Area Forecast Discussion
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000
FXUS62 KKEY 210137
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
945 PM EDT WED AUG 20 2014

.DISCUSSION...IN THE MID AND UPPER LEVELS...LATEST AVAILABLE IR
IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF 900 PM DEPICT
A MORE LOWER AMPLITUDE CYCLONIC AND ANTICYCLONIC FLOW PATTERN ACROSS
MUCH OF THE NORTHERN CONUS THAN AS OF LATE. FARTHER TO THE SOUTH...A
MID AND UPPER ANTICYCLONE IS POSITIONED FROM NEAR 35 NORTH 60 WEST
SOUTHWESTWARD TO ACROSS CENTRAL FLORIDA AND THE EAST CENTRAL GULF.

AT THE SURFACE AND IN THE LOWER TO MIDDLE LEVELS...SURFACE TO 700
MB...LATEST IR IMAGERY OVERLAID WITH MARINE AND LAND SURFACE
OBSERVATIONS AND ANALYSIS AS OF 900 PM DETAIL FRAGMENTED LOWER
LEVEL SURFACE RIDGING...WITH SLIGHTLY STRONGER NEAR 1018-1020
SURFACE RIDGING LOCATED JUST EAST OF THE BAHAMAS...AND ACROSS THE
EASTERN GULF OF MEXICO. LATEST MIMIC IMAGERY FROM THE UNIVERSITY OF
WISCONSIN CONTINUES TO INDICATE DEEP MOISTURE EXISTS IN THE LOWER
TO MIDDLE LEVELS OF THE BOUNDARY LAYER ACROSS SOUTH FLORIDA...THE
FLORIDA KEYS...AND THE NORTHERN AND CENTRAL BAHAMAS UPSTREAM. AS A
RESULT...THE 00Z EVENING SOUNDING ILLUSTRATED A CONDITIONALLY
UNSTABLE MOIST GENTLE TO MODERATE NORTHEAST FLOW FROM OFF THE
SURFACE TO 700 MB...WITH PWAT(PRECIPITABLE WATER) AT 2.14 INCHES.

.CURRENTLY...AS OF 900 PM...KEY WEST RADAR ONLY DETECTS A FEW
SHOWERS AND THUNDERSTORMS ACROSS THE FLORIDA STRAITS...BUT ALL
CONVECTIVE ACTIVITY HAS SEIZED ATTM ALONG LEFTOVER FLORIDA MAINLAND
AND CUMULUS LINE BOUNDARIES. TEMPERATURES ALONG THE ISLAND CHAIN ARE
IN THE MIDDLE 80S WITH DEWPOINTS IN THE MIDDLE TO UPPER 70S. C-MAN
STATIONS ALONG THE ISLAND CHAIN ARE REGISTERING LIGHT TO GENTLE
NORTHEAST TO SOUTHEAST AT 5 TO 10 KNOTS EXCEPT VARIABLE OVER FLORIDA
BAY.

.SHORT TERM FORECAST...OVERNIGHT...LEFTOVER BOUNDARIES COLLISIONS
WILL CONTINUE. GIVEN THAT MODEL FORECAST SOUNDINGS ILLUSTRATE MODEL
FORECAST SOUNDINGS PWAT REMAINING NEAR 2.00 INCHES...THERE IS PLENTY
OF AVAILABLE MOISTURE AVAILABLE TO SUPPORT COVERAGE OF ISOLATED
SHOWERS AND THUNDERSTORMS. WILL BE REMOVING TRANSITIONAL WORDING TO
LOWER POPS FOR THE BALANCE OF THE NIGHT. NO OTHER CHANGES ON THIS
UPDATE. FOR TOMORROW...18Z GFS AND ECMWF MODEL FORECAST SOUNDINGS
CONTINUE TO ILLUSTRATE VERY FAVORABLE CONDITIONS AGAIN ON THURSDAY
FOR SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE ISLANDS.

&&

.MARINE...LIGHT TO GENTLE NORTHEAST TO EAST WINDS EXPECTED OVERNIGHT
AND DURING THURSDAY. MARINERS WILL NEED TO CONTENT WITH ELEVATED
WINDS AND SEAS IN AND NEAR SCATTERED SHOWERS AND STORMS DEVELOPING
ALONG INTERSECTING BOUNDARIES AND CLOUD LINES AGAIN DURING THE DAY
ON THURSDAY. KEEP THE WEATHER RADIO TUNED IN AT ALL TIMES.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT THE ISLAND TERMINALS.
THERE WILL BE A CHANCE FOR BRIEF MVFR CONDITIONS OVERNIGHT. SURFACE
WINDS WILL SETTLE INTO A LIGHT EAST BREEZE.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1963...2.06 INCHES OF RAIN
FELL AT KEY WEST INTERNATIONAL AIRPORT. THIS SET THE DAILY RECORD
FOR MAXIMUM RAINFALL MEASURED IN KEY WEST ON AUGUST 20TH...A RECORD
WHICH STILL STANDS 51 YEARS LATER. RAINFALL RECORDS AT KEY WEST DATE
BACK TO 1871.

&&

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

$$

PUBLIC/MARINE/GRIDS......................DAF
AVIATION/NOWCASTS/WARNINGS/STATEMENTS....11
DATA COLLECTION/UPPER AIR................SC/MP

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