000
FXUS62 KKEY 180214
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1014 PM EDT FRI MAY 17 2013

.DISCUSSION...
THE ATMOSPHERE ABOVE THE FLORIDA KEYS UNDERWENT SOME CHANGES DURING
THE LAST 24 HOURS. THE DEEP RIDGE WHICH HAD SUSTAINED LARGE-SCALE
SUBSIDENCE AND A FAIR WEATHER PATTERN DURING THE LAST FEW DAYS
FINALLY DISINTEGRATED. IN ITS PLACE IS A RATHER DEEP BELT OF
COOLER...MORE CYCLONIC VORTICITY-RICH WESTERLIES ABOVE A WEAK TO
MODERATE LAYER OF EASTERLIES. THE NEAR SURFACE LAYER RESPONDED TO
THE REDUCTION IN LARGE-SCALE DESCENT BY MOISTENING. THE COMBINATION
OF INCREASED BOUNDARY-LAYER MOISTURE AND COOLING ALOFT BOTH
DESTABILIZED THE ATMOSPHERE IN THE VERTICAL AND REDUCED CONVECTIVE
INHIBITION ENERGY DOWN BELOW. THEREFORE...SHOWERS DEVELOPED WHERE
MESOSCALE LIFTING WAS PRESENT LATE THIS AFTERNOON AND EARLY THIS
EVENING...MAINLY ADJACENT TO THE SOUTH FLORIDA PENINSULAR SEA-BREEZE
CONVERGENCE ZONES AND ASSOCIATED CONVECTIVE CELLS/OUTFLOW. AT THE
MOMENT...ONLY ISOLATED MODERATE SHOWERS ARE DETECTED BY KEY WEST
DOPPLER RADAR OVER PORTIONS OF THE UPPER KEYS AND FLORIDA BAY.

WITH THE LOSS OF DIABATIC HEATING...DIFFERENTIAL HEATING CIRCULATIONS
WILL BE ON THE WANE. HOWEVER...CONDITIONAL INSTABILITY WILL BE
SUFFICIENT FOR A FEW THUNDERSTORMS CONTINGENT UPON SURFACE FORCING
FOR ASCENT....WHICH WILL BE LACKING. THEREFORE...IN THE EVENING
FORECAST UPDATES WE HAVE REDUCED RAIN CHANCES TO 10 PERCENT...BUT
KEPT THE MENTION OF THUNDER.

HAVE A PLEASANT EVENING.
&&

.MARINE...
MODERATE TO OCCASIONALLY FRESH EAST TO SOUTHEAST BREEZES WILL PERSIST
OVER THE LOWER STRAITS BEYOND 20 NAUTICAL MILES SOUTH OF THE LOWER
FLORIDA KEYS AND MARQUESAS KEYS OVERNIGHT...WITH SEAS UP TO 5 FEET IN
THE GULF STREAM. HOWEVER...LIGHT TO GENTLE BREEZES ARE EXPECTED MOST
OTHER LOCATIONS...WITH LIGHTEST WINDS NEAR THE KEYS AND OVER FLORIDA
BAY. SHOWER COVERAGE WILL BE ISOLATED WITH A FEW THUNDERSTORMS
POSSIBLE.
&&

.AVIATION...
THROUGH 00Z/19TH...VFR SHOULD PREVAIL ACROSS AT THE ISLAND TERMINALS
THROUGH THE PERIOD. LIGHT ESE WINDS SHOULD NOT VARY BY MUCH THROUGH
SATURDAY. CANNOT RULE OUT A STRAY SHOWER OR TWO... BUT CONFIDENCE IS
GROWING THAT SATURDAY SHOULD LARGELY REMAIN DRY AT THE TERMINALS.
&&

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

$$

PUBLIC/MARINE.........KASPER
AVIATION/NOWCASTS.....MSB
DATA COLLECTION.......PARKE-DEVANAS

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