000
WTNT43 KNHC 020245
TCDAT3
TROPICAL STORM FIONA DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082010
1100 PM AST WED SEP 01 2010
 
DESPITE THE POOR SATELLITE PRESENTATION...RECONNAISSANCE DATA SINCE
THE LAST ADVISORY INDICATE THAT THERE HAS BEEN LITTLE CHANGE TO THE
INTENSITY OF FIONA.  THE AIRCRAFT FOUND PEAK 850 MB FLIGHT-LEVEL
WINDS OF 58 KT AND SFMR WINDS TO 53 KT TO THE NORTHEAST OF THE
CENTER.  THE AIRCRAFT DATA AND OBSERVATIONS FROM NOAA BUOY 41043
THIS EVENING SUGGEST THAT THE CIRCULATION OVER THE SOUTHWESTERN
QUADRANT HAS BECOME LESS DEFINED...AND A RECENT SSMIS IMAGE
DEPICTED A CIRCULATION THAT APPEARED ELONGATED FROM SOUTHEAST TO
NORTHWEST.  THE ENVIRONMENT AHEAD OF FIONA APPEARS QUITE
HOSTILE...WITH STRONG UPPER-LEVEL WINDS SHOWN BY THE GLOBAL MODELS.
THE NHC FORECAST INDICATES GRADUAL WEAKENING AND IS AT THE LOWER
END OF THE GUIDANCE. IT IS POSSIBLE THAT THE CIRCULATION WILL
DEGENERATE INTO AN OPEN TROUGH IN THE STRONG SOUTH TO SOUTHWEST
LOW-LEVEL FLOW ON THE EAST SIDE OF HURRICANE EARL. THIS SOLUTION IS
SUPPORTED BY MOST OF THE GLOBAL MODELS AND DISSIPATION OF FIONA
COULD OCCUR EARLIER THAN SHOWN BELOW.
 
FIXES FROM THE AIRCRAFT SHOW THAT FIONA ACCELERATED THIS
AFTERNOON...WITH AN ESTIMATED MOTION OF 320/20 KT.  THE CYCLONE
IS FORECAST TO MOVE AROUND THE WESTERN PORTION OF THE SUBTROPICAL
RIDGE DURING THE NEXT DAY OR SO.  THEREAFTER...FIONA IS FORECAST
TO TURN NORTHWARD...THEN NORTHEASTWARD IN DEEP-LAYER SOUTHWESTERLY
FLOW BETWEEN THE RIDGE AND EARL TO THE NORTHWEST.  THE NEW TRACK
FORECAST IS FASTER THAN THE PREVIOUS ADVISORY AND IS A BLEND OF
THE GFS...ECMWF...NOGAPS...AND UKMET MODELS.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/0300Z 21.8N  64.1W    50 KT
 12HR VT     02/1200Z 23.8N  65.7W    45 KT
 24HR VT     03/0000Z 26.2N  67.1W    45 KT
 36HR VT     03/1200Z 28.8N  67.4W    40 KT
 48HR VT     04/0000Z 31.5N  66.3W    40 KT
 72HR VT     05/0000Z 35.5N  63.5W    35 KT
 96HR VT     06/0000Z...DISSIPATED
 
$$
FORECASTER BROWN