Special Marine Warning 52, NWS Key West, FL

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1012 PM EDT FRI APR 20 2012

.DISCUSSION...
IR SATELLITE IMAGES SHOW CLOUDS INCREASING IN COVERAGE ACROSS THE
KEYS SERVICE AREA THIS EVENING. KBYX RADAR HAS SHOWN THAT THE HIGHEST
COVERAGE OF SHOWERS THUS FAR HAS MAINTAINED ALONG AND OUTSIDE OF OUR
NORTHWESTERN MARINE ZONES. EARLIER CUBAN CONVECTION BASICALLY FELL
APART BEFORE MAKING SIGNIFICANT SEPARATION FROM LAND AND INTO OUR
OUTER ATLANTIC ZONES. WINDS ARE FROM THE SOUTHEAST CLOSER TO 10 MPH
AT THE ISLAND SENSORS...AND CURRENTLY BETWEEN 10 TO 15 KNOTS AT THE
REPORTING CMAN SITES.

THE LATE EVENING LOCAL SOUNDING SHOWS A CONVECTIVELY INHIBITING
LAYER JUST OFF THE SURFACE. BUT THIS IS NOT VERY STRONG AND SHOULD
DIMINISH THROUGH THE OVERNIGHT PERIOD BY INCREASINGLY VEERED PROFILE. WINDS
SHOULD CONTINUE TO INCREASE LATE IN THE OVERNIGHT PERIOD AS WELL.
ALTHOUGH CONVECTIVE ACTIVITY UPSTREAM HAS HAD DIFFICULTY MAINTAINING
ITSELF...SCATTERED SHOWERS AND THUNDERSTORMS ARE A GOOD BET THROUGH
THE LATER HOURS OF THE OVERNIGHT PERIOD. MOISTURE SHOULD CONTINUE TO
INCREASE...AND WE SHOULD REMAIN IN A FAVORABLE LOCATION UNDER A JET
STREAKING THROUGH THE SOUTHERN GULF. HAVE ALREADY SENT A ZONE UPDATE TO
ADJUST SKY WORDING TO INCREASING CLOUDINESS...AND NUDGED OUR TEMPERATURES UP
TO THE MID 70S AS AN OVERNIGHT LOW MOST LOCATIONS. NO OTHER CHANGES
WERE MADE TO ANY OTHER PERIOD OF THE AFTERNOON ZONE ISSUANCE.

&&

.MARINE...
WINDS CONTINUE TO MODERATE FROM THE SOUTHEAST. THEY WILL TURN
STEADILY THROUGH THE SOUTH OVERNIGHT AND STRENGTHEN FROM THE
SOUTH SOUTHWEST ON SATURDAY. SHOWER AND THUNDERSTORM COVERAGE IS
EXPECTED TO INCREASE LATER TONIGHT...AND MORESO ON SATURDAY. BOATERS
SHOULD BE AWARE THAT WINDS WILL ALSO INCREASE...EVEN AWAY FROM ANY
CONVECTIVE ACTIVITY...AND AN ADVISORY FOR SMALL CRAFT IS LIKELY ON
ALL WATERS...MAYBE AS EARLY AS SATURDAY EVENING. ALSO...THERE IS A
HIGH PROBABILITY FOR SPECIAL MARINE WARNINGS THROUGH THE DAY
SATURDAY. THAT POTENTIAL WILL CARRY THROUGH SATURDAY NIGHT AND AT
LEAST EARLY SUNDAY. TAKE THESE EXPECTATIONS INTO CONSIDERATION IF
PLANNING ANY BOATING ACTIVITIES THIS WEEKEND.

&&

.AVIATION...
THROUGH 22/00Z: VFR CONDITIONS WILL PREVAIL AT EYW AND MTH THROUGH
08Z. SHOWERS AND POTENTIALLY STRONG THUNDERSTORMS WILL INCREASE IN
COVERAGE AND PERIODICALLY CROSS EYW AND MTH AFTER 08Z...BRINGING
EXTENDED PERIODS OF SUB-VFR CONDITIONS. PLEASE CHECK FUTURE TERMINAL
FORECASTS FOR UPDATES ON TIMING AND INTENSITY. SOUTHEAST TO SOUTH
WINDS WILL INCREASE TO 15 TO 20 KNOTS FROM JUST OFF THE SURFACE UP
TO 3000 FEET BY 06Z. SOUTH TO SOUTHWESTERLY WINDS WILL THEN INCREASE
TO 20 TO 35 KNOTS FROM JUST OFF THE SURFACE BY 21Z AT EYW AND MTH.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1877...THE HIGH
TEMPERATURE AT KEY WEST SOARED TO 89 DEGREES. THIS RECORD HIGH
TEMPERATURE FOR APRIL 20TH REMAINS STANDING 135 YEARS LATER.
TEMPERATURE RECORDS AT KEY WEST DATE BACK TO 1872.

