Area Forecast Discussion
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000
FXUS62 KKEY 301311
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
910 AM EDT WED JUL 30 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 DEPICT AN UNSEASONABLY DEEP COOL SEASON TROUGH
ENCOMPASSING THE EASTERN CONUS...WITH THE BASE OF THIS TROUGH
REACHING TO NEAR 30 NORTH EAST OF SOUTH GEORGIA AND NORTH FLORIDA.
SOUTH OF THAT...THERE IS A ELONGATED EAST TO WEST MID AND UPPER
RIDGE AXIS DRAPED FROM THE DESERT SOUTHWEST EAST SOUTHEASTWARD TO
ACROSS SOUTH FLORIDA AND THE NORTHERN BAHAMAS. A DECAYING TUTT DELL
IS EAST OF THAT FEATURE 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 COLD FRONT WHICH
EXTENDS EXCEEDINGLY FAR SOUTH AT THIS TIME OF YEAR AND BISECTS
CENTRAL FLORIDA FROM LOW PRESSURE UP OVER NORTHEAST CANADA. CLOSER
TO THE KEYS...A PREFRONTAL TROUGH LIKE FEATURE IS ASSOCIATED WITH
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS GMZ676 AND 657.
AS A RESULT...AN ABNORMAL LIGHT TO GENTLE SOUTHWEST TO WESTERLY
FLOW PATTERN REMAINS IN PLACE ACROSS SOUTH FLORIDA AND THE FLORIDA
KEYS.

.CURRENTLY...AS OF 800 AM...LATEST AVAILABLE VISIBLE SATELLITE
IMAGERY COMBINED WITH WSR-88D SCANS SHOWS THAT SKIES ARE PARTLY
CLOUDY ACROSS THE KEYS AND ADJOINING WATERS...WITH ISOLATED SHOWERS
AND THUNDERSTORMS DOTTING AREAS NEAR THE KEYS ISLAND CHAIN AND
POINTS NORTHWARD IN FLORIDA BAY AND WESTWARD ACROSS THE NEARSHORE
GULF WATERS INSIDE THE 5 FATHOM LINE AS WELL AS THE OFFSHORE GULF
WATERS 20 TO 60 NM WEST OF MAINLAND MONROE.

.SHORT TERM...REST OF TODAY...AN UNUSUALLY FAR SOUTH COOL
SURFACE/LOWER LEVEL FRONTAL BOUNDARY WILL GRADUALLY HANG UP AS IT
SLIDES SOUTHWARD DOWN THE FLORIDA PENINSULA TROUGH THIS
AFTERNOON...HOWEVER SOME INFLUENCE OF THIS PREFRONTAL BOUNDARY SEEMS
PLAUSIBLE IN ENHANCEMENT IN THE COVERAGE OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. IN ADDITION...SLIGHTLY ELEVATED CONFLUENT
FLOW SHOULD ALLOW FOR GENTLE TO MODERATE SOUTHWEST TO WESTERLY WINDS
TO DEVELOP ACROSS THE UPPER KEYS AND SURROUNDING WATERS OF FLORIDA
BAY THIS AFTERNOON...AS WELL AS ACROSS THE ADJOINING HAWK CHANNEL
AND ATLANTIC WATERS...GIVEN PROXIMITY TO LAND. SO WILL BE SPLITTING
OF THIS SECTION OF THE UPPER KEYS AND SURROUNDING WATERS TO INDICATE
INCREASING WINDS TO BETWEEN 10 AND 15 KNOTS...WITH ONLY LIGHT TO
GENTLE SOUTHWEST TO WESTERLY FLOW IS ANTICIPATED ELSEWHERE.

LATEST AVAILABLE ECMWF AND GFS MODEL FORECAST SOUNDINGS ARE ALSO
ILLUSTRATING INCREASING BOUNDARY LAYER MOISTURE AND INSTABILITY
ALONG THE KEYS AS WELL...WITH PWAT INCREASING TO AROUND 1.75 INCHES
FROM ~ 1.60 INCHES THIS MORNING. AND GIVEN HEATING...SLIGHT BACKING
OF WINDS IN THE LOWER TO MID TROPOSPHERE WILL CREATE A FAVORABLE
ENVIRONMENT FOR MESOSCALE CUMULUS CLOUD LINE FORMATION NEAR THE
KEYS. FOR THIS REASON...WILL BE INTRODUCING MIDDLE OF THE ROAD
CHANCE POPS FOR THE BALANCE OF THE DAY ACROSS THE ISLANDS AND
SURROUNDING WATERS...WITH THE EXCEPTION OF THE FLORIDA STRAITS WHICH
WILL BE FARTHER AWAY FROM THE BOUNDARY.

&&

.MARINE...LIGHT TO GENTLE SOUTHWEST TO WESTERLY WINDS ARE
ANTICIPATED ACROSS ALL WATERS...EXCEPT GENTLE TO MODERATE SOUTHWEST
TO WEST WINDS ACROSS FLORIDA BAY...HAWK CHANNEL...AND THE FLORIDA
STRAITS OUT 60 NM FROM OCEAN REEF TO CRAIG KEY. MARINERS IN HAWK
CHANNEL OFF OF THE LOWER AND MIDDLE KEYS SHOULD BE ON THE LOOKOUT
FOR POSSIBLE WATERSPOUT FORMATION AS WELL. KEEP NOAA WEATHER RADIO
TUNED IN.

&&

.AVIATION...
VFR WILL PREVAIL AT THE EYW AND MTH TERMINALS. EXPECT MAINLY WEST
WINDS OF 5 TO 10 KNOTS. AN AFTERNOON CLOUD LINE IN THE LEE OF THE
LOWER KEYS AND BIG PINE KEY WILL INTRODUCE THE CHANCE FOR SHOWERS
AND THUNDERSTORMS TO MTH. EXPECT BRIEF EPISODES OF MVFR
CIGS/VIS...AND CONVECTIVE WIND GUSTS UP TO 25 KNOTS IF THESE STORMS
DEVELOP.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1886...2.65 INCHES OF RAIN
FELL IN KEY WEST. THIS SET THE DAILY RECORD FOR MAXIMUM RAINFALL
MEASURED IN KEY WEST ON JULY 30TH...A RECORD WHICH STILL STANDS 128
YEARS LATER. RAINFALL RECORDS AT KEY WEST DATE BACK TO 1871.

&&

.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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