Area Forecast Discussion
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000
FXUS62 KKEY 310134
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
934 PM EDT SAT AUG 30 2014

.DISCUSSION...
.CURRENTLY...
THE KEY WEST EVENING SOUNDING FOUND A RELATIVELY DRY BOUNDARY
LAYER WITH AN OVERALL PWAT NEAR 1.5 INCHES. SBCAPE IS AROUND 1300
J/KG...WITH A LITTLE INHIBITION. DESPITE THIS...KBYX RADAR IS
PICKING UP SEVERAL LONGITUDINALLY ORIENTED BROKEN LINES OF SHOWERS
MOVING TOWARDS THE EAST AROUND 20 KNOTS. ONE IS IMPACTING THE
UPPER KEYS...ANOTHER MOVING THROUGH THE MIDDLE KEYS NEAR
MARATHON...AND A THIRD LINE HALFWAY BETWEEN THE LOWER KEYS AND
CUBA. CMAN STATION WINDS FROM SOMBRERO TO PULASKI SHOAL ARE IN THE
20 KNOT RANGE WITH GUSTS OVER 25 KNOTS...AND A THUNDERSTORM MOVING
OVER SOMBRERO PRODUCED A 48 KNOT GUST. MOLASSES REEF OFF THE UPPER
KEYS CAME IN AT 15 KNOTS THE LAST HOUR WITH A GUST OF 24 KNOTS.
ISLAND STATIONS IN THE LOWER AND MIDDLE KEYS HAVE BEEN PICKING UP
WINDS A FEW KNOTS ABOUT 15...WITH THE KEY LARGO HANDAR STATION
COMING IN NEAR 10 KNOTS.

.SHORT TERM...
THE TIGHT PRESSURE GRADIENT FROM THE MIDDLE KEYS TO CUBA CAUSING
THE WINDY CONDITIONS IS A RESULT OF STRONG HIGH PRESSURE OFF THE
ATLANTIC SEABOARD AND A BROAD AREA OF LOW PRESSURE IN THE WESTERN
CARIBBEAN. MODEL CONSENSUS GENERALLY RELAXES THIS GRADIENT
OVERNIGHT AS THE RIDGE MOVES SLIGHTLY EASTWARD AND THE LOWER
PRESSURE AREA IN THE CARIBBEAN PROGRESSES OVER THE YUCATAN
PENINSULA. IN THE INTERIM HOWEVER...WINDS IN EXCESS OF 20 KNOTS
FROM THE MIDDLE KEYS SOUTHWARD WILL LIKELY PERSIST THROUGH 06Z. THE
DRIER CONDITIONS FOUND IN THE EVENING SOUNDING ARE LIKELY NOT
REPRESENTATIVE OF WHAT CONDITIONS WILL BE OVERNIGHT AS THE GFS
SHOWS A MOISTURE PLUG MOVING IN FROM THE EAST...WHICH SEEMS TO BE
CONFIRMED BY THE SHOWER ACTIVITY IN THE STRAITS. THE COVERAGE IS
STILL SOMEWHAT ISOLATED...BUT ENOUGH TO BUMP THE EVENING POPS UP
TO CHANCE FROM SLIGHT CHANCE.

&&

.MARINE...
A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE FLORIDA STRAITS SOUTH
OF THE MIDDLE KEYS AND FOR THE GULF WATERS WEST OF THE LOWER KEYS.
WINDS AT THE CMAN STATIONS AT SOMBRERO...SAND KEY...AND PULASKI
SHOAL HAVE BEEN COMING IN ABOVE 20 KNOTS...AND IT IS LIKELY WINDS
IN THE STRAITS BETWEEN THE KEYS AND CUBA ARE SUSTAINED NEAR 25
KNOTS. WINDS WILL BEGIN TO RELAX SLOWLY OVERNIGHT...BECOMING NEAR
15 KNOTS IN THE STRAITS BY SUNRISE.

&&

.AVIATION...
SURFACE WINDS WILL BE OUT OF THE EAST AT 12 TO 17 KNOTS AND GUSTY.
WHILE VFR CONDITIONS WILL PREVAIL...ISOLATED TO SCATTERED FAST
MOVING SHOWERS AND THUNDERSTORMS MAY DELIVER A QUICK SHOT OR TWO OF
MVFR/IFR CONDITIONS ALONG WITH STRONG GUSTY WINDS AT THE ISLAND
TERMINALS.

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR GMZ034-044-
     054-055-074-075.

&&

$$

PUBLIC/MARINE.........DEVANAS
AVIATION/NOWCASTS.....11
DATA COLLECTION.......FLING

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