&&

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

&&

PUBLIC/MARINE.........04
AVIATION/NOWCASTS.....NELSON
DATA COLLECTION.......PARKE

VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE KEY WEST FL
642 AM EDT FRI APR 20 2012

FLZ076>078-GMZ031>034-042>044-052>055-072>075-211100-
MONROE UPPER KEYS-MONROE MIDDLE KEYS-MONROE LOWER KEYS-
FLORIDA BAY INCLUDING BLACKWATER AND BUTTONWOOD SOUNDS-
BAYSIDE AND GULF SIDE FROM CRAIG KEY TO HALFMOON SHOAL OUT TO
5 FATHOMS-
GULF WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE 20 TO 60 NM OUT
AND BEYOND 5 FATHOMS-
GULF OF MEXICO INCLUDING DRY TORTUGAS AND REBECCA SHOAL CHANNEL-
HAWK CHANNEL FROM OCEAN REEF TO CRAIG KEY OUT TO THE REEF-
HAWK CHANNEL FROM CRAIG KEY TO WEST END OF SEVEN MILE BRIDGE OUT
TO THE REEF-
HAWK CHANNEL FROM WEST END OF SEVEN MILE BRIDGE TO HALFMOON SHOAL
OUT TO THE REEF-
STRAITS OF FLORIDA FROM OCEAN REEF TO CRAIG KEY OUT 20 NM-
STRAITS OF FLORIDA FROM CRAIG KEY TO WEST END OF SEVEN MILE
BRIDGE OUT 20 NM-
STRAITS OF FLORIDA FROM WEST END OF SEVEN MILE BRIDGE TO SOUTH OF
HALFMOON SHOAL OUT 20 NM-
STRAITS OF FLORIDA FROM HALFMOON SHOAL TO 20 NM WEST OF DRY
TORTUGAS OUT 20 NM-
STRAITS OF FLORIDA FROM OCEAN REEF TO CRAIG KEY 20 TO 60 NM OUT-
STRAITS OF FLORIDA FROM CRAIG KEY TO WEST END OF SEVEN MILE
BRIDGE 20 TO 60 NM OUT-
STRAITS OF FLORIDA FROM WEST END OF SEVEN MILE BRIDGE TO SOUTH OF
HALFMOON SHOAL 20 TO 60 NM OUT-
STRAITS OF FLORIDA FROM HALFMOON SHOAL TO 20 NM WEST OF DRY
TORTUGAS 20 TO 60 NM OUT-
642 AM EDT FRI APR 20 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE FLORIDA KEYS AND
ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

THERE WILL BE A CHANCE OF THUNDERSTORMS AFFECTING THE FLORIDA KEYS
AND SURROUNDING WATERS FROM THIS EVENING THROUGH TONIGHT. THE PRIMARY
THUNDERSTORM HAZARDS WILL BE STRONG GUSTY WINDS AND CLOUD TO SURFACE
LIGHTNING STRIKES.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

...A FEW THUNDERSTORMS MAY BE STRONG SATURDAY THROUGH
   SUNDAY MORNING...
...A SMALL CRAFT ADVISORY WILL LIKELY BE REQUIRED ON ALL KEYS COASTAL
   WATERS SATURDAY NIGHT THROUGH SUNDAY NIGHT...

A MIGRATING LOW PRESSURE SYSTEM IS EXPECTED TO PULL A TROUGH THROUGH
OUR REGION SUNDAY. AHEAD OF THIS TROUGH...SHOWERS AND THUNDERSTORMS
WILL INCREASE IN COVERAGE SATURDAY AND SATURDAY NIGHT. SOME OF THE
STRONGER SHOWERS AND THUNDERSTORMS MAY WARRANT WARNINGS AND OR
STATEMENTS.

THE PRIMARY THUNDERSTORM HAZARDS WILL BE STRONG GUSTY WINDS AND
CLOUD TO SURFACE LIGHTNING STRIKES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED THIS WEEKEND.