[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 171507
TCDAT1
TROPICAL STORM FAY DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062008
1100 AM EDT SUN AUG 17 2008

FAY APPEARS A LITTLE RAGGED IN SATELLITE IMAGERY THIS MORNING...WITH
THE MAIN CONVECTION IN BANDS WELL SOUTHEAST OF THE CENTER AND ONLY
A SMALL AMOUNT OF CONVECTION NEAR THE CENTER.  SATELLITE INTENSITY
ESTIMATES FROM TAFB AND SAB ARE 45 AND 35 KT RESPECTIVELY...AND A
SYNOPTIC OBSERVATION FROM CABO CRUZ CUBA REPORTED 45 KT.  BASED ON
THIS...THE INITIAL INTENSITY REMAINS 45 KT.

THE INITIAL MOTION IS 290/11...A LITTLE MORE TO THE RIGHT THAN 6 HR
AGO.  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 NORTHERN GULF COAST.  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...GFS...AND GFDL FORECAST A
NORTHEASTWARD TURN TAKING FAY ACROSS THE FLORIDA PENINSULA INTO THE
ATLANTIC.  THE HWRF...UKMET...AND CANADIAN MODELS CALL FOR A
NORTHWARD MOTION OVER OR JUST WEST OF THE FLORIDA PENINSULA INTO
THE SOUTHEASTERN UNITED STATES.  THEN...THE NOGPAS CALLS FOR A
NORTH-NORTHWESTWARD MOTION TOWARD THE FLORIDA PANHANDLE.
OVERALL...THE MODEL CONSENSUS HAS CHANGED LITTLE FOR THE FIRST
36-48 HR OF THE FORECAST PERIOD...THEN SHIFTED A LITTLE TO THE EAST
THEREAFTER.  THE NEW FORECAST TRACK IS THUS SIMILAR TO THE PREVIOUS
TRACK FOR THE FIRST 48 HR...THEN SHIFTED A LITTLE TO THE EAST OF
THE PREVIOUS TRACK.

THE INTENSITY FORECAST REMAINS PROBLEMATIC.  UPPER-LEVEL WINDS HAVE
BECOME A LITTLE LESS FAVORABLE FOR DEVELOPMENT THIS MORNING...WITH
THE SHIPS MODEL SHOWING 10 TO 15 KT OF WESTERLY VERTICAL WIND
SHEAR.  HOWEVER...THE SHEAR IS STILL LIGHT ENOUGH FOR STRENGTHENING
TO OCCUR IF FAY CAN DEVELOP AN INNER CORE.  THE SHIPS AND GFDL
MODELS FORECAST FAY TO BE AT OR NEAR HURRICANE STRENGTH IN 36-48
HR...WHILE THE HWRF...WHICH KEEPS FAY OVER WATER LONGER...FORECASTS
A BORDERLINE CATEGORY 1/2 HURRICANE IN 48-60.  THE INTENSITY
FORECAST CALLS FOR GRADUAL STRENGTHENING IN AGREEMENT WITH THE
SHIPS MODEL...WITH FAY REACHING HURRICANE STRENGTH BEFORE LANDFALL
ON THE WEST COAST OF FLORIDA.  FAY COULD STRENGTHEN MORE THAN
FORECAST IF A WELL-DEFINED INNER CORE FORMS...OR IF IT TRACKS MORE
TO THE WEST AND STAYS LONGER OVER WATER.

FORECAST POSITIONS AND MAX WINDS

INITIAL      17/1500Z 20.5N  78.6W    45 KT
 12HR VT     18/0000Z 21.3N  80.0W    50 KT
 24HR VT     18/1200Z 22.9N  81.4W    55 KT...INLAND
 36HR VT     19/0000Z 24.5N  82.0W    60 KT...OVER WATER
 48HR VT     19/1200Z 26.2N  82.2W    70 KT
 72HR VT     20/1200Z 29.5N  82.0W    50 KT...INLAND
 96HR VT     21/1200Z 32.5N  81.5W    35 KT...INLAND
120HR VT     22/1200Z 36.0N  81.5W    20 KT...INLAND REMNANT LOW

$$
FORECASTER BEVEN
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