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000
FXUS62 KKEY 111348
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS...UPDATED
NATIONAL WEATHER SERVICE KEY WEST FL
945 AM EDT TUE MAR 11 2014

UPDATED TO ADD NEWER AVIATION AND MARINE SECTION

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)LATEST
AVAILABLE SATELLITE IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS
AS OF 800 AM DEPICT A DEVELOPING MID AND UPPER LEVEL CYCLONE WITHIN
THE SOUTHERN BRANCH OF THE JET STREAM...NOW MOVING TOWARDS THE
NORTHERN GULF AS IT MIGRATES QUICKLY ACROSS EAST TEXAS. AMPLE
POSITIVE VORTICITY ADVECTION (PVA) AT 500 MB IS INDICATED IN
ASSOCIATION WITH THIS FEATURE AND LOTS OF LIGHTNING HAS BEEN
OBSERVED AND TRACKED DURING THE LAST 8 HOURS. SOME AMPLIFICATION OF
THE NORTHERN STREAM ALREADY HAS BEGUN ACROSS THE WESTERN
CONUS...ACROSS THE NORTHERN ROCKIES. LOCALLY...THE FLORIDA KEYS
REMAIN BENEATH A DEEP AND WARM ANTICYCLONE CENTERED OVER THE LOWER
CARIBBEAN.

AT THE SURFACE AND IN THE LOWER LEVELS...LATEST SURFACE ANALYSIS
OVERLAID WITH MARINE AND LAND SURFACE OBSERVATIONS AND ANALYSIS AS
OF 800 AM DETAIL A DEVELOPING NEAR 1000 MB LEE SIDE CYCLONE OVER
WESTERN KANSAS. WELL TO THE SOUTH OF THAT...THERE IS A 1009 MB
SURFACE LOW OVER THE NORTHWESTERN GULF OF MEXICO. OUT AHEAD OF THAT
FEATURE IS A LARGE MCS (MESOSCALE CONVECTIVE SYSTEM) BETWEEN 90 WEST
AND THE ASSOCIATED COLD FRONT TIED INTO THIS LOW PRESSURE...BUT
LOCALLY A WEAK PRESSURE PATTERN REMAINS IN PLACE ACROSS SOUTH
FLORIDA...THE FLORIDA KEYS...AND THE NORTHERN BAHAMAS WITH A NEAR
1015 MB RIDGE COVERING THE AREA. AS A RESULT...THE 12Z MORNING
PROFILE AT KEY WEST ILLUSTRATED A LIGHT VEERING PROFILE FROM THE
SURFACE TO 5KT...WITH A STALWART 3 DEGREE C INVERSION FROM ABOUT 890
TO 855 MB. A DRY LOWER TO MID TROPOSPHERE AND COLUMNAR PWAT
(PRECIPITABLE WATER) AT 1.11 INCHES.

.CURRENTLY...AS OF 800 AM...SATELLITE IMAGERY SHOWS MOSTLY SUNNY
SKIES OVER THE ISLANDS AND SURROUNDING WATERS...WITH TEMPERATURES
OVER THE ISLANDS RANGING FROM THE MID 60S TO THE LOWER 70S...AFTER
RADIATING OUT INTO THE LOWER 60S ACROSS THE LARGER ISLANDS
OVERNIGHT. C-MAN STATIONS ALONG THE FLORIDA REEF AND THE ISLAND
SENSORS ARE ALL VARIABLE AT ABOUT 5 KNOTS.

.SHORT TERM...WEAK RIDGING WILL BECOME MORE ESTABLISHED NORTH OF THE
KEYS...ALLOWING LIGHT TO GENTLE BREEZES TO TREND BACK TO
SOUTHEASTERLY. MID LEVEL DRY AIR WILL STILL KEEP THE RAIN CHANCES
NIL. GIVEN THE LIGHT WINDS AND ELEVATED INVERSION...WILL STILL HAVE
A FEW CLOUDS AROUND...BUT SKIES WILL BE MOSTLY SUNNY. TEMPERATURES
WILL STILL REACH NEAR 80 DEGREES. NO CHANGES

&&

.MARINE...A HIGH PRESSURE CELL OVER FLORIDA WILL SHIFT EASTWARD
TODAY. LIGHT BREEZES THIS MORNING WILL BECOME GENTLE SOUTHEAST
BREEZES THIS AFTERNOON AND EVENING.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT THE KEY WEST AND MARATHON TERMINALS
TODAY AND TONIGHT. A GENTLE SOUTHEASTERLY BREEZE WILL PERSIST THROUGH
THE AFTERNOON AND THIS EVENING...AND TURN MORE TO THE SOUTH
OVERNIGHT.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1948...THE HIGH
TEMPERATURE IN KEY WEST REACHED 85 DEGREES. THIS SET THE HIGH
TEMPERATURE RECORD FOR MARCH 11 IN KEY WEST. TEMPERATURE RECORDS FOR
KEY WEST DATE BACK TO 1872.

&&

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

$$

PUBLIC/MARINE/CLIMATE/GRIDS..........DAF
AVIATION/NOWCASTS....................04
DATA COLLECTION/UPPER AIR............EV

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