Subtropical Storm GABRIELLE

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SUBTROPICAL STORM GABRIELLE DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
500 AM EDT SAT SEP 08 2007
 
THE SATELLITE PRESENTATION OF GABRIELLE HAS IMPROVED EARLY THIS
MORNING. A CURVED CONVECTIVE BAND IS NOW LOCATED CLOSER TO THE
CENTER OF CIRCULATION OVER THE NORTHERN AND WESTERN QUADRANTS...
WHICH COULD BE AN INDICATION THAT GABRIELLE IS GRADUALLY ACQUIRING
TROPICAL CHARACTERISTICS. DVORAK INTENSITY CLASSIFICATIONS ARE 
T 2.5/35 KT FROM SAB AND ST 2.5/35-40 KT FROM TAFB. BASED ON THIS...
GABRIELLE WILL REMAIN A SUBTROPICAL 40 KT STORM FOR THIS ADVISORY.
WHILE THE CYCLONE IS CURRENTLY OVER WARM WATERS...THE UPPER LEVEL
ENVIRONMENT IS NOT FAVORABLE FOR SIGNIFICANT STRENGTHENING.
THEREFORE...ONLY SLIGHT STRENGTHENING IS INDICATED AS GABRIELLE
APPROACHES THE COAST. THIS IS CONSISTENT WITH A BLEND OF THE
SHIPS...GFDL...AND HWRF INTENSITY GUIDANCE.

THE INITIAL MOTION IS 300/10.  GABRIELLE IS SITUATED BETWEEN AN
UPPER-LEVEL LOW TO ITS SOUTHWEST AND A DEEP-LAYER RIDGE OVER THE
NORTHWESTERN ATLANTIC.  AS THE UPPER-LEVEL LOW MOVES WESTWARD AND
WEAKENS...GABRIELLE WILL BE STEERED AROUND THE WESTERN PERIPHERY OF
THE RIDGE TOWARD THE COAST OF NORTH AND SOUTH CAROLINA IN THE NEXT
DAY OR TWO.  THEREAFTER...GABRIELLE IS EXPECTED TO BE EMBEDDED
WITHIN THE MID-LATITUDE SOUTHWESTERLY FLOW RESULTING IN AN
ACCELERATION TOWARD THE NORTHEAST.  BY DAYS 4 AND 5 GABRIELLE
SHOULD BE AN EXTRATROPICAL CYCLONE...MOVING AWAY FROM THE UNITED
STATES.  THE OFFICIAL TRACK FORECAST IS CLOSE TO THE DYNAMICAL
MODEL CONSENSUS AND IS NOT SIGNIFICANTLY DIFFERENT FROM THE
PREVIOUS ADVISORY.   

TROPICAL STORM WARNINGS WILL LIKELY BE REQUIRED LATER TODAY FOR A
PORTION OF THE TROPICAL STORM WATCH AREA.    
 

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/0900Z 30.9N  73.5W    40 KT
 12HR VT     08/1800Z 31.8N  74.9W    45 KT
 24HR VT     09/0600Z 33.1N  76.2W    50 KT...TROPICAL
 36HR VT     09/1800Z 34.5N  76.6W    55 KT
 48HR VT     10/0600Z 36.0N  75.5W    55 KT
 72HR VT     11/0600Z 38.5N  71.0W    50 KT
 96HR VT     12/0600Z 41.0N  62.0W    45 KT...EXTRATROPICAL
120HR VT     13/0600Z 45.0N  50.0W    45 KT...EXTRATROPICAL
 
$$
FORECASTER MAINELLI/AVILA
 
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