THU SEP 29 2011 THERE HAS BEEN LITTLE CHANGE IN THE SATELLITE APPEARANCE OF PHILIPPE SINCE THE LAST ADVISORY. THE CLOUD PATTERN CONSISTS OF A LARGE BALL OF COLD-TOPPED CONVECTION...WITH THE LOW-LEVEL CENTER ESTIMATED TO BE TO THE SOUTH OF THIS CONVECTIVE MASS. SINCE THE OVERALL STRUCTURE OF THE SYSTEM DOES NOT APPEAR TO HAVE CHANGED SIGNIFICANTLY...THE CURRENT INTENSITY IS HELD AT 40 KT. UW-CIMSS AND SHIPS ANALYSES CONTINUE TO DIAGNOSE CLOSE TO 20 KT OF SOUTHWESTERLY SHEAR OVER THE CYCLONE...ASSOCIATED WITH AN UPPER-TROPOSPHERIC COLD LOW NEAR 17N46W. GLOBAL MODELS FORECAST A BRIEF PERIOD OF REDUCED SHEAR OVER PHILIPPE WITHIN THE NEXT 24-36 HOURS AS THE UPPER LOW SHIFTS WESTWARD. THIS SUGGESTS THAT SOME INTENSIFICATION COULD TAKE PLACE IN THE EARLY PART OF THE FORECAST PERIOD. THEREAFTER...PHILIPPE IS LIKELY TO WEAKEN AS IT BECOMES AFFECTED BY EXTREMELY STRONG NORTH-NORTHWESTERLY SHEAR ASSOCIATED WITH THE UPPER-LEVEL OUTFLOW OF TROPICAL CYCLONE OPHELIA. THIS ENVIRONMENT SHOULD RESULT IN THE SYSTEM DEGENERATING INTO A REMNANT LOW BY DAY 4. SINCE IT IS NOT CLEAR JUST HOW FAR TO THE SOUTH OF THE DEEP CONVECTION THE CENTER IS LOCATED...THE INITIAL MOTION IS A RATHER UNCERTAIN 300/11. PHILIPPE IS LIKELY TO CONTINUE TO MOVE WEST-NORTHWESTWARD ON THE SOUTHWESTERN SIDE OF A SUBTROPICAL HIGH OVER THE EASTERN ATLANTIC FOR THE NEXT DAY OR TWO. LATER IN THE FORECAST PERIOD...A BUILDING SUBTROPICAL HIGH OVER THE CENTRAL ATLANTIC SHOULD CAUSE PHILIPPE TO TURN TOWARD THE WEST. THE OFFICIAL FORECAST TRACK IS ADJUSTED A LITTLE FARTHER SOUTH FROM THE PREVIOUS ONE AND IS ABOUT IN THE MIDDLE OF THE GUIDANCE ENVELOPE. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 17.8N 41.7W 40 KT 45 MPH 12H 29/1800Z 18.6N 43.2W 45 KT 50 MPH 24H 30/0600Z 19.9N 45.0W 50 KT 60 MPH 36H 30/1800Z 21.3N 46.8W 50 KT 60 MPH 48H 01/0600Z 22.3N 48.8W 45 KT 50 MPH 72H 02/0600Z 23.9N 52.7W 35 KT 40 MPH 96H 03/0600Z 24.5N 56.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 04/0600Z 24.5N 60.0W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ FORECASTER PASCH/KIMBERLAIN |