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Hurricane HELENE (Text)

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HURRICANE HELENE DISCUSSION NUMBER  27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082006
1100 PM EDT MON SEP 18 2006

ALTHOUGH THE CLOUD PATTERN OF HELENE IS SLIGHTLY ELONGATED TO THE
NORTH...THE SATELLITE PRESENTATION OF THE CORE OF THE HURRICANE HAS
BECOME MORE IMPRESSIVE OVER THE PAST FEW HOURS.  CENTRAL CONVECTION
IS COOLING AND THE EYE IS BECOMING BETTER DEFINED. CIRRUS OUTFLOW
IS RATHER SYMMETRICAL AND EXPANDING.  DVORAK T-NUMBERS OF 5.5 FROM
ALL AGENCIES SUPPORT KEEPING THE INTENSITY AT 100 KT AT THIS TIME. 
THE HURRICANE WILL CONTINUE TO MOVE OVER WARM OCEAN WATERS AND THE
VERTICAL SHEAR IS EXPECTED TO REMAIN WEAK OVER THE NEXT COUPLE OF
DAYS.  STRENGTHENING IS LIKELY AND THE OFFICIAL WIND SPEED FORECAST
IS SLIGHTLY HIGHER THAN THE SHIPS...GFDL...AND FSU SUPERENSEMBLE
INTENSITY GUIDANCE.  INDEED...GIVEN THE INCREASING ORGANIZATION OF
THE INNER CORE...THIS INTENSITY FORECAST COULD BE CONSERVATIVE...
AND HELENE CERTAINLY HAS THE POTENTIAL TO BECOME A CATEGORY 4
HURRICANE.

HELENE IS MOVING SLOWLY WEST-NORTHWESTWARD...300/7.  A MORE WESTWARD
COMPONENT OF MOTION IS EXPECTED DURING THE NEXT DAY OR SO AS A
MID-TROPOSPHERIC RIDGE TEMPORARILY BUILDS TO THE NORTH OF THE
TROPICAL CYCLONE.  THE GFDL MODEL EVEN DEPICTS A TURN TOWARD THE
WEST-SOUTHWEST IN 12 HOURS OR SO.  BY 48 HOURS...HOWEVER...A VERY
LARGE 500 MB TROUGH MOVING EASTWARD NEAR THE U.S. EAST COAST SHOULD
INDUCE A TURN TOWARD THE NORTHWEST AND NORTH-NORTHWEST.  IN 3 TO 5
DAYS HELENE SHOULD BEGIN TO BE STEERED BY THE FLOW ON THE SOUTHERN
PART OF THE TROUGH AND TURN TOWARD THE NORTH AND NORTHEAST.  THE
OFFICIAL FORECAST FOR THIS ADVISORY PACKAGE IS IN REASONABLE
AGREEMENT WITH THE DYNAMICAL MODEL CONSENSUS AS WELL AS THE
GFDL...AND ALSO SIMILAR TO THE PREVIOUS NHC TRACK.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/0300Z 24.2N  51.4W   100 KT
 12HR VT     19/1200Z 24.6N  52.7W   105 KT
 24HR VT     20/0000Z 25.0N  54.4W   110 KT
 36HR VT     20/1200Z 25.4N  55.9W   110 KT
 48HR VT     21/0000Z 26.7N  57.1W   110 KT
 72HR VT     22/0000Z 31.0N  58.0W   100 KT
 96HR VT     23/0000Z 35.5N  56.0W    90 KT
120HR VT     24/0000Z 39.0N  51.0W    80 KT
 
$$
FORECASTER PASCH
 
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