Tropical Storm FABIAN

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TROPICAL STORM FABIAN DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT THU AUG 28 2003
 
THE DEEP CONVECTION HAS BEEN INTERMITTENT BUT THE OVERALL CLOUD
PATTERN IS GRADUALLY IMPROVING. THERE IS A CURVED BAND TO THE WEST
OF THE CENTER WITH OUTFLOW EXPANDING NORTHWARD AND WESTWARD. THE
LATEST SSMI REVEALED A DISTINCT CENTER AND THE QUIKSCAT SHOWED A
WELL-ESTABLISHED CIRCULATION. DVORAK T-NUMBERS ARE 3.0 FROM ALL
AGENCIES SUGGESTING THAT THAT THE WINDS HAVE INCREASED TO 45 KNOTS.
CURRENTLY...THERE IS A PERSISTENT BAND OF STRONG UPPER-LEVEL
WESTERLIES CENTERED AT 20 DEGREES NORTH EXTENDING FROM THE BAHAMAS
EASTWARD TO NEAR 50 DEGREES WEST. IF THIS PATTERN CONTINUES IT
WOULD NOT BE FAVORABLE FOR FABIAN TO STRENGTHEN SIGNIFICANTLY. ON
THE CONTRARY...SHIPS MODEL SUGGESTS THAT THERE WILL BE LIGHT
SHEAR...LESS THAN 10 KNOTS...AHEAD OF THE TROPICAL CYCLONE. BECAUSE
THE SHIPS MODEL IS BASED ON THE GFS OUTPUT WHICH HAS BEEN REMOVING
THE UPPER-LEVEL WESTERLIES TOO FAST...ONLY A MODEST STRENGTHENING
IS INDICATED IN THE OFFICIAL FORECAST.

FABIAN CONTINUES TO MOVE TOWARD THE WEST OR 275 DEGREES AT ABOUT 17
KNOTS TO THE SOUTH OF THE SUBTROPICAL RIDGE. THE RIDGE IS FORECAST
TO WEAKEN GRADUALLY RESULTING IN A DECREASE IN FORWARD SPEED. THIS
IS CONSISTENT WITH MOST OF THE TRACK GUIDANCE WHICH MOVES FABIAN AT
ABOUT 10 KNOTS BEYOND 48 HOURS AND BRINGS THE CYCLONE WELL TO THE
NORTH OF THE LEEWARD ISLANDS. THE OFFICIAL TRACK IS ON THE SOUTHERN
EDGE OF THE GUIDANCE ENVELOPE BUT VERY CLOSE TO THE GFS AND UK
MODELS.         
 
FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/0300Z 15.3N  40.9W    45 KT
 12HR VT     29/1200Z 15.5N  43.5W    50 KT
 24HR VT     30/0000Z 16.2N  46.0W    55 KT
 36HR VT     30/1200Z 17.0N  48.5W    60 KT
 48HR VT     31/0000Z 17.5N  50.5W    65 KT
 72HR VT     01/0000Z 19.0N  54.0W    70 KT
 96HR VT     02/0000Z 20.0N  58.0W    70 KT
120HR VT     03/0000Z 21.0N  62.0W    70 KT
 
 
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