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| #290690 (Received by flhurricane at: 10:49 AM 23.Aug.2009) TCDAT3 HURRICANE BILL DISCUSSION NUMBER 33 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009 1100 AM AST SUN AUG 23 2009 AFTER THE LAST AIR FORCE MISSION INTO BILL....JUST BEFORE 1200 UTC...THE CLOUD PATTERN OF THE HURRICANE HAS BEGUN TO LOOK A LITTLE LESS TROPICAL. THE AIRCRAFT REPORTED A PEAK FLIGHT-LEVEL WIND OF 105 KT OVER THE EASTERN QUADRANT AROUND 1100 UTC. TYPICALLY THIS WOULD SUPPORT A HIGHER INTENSITY OF GREATER THAN 75 KT. HOWEVER...SINCE THE CYCLONE IS TRAVERSING COOLER WATERS...IT IS BECOMING INCREASINGLY DIFFICULT FOR IT TO TRANSPORT STRONG WINDS TO THE SURFACE. GIVEN THAT...ALONG WITH THE DETERIORATION OF THE CLOUD PATTERN...THE CURRENT INTENSITY IS HELD AT 75 KT. BILL IS EXPECTED TO BECOME AN EXTRATROPICAL STORM WITHIN A DAY OR SO AND GRADUALLY WEAKEN AS IT MOVES RAPIDLY ACROSS THE NORTH ATLANTIC. GLOBAL MODELS SUGGEST THAT THE SYSTEM WILL MERGE WITH A BROADER CYCLONIC CIRCULATION NEAR THE BRITISH ISLES IN 3-4 DAYS. CURRENT MOTION IS AROUND 045/29. BILL SHOULD CONTINUE ACCELERATING OVER THE NEXT 24-36 HOURS AS IT BECOMES WELL EMBEDDED IN THE MID-LATITUDE WESTERLIES. SOME SLOWING OF THE FORWARD SPEED IS LIKELY LATER IN THE PERIOD AS THE EXTRATROPICAL REMNANT OF BILL INTERACTS WITH THE LARGE CYCLONIC CIRCULATION OVER THE NORTHEAST ATLANTIC. THE CURRENT OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS ONE. LARGE AND DANGEROUS SWELLS ASSOCIATED WITH BILL WILL BE IMPACTING THE CANADIAN MARITIMES DURING THE NEXT 24 HOURS. SWELLS ALONG THE EAST COAST OF THE UNITED STATES SHOULD BE DIMINISHING TODAY. FORECAST POSITIONS AND MAX WINDS INITIAL 23/1500Z 43.3N 64.0W 75 KT 12HR VT 24/0000Z 46.3N 59.1W 65 KT 24HR VT 24/1200Z 49.0N 49.7W 55 KT...EXTRATROPICAL 36HR VT 25/0000Z 50.8N 37.4W 45 KT...EXTRATROPICAL 48HR VT 25/1200Z 52.5N 26.5W 35 KT...EXTRATROPICAL 72HR VT 26/1200Z 57.0N 8.0W 30 KT...EXTRATROPICAL 96HR VT 27/1200Z...MERGED WITH ANOTHER LOW $$ FORECASTER PASCH |
