474
FXUS62 KKEY 050230
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1030 PM EDT SUN MAY 4 2025
..NEW DISCUSSION, MARINE, AVIATION
DISCUSSION
ISSUED AT 1030 PM EDT SUN MAY 4 2025
THE FLORIDA KEYS ARE QUIET THIS EVENING BUT IT DIDN'T START OUT
THAT WAY DURING THE LATE AFTERNOON. KBYX RADAR DEVELOPED SHOWERS
ALONG A REVERSE CLOUD LINE ACROSS THE LOWER KEYS WHICH DID
EVENTUALLY GROW TALL ENOUGH TO BE A THUNDERSTORM. HOWEVER, NOT
ONLY DID WE HAVE SHOWERS BUT IT ENDED UP BEING A SPOUTY DAY OUT
THERE. WE HAD NUMEROUS REPORTS OF WATERSPOUTS FROM SUMMERLAND KEY
EAST TO BAHIA HONDA KEY. IT WAS A FAMILY OF WATERSPOUTS TYPE OF A
DAY WITH SOME REPORTS COMING IN SHOWING TWO OCCURRING
SIMULTANEOUSLY. THE CATALYST APPEARED TO HAVE BEEN A WEAK BOUNDARY
MOVING EASTWARD WHICH IN CONCERT INTERACTED WITH THE CLOUD LINE
WHICH HELPED TO INITIATE THE CONDITIONS FOR A WATERSPOUT BONANZA
TYPE OF LATE AFTERNOON. THIS RESULTED IN AT LEAST TWO SPECIAL
MARINE WARNINGS AND A SPECIAL WEATHER STATEMENT FOR THE
AFOREMENTIONED PORTION OF THE LOWER KEYS JUST IN CASE ONE OF THESE
WATERSPOUTS DECIDED TO MOVE ON LAND. MRMS DATA SUGGEST ESTIMATED
RAINFALL AMOUNTS OF A QUARTER OF AN INCH ON LAND TO AS MUCH AS A
HALF INCH TO THREE QUARTERS OF AN INCH OVER THE WATER NEAR NILES
CHANNEL. SINCE THEN ALL ACTIVITY HAS WANED ACROSS THE AREA WITH
KBYX RADAR NOT DETECTING ANY SHOWERS AND GOES EAST NIGHTTIME
MICROPHYSICS SHOWING AN OUTFLOW BOUNDARY PROPAGATING SOUTHWESTWARD
TOWARDS THE LOWER KEYS WHICH ORIGINATED ON THE SOUTHERN MAINLAND.
TEMPERATURES ALONG THE ISLAND CHAIN ARE IN THE UPPER 70S WITH DEW
POINTS IN THE LOWER 70S.
THE FLORIDA KEYS ARE ON THE WESTERN PERIPHERY OF THE SURFACE
ATLANTIC RIDGE AS THE WEAK BOUNDARY THAT PUSHED THROUGH THE KEYS
TODAY HELPED TO ERODE THE RIDGE SOME. THIS IS LEAVING THE KEYS
SORT OF SPLIT WITH THE WESTERN ZONES MORE IN A COL REGION WITH
JUST ENOUGH INFLUENCE FROM THE BERMUDA HIGH HANGING ON FOR THE
EASTERN AREAS, ESPECIALLY THE EASTERN STRAITS OF FLORIDA. THIS IS
RESULTING IN MARINE PLATFORMS AROUND THE KEYS OBSERVING NORTHEAST
TO EAST BREEZES OF 5 TO 10 KNOTS AND ISLAND CHAIN COMMUNITIES
OBSERVING NEAR 5 MPH.
SHORT TERM FORECAST
THE 00Z EVENING SOUNDING SHOWS 3 DISTINCT MOIST LAYERS WITH THE
FIRST IN THE LOW LEVELS BETWEEN 950-925 MB, THE SECOND ONE
BETWEEN 575-525 MB, AND THE THIRD ONE BETWEEN 350-325 MB. THE PWAT
VALUE MEASURED WAS 1.51 INCHES IS CLOSE TO THE 75TH PERCENTILE
FOR THE DATE. SO WE HAVE MOISTURE. INSTABILITY WISE, WE HAVE MIXED
LAYER CAPE OF ~1300 J/KG SO SUFFICIENT BUT NOT A TON, LAPSE RATES
ARE 7-8 DEGREES CELSIUS WHICH IS DECENT. HOWEVER, WE STILL LACK A
TRIGGER TO PROVIDE MEANINGFUL FORCING TO RAISE THE AIR PARCELS.
THE ONLY THING THAT MAY STILL TRIGGER A SHOWER OR TWO OVERNIGHT IS
AN OUTFLOW BOUNDARY CONTINUING TO PROPAGATE SOUTHWESTWARD WHICH
ORIGINATED FROM THE CONVECTION EARLIER ON THE SOUTHERN MAINLAND.
BASED ON THIS, NO CHANGES TO THE ONGOING FORECAST.
MARINE
ISSUED AT 1030 PM EDT SUN MAY 4 2025
THERE ARE CURRENTLY NO WATCHES, WARNINGS, OR ADVISORIES IN EFFECT
ACROSS THE FLORIDA KEYS COASTAL WATERS. FROM SYNOPSIS, AN OUTFLOW
BOUNDARY WHICH MOVED OFF THE SOUTH FLORIDA MAINLAND CONTINUES TO
PROPAGATE SOUTHWESTWARD THROUGH THE FLORIDA KEYS COASTAL WATERS
THIS EVENING. AS A RESULT, NORTHEAST TO EAST BREEZES ARE EXPECTED
TO CONTINUE THROUGH MUCH OF THE OVERNIGHT BEFORE RESUMING A
UNIFORM EAST TO SOUTHEAST DIRECTION BY MONDAY MORNING. BREEZES ARE
EXPECTED TO GRADUALLY FRESHEN HEADING INTO MID WEEK AS THE
ATLANTIC RIDGE LIFTS NORTHWARD INTO FLORIDA AND PRESSURES FALL IN
THE GULF.
AVIATION
(00Z TAFS)
ISSUED AT 1030 PM EDT SUN MAY 4 2025
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH EYW AND MTH
TERMINALS THROUGH THE TAF PERIOD. NEAR SURFACE WINDS ARE EXPECTED
TO REMAIN NORTHEAST TO EAST AT 5 KNOTS OR LESS FOR THE NEXT FEW
HOURS BEFORE RESUMING A EAST TO SOUTHEAST DIRECTION AT 5 TO 9
KNOTS THROUGH THE REMAINDER OF THE TAF PERIOD.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 84 76 85 77 / 20 20 20 20
MARATHON 84 77 84 77 / 20 30 30 20
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...MJV
AVIATION/NOWCASTS....MJV
DATA ACQUISITION.....AJP
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