856
FXUS62 KKEY 090216
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1016 PM EDT TUE SEP 8 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 TUE SEP 8 2026
A QUIET LATE AFTERNOON CAME TO AN END THIS EVENING OVER THE WATERS
NORTH OF THE FLORIDA KEYS. SHORTLY BEFORE SUNSET, ISOLATED
SHOWERS RAPIDLY DEVELOPED INTO THUNDERSTORMS JUST NORTH OF KEY
WEST. ADDITIONAL THUNDERSTORMS THAT DEVELOPED OVER THE EVERGLADES
ALSO SENT OUTFLOW BOUNDARIES TOWARDS THE KEYS, ONE CAPABLE OF
GENERATING WIND GUSTS UP TO 34 KNOTS. THIS BURST OF CONVECTION IS
WHY, DESPITE A NEARLY CLEAR RADAR FOR MOST OF THE DAY, WE HAVE
BEEN KEEPING SHOWER CHANCES NEAR NORMAL. TYPICAL WEATHER
CONDITIONS FOR THE KEYS IN SEPTEMBER MEANS EVEN TINY SHOWERS CAN
RAPIDLY BUILD INTO 40,000 TO 50,000 FT BEHEMOTHS. EXPECT SHOWERS
THAT DO FORM OVERNIGHT TO DEVELOP AND COLLAPSE RAPIDLY.
AWAY FROM THE NEARBY SHOWERS AND THUNDERSTORMS, CONDITIONS REMAIN
RELATIVELY BENIGN TONIGHT. ANEMOMETERS ALONG THE REEF WERE TOO FAR
FROM THE THUNDERSTORMS TO OBSERVE DOWNDRAFTS. TEMPERATURES ALONG
THE KEYS ARE SLOWLY DECREASING TOWARDS THE LOWER 80S. CIMSS-MIMIC
PWAT ESTIMATES STILL CALCULATE OVER 2 INCHES OVER THE FLORIDA
KEYS. NIGHTTIME SHOWERS HAVE ALSO BEEN ABLE TO GENERATE LAYERS OF
CIRRUS CLOUDS THAT WILL LINGER OVER THE WATERS SURROUNDING THE
ISLAND CHAIN. SURFACE WINDS ARE FORECAST TO BECOME PREVAILING EAST
TO SOUTHEASTERLIES AS THE ATLANTIC RIDGE LIFTS NORTH, AWAY FROM
SOUTHERN FLORIDA. WE MAY SEE SHOWER DEVELOPMENT AHEAD OF
FRESHENING BREEZES. HOWEVER, FOR THE TYPICAL PERSON IN THE KEYS?
TONIGHT, EXPECT LOWS IN THE LOWER TO MID 80S ONCE AGAIN, LIGHT
WINDS, AND SHORT LIVED SHOWERS. TOMORROW, BRACE FOR HIGHS NEAR 90,
DEW POINTS IN THE UPPER 70S, HEAT INDICES FROM 100 TO 105 DEGREES,
AND A CHANCE OF SHOWERS.
MARINE
ISSUED AT 1016 PM EDT TUE SEP 8 2026
NO WATCHES, WARNINGS, OR ADVISORIES ARE IN EFFECT FOR THE FLORIDA
KEYS COASTAL WATERS. FROM SYNOPSIS, FLORIDA KEYS COASTAL WATERS
WILL INITIALLY REMAIN UNDER A BROAD NEBULOUS PRESSURE PATTERN
TONIGHT, LEADING TO LIGHT AND VARIABLE WINDS. BY EARLY WEDNESDAY,
THE WESTERN EXTENT OF THE ATLANTIC RIDGE WILL BEGIN BUILDING IN
AND ALLOW BREEZES TO BECOME MORE EASTERLY WHILE FRESHENING TO
GENTLE TO MODERATE. WAVES OF LOW- LEVEL MOISTURE PUSHING ACROSS
THE KEYS WILL SUPPORT ELEVATED RAIN AND THUNDER CHANCES THROUGH
SUNDAY.
AVIATION
(00Z TAFS)
ISSUED AT 1016 PM EDT TUE SEP 8 2026
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH. SURFACE WINDS WILL BE
LIGHT AND VARIABLE EARLY IN THE PERIOD, BUT ARE FORECAST TO BECOME
PREVAILING EAST TO SOUTHEASTERLIES. LIGHT WINDS AND COPIOUS
MOISTURE INDICATES SHOWER AND THUNDERSTORMS MAY BE ABLE TO FORM
NEAR THE TERMINALS AND CAUSE BRIEF BOUTS OF SUB VFR CONDITIONS AND
POSSIBLE VCTS.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 82 92 82 92 / 30 30 30 50
MARATHON 84 91 83 90 / 30 30 50 40
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....DM
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