[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 152127
TCDAT1
TROPICAL STORM FAY DISCUSSION NUMBER   1...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062008
500 PM EDT FRI AUG 15 2008

...CORRECTION OF THE 72H POSITION TEXT

REPORTS FROM NOAA AND AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT
INDICATE THAT THE CIRCULATION ASSOCIATED WITH THE LOW PRESSURE AREA
IN THE MONA PASSAGE BECAME BETTER DEFINED...WITH 1500 FT
FLIGHT-LEVEL WINDS OF 49 KT TO THE NORTHEAST OF THE CENTER.  THE
AIRCRAFT ALSO FOUND ENOUGH WESTERLY WINDS SOUTH OF THE CENTER TO
JUSTIFY CALLING THE SYSTEM A TROPICAL CYCLONE...ALTHOUGH THESE
WESTERLIES ONLY EXTEND ABOUT 45 N MI SOUTH OF THE CENTER.  BASED ON
THIS...THE LOW WAS UPGRADED TO TROPICAL STORM FAY...THE SIXTH OF
THE ATLANTIC SEASON.

THE INITIAL MOTION IS 275/12.  FAY IS ON THE SOUTH SIDE OF A
LOW/MID-LEVEL RIDGE...WITH THE LARGE-SCALE MODELS FORECASTING A
WEAKNESS TO DEVELOP IN THE RIDGE OVER THE EASTERN GULF OF MEXICO
OR FLORIDA DURING THE NEXT 48-96 HR.  WHILE ALL THE TRACK GUIDANCE
AGREES THAT THIS WEAKNESS WILL CAUSE FAY TO TURN NORTH-
NORTHWESTWARD TO NORTHWARD BY THE END OF THE FORECAST PERIOD...THIS
IS A CONSIDERABLE SPREAD IN THE GUIDANCE ON JUST WHERE FAY WILL
TRACK.  THE NAM CALLS FOR FAY TO PASS EAST OF THE FLORIDA
PENINSULA...WHILE THE HWRF CALLS FOR LANDFALL IN SOUTHEASTERN
FLORIDA.  THE GFDL AND NOGAPS FORECAST A MORE WESTWARD TRACK TOWARD
THE NORTHERN GULF COAST...WHILE THE GFS...ECMWF...AND THE MODEL
CONSENSUS FORECASTS FAY TO TRACK NEAR OR OVER THE WEST COAST OF
FLORIDA.  COMPLICATING MATTERS IS THE POSSIBILITY OF LAND
INTERACTION CAUSING ERRATIC MOTION AND REFORMATION OF THE CENTER.
THE FORECAST TRACK WILL FOLLOW THE MODEL CONSENSUS AND CALL FOR FAY
TO CROSS HISPANIOLA AND THE EASTERN PORTION OF CUBA...THEN PASS
NEAR OR OVER THE FLORIDA KEYS AND THE WEST COAST OF FLORIDA.

THE LARGE-SCALE MODELS FORECAST FAY TO BE IN A LIGHT VERTICAL WIND
SHEAR ENVIRONMENT FOR THE NEXT 72-96 HR.  THUS...THE INTENSITY WILL
BE CONTROLLED BY LAND INTERACTION AND INTERNAL STRUCTURE.  THE
FORECAST TRACK CALLS FOR FAY TO CROSS LARGE PORTIONS OF HISPANIOLA
AND CUBA...WHICH SHOULD LIMIT INTENSIFICATION.  SIGNIFICANT
STRENGTHENING IS EXPECTED WHEN THE CENTER EMERGES FROM THE NORTH
COAST OF CUBA...ALTHOUGH IT IS UNCERTAIN HOW WELL ORGANIZED THE
STORM WILL BE AT THAT TIME.  THE INTENSITY FORECAST WILL CALL FOR A
PEAK INTENSITY OF 60 KT...AND THERE IS ABOUT A 30 PERCENT CHANCE
THAT FAY COULD BECOME A HURRICANE AT THAT TIME.  IT SHOULD BE NOTED
THAT ANY DEVIATIONS FROM THE FORECAST TRACK THAT ALLOW FAY MORE
TIME OVER WATER WOULD RESULT IN A STORM STRONGER THAN CURRENTLY
FORECAST.


FORECAST POSITIONS AND MAX WINDS

INITIAL      15/2100Z 18.5N  69.4W    35 KT...INLAND
 12HR VT     16/0600Z 18.9N  71.3W    35 KT...INLAND
 24HR VT     16/1800Z 19.4N  74.1W    35 KT...OVER WATER
 36HR VT     17/0600Z 19.9N  76.5W    40 KT
 48HR VT     17/1800Z 20.7N  78.2W    40 KT
 72HR VT     18/1800Z 23.5N  81.0W    40 KT...NORTH COAST OF CUBA
 96HR VT     19/1800Z 26.5N  82.0W    60 KT...INLAND OVER FLORIDA
120HR VT     20/1800Z 30.0N  83.0W    40 KT...INLAND

$$
FORECASTER BEVEN



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