HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM FLOYD DISCUSSION NUMBER   9
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT THU SEP 09 1999
 
AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT INVESTIGATING
FLOYD THIS AFTERNOON HAS PRESENTED US WITH MIXED SIGNALS.  THE
CENTER LOCATED BY THE AIRCRAFT WAS NORTHWEST OF THE PREVIOUS
SATELLITE ESTIMATES...AND REMOVED FROM THE DEEP CONVECTION.  ON THE
OTHER HAND...THE AIRCRAFT ALSO FOUND 68 KT AT FLIGHT LEVEL ON THE
NORTHEAST SIDE...SO THE OFFICIAL INTENSITY IS RAISED TO 60 KT FOR
THIS PACKAGE.  GIVEN THE SEPARATION OF THE CENTER FROM THE
CONVECTION...NOT MUCH MORE SHORT TERM STRENGTHENING IS LIKELY. 
HOWEVER...THE SHIPS INTENSITY MODEL FORECASTS A 103 KT HURRICANE IN
72 HOURS AND THE OFFICIAL FORECAST IS SIMILAR TO THIS GUIDANCE.

THE WESTWARD MOTION NOTED THIS MORNING HAS ENDED.  WITH THE AIRCRAFT
FIXES...THE INITIAL MOTION IS NOW BACK TO THE RIGHT...AT 290/13. 
THE 12Z AVIATION MODEL INITIALIZES THE CYCLONE WITH SOME STRANGE-
LOOKING SIDE LOBES OF VORTICITY.  THESE INDUCE A SHARP NORTHWARD...
AND THEN WESTWARD TURN IN THE MODEL OVER THE NEXT 72 HOURS.  THIS
DOES NOT SEEM REASONABLE AND I HAVE SMOOTHED OUT THESE WIGGLES TO
GIVE A WEST-NORTHWEST TO NORTHWEST TRACK THAT IS VERY SIMILAR TO THE
PREVIOUS ADVISORY.  

WIND RADII HAVE BEEN ADJUSTED BASED ON THE AIRCRAFT RECONNAISSANCE
DATA.  ALTHOUGH THE FORECAST TRACK IS STILL NORTH OF THE
ISLANDS...GIVEN THESE RADII AND THE TYPICAL ERROR IN THE OFFICIAL
FORECAST...A TROPICAL STORM WATCH IS NOW REQUIRED FOR THE
NORTHEASTERN-MOST LEEWARD ISLANDS.

FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     09/2100Z 18.2N  56.9W    60 KTS
12HR VT     10/0600Z 18.9N  58.8W    60 KTS
24HR VT     10/1800Z 19.8N  60.6W    70 KTS
36HR VT     11/0600Z 21.0N  62.4W    80 KTS
48HR VT     11/1800Z 22.0N  64.0W    90 KTS
72HR VT     12/1800Z 23.5N  66.0W   100 KTS
 
 
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