000 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