404 
 WTNT44 KNHC 021444
 TCDAT4
 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