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000
FXUS62 KKEY 190713
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
315 AM EDT SUN MAY 19 2013

.DISCUSSION...IN THE MID AND UPPER LEVELS...LATEST AVAILABLE IR
SATELLITE IMAGERY OVERLAID WITH MODEL STREAMLINES AS OF 200 AM
DEPICT A DEEP POSITIVELY TILTED TROUGH POSITIONED ACROSS THE WESTERN
CONUS. DOWNSTREAM OF THAT FEATURE...THE AXIS OF LOW AMPLITUDE MID
AND UPPER ANTICYCLONIC RIDGING IS LOCATED FROM THE MID MISSISSIPPI
VALLEY SOUTHWARD INTO THE CENTRAL GULF OF MEXICO...WITH SOUTH
FLORIDA AND THE FLORIDA KEYS ON THE RIGHT SIDE OF THIS FEATURE. AT
THE SURFACE...A NEAR 1020 MB AREA OF HIGH PRESSURE IS LOCATED ACROSS
THE EASTERN GULF AND MUCH OF THE FLORIDA PENINSULA SOUTHWARD TO
NORTH OF MIAMI. AS SUCH...LAST EVENINGS 00Z SOUNDING ILLUSTRATED A
MAINLY GENTLE NORTHEAST TO EAST FLOW FROM THE SURFACE UP TO ABOUT
800 MB...WITH COLUMNAR PWAT AT 1.28 INCHES.

.CURRENTLY...AS OF 200 AM...SKIES ARE MOSTLY CLEAR OVER THE ISLANDS
AND ADJOINING WATERS. TEMPERATURES ACROSS THE ISLANDS REMAIN NEAR 80
DEGREES WITH DEWPOINTS AROUND 70. C-MAN STATIONS ALONG THE FLORIDA
REEF ARE RECORDING MAINLY EAST WINDS NEAR 10 KNOTS WITH ISLAND
SENSORS RECORDING WINDS NEAR 10 MPH. KEY WEST RADAR DOES NOT DETECT
ANY RADAR ECHOES ATTM.

.SHORT TERM (TODAY THROUGH WEDNESDAY)...MID AND UPPER TROUGHING OVER
THE WESTERN CONUS WILL SLOWLY MOVE EASTWARD INTO THE PLAIN STATES
THIS AFTERNOON THROUGH WEDNESDAY. AS A RESULT...DECENT MID LEVEL
RIDGING WILL STILL REMAIN ACROSS SOUTH FLORIDA...CUBA...THE EASTERN
GULF OF MEXICO...AND THE FLORIDA KEYS THROUGH THIS TIME. 00Z GFS AND
ECMWF MODEL FORECAST SOUNDINGS ILLUSTRATED COLUMNAR PWAT
(PRECIPITABLE WATER) REMAINING AROUND 1.25 INCHES TODAY...RISING TO
BETWEEN 1.25 AND 1.5 INCHES BY 12 MONDAY...REACHING AROUND 1.50
INCHES OR HIGHER MONDAY AFTERNOON THROUGH 18Z WEDNESDAY.

