Tropical Storm FLORENCE

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TROPICAL STORM FLORENCE DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062006
500 AM EDT THU SEP 07 2006
 
FRUSTRATION CONTINUES OVERNIGHT TRYING TO LOCATE THE PRIMARY
LOW-LEVEL CIRCULATION OF FLORENCE.  A 0345 UTC TRMM OVERPASS AND A
0507 UTC AMSU OVERPASS PROVIDED SOME INDICATIONS OF AN OVERALL
SYSTEM CENTER...BUT ALSO SHOWED AT LEAST ONE WELL-DEFINED LOW-LEVEL
CENTER TO THE SOUTHEAST OF THAT LOCATION.  ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS THE APPEARANCE OF FLORENCE VERY SIMILAR
TO 24 HOURS AGO...WITH A SLIGHT CURVED BANDING FEATURE AND WARMER
CLOUD TOPS.  THE INITIAL INTENSITY REMAINS AT 45 KT IN AGREEMENT
WITH DVORAK CLASSIFICATIONS FROM BOTH TAFB AND SAB...AS WELL AS A
RECENT AMSU INTENSITY ESTIMATE. 
 
THE INITIAL MOTION IS ESTIMATED AT 300/9.  DESPITE THE QUANDARY
IN FINDING THE INITIAL POSITION...THE TRACK MODEL GUIDANCE
CONTINUES TO BE CONSISTENT AND IN VERY GOOD AGREEMENT.  CONSEQUENTLY
THE REASONING IN THE FORECAST TRACK REMAINS UNCHANGED.  FLORENCE IS
EXPECTED TO CONTINUE TOWARD THE WEST-NORTHWEST FOR THE NEXT 2-3
DAYS WITH SOME INCREASE IN FORWARD SPEED...THEN SLOW A BIT AS THE
CYCLONE TURNS MORE TO THE NORTH AS IT IS STEERED AROUND THE
PERIPHERY OF A STRONG ANTICYCLONE TO THE NORTHEAST.  THE OFFICIAL
FORECAST FOLLOWS THE PREVIOUS FORECAST AND DYNAMICAL MODEL
CONSENSUS CLOSELY THROUGH 5 DAYS. 
 
FLORENCE IS EXPECTED TO REMAIN OVER WARM WATERS AND ENCOUNTER LESS
SHEAR IN 24 TO 36 HOURS AS THE UPPER-LEVEL LOW...LOCATED A FEW
HUNDRED MILES WEST OF THE CYCLONE...MOVES WESTWARD AND WEAKENS. 
THIS SCENARIO SHOULD ALLOW FLORENCE TO GRADUALLY STRENGTHEN THROUGH
MOST OF THE FORECAST.  THE OFFICIAL INTENSITY FORECAST HOLDS
FLORENCE TO JUST UNDER MAJOR HURRICANE STATUS...HOWEVER IT STILL
COULD REACH CATEGORY THREE IN BETWEEN THE FORECAST PERIODS.  THIS
FOLLOWS CLOSELY WITH THE GUIDANCE FROM BOTH SHIPS AND THE FSU
SUPERENSEMBLE. ONCE AGAIN...IT IS IMPORTANT TO REMEMBER THAT THERE
IS LIMITED SKILL IN TROPICAL CYCLONE INTENSITY PREDICTION
PARTICULARLY IN THE 3 TO 5 DAY TIME FRAME. 

A SHIP REPORT AT 0600 UTC...FROM MSJZ8...REPORTED A 34 KT SUSTAINED
WIND SOUTHEAST OF THE CENTER.  THIS REPORT JUSTIFIED EXPANDING THE
WIND RADII OUT TO 250 N MI OVER THE SOUTHEAST QUADRANT.  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/0900Z 20.1N  53.2W    45 KT
 12HR VT     07/1800Z 21.1N  54.9W    50 KT
 24HR VT     08/0600Z 22.6N  57.7W    55 KT
 36HR VT     08/1800Z 24.0N  60.5W    65 KT
 48HR VT     09/0600Z 25.0N  63.0W    75 KT
 72HR VT     10/0600Z 27.5N  66.0W    90 KT
 96HR VT     11/0600Z 30.5N  67.0W    95 KT
120HR VT     12/0600Z 35.0N  66.0W    95 KT
 
$$
FORECASTER MAINELLI/BEVEN
 
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