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HURRICANE GERT DISCUSSION NUMBER  29
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT SAT SEP 18 1999

GERT CONTINUES TO BE WELL ORGANIZED WITH BANDING FEATURES AND A
LARGE EYE.  HOWEVER...THE RING OF DEEP CONVECTION SURROUNDING THE
EYE HAS BEEN GRADUALLY WEAKENING.  CONSEQUENTLY...DVORAK T-NUMBERS
CONTINUE TO DECREASE. WIND ESTIMATES ARE 105 KNOTS AND NO
SIGNIFICANT CHANGES IN INTENSITY ARE FORECAST.  GERT MAY RE-
STRENGTHEN...IF THERE IS TROUGH INTERACTION LATER IN THE PERIOD.
THERE IS A LARGE DISCREPANCY IN THE INTENSITY FORECAST PROVIDED BY
THE GFDL AND GFDL COUPLED MODELS. THE GFDL BRINGS THE MINIMUM
PRESSURE DOWN TO NEAR 930 MB AND THE COUPLED KEEPS IT ABOUT 950 MB
AND RISING.  SHIPS SHOWS NO SIGNIFICANT CHANGE IN INTENSITY. 

INITIAL MOTION IS 325/09. 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 A
COLD FRONT ARE FORECAST TO SWEEP EASTWARD OVER THE EASTERN UNITED
STATES DURING THE NEXT FEW DAYS.  THIS TROUGH APPEARS TO BE STRONG
ENOUGH TO KEEP GERT OVER THE OPEN ATLANTIC BUT DANGEROUSLY CLOSE TO
BERMUDA. THIS IS CONSISTENT WHICH TRACK GUIDANCE.
 
INTERESTS IN BERMUDA SHOULD CONTINUE TO MONITOR THE PROGRESS OF
GERT.
 
AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     18/1500Z 22.6N  57.9W   105 KTS
12HR VT     19/0000Z 23.7N  58.8W   105 KTS
24HR VT     19/1200Z 25.0N  60.0W   105 KTS
36HR VT     20/0000Z 26.5N  61.5W   105 KTS
48HR VT     20/1200Z 28.0N  63.0W   105 KTS
72HR VT     21/1200Z 30.0N  65.0W   105 KTS
 
 
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