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000
FXUS62 KKEY 311328
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
930 AM EDT THU JUL 31 2014

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY OVERLAID WITH SATELLITE IMAGERY AS OF 800 AM
CONTINUES TO SHOW AN UNUSUALLY DEEP FULL LATITUDINAL TROUGH
CONTINUING ACROSS THE EASTERN HALF OF THE CONUS...ALTHOUGH IS SHOULD
BE NOTED THAT THE 24 HOUR TREND IS SLIGHTLY DEAMPLIFICATION OF THIS
FEATURE. TO THE SOUTH OF THAT...THERE REMAINS AN ELONGATED
ANTICYCLONIC RIDGE WITH TWO CENTERS WITHIN THE EAST TO WEST
CONFIGURATION ACROSS THE SOUTHERN CONUS...GULF OF MEXICO...AND
FLORIDA. A WEAKENING TUTT (TROPICAL UPPER TROPOSPHERIC TROUGH) CELL
CONTINUES TO AMBLE ABOUT NEAR 25 NORTH 66 WEST.

AT THE SURFACE AND IN THE LOWER LEVELS...(SURFACE TO 700 MB) LATEST
IR IMAGERY OVERLAID WITH AVAILABLE MARINE AND LAND SURFACE
OBSERVATIONS AND ANALYSIS AS OF 800 AM DETAIL A DECAYING COOL
FRONTAL SYSTEM DRAPED FROM THE NORTHWEST ATLANTIC SOUTH
SOUTHWESTWARD TO ACROSS SOUTHWEST FLORIDA...THENCE WESTWARD ACROSS
THE SOUTHEASTERN GULF OF MEXICO A FEW HUNDRED MILES WEST OF KEY
WEST. THE 12Z MORNING SOUNDING WAS TYPICALLY CONDITIONALLY UNSTABLE
TO UNSTABLE...AND WAS VERY MOIST WITH PWAT (PRECIPITABLE WATER) AT
2.15 INCHES. SURFACE TO 500 MB WINDS WERE LIGHT TO GENTLE SOUTH TO
SOUTHWESTERLY...BUT AVERAGE 0-6 KM STORM MOTION WAS ONLY 1 KNOT FROM
204 DEGREES.

.CURRENTLY...AS OF 800 AM...KEY WEST RADAR DETAILS SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ASSOCIATED WITH THE AFOREMENTIONED NEARLY
STATIONARY BOUNDARY JUST WEST OF KEY WEST...HENCE THEY ARE MOST
CONCENTRATED NEAR THE LOWER FLORIDA KEYS AND SURROUNDING GULF WATERS
WEST THROUGH NORTH OF KEY WEST...WITH WIDELY SEPARATED SHOWERS AND
ISOLATED THUNDERSTORMS ELSEWHERE ACROSS THE REST OF THE REGION.
TEMPERATURES ALONG THE ISLANDS OUTSIDE OF THE CONVECTIVE ACTIVITY
ARE IN THE LOWER TO MID 80S WITH DEWPOINTS IN THE MID 70S. C-MAN
STATIONS ALONG THE FLORIDA REED ARE SOUTH TO SOUTHWEST NEAR 10
KNOTS...EXCEPT SOUTHWEST TO WEST 5 TO 10 KNOTS OUT AT PULASKI
SHOAL.

