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HURRICANE GABRIELLE DISCUSSION NUMBER  25
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT MON SEP 17 2001
 
GABRIELLE REMAINS A FAIRLY IMPRESSIVE SYSTEM DESPITE THE 
SOUTHWESTERLY UPPER-LEVEL SHEAR. IN FACT...VISIBLE IMAGERY DURING 
THE PAST FEW HOURS SUGGESTS THAT A BANDING EYE FEATURE MAY BE TRYING 
TO FORM AS MODERATE CONVECTION HAS WRAPPED ABOUT THREE-FOURTHS OF 
THE WAY AROUND THE LOW-LEVEL CENTER.  OUTFLOW REMAINS QUITE GOOD IN 
THE NORTH SEMICIRCLE...BUT IS ALMOST NON-EXISTENT TO THE SOUTH.
 
THE INITIAL MOTION ESTIMATE IS 060/15. GABRIELLE HAS RETURNED TO THE 
PREVIOUS EAST-NORTHEASTWARD BASE COURSE.  THE NHC MODEL GUIDANCE IS 
IN MUCH BETTER AGREEMENT ON TAKING GABRIELLE OFF IN A GENERAL 
NORTHEASTWARD DIRECTION.  THE UKMET IS NOW IN THE MIDDLE OF THE 
MODEL PACK AND NO LANGER TAKES THE CYCLONE ACROSS SOUTHEAST 
NEWFOUNDLAND.  THIS APPEARS VERY REASONABLE GIVEN THE LONG FETCH OF 
MID- TO UPPER-LEVEL WESTERLY FLOW ACROSS THE NORTHEAST U.S. AND 
EASTERN CANADA.  IN 24 TO 36 HOURS...GABRIELLE IS FORECAST TO GET 
PICKED UP BY A MID-LATITUDE TROUGH AND BECOME AN EXTRATROPICAL LOW 
PRESSURE SYSTEM.
 
AS LONG AS DEEP CONVECTION REMAINS NEAR THE LOW-LEVEL CIRCULATION 
CENTER...GABRIELLE WILL REMAIN A WARM-CORE SYSTEM AND COULD EVEN 
STRENGTHEN A LITTLE MORE. HOWEVER...BY THE TIME THE CYCLONE REACHES 
40N LATITUDE IN ABOUT 24 HOURS...SSTS WILL DECREASE SHARPLY BELOW 
22C AND THAT SHOULD AID THE TRANSITION TO AN EXTRATROPICAL SYSTEM 
AND BRING ABOUT MORE SIGNIFICANT WEAKENING.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     17/2100Z 36.5N  64.2W    70 KTS
12HR VT     18/0600Z 37.8N  62.0W    70 KTS
24HR VT     18/1800Z 39.9N  58.8W    65 KTS...BECOMING EXTRATROPICAL
36HR VT     19/0600Z 41.9N  56.1W    60 KTS...EXTRATROPICAL
48HR VT     19/1800Z 45.3N  50.9W    55 KTS...EXTRATROPICAL
72HR VT     20/1800Z 49.5N  42.5W    50 KTS...EXTRATROPICAL
 
 
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