HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM DENNIS DISCUSSION NUMBER  39
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT THU SEP 02 1999

VISIBLE SATELLITE IMAGES SHOW A WELL-ORGANIZED SYSTEM...WITH DENSER
CLOUDS NEAR AND OVER THE CENTER.  HOWEVER THE CLOUD TOPS ARE NOT
VERY HIGH AND RADAR OBSERVATIONS DO NOT SHOW A CLEARLY-DEFINED
CENTER.  THERE HAS BEEN LITTLE CHANGE IN STRENGTH SINCE YESTERDAY.
TYPICALLY FOR A CYCLONE THAT REMAINS STALLED FOR THIS LENGTH OF
TIME...THE OCEAN IS COOLED SUBSTANTIALLY BY THE SURFACE WIND
CIRCULATION.  HOWEVER IN THIS INSTANCE THE CENTER HAS REMAINED OVER
THE GULF STREAM...A VAST OCEANIC HEAT SOURCE.   SO THERE IS CONSTANT
REPLENISHMENT OF WARM WATER INTO THE AREA.  THE SHIPS AND GFDL MODEL
PREDICT STRENGTHENING TO A HURRICANE LATE IN THE FORECAST PERIOD. 
BECAUSE OF THE USUAL UNCERTAINTY IN PREDICTING INTENSITY CHANGE...
THE OFFICIAL FORECAST SHOWS NO CHANGE IN STRENGTH.

THERE HAS BEEN LITTLE OVERALL MOTION SINCE YESTERDAY.  OBJECTIVE
TRACK GUIDANCE INSISTS ON A MOVEMENT TOWARD THE COAST.  THIS IS
CONSISTENT WITH THE 2-3 DAY FORECAST OF A MID-LEVEL ANTICYCLONE OVER
THE NORTHEASTERN U.S. SHOWN BY THE AVN MODEL.  HOWEVER THERE IS ALSO
AN ANTICYCLONE SHOWN OVER THE GULF OF MEXICO AROUND THAT TIME.  THIS
COULD NEGATE THE WESTWARD MOVEMENT.  THE CURRENT OFFICIAL TRACK
FORECAST IS ABOUT THE SAME AS THE PREVIOUS ONE...MOVING THE SYSTEM
VERY SLOWLY DURING THE FIRST HALF OF THE PERIOD AND THEN TOWARD THE
WEST-SOUTHWEST LATER ON.

PASCH

FORECAST POSITIONS AND MAX WINDS
 
INITIAL     02/1500Z 35.3N  73.6W    50 KTS
12HR VT     03/0000Z 35.3N  73.6W    50 KTS
24HR VT     03/1200Z 35.2N  74.4W    50 KTS
36HR VT     04/0000Z 34.9N  75.2W    50 KTS
48HR VT     04/1200Z 34.5N  76.0W    50 KTS
72HR VT     05/1200Z 33.5N  78.0W    50 KTS
 
 
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