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HURRICANE GERT DISCUSSION NUMBER  31
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT SAT SEP 18 1999
 
GERT REMAINS A HEALTHY HURRICANE WITH A 30 NMI DIAMETER EYE
SURROUNDED BY VERY COLD CLOUD TOPS. DVORAK INTENSITY ESTIMATES 
FROM TAFB AND SAB ARE 6.5 AND 6.0...RESPECTIVELY.  OBJECTIVE-
BASED ESTIMATES ARE RUNNING IN THE SAME RANGE.  THE INITIAL
INTENSITY IS INCREASED TO 110 KT FOR THIS ADVISORY AND SOME
FLUCTUATIONS IN INTENSITY ARE LIKELY DURING THE NEXT 24 HRS.
 
THE INITIAL MOTION ESTIMATE IS 330/09 KT. THE HURRICANE IS MOVING
AROUND THE PERIPHERY OF THE SUBTROPICAL RIDGE WHICH IS FORECAST
TO PERSIST OVER THE EASTERN ATLANTIC.  HOWEVER...A VERY STRONG 
UPPER TROUGH AND THE ASSOCIATED A COLD FRONT ARE FORECAST TO MOVE 
THROUGH THE EASTERN U.S. DURING THE NEXT FEW DAYS.  THIS TROUGH
APPEARS TO BE STRONG ENOUGH TO KEEP GERT OVER THE OPEN ATLANTIC
BUT IT MAY STILL POSE A THREAT TO BERMUDA. MOST OF THE OBJECTIVE
TRACK GUIDANCE TAKES THE HURRICANE ON A GENERAL NORTH-NORTHWEST
TRACK THROUGH 48 HRS WITH A BEND TOWARDS THE NORTH THEREAFTER.
THE OFFICIAL FORECAST TRACK FOLLOWS THIS SCENARIO...ALTHOUGH A
SLOWER THAN THE GFDL AND THE UKMET.
 
INTERESTS IN BERMUDA SHOULD CONTINUE TO MONITOR THE PROGRESS OF
GERT.
 
GUINEY
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     19/0300Z 24.0N  58.5W   110 KTS
12HR VT     19/1200Z 25.0N  59.1W   110 KTS
24HR VT     20/0000Z 26.3N  59.9W   105 KTS
36HR VT     20/1200Z 27.5N  60.7W   105 KTS
48HR VT     21/0000Z 29.5N  61.5W   100 KTS
72HR VT     22/0000Z 31.5N  63.0W   105 KTS
 
 
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