Tropical Storm Fay Advisory 3, Plus Forecast Discussion, Fay Remains A Threat To Florida

BULLETIN
TROPICAL STORM FAY ADVISORY NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062008
5:00 AM EDT SAT AUG 16 2008
FAY WILL CROSS HAITI AND EMERGE OVER WATER LATER TODAY...
AT 5 AM EDT, 9:00 UTC, THE TROPICAL STORM WARNING FOR THE COAST OF THE
DOMINICAN REPUBLIC FROM EAST OF CABO FRANCES VIEJO ON THE NORTHERN COAST TO
SAN PEDRO DE MACORIS ON THE SOUTHERN COAST HAS BEEN DISCONTINUED. A TROPICAL
STORM WARNING REMAINS IN EFFECT ALONG THE NORTHERN COAST OF THE DOMINICAN
REPUBLIC FROM CABO FRANCES VIEJO WESTWARD TO THE NORTHERN BORDER WITH HAITI,
AND FOR THE ENTIRE COAST OF HAITI. A TROPICAL STORM WARNING IS ALSO IN
EFFECT FOR THE TURKS AND CAICOS ISLANDS, THE SOUTHEASTERN BAHAMAS AND THE
CUBAN PROVINCES OF GUANTANAMO, SANTIAGO DE CUBA AND GRANMA.
A TROPICAL STORM WATCH IS IN EFFECT FOR THE CUBAN PROVINCES OF HOLGUIN AND
LAS TUNAS, AND FOR THE CENTRAL BAHAMAS. TROPICAL STORM CONDITIONS ARE ALSO
POSSIBLE IN THE PROVINCES OF CENTRAL CUBA WITHIN THE NEXT 36 HOURS.
INTERESTS IN WESTERN CUBA, THE FLORIDA KEYS AND THE SOUTHERN FLORIDA
PENINSULA SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. FOR STORM INFORMATION
SPECIFIC TO YOUR AREA, PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL WEATHER
OFFICE.
AT 5:00 AM EDT, 9:00 UTC, THE CENTER OF TROPICAL STORM FAY WAS LOCATED NEAR
LATITUDE 18.7 NORTH, LONGITUDE 72.0 WEST, OR ABOUT 20 MILES, 35 KM,
EAST-NORTHEAST OF PORT AU PRINCE HAITI AND ABOUT 235 MILES, 375 KM,
EAST-SOUTHEAST OF GUANTANAMO CUBA. FAY IS MOVING TOWARD THE WEST NEAR 14
MPH, 22 KM/HR. A TURN TOWARD THE WEST-NORTHWEST IS EXPECTED LATER TODAY,
FOLLOWED BY A TURN TOWARD THE NORTHWEST BY SUNDAY NIGHT. ON THIS TRACK, THE
CENTER OF FAY WILL MOVE ACROSS HAITI THIS MORNING, AND WILL BE MOVING NEAR
THE SOUTHERN COAST OF EASTERN AND CENTRAL CUBA TONIGHT AND SUNDAY.
DATA FROM AN AIR FORCE RECONNAISSANCE AIRCRAFT INDICATE THAT MAXIMUM
SUSTAINED WINDS REMAIN NEAR 45 MPH, 75 KM/HR, WITH HIGHER GUSTS. FAY COULD
WEAKEN SLIGHTLY WHILE MOVING OVER HISPANIOLA THIS MORNING, BUT SOME
STRENGTHENING IS POSSIBLE LATER TODAY AND ON SUNDAY AFTER THE CENTER MOVES
BACK OVER WATER. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 105 MILES,
165 KM FROM THE CENTER. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB,
29.74 INCHES.
TIDES OF 1 TO 2 FEET ABOVE NORMAL CAN BE EXPECTED IN THE WARNING AREA IN
AREAS OF ONSHORE FLOW. FAY IS EXPECTED TO PRODUCE TOTAL RAINFALL
ACCUMULATIONS OF 4 TO 8 INCHES OVER HISPANIOLA, EASTERN AND CENTRAL CUBA,
JAMAICA AND THE NORTHERN CAYMAN ISLANDS, WITH ISOLATED MAXIMUM AMOUNTS OF 12
INCHES. THESE RAINS COULD PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES.
REPEATING THE 5:00 AM EDT POSITION, 18.7 N, 72.0 W. MOVEMENT TOWARD, WEST
NEAR 14 MPH. MAXIMUM SUSTAINED WINDS, 45 MPH. MINIMUM CENTRAL PRESSURE,
1007 MB. AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 8:00 AM EDT, FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 11:00
AM EDT.
