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TROPICAL STORM GABRIELLE DISCUSSION NUMBER  13
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT FRI SEP 14 2001

CONVECTION ASSOCIATED WITH GABRIELLE HAS DECREASED MARKEDLY
DURING THE AFTERNOON...WITH THE STRONGEST REMAINING CONVECTION
IN BANDS WELL REMOVED FROM THE CENTER TO THE NORTH AND EAST.
THE INITIAL INTENSITY OF 40 KT IS BASED ON SYNOPTIC OBSERVATIONS
OF 35-40 KT WINDS NEAR THE FLORIDA EAST COAST...PARTICULARLY AT
THE ST. AUGUSTINE C-MAN STATION.
 
THE INITIAL MOTION IS 040/10...ALTHOUGH RADAR AND SURFACE DATA
SUGGEST THAT A NORTHWARD WOBBLE MAY BE STARTING.  WATER VAPOR
IMAGERY SUGGEST AN UPPER LEVEL LOW IS DEVELOPING OVER THE
NORTHEASTERN GULF OF MEXICO...WITH AN UPPER LEVEL TROUGH DEVELOPING
OVER THE EASTERN UNITED STATES.  THIS PATTERN SHOULD SUPPORT A
GENERAL NORTHEASTERLY MOTION...WITH PERHAPS A CHANCE OF A NORTHWARD
JOG EARLY IN THE FORECAST PERIOD.  NHC HURRICANE GUIDANCE GENERALLY
SUPPORTS THIS WITH SOME VARIATIONS IN SPEED.  THE OFFICIAL FORECAST
IS SIMILAR TO THE PREVIOUS PACKAGE AND CALLS FOR SOME SLOWING IN
THE FIRST 24 HR...FOLLOWED BY GRADUAL ACCELERATION TO THE NORTHEAST.
SHOULD THE POSSIBLE WOBBLE TURN OUT TO BE AN ACTUALLY TRACK
CHANGE...THE FORECAST TRACK MIGHT HAVE TO BE SHIFTED CLOSER TO THE
SOUTHEASTERN U.S. COAST.
 
GABRIELLE SHOULD CONTINUE TO WEAKEN WHILE OVER LAND.  THE INTENSITY
FORECAST REMAINS 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...AND
STRONG MID/UPPER LEVEL DRYING INTRUDING INTO THE STORM ON WATER
VAPOR IMAGERY.  THE FORECAST WILL CALL FOR SOME STRENGTHENING OVER
THE ATLANTIC...BUT AT A SLOWER RATE THAN IN THE PREVIOUS PACKAGE
GIVEN THE CURRENT LACK OF STRONG CONVECTION NEAR THE CENTER.

WHILE IT IS POSSIBLE THAT GABRIELLE COULD THREATEN OTHER PORTIONS
OF THE SOUTHEASTERN U.S...THAT THREAT WILL BE A FUNCTION OF BOTH
THE ACTUAL TRACK AND HOW MUCH OF THE STORM IS LEFT WHEN IT EMERGES
INTO THE ATLANTIC.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     14/2100Z 28.6N  81.6W    40 KTS...INLAND
12HR VT     15/0600Z 29.4N  80.6W    35 KTS...OVER WATER
24HR VT     15/1800Z 30.6N  79.4W    40 KTS
36HR VT     16/0600Z 31.7N  77.5W    45 KTS
48HR VT     16/1800Z 33.0N  75.0W    50 KTS
72HR VT     17/1800Z 36.5N  69.5W    50 KTS
 
 
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