HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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HURRICANE DENNIS DISCUSSION NUMBER  32
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT TUE AUG 31 1999
 
OVER THE PAST SEVERAL HOURS...THERE HAS BEEN A NET WESTWARD MOTION
OF THE CENTER AT 4 OR 5 KNOTS.  THE TRACK FORECAST IS NOT AN EASY
ONE.  IF ENOUGH RIDGING DEVELOPS TO THE NORTH OF DENNIS...THEN THE
CYCLONE COULD MOVE TO THE COAST.  HOWEVER RIDGING OVER THE SOUTHEAST
U.S. AND FLORIDA COULD BLOCK THE FORWARD MOVEMENT.  EVEN THOUGH THE
TRACK MODELS ARE DIVERGENT...A ROUGH CONSENSUS OF THE MORE RELIABLE
MODELS SUGGESTS A WEST TO SOUTHWEST MOTION DURING THE FORECAST
PERIOD.  THE OFFICIAL FORECAST FOLLOWS THIS IDEA...BUT QUITE SLOW
MAINLY DUE TO THE UNCERTAINTY.
 
SINCE THE MOTION AND FORECAST IS BACK TOWARD THE COAST...A HURRICANE
WATCH IS PUT INTO EFFECT ACROSS THE TROPICAL STORM WARNING AREA.
ANOTHER BIG QUESTION IS THE INTENSITY.  DENNIS WEAKENED BECAUSE OF
THE INTRUSION OF COOL DRY AIR INTO ITS CENTRAL CORE...AND LIKELY
ALSO BECAUSE OF STRONG HIGH-LEVEL WEST-SOUTHWESTERLY WINDS.  SINCE
THE MID-LATITUDE WESTERLIES HAVE SHIFTED NORTH OF THE EASTERN U.S.
NO NEW COLD FRONTS ARE EXPECTED TO ENTER INTO THE ENVIRONMENT OF
DENNIS DURING THE NEXT FEW DAYS.  OCEAN TEMPERATURES ARE NEAR 27 DEG
C.  TROPICAL CYCLONES RARELY COME BACK AFTER ALL DEEP CONVECTION HAS
BEEN REMOVED.  THERE WAS A TRANSIENT RE-DEVELOPMENT OF CONVECTION
NEAR THE CENTER...BUT THIS HAS FADED.  BECAUSE OF OUR LACK OF SKILL
IN FORECASTING INTENSITY CHANGE...AND THE POSSIBILITY...ALBEIT
SLIM... THAT DENNIS COULD RE-STRENGTHEN...THE OFFICIAL FORECAST
MERELY MAINTAINS 65 KNOTS THROUGH THE PERIOD.
 
PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     31/2100Z 35.1N  73.3W    65 KTS
12HR VT     01/0600Z 35.1N  74.0W    65 KTS
24HR VT     01/1800Z 35.0N  74.7W    65 KTS
36HR VT     02/0600Z 34.9N  75.5W    65 KTS
48HR VT     02/1800Z 34.7N  76.0W    65 KTS
72HR VT     03/1800Z 33.5N  77.0W    65 KTS
 
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