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Hurricane FLORENCE (Text)

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HURRICANE FLORENCE DISCUSSION NUMBER  35
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062006
500 AM EDT TUE SEP 12 2006

FLORENCE IS MOVING JUST A LITTLE TO THE RIGHT OF THE PREVIOUS
FORECAST TRACK WITH AN ESTIMATED INITIAL MOTION OF 035/17. TRACK
GUIDANCE REMAINS TIGHTLY CLUSTERED AND THE OFFICIAL FORECAST TRACK
IS LITTLE CHANGED FROM THE PREVIOUS ADVISORY. 
 
THE SATELLITE PRESENTATION OF FLORENCE INDICATES THAT THE CYCLONE IS
IN THE EARLY TO MID STAGES OF EXTRATROPICAL TRANSITION. THE CLOUD
SHIELD HAS BECOME ASYMMETRICALLY DISPLACED NORTHWARD OF THE
CENTER...DRY MIDDLE TO UPPER LEVEL AIR WRAPPING AROUND THE SOUTHERN
PERIPHERY OF THE CYCLONE HAS ERODED MOST OF THE INNER CORE DEEP
CONVECTION...AND FRONTAL-LIKE FEATURES ARE STARTING TO FORM.
ADDITIONALLY...AN EARLIER QUIKSCAT PASS AND NEARBY SURFACE
OBSERVATIONS SHOW THAT THE WIND FIELD IS EXPANDING.  THE ONLY THING
KEEPING THIS SYSTEM TROPICAL IS A SMALL AND RAPIDLY DIMINISHING
AREA OF DEEP CONVECTION NORTH OF THE CENTER. GIVEN THE DEGRADATION
OF THE INNER CORE CONVECTION...THE INITIAL INTENSITY IS LOWERED TO
65 KT. MOST OF THE GLOBAL MODELS INDICATE THAT EXTRATROPICAL
TRANSITION WILL NOT BE COMPLETE FOR ANOTHER DAY OR TWO. 
HOWEVER...IF WHAT LITTLE REMAINS OF THE CORE CONVECTION CONTINUES
TO DISSIPATE...TRANSITION COULD OCCUR MUCH EARLIER.  
 
GIVEN THE LOSS OF DEEP CONVECTION...BAROTROPIC FORCING
APPEARS TO BE WANING.  HOWEVER...WATER VAPOR IMAGERY AND GLOBAL
MODELS SHOW THAT FLORENCE IS STARTING TO INTERACT WITH AN UPSTREAM
MIDDLE TO UPPER-LEVEL TROUGH.  THIS INTERACTION IS EXPECTED TO
PRODUCE BAROCLINIC FORCING AND AN INCREASE IN WINDS ON THE LARGER
SCALE EVEN AS THE INNER CORE CONVECTION AND WINDS DECAY.
ACCORDINGLY...THE OFFICIAL FORECAST WILL SHOW LITTLE CHANGE IN
INTENSITY DURING THE EXTRATROPICAL TRANSITION. THEREAFTER...THE
CYCLONE IS EXPECTED TO SLOWLY WEAKEN AND BE ABSORBED BY A SYSTEM TO
THE NORTH BY DAY 5. 

THE PRESSURE GRADIENT BETWEEN FLORENCE AND A HIGH CENTERED OVER
SOUTHEASTERN CANADA WILL LIKELY PRODUCE STRONG NORTHEASTERLY WINDS
ALONG AND OFFSHORE OF THE EAST COAST OF THE UNITED STATES AND THE
CANADIAN MARITIMES. THESE WINDS ARE EXPECTED TO CAUSE VERY ROUGH
AND DANGEROUS SURF CONDITIONS WITH POTENTIALLY DEADLY RIP CURRENTS
ALONG NEARLY THE ENTIRE ATLANTIC EAST COAST OF NORTH AMERICA FOR
THE NEXT FEW DAYS. 

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0900Z 37.2N  62.4W    65 KT
 12HR VT     12/1800Z 39.4N  60.5W    60 KT
 24HR VT     13/0600Z 42.7N  57.3W    60 KT...EXTRATROPICAL
 36HR VT     13/1800Z 45.7N  53.3W    60 KT...EXTRATROPICAL
 48HR VT     14/0600Z 47.6N  48.2W    55 KT...EXTRATROPICAL
 72HR VT     15/0600Z 49.5N  33.0W    45 KT...EXTRATROPICAL
 96HR VT     16/0600Z 53.0N  17.0W    40 KT...EXTRATROPICAL
120HR VT     17/0600Z...ABSORBED
 
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FORECASTER RHOME/FRANKLIN
 
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