000
FXUS62 KKEY 091943
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
345 PM EDT SAT MAY 9 2009

.DISCUSSION...
CURRENTLY - THE WEAK WESTERN PERIPHERY OF THE SURFACE ATLANTIC RIDGE
EXTENDS ACROSS FLORIDA...AS HAS BEEN THE CASE FOR OVER A WEEK NOW.
AS A RESULT MOSTLY LIGHT TO GENTLE EAST TO SOUTHEAST BREEZES HAVE
BEEN OBSERVED OVER THE KEYS AND ALONG THE REEF. HEATING OVER SOUTH
FLORIDA HAS ALLOWED THE FLOW NEARBY TO LIGHTEN UP
SIGNIFICANTLY...WITH LONG KEY REPORTING SOUTH AT 6 KNOTS.
WEAK...STABLE...AND DRY LOWER LEVEL FLOW HAS KEPT SKIES MOSTLY CLEAR
TODAY...WITH NO PRECIPITATION ECHOES DETECTED IN THE KEYS AREA...AND
SO FAR OVER SOUTH FLORIDA. HOWEVER...A FEW SHOWERS AND THUNDERSTORMS
HAVE BEEN ABLE TO DEVELOP OVER ANDROS ISLAND.

FORECAST - LITTLE CHANGE TO THE FORECAST IN THE SHORT TERM. DIURNAL
OSCILLATIONS WILL CONTINUE TO DRIVE THE SURFACE FLOW ACROSS THE KEYS
THROUGH THE NEXT SEVERAL DAYS DUE TO THE WEAK RIDGING TO OUR
NORTH...AND ZONAL FLOW ALOFT. SATELLITE DERIVED PWAT IMAGERY AND
MORE ACTIVITY OVER ANDROS THAN PRIOR DAYS INDICATE THAT A SWATH OF
INCREASED LOWER LEVEL MOISTURE IS GRADUALLY SHIFTING WESTWARD
TOWARDS OUR AREA. THIS IS CONSISTENT WITH GUIDANCE. WILL INSERT
SLIGHT POPS FOR SUNDAY NIGHT.

IN THE MEDIUM RANGE...A DYING COLD FRONT IS EXPECTED TO DRAPE ACROSS
THE SOUTHEAST AND SAG INTO FLORIDA THE FIRST HALF OF NEXT WEEK. THIS
WILL PINCH THE LOWER TROPOSPHERIC RIDGE...ALLOWING FOR A MORE BACKED
FLOW. IN ADDITION GUIDANCE HAS BEEN CONSISTENT IN PICKING UP THE
PWAT ABOUT .1 TO .2 INCHES. THIS WILL SET UP A MORE FAVORABLE
ENVIRONMENT FOR BOTH CLOUD LINES AND MIGRATING SHOWERS AND
BOUNDARIES OFF OF SOUTH FLORIDA. WITH THAT BEING SAID...CHANCE OF
RAIN STILL APPEAR SLIGHT THROUGH THE MEDIUM INTO LONG TERM.

IN THE LONG RANGE...UNCERTAINTY IS STILL A SIGNIFICANT FACTOR...BUT
IT APPEARS THAT THE ATLANTIC RIDGE WILL GET A BOOST BY A NEW HIGH
ROLLING OFF OF THE CONUS...AS A MORE AMPLIFIED FLOW BUILDS A MID AND
UPPER LEVEL RIDGE ACROSS THE EASTERN STATES. IN RESPONSE...SURFACE
WINDS SHOULD BECOME MORE EASTERLY AND MODERATE OVER THE SECOND HALF
OF THE WEEK.
&&

.MARINE...
A WEAKENED RIDGE TO OUR NORTH WILL ALLOW DIURNAL HEATING AND COOLING
OVER SOUTH FLORIDA AND CUBA TO ONCE AGAIN DOMINATE THE LOCAL FLOW
REGIME. WINDS ARE EXPECTED TO PICK UP OUT OF THE EAST TO SOUTHEAST
IN THE EVENINGS AND OVERNIGHT AFTER THE AFTERNOON LULL. THIS GENERAL
PATTERN WILL PERSIST THROUGH THE FORECAST PERIOD. TOWARDS THE END OF
THE FORECAST...WINDS ARE EXPECTED TO PICK UP FURTHER AS THE RIDGE TO
OUR NORTH GETS REINFORCED...THUS TIGHTENING THE LOCAL PRESSURE
GRADIENT. FOR NOW WILL HOLD WINDS SHY OF CAUTIONS.
&&

.AVIATION...
EXPECT VFR CONDITIONS AT THE KEY WEST AND MARATHON ISLAND TERMINALS
THROUGH LATE THIS EVENING AND OVERNIGHT. ONLY A FEW SHALLOW CUMULUS
ARE EXPECTED AOA FL025 AT ANY TIME. LIGHT TO GENTLE SOUTHEAST
SURFACE BREEZES WILL BACK A LITTLE TOWARDS THE EAST LATE IN THE
OVERNIGHT PERIOD.
&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  77  85  77  85 / 05 05 05 05
MARATHON  77  87  77  88 / 05 05 05 05
&&

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

&&

$$

11/04/TF

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