TROPICAL STORM FAY DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062008
5:00 AM EDT SAT AUG 16 2008
EVEN THOUGH WE CANNOT DETERMINE EXACTLY WHERE THE CENTER OF FAY IS LOCATED,
SATELLITE IMAGERY AND DATA FROM AN AIR FORCE RECONNAISSANCE AIRCRAFT SUGGEST
IT IS STILL INLAND OVER SOUTH-CENTRAL HISPANIOLA NEAR THE BORDER BETWEEN THE
DOMINICAN REPUBLIC AND HAITI. THE AIR FORCE PLANE CIRCUMNAVIGATED THE
ENTIRE ISLAND OF HISPANIOLA DURING THE PAST FEW HOURS, ENDURING SOME RATHER
TURBULENT CONDITIONS, ESPECIALLY WITHIN THE STRONGEST THUNDERSTORMS NEAR THE
SOUTHERN COAST AND WE APPRECIATE THE HARD WORK OF THE CREW. FLIGHT-LEVEL
AND SFMR DATA FROM THE AIRCRAFT SUPPORT MAINTAINING THE INTENSITY AT 40 KT.
FAY REMAINS BENEATH A LARGE UPPER-LEVEL ANTICYCLONE, RESULTING IN
WELL-ESTABLISHED OUTFLOW ALOFT, AND DESPITE THE INTERACTION WITH MOUNTAINOUS
TERRAIN, THE STORM HAS A RELATIVE WELL-ORGANIZED APPEARANCE IN SATELLITE
IMAGERY.
THE SYSTEM APPEARS TO BE CONTINUING WESTWARD AT ABOUT 270/12 TO THE SOUTH OF
A NARROW MID-LEVEL RIDGE OVER THE WESTERN ATLANTIC. THE SYNOPTIC REASONING,
DYNAMICAL MODEL TRACKS AND THE OFFICIAL FORECAST TRACK ARE NOT SIGNIFICANTLY
CHANGED FROM THE PREVIOUS ADVISORY. ALL OF THE MODELS FORECAST THE MID- TO
UPPER-LEVEL TROUGH OVER THE EASTERN U.S. TO GRADUALLY ERODE THE RIDGE DURING
THE NEXT COUPLE OF DAYS, ALLOWING FAY TO TURN TO THE RIGHT INTO THE
WEAKNESS, EVENTUALLY LEADING TO A NORTH-NORTHWESTWARD MOTION IN 3-5 DAYS.
THE NEW OFFICIAL TRACK IS VERY CLOSE TO THE PREVIOUS ONE AND TO THE MODEL
CONSENSUS, BUT THERE ARE RELIABLE MODELS ON BOTH SIDES OF THAT TRACK. THE
GFDL AND HWRF TRACKS HEAD UP THE WESTERN PORTION OF THE FLORIDA PENINSULA IN
A FEW DAYS, WHILE THE GFS AND UKMET ARE FARTHER WEST OVER THE EASTERN GULF
OF MEXICO. IN THE SHORTER TERM, THE MODELS ALSO DO NOT AGREE ON WHETHER THE
CENTER OF FAY WILL PASS OVER OR JUST SOUTH OF SOUTHEASTERN CUBA BEFORE
TURNING NORTHWESTWARD. THESE DIFFERING SOLUTIONS AGAIN HIGHLIGHT THE
PITFALLS OF FOCUSING TOO MUCH ON THE EXACT OFFICIAL FORECAST TRACK,
ESPECIALLY AT THE LONGER RANGES.
INTENSITY FORECASTING IS ALWAYS DIFFICULT, BUT IN THIS CASE, IS MADE EVEN
MORE COMPLICATED BY THE LIKELY INTERACTIONS WITH LAND DURING THE NEXT FEW
DAYS. ATMOSPHERIC AND OCEAN CONDITIONS ALONG THE FORECAST TRACK APPEAR
RATHER CONDUCIVE FOR STRENGTHENING, SO THE MORE TIME FAY SPENDS OVER WATER,
THE STRONGER IT IS LIKELY TO BECOME AND VICE VERSA. DYNAMICAL MODEL FIELDS
INDICATE THAT THE WEAK-SHEAR ENVIRONMENT AROUND FAY SHOULD PERSIST
THROUGHOUT MOST OF THE FIVE-DAY FORECAST PERIOD, WITH PERHAPS A MODEST BUT
TEMPORARY INCREASE IN SHEAR IN ROUGHLY 48 HOURS. WHEN FAY IS OVER WATER,
THOSE WATERS WILL BE VERY WARM. SINCE THE OFFICIAL TRACK IMPLIES AMPLE
AMOUNT OF TIME OVER WATER, STEADY STRENGTHENING IS FORECAST IN A MANNER
SIMILAR TO THE GFDL MODEL. FAY COULD BE WEAKER THAN FORECAST IF ITS STAY
OVER HISPANIOLA HAS SUBSTANTIALLY DISRUPTED THE CIRCULATION, OR IF IT MOVES
FARTHER NORTH AND EAST AND SPENDS MORE TIME OVER CUBA. A TRACK FARTHER
SOUTH AND WEST, HOWEVER, COULD ALLOW FAY TO GET STRONGER THAN WHAT IS SHOWN
BELOW.