Hurricane Helene

000WTNT43 KNHC 191454TCDAT3HURRICANE HELENE DISCUSSION NUMBER 29NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD1100 AM EDT TUE SEP 19 2006HURRICANE HELENE REMAINS AN IMPRESSIVE TROPICAL CYCLONE THISMORNING. THE SYSTEM IS SLIGHTLY ELONGATED BUT MAINTAINS ITS CENTRALCORE OF DEEP CONVECTION... EYE FEATURE AND ALMOST PERFECT OUTFLOW.DVORAK INTENSITY T-NUMBERS PERSIST AT 5.5 FROM ALL AGENCIES... THEINITIAL INTENSITY WILL REMAIN AT 100 KTS AND THE INITIAL MOTIONWILL BE 285/7.AT THIS MOMENT AND FOR THE NEXT 24 HOURS OR SO... HELENE WILL REMAINUNDER A DOMINANT UPPER-LEVEL RIDGE BASED OVER THE CENTRAL ATLANTIC.THIS RIDGE WILL SHOULD STEER HELENE OFF TO THE WEST NORTHWEST FORTHE NEXT 24 TO 36 HOURS AND PERHAPS ALLOW FOR SOME FURTHERSTRENGTHENING. A LARGE UPPER LOW... JUST OFF THE EAST COAST... ANDVERY AMPLFIED UPPER-LEVEL TROUGH... OVER THE EASTERN STATES... WILLTHEN PHASE AND BEGIN TO INFLUENCE HELENE. THE UPPER RIDGE OVER THEATLANTIC WILL BREAK DOWN... HELENE WILL GET CAUGHT UP IN THE STRONGWESTERLIES AND BEGIN TO RECURVE/PROGRESS RAPIDLY DOWNSTREAM INTOTHE OPEN WATERS OF THE NORTH ATLANTIC. AFTER 36 HOURS...HELENE SHOULD BEGIN TO GRADUALLY WEAKEN.THE DYNAMICAL MODELS/OBJECTIVE AIDS AND GLOBAL MODELS ARE TIGHTLYCLUSTERED WITH THIS OVERALL TRACK AND RECURVATURE BEFORE 60W. THEONLY SPREAD WITH THE GUIDANCE IS THE FORWARD SPEED AS HELENE TURNSNORTHWARD AND THE WESTERLIES BECOME INVOLVED. THE OPERATIONAL GFSIS THE MOST PROGRESSIVE WHILE THE UKMET AND ESPECIALLY THE HI-RESECMWF ARE THE SLOWEST SOLUTIONS INTO THE MEDIUM RANGE PERIOD. HPCWILL FOLLOW THE CLOSE CONSENSUS OF THE DYNAMICAL MODELS... WHICH ISA COMPROMISE OF THESE TWO IDEAS. FORECAST POSITIONS AND MAX WINDSINITIAL 19/1500Z 24.6N 52.9W 100 KT 12HR VT 20/0000Z 25.0N 54.1W 105 KT 24HR VT 20/1200Z 25.9N 55.7W 110 KT 36HR VT 21/0000Z 27.5N 56.5W 110 KT 48HR VT 21/1200Z 29.7N 56.7W 105 KT 72HR VT 22/1200Z 35.0N 55.0W 100 KT 96HR VT 23/1200Z 39.5N 49.5W 90 KT120HR VT 24/1200Z 45.0N 40.5W 80 KT$$FORECASTER MUSHER