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HURRICANE GABRIELLE DISCUSSION NUMBER  22
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT SUN SEP 16 2001

A NOAA AIRCRAFT GPS DROPSONDE MEASURED 68 KNOTS NEAR THE CENTER JUST 
ABOVE THE SURFACE AT ABOUT 00Z.  GABRIELLE IS UPGRADED TO 65 
KNOTS...A HURRICANE...ON THIS BASIS.  THE SYSTEM LOOKS HIGHLY 
SHEARED AND ASYMMETRIC WITH DEEP CONVECTION NORTH AND EAST OF THE 
CENTER.  IS THE SYSTEM STILL TROPICAL?  PERHAPS.  ACCORDING TO THE 
PENN STATE CYCLONE PHASE ANALYSIS FROM THE 12Z AVIATION MODEL...THE 
TEMPERATURE STRUCTURE IS NEAR NEUTRAL.  SO WE WILL HOLD ON TO 
TROPICAL STATUS FOR A WHILE LONGER.  ONLY SLIGHT WEAKENING IS 
FORECAST DURING THE NEXT 72 HOURS FOLLOWING THE SHIPS MODEL.  IN 
CONTRAST THE GFDL AND UKMET FORECAST SIGNIFICANT STRENGTHENING.

THE INITIAL MOTION AND FORECAST TRACK ARE A LITTLE LEFT OF THE 
PREVIOUS ADVISORY.  OTHERWISE THERE IS NO CHANGE IN PHILOSOPHY FROM 
THE PREVIOUS ADVISORY.  GABRIELLE IS EMBEDDED IN THE WESTERLIES AND 
ALL OF THE GUIDANCE IS IN GOOD AGREEMENT ABOUT A CONTINUED 
EAST-NORTHEAST TRACK FOR THE NEXT 72 HOURS.

SHIP REPORTS AND QUIKSCAT DATA ARE THE BASIS FOR EXPANDING THE 
34-KNOT WIND RADII.

THE GALE WARNING FOR BERMUDA IS CHANGED TO A TROPICAL STORM WARNING.

FORECASTER LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     17/0300Z 33.6N  70.5W    65 KTS
12HR VT     17/1200Z 34.8N  67.7W    65 KTS...EXTRATROPICAL
24HR VT     18/0000Z 36.5N  64.5W    60 KTS...EXTRATROPICAL
36HR VT     18/1200Z 38.0N  62.0W    60 KTS...EXTRATROPICAL
48HR VT     19/0000Z 39.5N  59.5W    60 KTS...EXTRATROPICAL
72HR VT     20/0000Z 44.0N  53.0W    50 KTS...EXTRATROPICAL
 
 
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