Area Forecast Discussion
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000
FXUS62 KKEY 140041
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
845 PM EDT SUN JUL 13 2014

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY AS OF 800 PM OVERLAID WITH MODEL STREAMLINE
ANALYSIS DEPICT THE CENTER OF A DEEP AND WARM ANTICYCLONE CENTERED
OVER NORTHERN ALABAMA WITH ITS EXPANSE ENCOMPASSING THE SOUTHEASTERN
UNITED STATES. ACROSS THE TROPICS...A WAVERING TUTT (TROPICAL UPPER
TROPOSPHERIC TROUGH) CELL IS JUST SOUTH OF WESTERN CUBA. THERE IS
ANOTHER LESS DEFINED TROUGH UPSTREAM NEAR THE CENTRAL BAHAMAS. AS
SUCH...THERE REMAINS SOME SLIGHTLY ELEVATED LARGE SCALE LIFT ACROSS
THE FLORIDA KEYS SERVICE AREA. IN THE MID LEVELS...BROAD WEAK
RIDGING IS INDICATED AT AROUND 500 MB ACROSS SOUTH FLORIDA AND THE
KEYS.

AT THE SURFACE AND IN THE LOWER LEVELS...SURFACE TO 700 MB...THE
WESTERN EDGE OF A 1020 MB SURFACE RIDGE POKES INTO CENTRAL
FLORIDA...WHILE TO THE SOUTH OF THAT THE CENTER OF A MESOSCALE RIDGE
IS NEAR THE SOUTHWEST FLORIDA COAST...JUST NORTH OF THE KEYS ISLAND
CHAIN. A LOW LEVEL WAVE AXIS HAS MOVED PASSED KEYS LONGITUDE AND IS
APPROACHING THE YUCATAN PENINSULA. AS A RESULT...THE 00Z SOUNDING AT
KEY WEST ILLUSTRATED A LIGHT AND TYPICALLY MOIST AND A MOSTLY EAST
FLOW FROM THE SURFACE TO 700 MB...WITH PWAT (PRECIPITABLE WATER) AT
1.89 INCHES...AND THE FLOW BECOMING LIGHT AND VARIABLE FROM 700 UP
TO 450 MB.

.CURRENTLY...AS OF 800 PM...SKIES ARE PARTLY CLOUDY ACROSS THE KEYS
ISLAND CHAIN AND ADJOINING WATERS. ALL SHOWERS AND THUNDERSTORMS
HAVE ENDED ATTM...BUT IR IMAGERY DELINEATES THE LEFTOVER MIDDLE AND
HIGH CLOUD DEBRIS ASSOCIATED WITH A CLOUDLINES WITHIN 5 NM NORTH OF
THE LOWER KEYS...PLUS THERE ARE AMPLE REMNANT BOUNDARIES TO THE
NORTH WHICH ORIGINATED FROM SOUTH FLORIDA PENINSULAR CONVECTION.
BOUNDARIES ALSO EXIST ALONG THE NORTHERN CUBAN COAST...AS WELL AS
OFF OF ANDROS ISLAND. TEMPERATURES ACROSS THE ISLANDS ARE IN THE
MIDDLE TO HIGH 80S WITH DEWPOINTS IN THE MID TO UPPER 70S.

.FORECASTS...OVERNIGHT...ALTHOUGH THERE IS ALMOST NO ACTIVE
CONVECTION ATTM...THE PRESENCE OF UPPER DIVERGENCE ASSOCIATED WITH
THE SYNOPTIC PATTERN MENTIONED ABOVE WILL AID IN SLIGHTLY ELEVATED
LARGE SCALE FORCING.  AVAILABLE GFS AND ECMWF MODEL FORECAST
SOUNDINGS MAINTAIN PWAT (PRECIPITABLE WATER) BETWEEN 1.75 AND 2.00
INCHES OVERNIGHT...SO THERE REMAINS AVAILABLE MOISTURE. GIVEN THE
PRESENCE OF LEFTOVER BOUNDARIES...AM HESITANT TO LOWER RAIN CHANCES
FROM 30% WE ALREADY HAVE IN THE GRIDS...SO NO CHANGES WILL BE MADE
ON THIS CYCLE.

&&

.MARINE...SURFACE RIDGING WILL REMAIN JUST TO THE NORTH OF THE KEYS
OVERNIGHT...SO A LIGHT TO GENTLE EAST TO SOUTHEAST FLOW SHOULD
PREVAIL...BUT AS ALWAYS WITH AFOREMENTIONED BOUNDARIES AND POSSIBLE
COLLISIONS...MARINERS CAN EXPECT THAT WINDS AND SEAS WILL BE HIGHER
IN AND NEAR ANY SHOWERS AND THUNDERSTORMS. OTHERWISE EXPECT GOOD
BOATING CONDITIONS OVERNIGHT.

&&

.AVIATION...
MVFR CONDITIONS ARE CONCEIVABLE AT EYW AND MTH AFTER MIDNIGHT
TONIGHT. THIS POSSIBILITY IS NOT GREAT ENOUGH TO PLACE IN THE TAFS
AT THIS TIME. VFR CONDITIONS WILL PREVAIL AT EYW AND MTH MONDAY
MORNING. IFR OR LOWER CONDITIONS ARE LIKELY AT EYW MONDAY AFTERNOON
AS ISLAND CUMULUS CLOUD LINES BUILD NEAR OR DIRECTLY OVER THE LOWER
KEYS. VFR CONDITIONS WILL PREVAIL AT MTH MONDAY AFTERNOON. SUSTAINED
EAST WINDS OF 5 TO 10 KNOTS FROM JUST OFF THE SURFACE TO ABOUT 5000
FEET WILL BACK TO NORTHEAST MONDAY AFTERNOON.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1956...THE HIGH
TEMPERATURE AT KEY WEST INTERNATIONAL AIRPORT WAS 94 DEGREES. THIS
SET THE DAILY RECORD FOR MAXIMUM TEMPERATURE MEASURED IN KEY WEST ON
JULY 13TH...A RECORD WHICH STILL STANDS 58 YEARS LATER. TEMPERATURE
RECORDS AT KEY WEST DATE BACK TO 1872.

&&

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

&&

$$

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

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