Hurricane ISABEL

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HURRICANE ISABEL DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT MON SEP 08 2003
 
ISABEL CONTINUES TO GET BETTER ORGANIZED AND HAS IMPRESSIVE COLD
CLOUD TOPS SURROUNDING THE EYE WHICH HAS DECREASED IN DIAMETER SINCE
THE LAST ADVISORY.  THE INITIAL INTENSITY IS NOW 90 KT AND IS BASED
ON SATELLITE INTENSITY ESTIMATES OF 102 KTS FROM TAFB AND 90 KTS
FROM SAB AND AIR FORCE GLOBAL.  IN FACT...ISABEL MAY BE STRONGER BUT
I WANT TO SEE IF IT CAN MAINTAIN THESE SATELLITES ESTIMATES FOR AT
LEAST ANOTHER CYCLE BEFORE I GO ABOVE 90 KTS
 
THE INITIAL MOTION ESTIMATE IS 300/14. ISABEL IS MOVING IN THIS
DIRECTION IN RESPONSE TO A SUBTROPICAL RIDGE TO THE NORTH. BUT...
WATER VAPOR IMAGERY ALSO SHOWS AN UPPER COLD LOW THAT IS DEVELOPING
TO THE WEST OF ISABEL.  THE SOUTHERLY AND SOUTHWESTERLY FLOW ON THE
EAST SIDE OF THIS COLD LOW MAY BE ADDING A NORTHERLY COMPONENT TO
THE MOTION.  HOWEVER...THE GLOBAL MODELS EVENTUALLY MOVE THIS
SYSTEM TOWARD THE WEST AND WEAKEN IT.  THE GLOBAL MODELS ARE ALL IN
AGREEMENT THAT THE RIDGE WILL REMAIN THROUGHOUT THE FORECAST PERIOD
AND ISABEL SHOULD CONTINUE TO MOVE IN A WEST-NORTHWEST TO WEST
MOTION FOR THE NEXT FIVE DAYS WITH THE SYSTEM ENDING UP JUST TO THE
NORTHEAST OF THE LEEWARD ISLANDS ON DAY FIVE. THE OFFICIAL FORECAST
REFLECTS THIS AND IS ESSENTIALLY AN UPDATE OF THE PREVIOUS
FORECAST.
 
THE SHIPS MODEL INTENSIFIES ISABEL TO 115 KTS IN 48 HOURS AND THE
OFFICIAL INTENSITY FORECAST REFLECTS THIS.  HOWEVER...THE SYSTEM
MAY BE IN A RAPID DEEPENING MODE AND MAY GET STRONGER SOONER.
 
FORECASTER JARVINEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/0900Z 16.9N  41.4W    90 KT
 12HR VT     08/1800Z 17.9N  43.3W   100 KT
 24HR VT     09/0600Z 18.8N  45.7W   105 KT
 36HR VT     09/1800Z 19.4N  48.0W   110 KT
 48HR VT     10/0600Z 19.8N  50.3W   115 KT
 72HR VT     11/0600Z 19.9N  54.4W   115 KT
 96HR VT     12/0600Z 20.2N  58.0W   115 KT
120HR VT     13/0600Z 20.6N  60.7W   115 KT
 
 
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