Area Forecast Discussion
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FXUS62 KKEY 040814
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
414 AM EDT WED MAY 4 2016

.DISCUSSION...
CURRENTLY - A SURFACE TROUGH EXTENDS ALONG THE ATLANTIC
COAST...ACROSS NORTH FLORIDA AND INTO THE GULF OF MEXICO. WHILE A
RIDGE EXTENDS WESTWARD ACROSS CUBA. LIGHT AND VARIABLE WINDS HAVE
FIRMED UP A BIT OUT OF THE SOUTH EARLY THIS MORNING. LOW LEVEL
CONVERGENCE THAT HAD SUPPORTED CONVECTIVE ACTIVITY OVER THE FLORIDA
STRAITS EARLIER IN THE NIGHT CEASED AND ALONG WITH IT...SO DID THE
CONVECTION. CURRENTLY NO SHOWERS ARE PRESENT IN THE FORECAST AREA.
TEMPERATURES AND DEW POINTS REMAIN IN THE UPPER 70S THANKS TO THE
QUITE WARM AND MOIST AIR MASS THAT HAS INVADED THE AREA OVER THE PAST
SEVERAL DAYS. STEEPING BACK TO THE LARGER SCALE...A MID LATITUDE
TROUGH CONTINUES TO DIG SOUTHWARD INTO THE EXTREME SOUTHEASTERN
UNITED STATES AND NORTHERN GULF MEXICO...SUPPORTING THE ALREADY
MENTIONED SURFACE TROUGH. SHOWER AND THUNDERSTORMS ARE ALIGNED
ACROSS CENTRAL AND NORTHERN FLORIDA...AND THE ADJACENT LARGE BODIES
OF WATERS...AND AS YET...HAVE NOT STARTED TOWARDS THE KEYS.

SHORT TERM - SURFACE WINDS WILL STEADILY STRENGTHEN OUT OF THE
SOUTHWEST THEN WEST AS THE SURFACE TROUGH DIGS FURTHER SOUTHWARD
TOWARDS THE FLORIDA KEYS. OUTSIDE OF IMPULSES IN THE LAGGING TROUGH
ALOFT...THE BEST I CAN SEE IS A BROAD AREA OF DIFFLUENT FLOW. WITH
THAT SAID...EXCELLENT MOIST CYCLONIC FLOW ON THE LEADING FLANK OF THE
LOWER LEVEL TROUGH...ALONG WITH RICH DEEP LAYERED MOISTURE...NO
INHIBITION...AND DECENT CAPE WILL SUPPORT AT LEAST A ROUND OF
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON AND EVENING.

WINDS WILL TURN NORTHWEST THIS EVENING AS THE FIRST OF A NUMBER OF
SURFACE TROUGH SPOKES PUSH THROUGH THE KEYS. BREEZY NORTHWEST WINDS
WILL RELAX OVERNIGHT. A COOLER AND MUCH DRIER AIR MASS WILL SPREAD
ACROSS THE KEYS IN WAKE OF THE LATE SEASON COLD FRONT...CUTTING RAIN
CHANCES TO SLIM TO NONE. THE FOLLOWING SPOKES WILL PUSH THROUGH THE
KEYS OVER THE REMAINDER OF THE WORK WEEK...HOLDING WINDS NORTHWEST
TO NORTH. THE COMBINATION OF THE REINFORCING TROUGHS AND HEATING AND
COOLING CYCLES OVER SOUTH FLORIDA WILL RESULT IN CONSIDERABLE
VARIATIONS IN WIND SPEEDS...GENERALLY LULLING EARLY IN THE DAY...AND
SURGING IN THE LATE AFTERNOON AND EVENING. THE GREATEST SWINGS WILL
OCCUR IN LOCATIONS CLOSET TO THE FLORIDA PENINSULA. EXPECT
TEMPERATURES TO DIP ABOUT 5 DEGREES BELOW NORMAL WITH DEW POINTS
FALLING TO NEAR 60 DEGREES BY LATE IN THE WEEK.

