399
FXUS62 KKEY 161409
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1009 AM EDT TUE SEP 16 2025
..NEW DISCUSSION, MARINE, AVIATION
DISCUSSION
ISSUED AT 1015 AM EDT TUE SEP 16 2025
SKIES ACROSS THE FLORIDA KEYS ARE COMPARATIVELY CALM FOR A
SEPTEMBER DAY. THE KBYX RADAR IS CURRENTLY DETECTING INDIVIDUAL
SHOWERS WITH A STRAY THUNDERSTORM OVER THE WESTERN WESTERN WATERS.
SATELLITE OBSERVATIONS HIGHLIGHT DISORGANIZED LINES OF CUMULUS
CLOUDS OVER THE CWA AMIDST HIGH ALTITUDE BLOWOFF FROM
THUNDERSTORMS OVER THE WESTERN CARIBBEAN. LIGHT TO GENTLE NEAR
SURFACE BREEZES OUT OF THE EAST-SOUTHEAST WILL KEEP DIRECTING
MOISTURE ACROSS THE KEYS. DEW POINTS ALONG THE ISLAND CHAIN ARE IN
THE MID TO UPPER 70S. THE MORNING KKEY SOUNDING SAMPLED A PWAT
VALUE SLIGHTLY OVER THE 50TH PERCENTILE VALUE FOR THE DAY, WITH
DRIER LAYERS IN THE LOW ATMOSPHERE AND ABOVE 500 MB. WHILE THIS
TEMPTS FATE, THE OUTLOOK FOR THIS AFTERNOON APPEARS QUIET.
THE PRIOR COUPLE OF DAYS WERE DRIER ACROSS THE KEYS, BUT
ADVECTED LAYER PRECIPITABLE WATER DERIVED IMAGES FROM POLAR
ORBITING SATELLITES HIGHLIGHTS PLUMES OF MOISTURE FROM THE
SOUTHWEST ARE LIFTING BACK OVER THE KEYS. A WEAK BOUNDARY SOUTH OF
THE ISLAND CHAIN IS EXPECTED TO LIFT BACK NORTH THROUGH THE NEXT
24 HOURS AND BRING A RETURN OF DAMP CONDITIONS ACROSS THE CWA.
WHILE THE HEAVIEST SHOWERS ARE EXPECTED TOMORROW, RAINFALL COULD
START AS EARLY AS THIS EVENING. CHECKING THE RADAR AND MAKING SURE
YOU HAVE AN UMBRELLA IS ADVISED, AND REMEMBER TO TAKE SHELTER
DURING THUNDERSTORMS!
MARINE
ISSUED AT 1015 AM EDT TUE SEP 16 2025
THERE ARE CURRENTLY NO WATCHES, WARNINGS, OR ADVISORIES IN EFFECT
FOR THE FLORIDA KEYS COASTAL WATERS. FROM SYNOPSIS, A VERY
STUBBORN, WEAK FRONTAL BOUNDARY IN THE VICINITY OF THE FLORIDA
KEYS WILL DRAG CLOSER TO SOUTHERN FLORIDA OVER THE NEXT FEW DAYS.
THE RESULTING INCREASE IN MOISTURE WILL LEAD TO SHOWERS AND
THUNDERSTORMS WITH THE MOST ACTIVITY EXPECTED SOME TIME OVER
WEDNESDAY AND THURSDAY. FRESHENING NORTHEASTERLY TO EASTERLY
BREEZES WILL PEAK WEDNESDAY NIGHT, AND SMALL CRAFT SHOULD EXERCISE
CAUTION HEADLINES MAY BE NEEDED, ESPECIALLY ACROSS THE WATERS TO
THE SOUTH OF THE ISLAND CHAIN. BREEZES SHOULD SLACKEN AND WEATHER
CONDITIONS SHOULD DRY OUT TO SOME DEGREE AS WE HEAD INTO THE
WEEKEND.
