[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 162058
TCDAT1
TROPICAL STORM FAY DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062008
500 PM EDT SAT AUG 16 2008

REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER INDICATE THAT FAY
IS A LITTLE WEAKER THAN BELIEVED EARLIER...WITH THE INITIAL
INTENSITY NEAR 35 KT AND THE MINIMUM PRESSURE AT 1006 MB.  THE
SATELLITE APPEARANCE WAS RAGGED A FEW HOURS AGO...BUT A NEW CLUSTER
OF STRONG CONVECTION IS DEVELOPING IN THE SOUTHEASTERN QUADRANT.
THE CIRRUS OUTFLOW IS GOOD IN THE SOUTHEASTERN SEMICIRCLE AND FAIR
ELSEWHERE.

THE INITIAL MOTION IS 280/14.  FAY REMAINS ON THE SOUTH SIDE OF A
LOW/MID-LEVEL RIDGE...WITH THE LARGE-SCALE MODELS FORECASTING A
WEAKNESS IN THE RIDGE OVER THE EASTERN GULF OF MEXICO OR FLORIDA
THAT SHOULD ALLOW FAY TO TURN TOWARD THE NORTH-NORTHWEST OR NORTH
AFTER 36 HR.  THERE IS A LARGE SPREAD IN THE MODEL GUIDANCE ON WHEN
AND HOW SHARPLY FAY WILL TURN.  THE ECMWF AND NAM MODELS REMAIN ON
THE EASTERN SIDE OF THE GUIDANCE ENVELOPE...AND HAVE BEEN JOINED BY
THE GFDL WHICH HAS SHIFTED EASTWARD SINCE THE PREVIOUS RUN.  THESE
MODELS CALL FOR A SOUTHEASTERN FLORIDA LANDFALL.  THE GFS...HWRF...
GFDN...FLORIDA STATE SUPERENSEMBLE...AND THE CONSENSUS MODELS
FORECAST FAY TO CROSS WEST CENTRAL CUBA AND MOVE NEAR OR OVER THE
WEST COAST OF THE FLORIDA PENINSULA.  THE UKMET AND NOGAPS HAVE
BOTH SHIFTED EAST OF THEIR PREVIOUS RUNS...BUT ARE STILL ON THE
WEST SIDE OF THE GUIDANCE ENVELOPE IN CALLING FOR A MOTION TOWARD
THE FLORIDA PANHANDLE.  OVERALL...THE GUIDANCE ENVELOPE AND THE
MODEL CONSENSUS HAS CHANGED LITTLE SINCE THE LAST ADVISORY.  THE
NEW FORECAST TRACK IS A LITTLE FASTER THAN THE PREVIOUS TRACK AND
IS SHIFTED A LITTLE TO THE EAST AFTER THE 48 HR POINT.  EVERYONE IN
THE FLORIDA PENINSULA SHOULD MONITOR THE PROGRESS OF FAY...AS MOST
LOCATIONS THERE HAVE ABOUT THE SAME CHANCES OF EXPERIENCING
HURRICANE-FORCE WINDS ACCORDING TO THE NHC WIND SPEED PROBABILITY
PRODUCT.

WHEN FAY IS OVER WATER...IT APPEARS THAT ATMOSPHERIC CONDITIONS WILL
BE FAVORABLE FOR STRENGTHENING THROUGH 72 HR.  THUS...THE INTENSITY
WILL BE CONTROLLED BY LAND INTERACTION AND THE RESULTING IMPACTS ON
THE STORM STRUCTURE.  ALL GUIDANCE CONTINUES TO FORECAST
STRENGTHENING...AND THE INTENSITY FORECAST FOLLOWS SUIT IN BEST
AGREEMENT WITH THE SHIPS MODEL.  HOWEVER...THIS IS A LOW CONFIDENCE
INTENSITY FORECAST.  FAY COULD STRENGTHEN RAPIDLY IF IT BECOMES
WELL ORGANIZED OVER WATER...SUCH AS WHILE PASSING SOUTH OF CUBA OR
OVER THE STRAITS OF FLORIDA.  ON THE OTHER HAND...IT MIGHT NOT
STRENGTHEN MUCH AT ALL IF LAND INTERACTION PREVENTS ORGANIZATION.
THE INTENSITY FORECAST CALLS FOR FAY TO WEAKEN OVER THE UNITED
STATES AFTER LANDFALL.  SHOULD IT REMAIN OVER WATER AFTER 72
HR...THE LARGE-SCALE MODELS FORECAST INCREASING WESTERLY VERTICAL
SHEAR OVER THE SYSTEM.


FORECAST POSITIONS AND MAX WINDS

INITIAL      16/2100Z 19.3N  75.2W    35 KT
 12HR VT     17/0600Z 19.9N  77.0W    40 KT
 24HR VT     17/1800Z 20.9N  79.1W    50 KT...INLAND
 36HR VT     18/0600Z 22.2N  80.7W    55 KT
 48HR VT     18/1800Z 23.6N  81.6W    55 KT...INLAND
 72HR VT     19/1800Z 27.0N  82.5W    75 KT
 96HR VT     20/1800Z 30.0N  82.5W    50 KT...INLAND
120HR VT     21/1800Z 33.0N  82.5W    35 KT...INLAND

$$
FORECASTER BEVEN



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