Hurricane FLORENCE

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HURRICANE FLORENCE DISCUSSION NUMBER  28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062006
1100 AM EDT SUN SEP 10 2006
 
EARLY MORNING VISIBLE SATELLITE IMAGES INDICATED AN EYEWALL THAT WAS
PARTIALLY OPEN ON THE NORTH SIDE.  DVORAK INTENSITY ESTIMATES HAVE
NOT INCREASED FROM OVERNIGHT AND THE INITIAL INTENSITY WILL REMAIN
70 KT.  HOWEVER...IN THE PAST HOUR OR TWO THE EYE APPEARS TO HAVE
BECOME BETTER DEFINED.  AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM AROUND 1800 UTC
TODAY AND SHOULD PROVIDE A BETTER ASSESSMENT OF THE INTENSITY.  
CIRRUS OUTFLOW IS WELL DEFINED EXCEPT TO THE EAST...AND FLORENCE
WILL BE TRAVERSING SSTS 28 DEGREES CELSIUS OR HIGHER FOR THE NEXT
24 HOURS.  STRENGTHENING IS THEREFORE FORECAST AND FLORENCE COULD
BE A STRONG CATEGORY 2 HURRICANE WHEN IT IS NEAR BERMUDA. 
AFTERWARDS...INCREASING SOUTHWESTERLY SHEAR AND COOLER SSTS SHOULD
IMPART A GRADUAL WEAKENING.  HOWEVER... FLORENCE IS EXPECTED TO
REMAIN A VERY LARGE AND POWERFUL CYCLONE ONCE IT UNDERGOES
EXTRATROPICAL TRANSITION IN ABOUT 72 HOURS. 

THE INITIAL MOTION IS 340/11.  IT APPEARS THAT THE NORTHWARD TURN IS
BEGINNING TO MATERIALIZE AS PREDICTED.  THE TRACK GUIDANCE REMAINS
IN FAIRLY GOOD AGREEMENT FOR THE NEXT 36-48 HOURS.  THEREAFTER...AS
FLORENCE IS STEERED BY THE WESTERLIES...MODEL SOLUTIONS DIVERGE
SOMEWHAT WITH THE NOGAPS AND GFS MOVING THE SYSTEM MUCH CLOSER 
TO NEWFOUNDLAND.  THE OFFICIAL FORECAST REMAINS VERY CLOSE TO THE
PREVIOUS ADVISORY THROUGH 72 HOURS AND IS CLOSE TO THE FSU
SUPERENSEMBLE...WHICH HAS HAD A GOOD TRACK RECORD WITH THIS STORM.
AT 5 DAYS...THE CONSENSUS OF THE TRACK GUIDANCE HAS SHIFTED EASTWARD
REQUIRING SOME ADJUSTMENT OF THE OFFICIAL FORECAST FROM THE
PREVIOUS ONE. 

THE TROPICAL STORM FORCE WIND RADII ARE PREDICTED BY THE GLOBAL
MODELS TO EXPAND EVEN FURTHER AS A STRONG HIGH BUILDS SOUTHWARD
OVER THE NORTHEAST UNITED STATES...WHICH WOULD INCREASE THE
PRESSURE GRADIENT TO THE NORTHWEST OF FLORENCE.  THIS IS EXPECTED
TO CREATE ROUGH SURF CONDITIONS ALONG THE EAST COAST OF THE UNITED
STATES FOR THE NEXT FEW DAYS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/1500Z 28.7N  65.9W    70 KT
 12HR VT     11/0000Z 30.3N  66.2W    80 KT
 24HR VT     11/1200Z 32.7N  65.5W    95 KT
 36HR VT     12/0000Z 35.4N  63.8W    90 KT
 48HR VT     12/1200Z 38.1N  61.5W    80 KT
 72HR VT     13/1200Z 44.5N  55.0W    65 KT...EXTRATROPICAL
 96HR VT     14/1200Z 48.0N  46.0W    60 KT...EXTRATROPICAL
120HR VT     15/1200Z 48.0N  35.0W    50 KT...EXTRATROPICAL
 
$$
FORECASTER BROWN/PASCH
 
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