000 WTNT41 KNHC 220905 TCDAT1 TROPICAL STORM FAY DISCUSSION NUMBER 27 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062008 500 AM EDT FRI AUG 22 2008 SATELLITE...RADAR...AND SURFACE OBSERVATIONS SHOW LITTLE CHANGE IN THE STRUCTURE OF FAY DURING THE PAST SEVERAL HOURS...WITH THE STRONGEST WINDS 50 N MI OR MORE FROM THE CENTER AND THE STRONGEST RAINBANDS OVER THE ATLANTIC WELL TO THE EAST OF THE CENTER. WSR-88D DOPPLER WINDS DATA SUGGEST A SLIGHT DECREASE IN THE INTENSITY...WHICH IS SET AT 45 KT IN THIS ADVISORY. THE CIRRUS OUTFLOW IS GOOD IN THE NORTHERN SEMICIRCLE AND FAIR TO POOR ELSEWHERE. FAY HAS MOVED A LITTLE FASTER DURING THE PAST 6 HR WITH THE INITIAL MOTION OF 280/5. THE CYCLONE IS ON THE SOUTH SIDE OF AN AMPLIFYING DEEP-LAYER RIDGE OVER THE EASTERN UNITED STATES...AND THE LARGE-SCALE MODELS FORECAST THIS FEATURE TO PERSIST FOR THE NEXT 48-72 HR. THIS PATTERN SHOULD CAUSE FAY TO MOVE SLOWLY WESTWARD...WITH ALL TRACK GUIDANCE AGREEING WITH THIS SCENARIO. THE NEW FORECAST TRACK CALLS FOR FAY TO MOVE A LITTLE FARTHER WEST THAN PREVIOUSLY...AS THE GUIDANCE SHOWS A MORE WESTWARD MOTION BETWEEN 48 AND 72 HR THAN IT DID 6 HR AGO. AFTER 72 HR... MID/UPPER-LEVEL TROUGHING OVER THE CENTRAL UNITED STATES IS FORECAST TO WEAKEN THE RIDGE...WHICH SHOULD ALLOW FAY TO TURN NORTHEASTWARD OR EASTWARD. THE GUIDANCE SHOWS CONSIDERABLE SPREAD AT THIS POINT...SO THE TRACK FORECAST WILL CALL FOR A SLOW NORTHEASTERLY MOTION. DUE TO FAY'S PROXIMITY TO LAND...THE INTENSITY FORECAST IS DEPENDENT ON THE EXACT TRACK AND STRUCTURE. ON THE FORECAST TRACK...FAY WILL NOT LIKELY BE OVER WATER LONG ENOUGH TO INTENSITY. ON THIS BASIS...THE INTENSITY FORECAST CALLS FOR THE SYSTEM TO MOVE ALONG THE NORTHERN GULF COAST AS A MINIMAL TROPICAL STORM. IF FAY MOVES TO THE RIGHT OF THE FORECAST TRACK...IT WILL MOVE INLAND EARLIER AND WEAKEN FASTER. IF IT MOVES LEFT OF THE FORECAST TRACK MORE OVER OPEN WATER...IT COULD GET STRONGER THAN FORECAST. HOWEVER... THE CURRENT BROAD STRUCTURE IS LIKELY TO PRECLUDE RAPID INTENSIFICATION. THE LARGE-SCALE MODELS FORECAST WESTERLY SHEAR TO IMPACT FAY STARTING IN ABOUT 72 HR...WHICH SHOULD STOP INTENSIFICATION REGARDLESS OF WHETHER IT IS OVER WATER OR NOT. REGARDLESS OF ITS EXACT TRACK...FAY WILL BE MOVING RATHER SLOWLY DURING THE NEXT SEVERAL DAYS...POSING A SIGNIFICANT HEAVY RAINFALL AND FLOOD HAZARD TO A VERY LARGE AREA. FORECAST POSITIONS AND MAX WINDS INITIAL 22/0900Z 29.6N 82.2W 45 KT...INLAND 12HR VT 22/1800Z 29.7N 83.2W 40 KT...INLAND 24HR VT 23/0600Z 29.8N 84.6W 35 KT 36HR VT 23/1800Z 30.1N 86.1W 35 KT 48HR VT 24/0600Z 30.5N 87.5W 35 KT...INLAND 72HR VT 25/0600Z 31.0N 89.5W 30 KT...INLAND 96HR VT 26/0600Z 31.0N 90.0W 25 KT...INLAND 120HR VT 27/0600Z 32.0N 89.5W 20 KT...INLAND REMNANT LOW $$ FORECASTER BEVEN