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#290629 (Received by flhurricane at: 4:55 AM 23.Aug.2009) TCDAT3 HURRICANE BILL DISCUSSION NUMBER 32 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009 500 AM AST SUN AUG 23 2009 INFRARED SATELLITE IMAGERY SHOWS COLD CONVECTIVE CLOUD TOPS CONTINUE TO SURROUND THE CLOUD-FILLED EYE OF BILL. RECENT AIRCRAFT FIXES HAVE BEEN TO THE WEST AND SOUTHWEST OF THE EYE-FEATURE SEEN IN SATELLITE IMAGERY...SUGGESTING SOME VERTICAL TILT TO THE HURRICANE. THE AIRCRAFT RECENTLY REPORTED A PEAK 700 MB FLIGHT-LEVEL WIND OF 93 KT AND A SFMR SURFACE WIND OF 67 KT TO THE SOUTHEAST OF THE CENTER. A DROPSONDE MEASURED A MEAN WIND OF 98 KT IN THE LOWEST 150 METERS OF THE SOUNDING. THESE DATA SUPPORT MAINTAINING THE INITIAL INTENSITY AT 75 KT. THE HURRICANE IS MOVING NORTH-NORTHEAST OR 025/23. BILL IS FORECAST TO TURN NORTHEASTWARD AND RECURVE AHEAD OF A STRONG MID-LATITUDE TROUGH THAT IS MOVING ACROSS THE EASTERN UNITED STATES. THE NEW FORECAST TRACK IS VERY SIMILAR TO THE PREVIOUS ADVISORY AND REMAINS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE THROUGH 36 HOURS. THEREAFTER...THE TRACK HAS BEEN ADJUSTED A LITTLE SOUTHWARD IN LINE WITH THE GFS AND UKMET SOLUTIONS. BILL WILL BE MOVING ACROSS THE NORTH WALL OF THE GULF STREAM AND OVER MUCH COOLER WATERS VERY SOON. THE INTENSITY FORECAST CALLS FOR STEADY WEAKENING DURING THE NEXT 24 TO 36 HOURS. BILL SHOULD BEGIN ITS EXTRATROPICAL TRANSITION LATER TODAY AND BECOME FULLY EXTRATROPICAL IN ABOUT 36 HOURS. AFTER TRANSITION IS COMPLETE...THE GLOBAL MODELS CONTINUE TO SHOW GRADUAL WEAKENING OF THE CYCLONE...AS DOES THE OFFICIAL FORECAST. THE 34-KT WIND RADII HAS BEEN EXPANDED OVER THE EASTERN SEMICIRCLE BASED ON DATA FROM THE AIRCRAFT AND AN EARLIER QUIKSCAT PASS. LARGE SWELLS GENERATED BY BILL ARE STILL AFFECTING THE EAST COAST OF THE UNITED STATES. THESE SWELLS WILL CONTINUE TO SPREAD NORTHWARD INTO THE CANADIAN MARITIMES TODAY...CAUSING EXTREMELY DANGEROUS SURF AND LIFE-THREATENING RIP CURRENTS. PLEASE CONSULT STATEMENTS ISSUED BY YOUR LOCAL WEATHER OFFICE AND METEOROLOGICAL SERVICES FOR MORE DETAILS. FORECAST POSITIONS AND MAX WINDS INITIAL 23/0900Z 41.2N 66.5W 75 KT 12HR VT 23/1800Z 44.1N 63.0W 65 KT 24HR VT 24/0600Z 47.5N 55.1W 55 KT 36HR VT 24/1800Z 49.8N 43.8W 45 KT...EXTRATROPICAL 48HR VT 25/0600Z 50.5N 31.0W 40 KT...EXTRATROPICAL 72HR VT 26/0600Z 54.0N 10.0W 30 KT...EXTRATROPICAL 96HR VT 27/0600Z 61.0N 2.0W 25 KT...EXTRATROPICAL 120HR VT 28/0600Z...ABSORBED $$ FORECASTER BROWN |