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HURRICANE DENNIS DISCUSSION NUMBER  22
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT SUN AUG 29 1999

THE INITIL MOTION ESTIMATE IS 335/07.  ALL OF THE GUIDANCE MODELS
SHOW THE HURRICANE MOVING NORTH AND THEN NORTHEASTWARD AS A STRONG
TROUGH DROPS SOUTH FROM CANADA.  MOST OF THE MODELS SHOW AN
ACCELERATION TOWARD THE NORTHEAST BUT THE GFDL SUGGESTS THAT DENNIS
MAY NOT GET PICKED UP BY THE TROUGH AND COULD MEANDER OFF THE MID
ATLANTIC COAST.  THE OFFICIAL TRACK FORECAST IS SHIFTED TO THE RIGHT
OF THE PREVIOUS FORECAST BUT NOT ALL THE WAY TO THE NEAREST DYNAMIC
MODELS.  THIS BIAS TO THE LEFT OF THE GUIDANCE IS A RESULT OF NOT
WANTING TO DEPART FROM THE PREVIOUS OFFICIAL FORECAST TOO
DRASTICALLY.

THE FORECAST TRACK IN COMBINATION WITH THE LARGE RADIUS OF 34-KNOT
WINDS REQUIRES THAT A TROPICAL STORM WARNING BE ISSUED FOR SOUTH
CAROLINA AND PART OF NORTH CAROLINA.  THERE IS PROBABLY ONLY A 50
PERCENT OR LESS CHANCE THAT TROPICAL STORM CONDITIONS WILL ACTUALLY
OCCUR IN THE WARNING AREA...BUT THERE IS ENOUGH UNCERTAINTY TO
JUSTIFY THESE WARNINGS.

BASED ON RECON WIND OBSERVATIONS...THE WIND SPEED IS DECREASED TO 85
KNOTS WITH AN EXPECTATION OF SOME SLOW STRENGTHENING FOR THE NEXT
DAY OR TWO.  THIS IS BASED ON THE SHIPS MODEL GUIDANCE.

LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     29/0900Z 29.4N  78.2W    85 KTS
12HR VT     29/1800Z 30.3N  78.7W    90 KTS
24HR VT     30/0600Z 31.8N  78.7W    95 KTS
36HR VT     30/1800Z 33.0N  77.5W    95 KTS
48HR VT     31/0600Z 34.0N  75.5W    95 KTS
72HR VT     01/0600Z 36.0N  73.0W    95 KTS
 
 
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