857 
 WTNT41 KNHC 182104
 TCDAT1
 TROPICAL STORM FAY DISCUSSION NUMBER  13
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062008
 500 PM EDT MON AUG 18 2008
  
 SATELLITE...RADAR...AND AIRCRAFT DATA INDICATE THAT FAY HAS BECOME
 BETTER ORGANIZED THIS AFTERNOON.  THE CONVECTIVE BANDING HAS
 INCREASED AROUND THE CENTER...AND THE RADIUS OF MAXIMUM WINDS HAS
 CONTRACTED TO ABOUT 30 N MI.  ADDITIONALLY...THE CENTRAL PRESSURE
 HAS FALLEN TO 998 MB.  HOWEVER...THIS HAS NOT YET CAUSED THE WINDS
 TO INCREASE...AS AIRCRAFT...RADAR...AND SURFACE DATA SUGGEST THE
 MAXIMUM WINDS REMAIN ABOUT 50 KT.  IT SHOULD BE NOTED THAT A TCU
 WAS ISSUED NOTING LANDFALL WHEN THE WINDS AT KEY WEST WENT CALM AT
 3 PM.  LATER DATA SUGGESTS THIS WAS DUE TO A MESOSCALE FEATURE
 ROTATING AROUND THE LARGER CENTER OF THE STORM...AND THE TRUE
 CENTER OF FAY IS OVER KEY WEST NOW.
 
 THE INITIAL MOTION IS 340/10.  FAY IS ENTERING A BREAK IN THE
 SUBTROPICAL RIDGE OVER THE EASTERN GULF OF MEXICO AND FLORIDA
 CAUSED BY A MID/UPPER-LEVEL TROUGH MOVING THROUGH THE SOUTHEASTERN
 UNITED STATES.  BEYOND 36-48 HR...THE TROUGH IS FORECAST TO LIFT
 OUT...WITH A MID/UPPER-LEVEL RIDGE BUILDING OVER THE EASTERN UNITED
 STATES AHEAD OF A SECOND TROUGH OVER THE WESTERN GULF COAST STATES.
 THE MODEL GUIDANCE STILL SHOWS CONSIDERABLE SPREAD IN RESPONDING TO
 THIS PATTERN.  THE NOGAPS CONTINUES TO CALL FOR A NORTH-
 NORTHWESTWARD MOTION TOWARD THE FLORIDA PANHANDLE AND INLAND
 THEREAFTER.  THE UKMET HAS SHIFTED A LITTLE TO THE EAST AND
 FORECASTS A NORTHWARD MOTION THROUGH THE FLORIDA PENINSULA...WITH A
 SHARP TURN TO THE WEST AFTER 72 HR.  THE CANADIAN MODEL HAS A
 SIMILAR FORECAST.  THE GFS AND ECMWF CALL FOR FAY TO TURN
 NORTHEASTWARD INTO THE ATLANTIC...FOLLOWED BY A WESTWARD TURN AND
 MOTION BACK INTO NORTHERN FLORIDA AFTER 72 HR.  FINALLY...THE GFDL
 AND THE HWRF CONTINUE FOR A GENERALLY NORTHWARD MOTION WELL INLAND
 OVER THE EASTERN UNITED STATES.  GIVEN THE INCREASING SIGNAL FROM
 THE GLOBAL MODELS THAT NEW RIDGE TO THE NORTH WILL BLOCK FAY'S
 PROGRESS...THE NEW FORECAST TRACK CALLS FOR A SLOWER AND MORE
 WESTWARD MOTION AFTER 72 HR.  THE EARLIER PART OF THE TRACK...WHICH
 CALLS FOR LANDFALL IN SOUTHWESTERN FLORIDA IN ABOUT 18 HR FOLLOWED
 BY A TRACK OVER THE FLORIDA PENINSULA...IS SHIFTED A LITTLE TO THE
 EAST AND LIES NEAR THE MODEL CONSENSUS.
 
 WHILE FAY REMAINS IN A MODERATE SOUTHWESTERLY VERTICAL SHEAR
 ENVIRONMENT AND IS BATTLING DRY AIR ENTRAINMENT...THESE CONDITIONS
 ARE NOT SEVERE ENOUGH TO PREVENT STRENGTHENING.  THUS...THE
 INTENSITY FORECAST CALLS FOR STRENGTHENING UNTIL LANDFALL.  WHILE
 NOT EXPLICITLY A FORECAST POINT...IT IS LIKELY THAT FAY WILL MAKE
 LANDFALL AT OR NEAR HURRICANE STRENGTH.  AFTER 24 HR...THE
 INTENSITY WILL DEPEND MAINLY ON WHETHER FAY IS OVER LAND...AS THE
 UPPER-LEVEL WINDS ARE LIKELY TO BECOME MORE FAVORABLE.  THE CURRENT
 INTENSITY FORECAST IS BASED ON FAY REMAINING OVER LAND AND THUS
 DISSIPATING.  IF FAY REGAINS THE ATLANTIC OR THE GULF OF MEXICO
 DURING THE FORECAST PERIOD...IT WILL LIKELY REMAIN STRONGER THAN
 FORECAST.
  
 IT SHOULD BE NOTED THAT...SIMILAR TO CHARLEY IN 2004...SMALL
 DEVIATIONS FROM THE FORECAST TRACK COULD MAKE LARGE DIFFERENCES IN
 WHEN AND WHERE THE CENTER OF FAY MAKES LANDFALL ON THE FLORIDA
 COAST.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      18/2100Z 24.6N  81.9W    50 KT
  12HR VT     19/0600Z 25.8N  82.0W    60 KT
  24HR VT     19/1800Z 27.4N  81.9W    55 KT...INLAND
  36HR VT     20/0600Z 28.8N  81.7W    40 KT...INLAND
  48HR VT     20/1800Z 30.0N  81.5W    35 KT...INLAND
  72HR VT     21/1800Z 31.0N  81.5W    30 KT...INLAND
  96HR VT     22/1800Z 32.0N  82.5W    25 KT...INLAND
 120HR VT     23/1800Z 33.0N  84.0W    20 KT...INLAND REMNANT LOW
  
 $$
 FORECASTER BEVEN