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Hurricane HELENE (Text)

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HURRICANE HELENE DISCUSSION NUMBER  29
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082006
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1100 AM EDT TUE SEP 19 2006
 
HURRICANE HELENE REMAINS AN IMPRESSIVE TROPICAL CYCLONE THIS
MORNING. THE SYSTEM IS SLIGHTLY ELONGATED BUT MAINTAINS ITS CENTRAL
CORE OF DEEP CONVECTION... EYE FEATURE AND ALMOST PERFECT OUTFLOW.
DVORAK INTENSITY T-NUMBERS PERSIST AT 5.5 FROM ALL AGENCIES... THE
INITIAL INTENSITY WILL REMAIN AT 100 KTS AND THE INITIAL MOTION
WILL BE 285/7.

AT THIS MOMENT AND FOR THE NEXT 24 HOURS OR SO... HELENE WILL REMAIN
UNDER A DOMINANT UPPER-LEVEL RIDGE BASED OVER THE CENTRAL ATLANTIC.
THIS RIDGE WILL SHOULD STEER HELENE OFF TO THE WEST NORTHWEST FOR
THE NEXT 24 TO 36 HOURS AND PERHAPS ALLOW FOR SOME FURTHER
STRENGTHENING. A LARGE UPPER LOW... JUST OFF THE EAST COAST... AND
VERY AMPLFIED UPPER-LEVEL TROUGH... OVER THE EASTERN STATES... WILL
THEN PHASE AND BEGIN TO INFLUENCE HELENE. THE UPPER RIDGE OVER THE
ATLANTIC WILL BREAK DOWN... HELENE WILL GET CAUGHT UP IN THE STRONG
WESTERLIES AND BEGIN TO RECURVE/PROGRESS RAPIDLY DOWNSTREAM INTO
THE OPEN WATERS OF THE NORTH ATLANTIC. AFTER 36 HOURS...
HELENE SHOULD BEGIN TO GRADUALLY WEAKEN.

THE DYNAMICAL MODELS/OBJECTIVE AIDS AND GLOBAL MODELS ARE TIGHTLY
CLUSTERED WITH THIS OVERALL TRACK AND RECURVATURE BEFORE 60W. THE
ONLY SPREAD WITH THE GUIDANCE IS THE FORWARD SPEED AS HELENE TURNS
NORTHWARD AND THE WESTERLIES BECOME INVOLVED. THE OPERATIONAL GFS
IS THE MOST PROGRESSIVE WHILE THE UKMET AND ESPECIALLY THE HI-RES
ECMWF ARE THE SLOWEST SOLUTIONS INTO THE MEDIUM RANGE PERIOD. HPC
WILL FOLLOW THE CLOSE CONSENSUS OF THE DYNAMICAL MODELS... WHICH IS
A COMPROMISE OF THESE TWO IDEAS.   

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      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 KT
120HR VT     24/1200Z 45.0N  40.5W    80 KT
 
$$
FORECASTER MUSHER
 
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