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Tropical Storm ISAAC


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TROPICAL STORM ISAAC DISCUSSION NUMBER  20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL092006
1100 AM EDT MON OCT 02 2006
 
SOUTHWESTERLY SHEAR AND COOL SSTS HAVE TAKEN THEIR TOLL ON ISAAC
THIS MORNING.  THE CENTER OF ISAAC IS VERY DIFFICULT TO LOCATE IN
VISIBLE IMAGERY AND BUOYS OVER THE CANADIAN MARITIMES HAVE NOT BEEN
MUCH HELP THUS FAR.  THE INITIAL INTENSITY WILL BE SET AT 50 KT AND  
THIS COULD BE A LITTLE GENEROUS GIVEN THE CURRENT OBSERVATIONS.

ISAAC IS CONTINUING TO ACCELERATE NORTHEASTWARD AND THE INITIAL
MOTION ESTIMATE IS 030/36.  ALL OF THE AVAILABLE GUIDANCE SLOWS
ISAAC CONSIDERABLY IN THE NEXT 12 HOURS...POSSIBLY DUE TO THE
INTERACTION WITH THE ADJACENT EXTRATROPICAL LOW.  IN DEFERENCE TO
THE CURRENT ACCELERATION...THE OFFICIAL FORECAST IS FASTER THAN THE
GUIDANCE AND INDICATES THAT ISAAC WILL BE PASSING NEAR OF OVER
SOUTHEASTERN NEWFOUNDLAND LATER TODAY.  ISAAC IS QUICKLY LOSING
TROPICAL CHARACTERISTICS AND IS FORECAST TO MERGE WITH AN
EXTRATROPICAL CYCLONE WITHIN THE NEXT 36 HOURS.  THE GFS...
UKMET...AND ECMWF ALL AGREE ON THIS SCENARIO AND SO DOES THE 
NHC FORECAST. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/1500Z 44.3N  55.0W    50 KT
 12HR VT     03/0000Z 49.0N  51.0W    60 KT...EXTRATROPICAL
 24HR VT     03/1200Z 52.0N  47.0W    55 KT...EXTRATROPICAL
 36HR VT     04/0000Z...MERGED WITH EXTRATROPICAL LOW
 
$$
FORECASTER BROWN/PASCH
 
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