FXUS62 KKEY 110915
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
415 AM EST SAT FEB 11 2012

.DISCUSSION...
CURRENTLY - A STRONG COLD FRONT IS SWEEPING RAPIDLY SOUTHEASTWARD
ACROSS THE GULF OF MEXICO. SWATHES OF SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED AHEAD OF THE FRONT NEAR A PREFRONTAL TROUGH. THIS ACTIVITY
IS BEING SUPPORTED ALOFT BY THE SUBTROPICAL JETS RIGHT ENTRANCE
REGION PASSING OVERHEAD. THE SHOWERS AND THUNDERSTORMS ARE MOVING
RAPIDLY EASTWARD AT 25 TO 35 KNOTS ACROSS OUR GULF AND BAY ZONES AND
THE FLORIDA STRAITS. THUS FAR...ONLY THE EXTREME UPPER KEYS HAS BEEN
AFFECTED BY STRONGER ACTIVITY. SKIES HAVE BECOME CLOUDY WITH A
LOCALLY LIGHT WESTERLY FLOW DEVELOPING. A WARM AND MOIST AIR MASS
REMAINS ACROSS THE KEYS...WITH TEMPERATURES IN THE LOW TO MID 70S AND
DEW POINT TEMPERATURES IN THE LOWER 70S.

FORECAST - THE STRONG SHOWERS AND THUNDERSTORMS OVER OUR GULF WATERS
HAVE BEEN TRACKING GENERALLY EASTWARD AND IS NOT MAKING MUCH IN THE
WAY OF SOUTHWARD PROGRESS. THE BEST CHANCE FOR PRECIPITATION IN THE
KEYS WILL LIKELY BE FROM ACTIVITY FORMING IN THE STRAITS OUT AHEAD
OF THE MAIN LINE OF SHOWERS AND THUNDERSTORMS. WILL RAISE POPS TO
LIKELY FOR TODAY. IT SEEMS LIKELY THAT THE STRONGER SHOWERS AND
THUNDERSTORMS WILL REMAIN AWAY FROM THE KEYS...ESPECIALLY AS THE
SUPPORT ALOFT MOVES RAPIDLY NORTHEASTWARD OUT OF OUR AREA EARLY THIS
MORNING. THE FRONT WILL MOVE THROUGH THE KEYS TODAY SHUTTING OFF THE
POTENTIAL FOR HEAVY SHOWERS. RAIN WILL STILL BE POSSIBLE THROUGH THE
LATE AFTERNOON AND EVENING. THE DAY TIME HIGHS WILL OCCUR DURING
THE MORNING HOURS AS THICKNESSES BEGIN DECREASING BETWEEN 12 AND 18Z.

A STRONG ARCTIC HIGH IS DIVING SOUTHEASTWARD ACROSS THE GREAT PLAINS
AND SPREADING INTO THE GULF OF MEXICO. THE VERY TIGHT PRESSURE
GRADIENT ON ITS SOUTHEASTERN FLANK WILL BEGIN BUILDING INTO THE KEYS
AREA BEHIND THE COLD FRONT THIS AFTERNOON. NORTHWEST WINDS WILL
STRENGTHEN SIGNIFICANTLY. BREEZY CONDITIONS BY LATE THIS AFTERNOON
WILL BECOME WINDY TONIGHT...PEAKING SUNDAY MORNING. STRONG COLD AIR
ADVECTION WILL DRIVE TEMPERATURES DOWN TO THE MID TO UPPER 50S AND
DEW POINT TEMPERATURES INTO THE UPPER 30S. DRY CONDITIONS WILL SHUT
OFF ANY CHANCE OF RAIN FROM MID SATURDAY NIGHT THROUGH AT LEAST
MONDAY.