AT THE SURFACE...THE MAIN AREA OF RIDGING WILL REMAIN DRAPED ACROSS
THE FLORIDA PENINSULA TODAY THROUGH WEDNESDAY. GIVEN THE DRIER AIR
IN THE MID LEVELS TODAY AND TONIGHT...HAVE INSERTED JUST ISOLATED
SHOWERS ARE IN THE GRIDS. A SLIGHT MOISTENING OF THE MID-LEVELS IS
INDICATED MONDAY THROUGH WEDNESDAY. ALTHOUGH AVAILABLE 00Z
ECMWF...NAM AND GFS...MODEL FORECAST SOUNDINGS ILLUSTRATE THAT
SURFACE TO 700 MB WINDS ARE UNFAVORABLE FOR GOOD MESOSCALE
ACTIVITY...FORECAST SOUNDINGS STILL ILLUSTRATE ABOVE NORMAL MOISTURE
IN THE COLUMN FOR MONDAY THROUGH WEDNESDAY...AS MENTIONED ABOVE.
GIVEN THAT A SERIES OF LOW TO MIDDLE LEVEL UNDULATIONS WILL MOVE
ACROSS THE KEYS AND SURROUNDING WATERS FROM EAST TO WEST COMBINED
WITH THIS HIGHER MOISTURE VALUES...WILL MAINTAIN AT LEAST A LOW
CHANCE FOR SHOWERS MONDAY THROUGH WEDNESDAY...WITH THE BEST CHANCE
OCCURRING LATE EACH NIGHT AND EARLY EACH MORNING. WILL ALSO INCLUDE
ISOLATED THUNDER IN THE GRIDS FOR THE MONDAY THROUGH WEDNESDAY
PERIODS...GIVEN 500 MB TEMPS AVERAGING BETWEEN -8 AND -10C. OUTSIDE
OF ANY SHOWERS...EXPECT DAYTIME TEMPERATURES TO REACH THE UPPER 80S
WITH OVERNIGHT LOWS ONLY FALLING BACK IN THE UPPER 70S.

.LONG TERM (WEDNESDAY NIGHT THROUGH SATURDAY)...THE MAIN LOW
AMPLITUDE TROUGH OVER THE CENTRAL AND WESTERN CONUS IS PROGGED TO
FLATTEN OUT WHEN IT MOVES EASTWARD LATER IN THE WEEK. THIS WILL
MAINTAIN NEUTRAL/WEAKLY ANTICYCLONIC MID TO UPPER LEVEL FLOW
TENDENCIES OVER THE KEYS. THE ACTUAL SURFACE RIDGING AXIS DOES
APPEAR TO MOVE SOUTHWARD TO NEAR THE KEYS DURING WEDNESDAY AFTERNOON
AND NIGHT...WITH INDICATIONS OF IT ACTUALLY REMAINING NEAR THE KEYS
THURSDAY THROUGH SATURDAY. THIS MAY ALLOW FOR SLIGHTLY BETTER
ALIGNMENT OF LIGHT TO GENTLE SURFACE TO 700 MB WINDS...WHICH WOULD
LEAD TO DEVELOPMENT OF REVERSE CUMULUS OR CUMULUS CLOUD LINE(S)
THROUGH THIS PERIOD...ALTHOUGH COLUMNAR PWAT IS ONLY PROGGED TO
RANGE BETWEEN 1.00 AND 1.25 INCHES. THEREFORE WILL WILL KEEP IN JUST
ISOLATED CHANCES FOR SHOWERS AND THUNDERSTORMS...WHICH IS RIGHT AT
CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.MARINE...GENTLE TO MODERATE EAST TO SOUTHEAST BREEZES WILL PREVAIL
ACROSS FLORIDA KEYS COASTAL WATERS THROUGH LATE NEXT WEEK.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING AT THE
KEY WEST AND MARATHON TERMINALS. RAIN CHANCES WILL REMAIN EXTREMELY
LOW AT BOTH TERMINALS...WITH JUST FEW-SCT CU AROUND 2000 FEET
EXPECTED. SURFACE WINDS WILL REMAIN FROM THE EAST AT 6 TO 11 KNOTS.

&&

.CLIMATE...ON THIS DATE IN KEYS WEATHER HISTORY...MAY 19TH...THE
DAILY RECORD RAINFALL OF 5.83" WAS RECORDED IN 1904.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  87 78 87 78 87 / 10 20 30 30 30
MARATHON  90 78 89 78 90 / 10 20 30 30 30

&&

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

&&

$$

PUBLIC/MARINE/FIRE/DIGITAL/CLIMATE...FUTTERMAN
AVIATION/NOWCASTS....................JACOBSON

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