THE PARENT LOW WILL FINALLY LIFT NORTHEASTWARDS AWAY FROM FLORIDA ON
SATURDAY...LEAVING A WEAK RIDGE ACROSS SOUTH FLORIDA AND THE KEYS.
AFTER ANOTHER COOLER THAN NORMAL SATURDAY NIGHT...A GULF HIGH WILL
STRETCH EASTWARDS ACROSS FLORIDA INTO THE ATLANTIC THROUGH THE BACK
HALF OF THE WEEKEND. THIS WILL RETURN THE KEYS TO A MORE CUSTOMARY
LIGHT TO GENTLE EASTERLY FLOW AND A RETURN TO NEAR NORMAL CONDITIONS.

&&

.MARINE...
LIGHT SOUTHERLY BREEZES WILL STRENGTHEN AND VEER SOUTHWEST TO WEST
TODAY AS A LATE SEASON TROUGH MOVES NEARER THE FLORIDA KEYS. EXPECT
AT LEAST A ROUND OF SHOWERS AND THUNDERSTORMS TO AFFECT KEYS WATERS
THIS AFTERNOON INTO THIS EVENING. A SMALL CRAFT ADVISORY WILL LIKELY
BE REQUIRED FOR ALL KEYS WATERS BY TONIGHT. SURFACE WINDS WILL SHIFT
NORTHWEST BEHIND THE TROUGH AND SLACKEN SOMEWHAT OVERNIGHT. A FEW
MORE REINFORCING TROUGHS WILL PUSH THROUGH KEYS WATERS THURSDAY
THROUGH FRIDAY. THIS WILL KEEP WINDS MOSTLY MODERATE OUT OF THE
NORTHWEST. THIS SYNOPTIC SET UP USUALLY RESULTS IN CONSIDERABLE
VARIATIONS IN WIND SPEEDS...USUALLY LULLING EARLY IN THE DAY AND
SURGING LATE IN THE AFTERNOON AND EVENING ON WATERS CLOSEST TO THE
FLORIDA PENINSULA. EXPECT A COMPLICATED MIX OF CAUTIONS AND POSSIBLY
ADVISORIES FOR PORTIONS OF KEYS WATERS THROUGH THE SECOND HALF OF THE
WEEK. LIGHT WINDS SATURDAY AND SATURDAY NIGHT WILL SHIFT EAST AND
STRENGTHEN BACK TO A MORE NORMAL GENTLE EAST FLOW LATE IN THE WEEKEND
AS A RIDGE FILLS IN BEHIND THE LIFTING OUT LOW.

&&

.AVIATION...
UNTIL 06Z/5TH...VFR AND GENTLE SOUTHERLY BREEZES WILL
PREVAIL AT THE EYW AND MTH TERMINALS THIS MORNING. A LATE SEASON
COLD FRONT WILL PUSH THROUGH THE TERMINALS OVERNIGHT. AHEAD OF THE
FRONT...SHOWERS AND THUNDERSTORMS APPEAR LIKELY FOR BOTH TERMINALS
BETWEEN 21Z AND 03Z. CONVECTIVE MODE MAY FAVOR THE DEVELOPMENT OF A
SOLID LINE OF SHOWERS AND STORMS. BOTH TERMINALS CAN EXPECT IFR
CIG/VIS AND CONVECTIVE WIND GUSTS APPROACHING 30 KNOTS. A CLEARING
TREND APPEARS LIKELY AFTER 04-06Z...IN CONJUNCTION WITH MILD
NORTHWEST CROSSWINDS.

&&

.CLIMATE...MAY 4TH...ON THIS DATE IN KEY WEST CLIMATE HISTORY...IN
1977...THE DAILY RECORD RAINFALL OF 5.33" WAS RECORDED.
PRECIPITATION RECORDS IN KEY WEST DATE BACK TO 1871.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  83  74  81  72 / 70 70 10 10
MARATHON  87  74  81  71 / 70 70 10 10

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY FOR DEEP GULF ZONES GMZ033-034

&&

$$

PUBLIC/MARINE.........11
AVIATION/NOWCASTS.....CLR

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