270 
 WTNT41 KNHC 172105
 TCDAT1
 TROPICAL STORM FAY DISCUSSION NUMBER   9
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062008
 500 PM EDT SUN AUG 17 2008
  
 FAY HAS BECOME A LITTLE BETTER ORGANZIED IN SATELLITE AND RADAR
 IMAGERY THIS AFTERNOON...WITH INCREASED CURVED BANDS OF CONVECTION
 NEAR THE CENTER IN THE NORTHEASTERN SEMICIRCLE.  HOWEVER...THERE
 ARE SINGS OF SOUTHWESTERLY VERTICAL WIND SHEAR AND DRY AIR
 ENTRAINMENT IN THE WESTERN SEMICIRCLE...WHERE THERE IS LITTLE IN
 THE WAY OF ORGANIZED CONVECTION OR STRONG WINDS.  AN AIR FORCE
 RESERVE HURRICANE HUNTER AIRCRAFT RECENTLY REPORTED A CENTRAL
 PRESSURE OF 1003 MB...ALTHOUGH THE PLANE HAS NOT YET SAMPLED THE
 WINDS IN THE NORTHEASTERN QUADRANT.  THE INITIAL INTENSITY REMAINS
 45 KT BASED ON CONTINUITY AND A 45 KT SATELLITE INTENSITY ESTIMATE
 FROM TAFB.
 
 THE CENTER OF FAY SURGED TOWARD THE WEST-NORTHWEST DURING THE
 DAY...AT ONE TIME MOVING BETWEEN 18-20 KT.  THAT MOTION APPEARS TO
 HAVE ENDED...AND THE INITIAL MOTION FOR THIS ADVISORY IS A SOMEWHAT
 UNCERTAIN 300/13.  FAY IS APPROACHING A DEVELOPING WEAKNESS IN A
 LOW/MID LEVEL RIDGE OVER THE GULF OF MEXICO...WHICH IS DEVELOPING
 DUE TO A MID/UPPER-LEVEL TROUGH OVER THE SOUTHERN UNITED STATES. 
 THIS PATTERN SHOULD ALLOW FAY TO TURN MORE NORTHWARD AFTER 24 HR...
 BUT THERE REMAINS SIGNIFICANT DISAGREEMENT BETWEEN THE MODELS ON
 HOW MUCH OF A TURN WILL OCCUR.  THE ECMWF AND CANADIAN MODELS
 CONTINUE TO FORECAST A SHARPER TURN WITH LANDFALL IN SOUTHWESTERN
 FLORIDA...WITH THE ECMWF SHOWING FAY CROSSING TO THE ATLANTIC THEN
 MOVING WESTWARD TO HIT FLORIDA AGAIN.  THE GFS AND GFDL HAVE
 SHIFTED WEST SINCE THEIR PREVIOUS RUNS...WHILE THE UKMET HAS
 SHIFTED A LITTLE TO THE EAST.  THESE MODELS HAVE JOINED THE HWRF IN
 CALLING FOR A TRACK NEAR OR JUST OVER THE WEST COAST OF THE FLORIDA
 PENINSULA.  THE NOGAPS CONTINUES TO FORECAST A NORTH-NORTHWESTWARD
 MOTION TOWARD THE FLORIDA PANHANDLE.  OVERALL...THE GUIDANCE
 ENVELOPE HAS SHIFTED TO THE WEST SINCE THE PREVIOUS PACKAGE...
 POSSIBLY DUE TO THE CHANGE IN THE INITIAL POSITION CAUSED BY THE
 MOTION SURGE.  THE FORECAST TRACK IS SHIFTED ABOUT 60 N MI TO THE
 WEST OF THE PREVIOUS PACKAGE...BUT LIES TO THE EAST OF THE CENTER
 OF THE GUIDANCE ENVELOPE AND THE CONSENSUS MODELS.  THE NEW TRACK
 IS IN BEST AGREEMENT WITH THE HWRF.
  
 THE INTENSITY FORECAST REMAINS PROBLEMATIC.  THE SHIPS MODEL NOW
 FORECASTS PERSISTENT WIND SHEAR DURING THE FORECAST PERIOD...WITH
 PERHAPS A PERIOD OF LIGHTER SHEAR FROM 18-48 HR.  THE LARGE-SCALE
 MODELS HAVE A VARIETY OF SOLUTIONS FOR THE CURRENT UPPER-LEVEL
 TROUGH WEST OF FAY OVER THE GULF OF MEXICO AND THE CARIBBEAN...WITH
 NO CLEAR EVIDENCE AT THIS TIME OF WHICH IS CORRECT.  IT APPEARS THE
 SHEAR WILL BE LIGHT ENOUGH TO ALLOW FAY TO GRADUALLY STRENGTHEN AS
 SHOWN IN THE GFDL MODEL...AND THE NEW INTENSITY FORECAST THUS CALLS
 FOR INTENSIFICATION ALONG THOSE LINES.  IT SHOULD BE NOTED THAT THE
 HWRF CALLS FOR FAY TO BECOME A CATEGORY 2 HURRICANE OVER THE
 EASTERN GULF OF MEXICO...WHILE THE SHIPS MODEL FORECAST A PEAK JUST
 BELOW HURRICANE STRENGTH.
 
 THE FORECAST TRACK SITUATION IS SIMILAR TO THAT OF HURRICANE CHARELY
 FROM AUGUST 2004...IN THAT A SMALL CHANGE IN THE TRACK OF THE STORM
 COULD MAKE A BIG DIFFERENCE IN THE EVETUAL LANDFALL LOCATION.  THE
 NHC WIND SPEED PROBABILITIES PRODUCT SHOWS ABOUT AN EQUAL CHANCE OF
 HURRICANE-FORCE WINDS FOR THE ENTIRE WEST COAST OF THE FLORIDA
 PENINSULA.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      17/2100Z 21.0N  80.2W    45 KT
  12HR VT     18/0600Z 22.3N  81.7W    50 KT...INLAND
  24HR VT     18/1800Z 23.8N  82.8W    55 KT...OVER WATER
  36HR VT     19/0600Z 25.3N  83.1W    65 KT
  48HR VT     19/1800Z 27.0N  83.2W    75 KT
  72HR VT     20/1800Z 30.0N  83.0W    65 KT...INLAND
  96HR VT     21/1800Z 33.5N  82.0W    30 KT...INLAND
 120HR VT     22/1800Z 37.0N  82.0W    20 KT...INLAND REMNANT LOW
  
 $$
 FORECASTER BEVEN