Tropical Storm FLORENCE

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TROPICAL STORM FLORENCE DISCUSSION NUMBER  22
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062006
1100 PM EDT FRI SEP 08 2006
 
DURING THE EVENING...INNER-CORE CONVECTION ASSOCIATED WITH FLORENCE
HAS CONSOLIDATED AND A CENTRAL DENSE OVERCAST APPEARS TO BE FORMING.
CORRESPONDINGLY...DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB
AT 0000Z SUGGEST 55 KT...WHILE 2119Z AMSU ANALYSES FROM CIRA AND
CIMMS SUGGESTED A WEAKER SYSTEM AT THAT TIME.  GIVEN THE INCREASED
ORGANIZATION SEEN IN THE LAST FEW HOURS...THE INITIAL INTENSITY IS
SET AT 55 KT.  AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT IS
SCHEDULED TO INVESTIGATE FLORENCE IN A FEW HOURS AND PROVIDE A MORE
ACCURATE ASSESSMENT OF BOTH ITS INTENSITY AND POSITION.
 
THE INITIAL MOTION IS 305/13...THOUGH THIS IS SOMEWHAT UNCERTAIN
GIVEN THE DIFFICULTY IN DETERMINING THE EXACT CENTER WITH INFRARED
IMAGERY.  FLORENCE IS ON THE SOUTHWEST PERIPHERY OF A DEEP-LAYER
RIDGE AND IT SHOULD REACH ITS WESTERNMOST POINT IN ABOUT 36 TO 48
HOURS AS IT RECURVES INTO THE WESTERLIES.  THE DYNAMICAL MODELS ARE
TIGHTLY CLUSTERED THROUGH 72 HOURS AND NONE TAKE THE SYSTEM WEST OF
66W...SO IT APPEARS THAT THERE IS LITTLE DIRECT THREAT TO THE UNITED
STATES OUTSIDE OF LARGE SWELLS AND SURF.  BEYOND 72 HOURS...THERE
IS A SIGNIFICANT SPREAD IN THE MODEL GUIDANCE WITH NOGAPS...GFDL
AND ECMWF TO THE LEFT OF THE CONSENSUS...THE GFS SLOWER AND TO THE
RIGHT...AND THE UKMET SIGNIFICANTLY FASTER.  THE UKMET SOLUTION MAY
BE ERRONEOUS GIVEN THAT THE OTHER MODELS SUGGEST A SECONDARY
BAROCLINIC DEVELOPMENT IN THE REGION THAT THE UKMET CARRIES
FLORENCE. THE FORECAST TRACK IS SLIGHTLY TO THE WEST OF THE PREVIOUS
PREDICTION AND CLOSE TO THE MODEL CONSENSUS MINUS THE UKMET.

GIVEN THE INNER-CORE DEVELOPMENT...WARM WATERS...LOW SHEAR AND
ABUNDANT MOISTURE...FLORENCE SHOULD CONTINUE TO INTENSIFY OVER THE
NEXT 48 HOURS.  AFTER THAT TIME...COOLER WATERS...HIGHER SHEAR AND
A MORE STABLE ATMOSPHERE SHOULD START THE WEAKENING PROCESS. 
HOWEVER...MOST GLOBAL MODELS SUGGEST THAT FLORENCE MAY BECOME A
LARGE EXTRATROPICAL STORM AT DAYS FOUR AND FIVE.  THE INTENSITY
FORECAST IS CLOSE TO THE SHIPS AND FSU SUPER-ENSEMBLE GUIDANCE AND
SOMEWHAT ABOVE GFDL.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/0300Z 24.5N  61.4W    55 KT
 12HR VT     09/1200Z 25.5N  63.0W    65 KT
 24HR VT     10/0000Z 27.0N  64.5W    75 KT
 36HR VT     10/1200Z 28.7N  65.3W    85 KT
 48HR VT     11/0000Z 30.7N  65.4W    90 KT
 72HR VT     12/0000Z 35.5N  63.0W    85 KT
 96HR VT     13/0000Z 42.5N  57.5W    75 KT...EXTRATROPICAL
120HR VT     14/0000Z 48.0N  48.0W    65 KT...EXTRATROPICAL
 
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FORECASTER KNABB/LANDSEA
 
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