.SHORT TERM...REST OF TODAY...EXPECT CONTINUED EROSION OF THE
AFOREMENTIONED HUNGOVER LOW LEVEL SURFACE TROUGH NOW LOCATED
IMMEDIATELY NORTH THROUGH WEST OF THE KEYS. BUT GIVEN THE IMPACT OF
THIS FEATURE IN COMBINATION WITH VERY DEEP MOISTURE AS WELL AS LOWER
TO MIDDLE LEVEL TROPOSPHERIC WINDS EXPECT TO BECOME ALMOST CALM
(THROUGH 500 MB)...I WOULD ANTICIPATE EXCELLENT MESOSCALE FORCING
RIGHT OVER THE FLORIDA KEYS ISLAND CHAIN. THIS IS CLUED BY THE
AVAILABLE MODEL FORECAST SOUNDINGS ILLUSTRATION OF COLUMNAR PWAT
REMAINING BETWEEN 1.75 AND 2.00 INCHES THROUGH 00Z THIS EVENING. SO
TO REITERATE...EXPECT EPISODIC SHOWERS AND THUNDERSTORMS ALONG THE
CUMULUS/TOWERING CUMULUS CLOUD LINES SITUATED OVER MUCH OF THE
LENGTH OF THE FLORIDA KEYS.

IN ADDITION...GIVEN A NEARLY CALM STORM MOTION...SOME LOCATIONS WILL
EXPERIENCE PERIODS OF HEAVY RAINFALL WHICH COULD LEAD TO PONDING OF
WATER ACROSS LOCATIONS WITH NORMALLY POOR DRAINAGE. TEMPERATURES MAY
BE HELD DOWN A FEW DEGREES GIVEN LEFTOVER CIRRUS CLOUD-COVER.
THUS...WILL BE WATCHING FOR A FEW MORE HOURS AND MAY PERFORM A LATE
MORNING UPDATE TO INDICATE LIKELY CHANCES FOR SHOWERS AND A CHANCE
OF THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL POSSIBLE.

&&

.MARINE...A CLOUD LINE WILL REMAIN NEARLY OVERHEAD OF THE KEYS
ISLAND CHAIN THROUGH THE AFTERNOON AND EVENING HOURS. IT WILL BE
ACTIVE AND INACTIVE AT TIMES THROUGHOUT THE REST OF THE DAY.
WATERSPOUTS REMAIN A DISTINCT POSSIBILITY AND WILL ALSO VERY CLOSE
TO SHORE...SO MARINERS NEED TO BE ALERT FOR POSSIBLE WARNINGS IF ONE
IS SIGHTED. ADDITIONAL MARINE WEATHER STATEMENTS OR POSSIBLE
WARNINGS MAY BE ISSUED FOR THE HEAVIER SHOWERS AND STORMS DUE TO
ISOLATED WIND GUSTS TO 35 KNOTS...FREQUENT TO EXCESSIVE
LIGHTNING...AND VERY HEAVY RAINFALL. KEEP THE NOAA WEATHER RADIO
HANDY AND TUNED IN ON THIS SECOND DAY OF THE MINI LOBSTER SERIES.

&&

.AVIATION...
MOISTURE IS PLENTIFUL...BOUNDARIES ARE EMANATING EVERYWHERE...AND
INHIBITION IS MINIMAL. THUS...EPISODIC MVFR OR LOWER IS LIKELY AT
THE EYW AND MTH TERMINALS. THERE IS POOR CONFIDENCE IN THE TIMING OF
THESE CONDITIONS...AND YET...OUR PRECIPITATION CHANCES AT THE
TERMINALS ARE ABOVE AVAILABLE OUTPUT FROM NUMERICAL GUIDANCE. WINDS
WILL BECOME EAST SOUTHEASTERLY LATE THIS EVENING OR EARLY
TONIGHT...UNTIL THEN...EXPECT VARIABLE WINDS CONTROLLED BY NEARBY
CONVECTION.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1874...THE HIGH
TEMPERATURE IN KEY WEST WAS 95 DEGREES. THIS SET THE DAILY RECORD
FOR MAXIMUM TEMPERATURE MEASURED IN KEY WEST ON JULY 31ST...A RECORD
WHICH STILL STANDS 140 YEARS LATER. TEMPERATURE RECORDS AT KEY WEST
DATE BACK TO 1872.

&&

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

&&

$$

PUBLIC/MARINE/FIRE/DIGITAL............DAF
AVIATION/NOWCASTS.....................CLR
UPPER AIR/DATA ACQUISITION............BF

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