AVIATION
(12Z TAFS)
ISSUED AT 1015 AM EDT TUE SEP 16 2025
VFR CONDITIONS WILL PREVAIL FOR EYW AND MTH FOR THE 12Z TAF
PERIOD. SHOWERS AND THUNDERSTORMS WERE LEFT OUT OF THE TAFS DUE TO
LOW CONFIDENCE ON WHERE AND WHEN CONDITIONS WILL DEVELOP, AND
AMENDMENTS WILL BE ISSUED AS NECESSARY. NEAR SURFACE WINDS WILL
REMAIN IN THE 5 TO 10 KNOT RANGE AND SHIFT FROM EAST SOUTHEASTERLY
TO NORTHEASTERLY TONIGHT.
PREV DISCUSSION
ISSUED AT 443 AM EDT TUE SEP 16 2025
WEATHER CONDITIONS HAVE MOSTLY BEEN BENIGN DURING THIS OVERNIGHT
SHIFT. SOME MOISTURE IN THE LOWER TO MID LEVELS WAS NOTED ON THE
00Z KKEY SOUNDING FROM LAST NIGHT, AND THAT SEEMED TO BE ENOUGH TO
NURTURE A LITTLE BIT OF SHOWER AND THUNDERSTORM ACTIVITY A FEW
HOURS AGO. THOUGH OUR KBYX RADAR IS NOT CURRENTLY DETECTING ANY
ACTIVITY WITHIN OUR CWA, IT IS PICKING UP ON THE CLUSTERS OF
SHOWERS AND THUNDERSTORMS JUST OFF OF THE NORTH SHORE OF WESTERN
CUBA. WHILE IT DOESN'T LOOK LIKE THEY WILL TRIGGER ANY EXCITEMENT
NEARBY THIS MORNING, IT DOES TELL US THAT THE ENVIRONMENT IN THAT
DIRECTION IS MORE FAVORABLE FOR DEEP CONVECTION. FOR NOW, WE ARE
ADVERTISING A 30 PERCENT CHANCE FOR RAIN ALONG THE ISLAND CHAIN
TODAY. HOWEVER, THE FUTURE SOUNDING WHEN WE LAUNCH THE MORNING
BALLOON IN A FEW HOURS WILL BE TELLING, AND MAY WARRANT A FORECAST
UPDATE WITH HIGHER PRECIP CHANCES.
WE HAVE DONE A LOT OF TALKING (TYPING) ABOUT THIS WEAK BOUNDARY IN
THE GENERAL AREA, AND IT LOOKS LIKE IT WILL NUDGE ITS WAY BACK
INTO SOUTHERN FLORIDA TODAY AND TONIGHT. AS THAT HAPPENS, ENHANCED
MOISTURE WILL LEAD TO AN INCREASE IN SHOWER ACTIVITY. THE WETTEST
TIMEFRAME LOOKS LIKE IT WILL BE BETWEEN WEDNESDAY AFTERNOON
THROUGH THURSDAY EVENING AS PROBABILISTIC GUIDANCE IS SHOWING
ANYWHERE FROM A 70 TO 90 PERCENT CHANCE OF ANY ACCUMULATING
RAINFALL DURING THAT PERIOD. THERE IS STILL A LOT OF UNCERTAINTY
REGARDING HOW LONG THIS BOUNDARY LINGERS, BUT MOST OF THE GUIDANCE
SUGGESTS THAT SOME RELIEF MAY COME CLOSER TO THE START OF THE
WEEKEND. GUIDANCE WON'T BE ABLE TO PAINT A CLEARER PICTURE UNTIL
OUR WEATHER BECOMES MORE ACTIVE, SO WE WILL CONTINUE TO CONVEY THE
LOW CONFIDENCE IN THE EXTENDED FORECAST PERIOD. OVERALL, WE ARE
ENTERING YET ANOTHER WET AND SOGGY STRETCH, BUT THE FLORIDA
SUNSHINE HAS TO RETURN EVENTUALLY.
CLIMATE
ON THIS DAY IN 1935, THE DAILY RECORD RAINFALL OF 5.04" WAS RECORDED
IN KEY WEST. PRECIPITATION RECORDS FOR KEY WEST DATE BACK TO 1871.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 89 79 89 77 / 30 60 70 80
MARATHON 89 79 88 78 / 30 60 70 70
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....JAM
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