Area Forecast Discussion
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000
FXUS62 KKEY 040853
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
453 AM EDT TUE AUG 4 2015

.DISCUSSION...
ANALYSIS THIS MORNING REVEALS SLOWLY BUILDING GEOPOTENTIAL HEIGHTS
ACROSS THE WESTERN SUBTROPICAL NORTH ATLANTIC. A DEEP LAYER COL
REGION REMAINS OVER THE EXTREME SOUTHEASTERN GULF OF MEXICO.
HOWEVER...A DEEP BUT GENTLE EASTERLY FLOW HAS DEVELOPED OVER MOST OF
THE FLORIDA KEYS AND ADJACENT COASTAL WATERS...AND SHOULD PERSIST
THROUGH TODAY AND TONIGHT. LARGE-SCALE FORCING REMAINS WEAK. A VERY
SUBTLE LOW-LEVEL TROUGH IS EVIDENT IN THE STREAMLINE PATTERN FROM THE
BAHAMAS TO CUBA. HOWEVER...THE MOMENTUM IS WEAK ENOUGH THAT LOCAL
MESOSCALE DIFFERENTIAL HEATING CIRCULATIONS AND CONVECTIVE OUTFLOW
LIKELY WILL BE MORE IMPORTANT IN FORCING CHANGES TO LOCAL
THERMODYNAMICS OR CONVECTIVE POTENTIAL. CURRENT RADAR SCANS SHOW
ISOLATED SHOWERS AND THUNDERSTORMS MOVING STEADILY TOWARD THE WEST-
NORTHWEST NEAR 10 KNOTS...MAINLY OVER THE STRAITS OF FLORIDA. CURRENT
AIR TEMPERATURES IN MOST KEYS ISLAND COMMUNITIES ARE IN THE LOWER 80S
WITH DEWPOINT TEMPERATURES IN THE MID 70S. FOR TODAY...A FAIRLY DEEP
AND WEAK EASTERLY FLOW AMIDST A MOIST...UNSTABLY STRATIFIED...AND
RELATIVELY UNINHIBITED ATMOSPHERE SHOULD FACILITATE DEVELOPMENT OF
ISLAND CUMULUS LINES...SOME SHOWERS AND STORMS...AND POSSIBLY A FEW
WATERSPOUTS. RAIN CHANCES SHOULD SLOWLY DROP A FEW TICKS TONIGHT
TROUGH THURSDAY AS SOME DRIER AIR WORKS IN FROM THE EAST ALOFT.
HOWEVER...IT WILL REMAIN QUITE MOIST IN THE LOWER TROPOSPHERE...AND
WE COULD SEE HIGHEST COVERAGE AT NIGHT DURING SOME WEAK NOCTURNAL
WIND SURGES OVER THE STRAITS. GRADIENT FLOW PROBABLY WILL WEAKEN
AGAIN BY THE WEEKEND AS THE LARGE-SCALE RIDGE ONCE AGAIN WEAKENS AND
FRACTURES. &&

.MARINE...
AN ATLANTIC RIDGE OF HIGH PRESSURE OVER SOUTH FLORIDA WILL LIFT
NORTHWARD SLOWLY TODAY. THE RIDGE THEN WILL REMAIN NORTH OF THE
FLORIDA KEYS THROUGH AT LEAST SATURDAY.
&&

.AVIATION...
VFR CONDITIONS WILL CONTINUE TO PREVAIL AT BOTH THE KEY WEST AND
MARATHON TERMINALS THROUGHOUT THE REMAINDER OF THE TAF PERIOD.
SURFACE WINDS WILL BE LIGHT FROM THE NORTHEAST...BECOMING MORE
EASTERLY BETWEEN 5 AND 10 KNOTS BY SUNRISE. THERE IS A CHANCE OF
SHOWERS AND SLIGHT CHANCE OF THUNDERSTORMS TODAY...BUT CONFIDENCE ON
TIMING IS TOO LOW TO INCORPORATE AT THIS TIME. AMENDMENTS WILL BE
ISSUED AS NEEDED.
&&

.CLIMATE...IN 2007...THE DAILY RECORD WARM LOW TEMPERATURE OF 87F WAS
RECORDED. THIS IS ALSO THE WARMEST LOW TEMPERATURE EVER RECORDED IN
AUGUST...AND TIES FOR THE WARMEST LOW TEMPERATURE EVER RECORDED IN
KEY WEST.
&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  91  81  91  83 / 30 20 20 20
MARATHON  93  81  93  83 / 30 20 20 20
&&

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

$$

PUBLIC/MARINE.........KASPER
AVIATION/NOWCASTS.....VICKERY

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