THE DOMINATING HIGH CELL WILL BEGIN TRACKING EASTWARD ALONG THE GULF
STATES ON SUNDAY...QUICKLY VEERING OUR GRADIENT. WINDS WILL QUICKLY
TURN NORTHEAST AND WEAKEN SUNDAY AFTERNOON AND NIGHT. BY LATE
MONDAY...WINDS WILL DECREASE BELOW BREEZY. MONDAY NIGHT THE FLOW
ALOFT WILL BECOME MORE ZONAL WITH ONLY WEAK RIDGING THROUGH THE LOWER
LEVELS. WINDS WILL TURN EAST BY MONDAY NIGHT...RESULTING IN A RATHER
QUICK UPWARDS TREND IN SURFACE TEMPERATURES AND MOISTURE BY MID WEEK.

&&

.MARINE...
STRONG SHOWERS AND THUNDERSTORMS WILL AFFECT KEYS COASTAL WATERS
TODAY. THESE CELLS ARE EAST TO EAST NORTHEAST AT 35 TO 45 KNOTS...AND
WILL PRODUCE HAZARDOUS MARINE CONDITIONS. WEST TO NORTHWEST WINDS
WILL INCREASE STEADILY THROUGH THE DAY AS A PREFRONTAL TROUGH SHIFTS
EAST AND SOUTHEASTWARD. WINDS WILL THEN INCREASE SHARPLY THIS
AFTERNOON AND EVENING AS A STRONG HIGH PRESSURE SYSTEM MOVES INTO THE
SOUTHEASTERN UNITED STATES...BRINGING STRONG COLD AIR ADVECTION
ACROSS THE KEYS. WINDS WILL LIKELY PICK UP TO NEAR 25 KNOTS AND GUSTY
BY LATE TONIGHT/EARLY SUNDAY. A SMALL CRAFT ADVISORY WILL BE RAISED
FOR ALL KEYS WATERS FOR THESE INCREASING WINDS. THIS WIND SURGE WILL
BE FAIRLY SHORT LIVED...AS WINDS WILL GRADUALLY DECREASE AND VEER
NORTHEAST LATE SUNDAY INTO MONDAY. ALL CAUTIONS AND ADVISORIES WILL
LIKELY NO LONGER BE NECESSARY SOMETIME MONDAY.

&&

.AVIATION...
PERIODS OF MVFR AND BRIEF IFR CONDITIONS ARE EXPECTED AT THE KEY 
WEST AND MARATHON TERMINALS THROUGH 14Z...AS A COLD FRONT AND
ASSOCIATED LINES OF SHOWERS AND ISOLATED THUNDERSTORMS MOVE THROUGH 
THE AREA. GUSTY WEST TO NORTHWEST SURFACE WINDS WILL BE POSSIBLE 
WITH THIS ACTIVITY AS WELL. TAF AMENDMENTS FOR LOCALLY MORE INTENSE 
THUNDERSTORM ACTIVITY THAT MAY AFFECT THE TERMINALS WILL BE ISSUED 
AS NEEDED. SHOWER ACTIVITY SHOULD DECREASE ACROSS THE AREA DURING
THE MID TO LATE MORNING HOURS...WITH WINDS INCREASING OUT OF THE 
NORTHWEST THROUGH THE REST OF THE DAY. NORTHERLY CROSSWINDS WILL
BECOME A CONCERN THIS AFTERNOON...WITH SUSTAINED WIND SPEEDS AROUND
15 KNOTS AND FREQUENT GUSTS OF 20 TO 25 KNOTS. MVFR CIGS WILL BE 
LIKELY TO PERSIST THROUGH MUCH OF THE DAY AS WELL...DUE TO AREAS OF 
STRATUS AND STRATOCU MOVING OFF THE GULF BEHIND THE COLD FRONT.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  76  58  64  63 / 70 10 0 0 
MARATHON  77  56  65  62 / 70 10 0 0 

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SAMLL CRAFT ADVISORY IN EFFECT FOR ALL KEYS WATERS
     GMZ031>034-042>044-052>055-072>075. 
&&

$$

PUBLIC/MARINE.........11
AVIATION/NOWCASTS.....JACOBSON

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