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HURRICANE GERT DISCUSSION NUMBER  40
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT TUE SEP 21 1999
 
AIR FORCE AIRCRAFT FOUND THE CENTRAL PRESSURE OF 954 MB AT 0720Z
WITH MAX FLIGHT LEVEL WIND SPEED OF 98 KNOTS 71 NM SOUTHEAST OF THE
CENTER.  SATELLITE CURRENT INTENSITY NUMBERS REMAIN AT 90 KNOTS. 
SOME DEEP CONVECTION HAS OCCURRED ON THE NORTH SIDE OF THE SYSTEM
AND WILL PROBABLY DELAY THE WEAKENING PROCESS.  THEREFORE..THE
CURRENT INTENSITY REMAINS AT 95 KNOTS AND THE FORECAST INTENSITIES
REMAIN THE SAME.  A GRADUAL WEAKENING IS FORECAST DURING THE NEXT
FEW DAYS AS THE HURRICANE ENCOUNTERS SHEAR AND COOLER SEA SURFACE
TEMPERATURES.
 
INITIAL MOTION IS 360/9...THE SYSTEM IS AT OR CLOSE TO ITS
RECURVATURE POINT.  THE LATEST MODEL RUNS ARE IN GENERAL AGREEMENT
IN DIRECTION OUT TO 48 HOURS WITH A FEW OF THEM BEING SLOWER THAN
THE REST.  A WIDER SCATTER OCCURS AT THE 72 HOUR POSITION.  THE
OFFICIAL FORECAST POSITION AT 72 HOURS IS A COMPROMISE BETWEEN THE
UKMET THE CANADIAN AND MARINE PREDICTION CENTER FORECASTS.  
 
JARVINEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     21/0900Z 30.5N  62.8W    95 KTS
12HR VT     21/1800Z 31.9N  62.7W    90 KTS
24HR VT     22/0600Z 34.1N  62.0W    85 KTS
36HR VT     22/1800Z 37.4N  60.7W    80 KTS
48HR VT     23/0600Z 42.6N  56.6W    75 KTS
72HR VT     24/0600Z 54.0N  50.0W    65 KTS
 
 
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