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000
FXUS62 KKEY 220128
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
930 PM EDT SUN SEP 21 2014

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY OVERLAID AS OF 900 PM OVERLAID WITH MODEL
STREAMLINE ANALYSIS DEPICTS A DEEP CYCLONIC MID AND UPPER GYRE
ENCOMPASSING THE CONUS EAST OF THE MISSISSIPPI RIVER VALLEY
INCLUDING MUCH OF THE EASTERN GULF OF MEXICO. THE CENTER OF A BROAD
DEEP AND WARM ANTICYCLONE IS POSITIONED OVER NORTHERN OLD MEXICO.
THE EAST...THE CENTER OF ANOTHER DEEP AND WARM BUILDING MID AND
UPPER ANTICYCLONE IS POSITIONED NEAR 30 NORTH 63 WEST. FINALLY A
WEAKENED TUTT (TROPICAL UPPER TROPOSPHERIC TROUGH) LOW IS OVER THE
WESTERN CARIBBEAN SEA. AS A RESULT...ALL OF THE AFOREMENTIONED MID
AND UPPER FEATURES CONVERGE ASYMPTOTICALLY ACROSS THE SOUTHEAST
GULF...AND JUST TO THE WEST OF THE KEYS...WHICH IS ALLOWING FOR SOME
MID AND UPPER DRYING AT POINTS FROM THE CENTRAL FLORIDA STRAITS
EASTWARD.

AT THE SURFACE AND IN THE LOWER TO MIDDLE LEVELS...AS OF 900
PM...WEAK LOW PRESSURE IS DEVELOPING OVER THE GULF STREAM EAST OF
CHARLESTON ALONG A WEAK SURFACE FRONTAL BOUNDARY EXTENDING
SOUTHWESTWARD TO ACROSS CENTRAL FLORIDA. ILL DEFINED BROAD LOWER
PRESSURE IS EVIDENT FROM THE LOWER KEYS JUST TO THE WEST. A TROPICAL
WAVE AXIS WAS ANALYZED IN THE CARIBBEAN SEA 100 MILES WEST OF
JAMAICA. AN FINALLY...A WEAK RIDGING POKES FROM THE CENTRAL ATLANTIC
TO EXTREME SOUTH FLORIDA. AS A RESULT...THE 00Z EVENING SOUNDING WAS
SIMILAR TO 24 HOURS PRIOR...AND WAS VERY MOIST WITH PWAT AT 2.09
INCHES AND LIGHT MOSTLY EAST FLOW FROM THE SURFACE TO 850
MB...BECOMING GENTLE SOUTHWEST TO WEST ABOVE THAT TO 400 MB.

.CURRENTLY...LATEST IR IMAGERY COMBINED WITH RADAR AS OF 900 PM
DETAILS WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS CONFINED
TO WATERS ACROSS THE WESTERN FLORIDA STRAITS AND JUST EXITING THE
NORTH CENTRAL CUBAN COAST NEAR VARADERO. TEMPERATURES ACROSS THE
ISLANDS ARE IN THE LOWER TO MID 80S WITH DEWPOINTS IN THE MID 70S.
C-MAN STATIONS ALONG THE FLORIDA REEF AND SOUTHERN FLORIDA BAY...AS
WELL AS OTHER WEATHER STATIONS AT SMITH SHOAL LIGHT ARE RECORDING
LIGHT MOSTLY EAST WINDS NEAR 5 KNOTS.

.FORECAST...OVERNIGHT...A WEAK PRESSURE PATTERN WILL CONTINUE AT
LEAST ONE MORE NIGHT. AND ALTHOUGH LATEST MODEL FORECAST
SOUNDINGS...18Z...CONTINUES TO ILLUSTRATE DEEP MOISTURE IN THE LOWER
TO MID TROPOSPHERE...(WITH COLUMNAR PWAT AROUND 2.00 INCHES)...THE
BEST FORCING WILL REMAIN ACROSS THE WESTERN PORTIONS OF THE
ISLANDS...THE LOWER KEYS...AND ADJOINING WATERS. REASON FOR THIS IS
THAT AS THE AS THE AFOREMENTIONED WEAK TROPICAL WAVE AXIS CONTINUES
TO MOVE WESTWARD IN LONGITUDE...IT WILL APPROACH THE BROADER LOWER
PRESSURE IN THE SOUTHEASTERN GULF AND YUCATAN CHANNEL AREAS. THE
INTERACTION OF THESE FEATURES WILL PROMOTE DEVELOPMENT OF ADDITIONAL
CLUSTERS OF SHOWERS AND THUNDERSTORMS...ACROSS THE WESTERN FLORIDA
STRAITS FROM THE SEVEN MILE BRIDGE AND SURROUNDING WATERS WESTWARD.

EAST OF THE 7 MILE BRIDGE...LITTLE ACTIVITY IS CURRENTLY UPSTREAM OF
THE MIDDLE AND UPPER KEYS ATTM...AND THE WEAK STORM MOTION WILL NOT
BE FAVORABLE IN GETTING THE SHOWERS NEAR VARADERO INTO THE KEYS.
THEREFORE WILL KEEP MIDDLE OF THE ROAD CHANCE POPS IN PLACE WEST OF
THE 7 MILE BRIDGE...WITH ISOLATED TO THE EAST. THERE IS NO REAL NEED
TO SPLIT THIS IN THE GRIDS AS THE WORDING CAN BE ADJUSTED IN THIS
PARTICULAR CIRCUMSTANCE. SO JUST A MINOR EVENING UPDATE IS
FORTHCOMING.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH TONIGHT AND MONDAY.
SUSTAINED NORTHEAST TO EAST WINDS NEAR 5 KNOTS FROM JUST OFF THE
SURFACE TO ABOUT 3000 FEET WILL INCREASE TO NEAR 10 KNOTS AFTER
MIDNIGHT TONIGHT.

&&

.CLIMATE...
ON THIS DATE IN FLORIDA KEYS WEATHER HISTORY...IN 1948...A CATEGORY
THREE HURRICANE MADE ITS INITIAL UNITED STATES LANDFALL NEAR
SUGARLOAF KEY. THE WIND SPEED AT BOCA CHICA REACHED 122 MILES PER
HOUR BEFORE THE ANEMOMETER WAS BLOWN AWAY. A FIVE FOOT STORM TIDE
WAS OBSERVED AT TAVERNIER. 4.53 INCHES OF RAIN FELL IN KEY WEST...
SETTING THE DAILY RECORD FOR MAXIMUM RAINFALL MEASURED IN KEY WEST
ON SEPTEMBER 21ST...A RECORD WHICH STILL STANDS 66 YEARS LATER.
RAINFALL RECORDS AT KEY WEST DATE BACK TO 1871.

&&

.MARINE...OVERNIGHT AND SATURDAY...A NEARBY TROUGH WILL KEEP LIGHT
AND VARIABLE WINDS...TENDING MOSTLY SOUTHWESTERLY FOR THE OVERNIGHT
AND SATURDAY...BUT OF COURSE WINDS AND SEAS WILL BE HIGHER IN AND
AROUND SHOWERS AND THUNDERSTORMS ESPECIALLY.


&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&

$$

PUBLIC/MARINE/GRIDS.............DAF
AVIATION/NOWCASTS/CLIMATE.......BS
DATA COLLECTION/UPPER AIR.......EV

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