Hurricane ISABEL

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HURRICANE ISABEL DISCUSSION NUMBER  33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT SUN SEP 14 2003
 
AN AIR FORCE RECONNAISSANCE AIRCRAFT JUST MEASURED 700 MB PEAK WINDS
OF 148 AND 143 KNOTS TO THE NORTHEAST AND TO THE NORTHWEST OF THE
CENTER...RESPECTIVELY. THIS CORRESPONDS TO 135 KNOTS AT THE SURFACE
BUT ASSUMING THAT THE ENTIRE WIND FIELD HAS NOT BEEN SAMPLED...THE
INITIAL INTENSITY IS KEPT AT 140 KNOTS IN THIS ADVISORY. THE
CENTRAL PRESSURE IS 938 MB. SATELLITE PRESENTATION CONTINUES TO BE
SPECTACULAR WITH A DISTINCT EYE AND OUTFLOW IN ALL QUADRANTS.
GLOBAL MODELS MAINTAIN ISABEL WITH AN AVERAGE INTENSITY OF 140
KNOTS. THIS DOES NOT APPEAR TO BE REALISTIC SINCE THE SHEAR IS
FORECAST TO INCREASE BEYOND 48 HOURS.  THE OFFICIAL FORECAST CALLS
FOR SOME FLUCTUATIONS IN INTENSITY DURING THE NEXT DAY OR TWO WITH
A GRADUAL WEAKENING THEREAFTER.
 
THE HURRICANE HAS BEEN WOBBLING BETWEEN WEST AND WEST-NORTHWEST
DURING THE PAST FEW HOURS. HOWEVER...THE BEST ESTIMATE OF THE
INITIAL MOTION IS 290 DEGREES AT 11 KNOTS. THIS GENERAL TRACK
SHOULD CONTINUE FOR THE NEXT 12 TO 24 HOURS. A GRADUAL TURN TO THE
NORTHWEST WITH A DECREASE IN FORWARD SPEED IS ANTICIPATED AS A
SHORTWAVE SWINGS OFF THE U.S EAST COAST AND WEAKENS THE STEERING
CURRENTS. ONCE THE SHORTWAVE IS GONE IN ABOUT 72 HOURS...THE
SUBTROPICAL RIDGE IS FORECAST TO REBUILD AND ISABEL SHOULD BEGIN TO
INCREASE IN FORWARD SPEED. ON THIS TRACK...DANGEROUS ISABEL WILL BE
NEARING THE OUTER BANKS OF NORTH CAROLINA IN ABOUT 4 DAYS.
 
THE OFFICIAL FORECAST IS CONSISTENT WITH THE GLOBAL MODELS WHICH
UNANIMOUSLY BRING THE CORE OF THE HURRICANE TO THE U.S MID-ATLANTIC
COAST SOMEWHERE BETWEEN NORTH CAROLINA AND NEW JERSEY BETWEEN 4 OR
5 DAYS. THE OFFICIAL FORECAST IS ALSO VERY CLOSE TO THE GUNS
CONSENSUS WHICH HAS HAD A VERY LOW ERROR SO FAR.
 
FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      14/0900Z 23.3N  65.2W   140 KT
 12HR VT     14/1800Z 23.8N  66.8W   140 KT
 24HR VT     15/0600Z 24.5N  68.5W   135 KT
 36HR VT     15/1800Z 25.5N  69.5W   130 KT
 48HR VT     16/0600Z 26.5N  70.5W   125 KT
 72HR VT     17/0600Z 29.0N  72.5W   120 KT
 96HR VT     18/0600Z 33.1N  75.0W   110 KT
120HR VT     19/0600Z 39.5N  77.0W   100 KT...INLAND
 
 
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