HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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HURRICANE DENNIS DISCUSSION NUMBER  21
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT SAT AUG 28 1999
 
SATELLITE IMAGERY SHOWS A BANDING-TYPE EYE...ALTHOUGH RAGGED IN
APPEARANCE. 18/22Z RADAR IMAGERY FROM THE NOAA P-3 AIRCRAFT SHOWED 
A BROAD ILL-DEFINED EYE FEATURE WHILE QUOTING THE AIR FORCE THEY
COULD NOT SEE IT ON RADAR AND IT WAS NOT DISCERNABLE VISUALLY.  
THE LATEST RECON REPORTS THAT THE MINIMUM CENTRAL PRESSURE REMAINS
969 MB...A 11 MB DROP OVER THE LAST 24 HRS. THE INITIAL INTENSITY
ESTIMATE WILL BE HELD AT 90 KTS SUPPORTED BY THE MOST RECENT HRD
WIND ANALYSIS...ALTHOUGH SURFACE DROPSONDE WINDS ARE LOWER. THE
STRENGTHENING FORECAST IS MAINTAINED FROM THE PREVIOUS ADVISORY
WHICH BRINGS DENNIS TO A CATEGORY THREE HURRICANE IN 24 HRS.

WITH SUCH A LARGE AND RAGGED EYE FEATURE...THERE IS SOME DIFFERENCES
BETWEEN THE AIR FORCE RECON FIXES AND THE LATEST RADAR FIX
ESTIMATES. THE INITIAL MOTION ESTIMATE IS 330/06 KTS. MOST OF THE
OBJECTIVE TRACK GUIDANCE IS VERY SIMILAR TO THEIR 18Z COUNTERPARTS
INDICATING THAT THE NEXT EAST COAST MID- TO UPPER LEVEL TROUGH WILL
PICK UP DENNIS AND ACCELERATE IT NORTHEAST JUST OFFSHORE WHILE THE
GFDL BRINGS DENNIS NORTH-NORTHWEST/NORTHWARD INTO NORTH CAROLINA BY
72 HRS...SUGGESTING THAT THE TROUGH BY-PASSES THE HURRICANE. THIS
SHOWS THE SPLIT BETWEEN THE MODELS WITH SOME MOVING THE DENNIS OUT
TO OPEN WATERS WHILE OTHER HINT KEEPING DENNIS NEAR THE COAST FOR A
PROLONGED PERIOD. WITH THE CONTINUING UNCERTAINTY SURROUNDING THE
INFLUENCE OF THE APPROACHING TROUGH...THE OFFICIAL FORECAST TRACK
BRINGS DENNIS NORTH-NORTHWEST THEN NORTH TO JUST OFF THE NORTH
CAROLINA COAST BY 48 HRS BEFORE TURNING THE HURRICANE NORTHEAST...
ALBEIT AT A SLOWER MOTION THAN MOST OF THE GUIDANCE. 

BASED ON THE NEW TRACK... HURRICANE WATCHES WILL BE POSTED FOR THE
SOUTH CAROLINA AND PORTIONS OF THE NORTH CAROLINA COASTS.  A PORTION
OF THE WATCH AREA WILL LIKELY BE UPGRADED TO A TROPICAL STORM OR
HURRICANE WARNING SUNDAY MORNING.  DENNIS IS A LARGE HURRICANE WITH
THE 34-KT RADII EXTENDING 140 NM IN THE NORTHEAST QUADRANT AND COULD
IMPACT A LARGE PORTION OF THE SOUTHEAST COAST. ...ALL INTERESTS
ALONG THE COASTS OF GEORGIA...SOUTH AND NORTH CAROLINA SHOULD
CONTINUE TO CLOSELY MONITOR THE PROGRESS OF DENNIS.    

THE 50-KT AND 34-KT WIND RADII HAVE BEEN ADJUSTED USING THE HRD WIND
ANALYSIS.    

GUINEY
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     29/0300Z 28.6N  77.8W    90 KTS
12HR VT     29/1200Z 29.6N  78.2W    95 KTS
24HR VT     30/0000Z 30.9N  78.7W   100 KTS
36HR VT     30/1200Z 32.3N  78.7W   100 KTS
48HR VT     31/0000Z 33.5N  78.0W   100 KTS
72HR VT     01/0000Z 35.0N  76.0W   100 KTS
 
 
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