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000
FXUS62 KKEY 061444
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
945 AM EST FRI DEC 6 2013

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF
900 AM DEPICT THE CENTER OF A DEEP FULL LATITUDINAL POLAR TROUGH
CENTERED OVER SOUTHERN SASKATCHEWAN...WITH AN APPROXIMATE 100-150
KNOT SOUTHERN STREAM OF THE JET AT 250 MB MOVING ALONG THE BASE OF
THIS MASSIVE POLAR GYRE FROM NORTHERN OLD MEXICO NORTHEASTWARD INTO
SOUTHEASTERN CANADA. CLOSER TO THE KEYS...THERE REMAINS A STALWART
CENTER OF A DEEP AND WARM ANTICYCLONE CENTERED OVER PINAR DEL RIO
CUBA.

AT THE SURFACE AND IN THE LOWER LEVELS...SURFACE TO 700 MB...LATEST
AVAILABLE IR IMAGERY OVERLAID WITH SURFACE LAND AND MARINE
OBSERVATIONS AS WELL AS ANALYSIS DETAILS THE CENTER OF THE ARCTIC
1048 MB SURFACE ANTICYCLONE REMAINS OVER THE SOUTHERN PRAIRIE
PROVINCES. AN  ARCTIC COLD FRONT IS WELL OUT AHEAD THE
FEATURE...EXTENDING FROM EASTERN CANADA SOUTH SOUTHWESTWARD TO THE
WESTERN GULF OF MEXICO. YET CLOSER TO THE KEYS...THE WESTERN
PERIPHERY OF A WEAKER 1020 MB WESTERN ATLANTIC SURFACE RIDGE AXIS
CURRENTLY POKES ACROSS THE SOUTH CENTRAL FLORIDA PENINSULA FROM THE
WEST CENTRAL ATLANTIC. LOCALLY...AN UNDULATION IN THE SURFACE TO 850
MB LEVEL IS RESPONSIBLE FOR A FEW CONFLUENT BANDS OF SHOWERS OFF OF
THE LOWER AND MIDDLE KEYS. THE 12Z MORNING SOUNDING AT KEY WEST
ILLUSTRATED A TYPICALLY DRY WITH PWAT (PRECIPITABLE WATER) AT 1.10
INCHES WITH MODERATE TO FRESH SOUTHEASTERLY FLOW FROM THE SURFACE TO
5 KFT...AND A 4 DEGREE C INVERSION FROM 700 TO 675 MB.

.CURRENTLY...AS OF 900 AM...RADAR DETECTS A BAND OF SHOWERS OF
MODERATE RAIN SITUATED ACROSS THE FLORIDA STRAITS JUST OFF THE
FLORIDA REEF SOUTH OF THE LOWER KEYS. TEMPERATURES AND HUMIDITY
LEVELS OVER THE ISLAND CHAIN ARE ALREADY EXCEEDINGLY WARM FOR EARLY
DECEMBER...NEAR 80 DEGREES WITH DEWPOINTS AROUND 70. AVAILABLE C-MAN
OBSERVATIONS...SHIP OBSERVATIONS...AND ASCAT DATA SUGGEST THAT
SOUTHEAST WINDS ARE NEAR 20 KNOTS IN THE FLORIDA STRAITS...BUT
REMAIN BETWEEN 15 AND 20 KNOTS AND GUSTY IN HAWK CHANNEL. ISLAND
SENSORS ARE RECORDING

.SHORT TERM (REST OF TODAY)...A LAST MINUTE UPDATE MAY BE MADE TO
REMOVE SHOWER THREAT OVER THE ISLANDS...AS ITS POSSIBLE THAT ENOUGH
DRY AIR WILL MIX DOWN FROM THE MID-LEVELS BY NOON. OTHERWISE...THE
NEAR BREEZY/BREEZY CONDITIONS WILL CONTINUE OVER THE
ISLANDS...ALLOWING FOR TEMPERATURES TO REACH INTO THE LOWER 80S ONCE
AGAIN. A SLIGHT CHANCE FOR SHOWERS WOULD LIKELY REMAIN ACROSS THE
FLORIDA STRAITS GIVEN THE PRESENCE OF THE PERTURBATION PLUS AMPLE
LOW LEVEL MOISTURE AND FLUXES.

&&

.MARINE...A SMALL CRAFT ADVISORY WILL BE NEEDED ACROSS THE FLORIDA
STRAITS OUT 60 NM FROM OCEAN REEF TO 20 NM WEST OF THE DRY TORTUGAS
THROUGH THE AFTERNOON FOR SUSTAINED EAST TO SOUTHEAST WINDS NEAR 20
KNOTS...DECREASING TO NEAR 15 KNOTS LATE. A CAUTIONARY HEADLINE WILL
BE REQUIRED INSIDE HAWK CHANNEL FOR SUSTAINED EAST TO SOUTHEAST
WINDS BETWEEN 15 AND 20 KNOTS...DECREASING TO 15 KNOTS LATE.
SUSTAINED WINDS BETWEEN 10 AND 15 KNOTS WILL BE EXPECTED ACROSS THE
SHALLOWER WATERS OF FLORIDA BAY AND THE GULF WATERS NORTH OF THE
LOWER AND MIDDLE KEYS...AS WELL AS THE OFFSHORE GULF WATERS.

&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH TODAY AND TONIGHT.
SUSTAINED EAST TO SOUTHEAST WINDS NEAR 20 KNOTS FROM JUST OFF THE
SURFACE TO ABOUT 5000 FEET WILL DECREASE TO NEAR 15 KNOTS THIS
AFTERNOON.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1876...THE LOW TEMPERATURE
IN KEY WEST WAS 49 DEGREES. THIS SET THE DAILY RECORD FOR MINIMUM
TEMPERATURE MEASURED IN KEY WEST ON DECEMBER 6TH...A RECORD WHICH
STILL STANDS 137 YEARS LATER. TEMPERATURE RECORDS AT KEY WEST DATE
BACK TO 1872.

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SCA GMZ052-055 & GMZ072-075
&&

$$

PUBLIC/MARINE/GRIDS..........FUTTERMAN
AVIATION/NOWCASTS/CLIMATE....BS
UPPER AIR/DATA ACQUISITION...PARKE

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