340
FXUS62 KKEY 100216
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1016 PM EDT WED SEP 9 2026
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
- MOISTURE WILL LINGER ACROSS THE REGION THROUGH THE END OF THE
WEEK, SUPPORTING RAIN AND THUNDERSTORM CHANCES.
- THE PRIMARY THREAT FOR ANY STRONGER THUNDERSTORMS WILL BE
DANGEROUS LIGHTNING STRIKES. WHEN THUNDER ROARS, GO INDOORS. IF
ON A BOAT, STAY LOW, OR GO BELOW.
- HEAT INDEX VALUES WILL RANGE FROM 100-108 DEGREES DAILY WITH
LITTLE RELIEF FROM THE MUGGY CONDITIONS OVERNIGHT. KNOW THE
SIGNS OF HEAT STRESS, TAKE FREQUENT BREAKS, AND STAY HYDRATED.
DISCUSSION
ISSUED AT 1016 PM EDT WED SEP 9 2026
AFTER DAYS OF LIGHT, OCCASIONALLY VARIABLE CONDITIONS, LIGHT TO
GENTLE EAST SOUTHEASTERLY BREEZES HAVE BECOME ESTABLISHED ACROSS
THE FLORIDA KEYS ISLAND CHAIN. BROAD SURFACE TO MID LEVEL RIDGING
WAS ABLE TO BECOME MORE ESTABLISHED OVER THE PAST DAY. BREEZES
WERE ABLE TO FRESHEN FROM LIGHT TO GENTLE TO MODERATE ACROSS THE
FLORIDA KEYS WATERS. IN THE MEANTIME, SURFACE TEMPERATURES ARE ON
TRACK TO DECREASE INTO THE LOWER 80S FOR THE NIGHT, AND DEW POINTS
CONTINUE TO LINGER IN THE MID TO UPPER 70S. SHOWER COVERAGE,
WHILE SPARSE IN THE EARLY EVENING, MAY STAY THAT WAY DURING THE
FIRST PART OF THE NIGHT. THE 00Z KKEY SOUNDING SAMPLED AN
ENVIRONMENT WITH A SURPRISING AMOUNT OF INHIBITION FOR SEPTEMBER.
HOWEVER, SUFFICIENT CAPE EXISTED IN THE UPPER ATMOSPHERE FOR
SHOWERS TO TAP INTO. THE SAMPLED PWAT, AROUND 2 INCHES, ALSO
MATCHED CIMSS-MIMIC LAYER PWAT ESTIMATES. THESE OBSERVATIONS OFFER
AN EXPLANATION AS TO WHY GOES EAST SATELLITE OBSERVATIONS SHOW A
SPARSE AMOUNT OF CLOUD COVER ACROSS THE KEYS AS OF THE EARLY
EVENING HOURS.
WHILE WEATHER IS ON THE UNEVENTFUL SIDE DURING THESE EARLY EVENING
HOURS, VIGOROUS SHOWERS NEAR THE BAHAMAS SUGGEST THE ENVIRONMENT
WILL SHIFT TO FAVORING SHOWERS AGAIN. DESPITE THE INHIBITION
SAMPLED BY THE SOUNDING, KBYX RADAR HAS DETECTED DEVELOPING
SHOWERS ACROSS THE WATERS. CONVECTIVE MODELS SUGGEST SHOWERS WILL
BE ABLE TO REDEVELOP OVER THE KEYS WATERS LATER TONIGHT. THE
ENVIRONMENT IS STILL PRIMED FOR SHOWERS AND THUNDERSTORMS. IT IS
ALSO SEPTEMBER, AND THE AVERAGE CHANCE FOR SHOWERS THIS TIME OF
YEAR IS 30 PERCENT. WE ALSO HAVE HIGH CONFIDENCE THAT A DIURNAL
TREND IN BREEZES, PEAKING IN THE EVENING WITH LULLS DURING THE
DAY, WILL BE THE NORM FOR THE REST OF THE WEEK. EXPECT ANOTHER DAY
OF EASTERLY WINDS, A CHANCE OF SHOWERS, AND HIGHS NEAR 90.
SEPTEMBER WEATHER IN THE FLORIDA KEYS CONTINUES.
MARINE
ISSUED AT 1016 PM EDT WED SEP 9 2026
NO WATCHES OR WARNINGS ARE IN EFFECT AT THIS TIME FOR THE
NEARSHORE AND OFFSHORE WATERS OF THE FLORIDA KEYS.
FROM SYNOPSIS: RIDGING ESTABLISHED ACROSS FLORIDA RESULTED IN GENTLE TO
OCCASIONALLY MODERATE EAST TO SOUTHEASTERLY BREEZES. EXPECT
BREEZES TO PEAK IN THE EVENING AND OVERNIGHT WHILE LULLING DURING
THE DAY DURING THE NEXT SEVERAL DAYS. A SERIES OF LOWER LEVEL
MOISTURE SWATHES WILL SUPPORT PERIODS OF ELEVATED RAIN AND THUNDER
CHANCES.
AVIATION
(00Z TAFS)
ISSUED AT 1016 PM EDT WED SEP 9 2026
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH FOR THE UPCOMING
PERIOD. NEAR SURFACE WINDS WILL REMAIN EAST TO SOUTHEASTERLY NEAR
10 KNOTS OUTSIDE OF SHOWERS. SHOWER COVERAGE IS EXPECTED TO
INCREASE AFTER MIDNIGHT, BUT EXACT TIMES ARE UNCERTAIN. IFR TO
LIFR CONDITIONS ARE POSSIBLE DURING THE HEAVIEST SHRA.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 92 83 92 82 / 50 40 60 30
MARATHON 90 83 90 82 / 40 50 40 30
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....DM
VISIT US ON THE WEB AT WEATHER.GOV/KEY
FOLLOW US ON FACEBOOK AND X AT:
WWW.FACEBOOK.COM/NWSKEYWEST
WWW.X.COM/NWSKEYWEST
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page