[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 230300
TCDAT1
TROPICAL STORM FAY DISCUSSION NUMBER  30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062008
1100 PM EDT FRI AUG 22 2008

THE CENTER OF FAY CROSSED THE COAST OF THE BIG BEND AREA OF FLORIDA
NEAR KEATON BEACH AT ABOUT 2200 UTC...EMERGING OVER APALACHEE BAY
IN THE EXTREME NORTHEASTERN GULF OF MEXICO.  THE CIRCULATION CENTER
ITSELF IS NOT ESPECIALLY WELL-DEFINED IN RADAR IMAGERY...BUT A
POTENT NARROW BAND OF CONVECTION HAS PERSISTED OVER WATER IN THE
SOUTHERN SEMICIRCLE.  FLIGHT-LEVEL AND SFMR DATA FROM AN AIR FORCE
RECONNAISSANCE AIRCRAFT SUGGEST THE MAXIMUM WINDS IN THIS BAND ARE
ABOUT 45 KT...SO THAT IS THE INITIAL INTENSITY.  AN EXPANSIVE RAIN
SHIELD EXTENDS WELL INLAND TO THE NORTH OF THE CENTER...AND WHILE
WINDS ARE GUSTY IN THOSE REGIONS...SUSTAINED WINDS OF TROPICAL
STORM FORCE DO NOT APPEAR TO BE OCCURRING INLAND.

THE AIRCRAFT FIXES LEAD TO AN INITIAL MOTION ESTIMATE OF 270/7...AS
FAY LUMBERS ALONG TO THE WEST ALONG THE SOUTHERN PERIPHERY OF A
MID-LEVEL RIDGE OVER THE NORTHEASTERN UNITED STATES.  THAT RIDGE
SHOULD CONTINUE TO FORCE FAY WESTWARD FOR THE NEXT COUPLE OF DAYS
AT SPEED SIMILAR TO THAT CURRENTLY OBSERVED.  AS A RESULT...FAY
WILL BE SKIRTING THE FLORIDA PANHANDLE...ALABAMA...AND MISSISSIPPI
COASTS DURING THE NEXT COUPLE OF DAYS.  THE VARIOUS TRACK MODELS
ARE IN QUITE GOOD AGREEMENT ON THIS SCENARIO THROUGH ABOUT 48
HOURS.  THEREAFTER...MODEL GUIDANCE FORECASTS THE STEERING CURRENTS
TO COLLAPSE AGAIN...AND VARIOUS SOLUTIONS ENSUE REGARDING WHERE AND
HOW FAST A WEAKENING FAY WILL GO.  MOST OF THE MODELS SHOW
RELATIVELY LITTLE NET MOTION ON DAYS 3 THROUGH 5.  THE NEW OFFICIAL
TRACK FORECAST ONLY SHOWS A SLOW BEND TO THE NORTH BY THE END OF
THE FORECAST PERIOD.

THE CENTER OF FAY WILL BE NEAR OR OVER WATER DURING THE NEXT 48
HOURS OR SO...WHILE ATMOSPHERIC CONDITIONS REMAIN CONDUCIVE TO
SUPPORT A TROPICAL STORM.  THERE IS NO OBVIOUS REASON TO FORECAST
WEAKENING DURING THE NEXT DAY OR SO...GIVEN THAT FAY WILL REMAIN
NEAR THE COAST AND APPEARS NOT LIKELY TO CHANGE MUCH IN STRUCTURE.
BEYOND 24 HOURS...INCREASING LAND INTERACTION AND A GRADUAL RAMPING
UP OF VERTICAL WIND SHEAR SHOULD INDUCE A WEAKENING TREND.  THE NEW
OFFICIAL FORECAST OF FAY TO REMAIN A TROPICAL STORM FOR THE NEXT
COUPLE OF DAYS REQUIRES A WESTWARD EXTENSION OF THE COASTAL WATCHES
AND WARNINGS.

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      23/0300Z 29.7N  84.2W    45 KT
 12HR VT     23/1200Z 29.8N  85.3W    45 KT...NEAR COAST
 24HR VT     24/0000Z 30.1N  86.9W    45 KT...OVER WATER
 36HR VT     24/1200Z 30.5N  88.5W    40 KT...NEAR COAST
 48HR VT     25/0000Z 30.5N  90.0W    35 KT...INLAND
 72HR VT     26/0000Z 30.5N  91.0W    30 KT...INLAND
 96HR VT     27/0000Z 31.5N  91.5W    25 KT...INLAND
120HR VT     28/0000Z 33.0N  90.5W    25 KT...REMNANT LOW

$$
FORECASTER KNABB

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