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TROPICAL STORM GABRIELLE DISCUSSION NUMBER  12
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT FRI SEP 14 2001

GABRIELLE TRIED TO BECOME A HURRICANE JUST BEFORE LANDFALL...AS
REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT
INDICATED THE PRESSURE DROPPED TO 980 MB AND 700 MB WINDS WERE
AS HIGH AS 81 KT.  HOWEVER...THOSE WINDS WERE NEAR THE VENICE
C-MAN STATION...WHICH AT THAT TIME WAS REPORTING GUSTS TO ABOUT
40 KT.  IT THUS APPEARS THAT THE FLIGHT-LEVEL WINDS DID NOT
FULLY MIX DOWN TO THE SURFACE AND THAT GABRIELLE REMAINED A 60
KT TROPICAL STORM.  SINCE THEN...THE CENTER HAS MOVED ASHORE NEAR
VENICE AND IS BEGINNING TO WEAKEN OVER LAND.  THE INITIAL INTENSITY
IS SET TO 50 KT BASED ON OBS FROM THE VENICE C-MAN STATION.
 
THE INITIAL MOTION IS NOW 040/13.  WATER VAPOR IMAGERY INDICATES
THAT A MID/UPPER LEVEL TROUGH IS JUST WEST AND NORTHWEST OF
GABRIELLE...WITH A SECOND TROUGH DIGGING SOUTHWARD THROUGH THE
EASTERN UNITED STATES TOWARDS THE STORM.  THIS PATTERN FAVORS
A CONTINUED NORTHEASTWARD MOTION.  NHC GUIDANCE AGREES WITH THIS
SCENARIO...ALTHOUGH WITH SOME DIFFERENCES IN SPEED.  THE AVN REALLY
SLOWS THE SYSTEM DOWN...TAKING MORE THAN 24 HR TO CROSS FLORIDA.
IN DEFERENCE TO THIS...THE TRACK FORECAST SLOWS THE CURRENT MOTION
DOWN SOMEWHAT WHILE CROSSING FLORIDA FOLLOWED BY GRADUAL
ACCELERATION OVER THE ATLANTIC.  THE TRACK IS SHIFTED SOMEWHAT TO 
THE NORTH OF THE PREVIOUS PACKAGE.
 
GABRIELLE SHOULD WEAKEN WHILE OVER LAND.  THE INTENSITY FORECAST
GETS A LITTLE TRICKY ONCE THE STORM EMERGES OVER THE ATLANTIC.
ON THE PLUS SIDE ARE THE WARM ATLANTIC WATERS AND UPPER LEVEL
DIVERGENCE DUE TO THE UPPER LEVEL TROUGHS.  ON THE MINUS SIDE IS
STRONG SHEAR AS INDICATED IN THE AVN AND SHIPS MODELS.  THE
FORECAST WILL CALL FOR SOME STRENGTHENING OVER THE ATLANTIC...BUT
NOT AS MUCH AS IN THE PREVIOUS PACKAGE.  SHOULD GABRIELLE MOVE
FASTER THAN FORECAST...IT COULD INTENSIFY MORE THAN CURRENTLY
FORECAST.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     14/1500Z 27.6N  82.2W    50 KTS...INLAND
12HR VT     15/0000Z 28.7N  81.4W    40 KTS...INLAND
24HR VT     15/1200Z 30.1N  80.3W    45 KTS...OVER WATER
36HR VT     16/0000Z 31.4N  78.5W    50 KTS
48HR VT     16/1200Z 32.5N  76.0W    50 KTS
72HR VT     17/1200Z 35.5N  71.0W    50 KTS
 
 
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