Tropical Storm FLORENCE

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TROPICAL STORM FLORENCE DISCUSSION NUMBER  20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062006
1100 AM EDT FRI SEP 08 2006
 
THE CLOUD PATTERN REMAINS SHAPELESS WITH VERY ASYMMETRIC
CONVECTION...AND DVORAK T-NUMBERS REMAIN UNCHANGED AT 35 KNOTS. I
WAS TEMPTED TO LOWER THE INTENSITY BUT I WILL HOLD IT AT 45 KNOTS
FOR THE SAKE OF CONTINUITY AND BASED ON SEVERAL..BUT LESS RELIABLE
HI-RES QUIKSCAT WIND VECTORS ON THE EDGE OF THE SWATH.  FLORENCE
HAS REFUSED TO STRENGTHEN WHILE IN THE TROPICS...LIKE MOST THE
SYSTEMS SO FAR THIS YEAR. HOWEVER...THE CYCLONE HAS THE OPPORTUNITY
TO DO SO AS IT MOVES NORTHWESTWARD AND NORTHWARD AHEAD OF THE
APPROACHING TROUGH DURING THE NEXT 2 TO 3 DAYS...AND BEFORE THE
SHEAR INCREASES SIGNIFICANTLY. THEREAFTER...IT SHOULD BECOME AN
INTENSE EXTRATROPICAL SYSTEM. THE INTENSITY FORECAST FOR FLORENCE
SEEMS MORE UNCERTAIN THAN USUAL.
 
THE LOW-LEVEL CENTER IS DIFFICULT TO FIND...BUT THERE MUST BE ONE
GIVEN THE LARGE AND WELL DEFINED CIRCULATION OF THE STORM. THE
AVERAGE MOTION OF THE LARGE GYRE IS ESTIMATED AT 300/15. THERE HAS
BEEN NO CHANGE IN THE STEERING CURRENTS AND FLORENCE CONTINUES
MOVING AROUND THE SUBTROPICAL RIDGE. IT SHOULD REACH THE WESTERN
PERIPHERY OF THE RIDGE IN ABOUT 36 HOURS AND GRADUALLY TURN
NORTHWARD WITH A DECREASE IN FORWARD SPEED. THEREAFTER...IT SHOULD
BEGIN TO ACCELERATE AS IT INTERACTS WITH THE TROUGH. THE GUIDANCE
IS CLUSTERED THROUGH THE NEXT 3 DAYS. THEREAFTER...ALL MODELS SHOW
THE NORTHEASTWARD TURN BUT THEY VARY ON THE FORWARD SPEED.
 
DUE TO THE UNUSUALLY LARGE AREA OF TROPICAL STORM FORCE WINDS...THE
BERMUDA WEATHER SERVICE WILL LIKELY ISSUE WATCHES OR WARNINGS
LATER TODAY.
 
NOTE: LAST TWO VISIBLE SATELLITE IMAGES PRIOR TO SENDING THIS
ADVISORY SUGGESTS THAT THE CLOUD PATTERN IS A LITTLE BETTER
ORGANIZED AND THE CENTER APPEARS TO BE TUCKED INTO THE CONVECTION.
IF THIS TREND TOWARD ORGANIZATION CONTINUES...SCIENCE WILL HAVE
PREVAILED.
 
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/1500Z 23.0N  59.1W    45 KT
 12HR VT     09/0000Z 23.8N  60.9W    50 KT
 24HR VT     09/1200Z 25.5N  63.2W    55 KT
 36HR VT     10/0000Z 27.0N  64.5W    65 KT
 48HR VT     10/1200Z 28.5N  65.0W    75 KT
 72HR VT     11/1200Z 33.0N  64.0W    85 KT
 96HR VT     12/1200Z 39.0N  60.0W    75 KT...EXTRATROPICAL
120HR VT     13/1200Z 48.0N  49.0W    65 KT...EXTRATROPICAL
 
$$
FORECASTER AVILA
 
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