500
FXUS62 KKEY 031828
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
228 PM EDT WED SEP 3 2025
..NEW DISCUSSION, MARINE, AVIATION, PREV DISCUSSION
AVIATION
(18Z TAFS)
ISSUED AT 228 PM EDT WED SEP 3 2025
EYW AND MTH TAFS WILL BE DOMINATED BY VCSH FOR THE 18Z PERIOD.
WAVES OF VCSH WITH AN OCCASIONAL VCTS OR TSRA WILL REQUIRE
FREQUENT UPDATES FOR MVFR TO IFR VIS. OUTSIDE OF SHOWERS, CIGS ARE
LIMITED TO MVFR TO VFR. WINDS OUTSIDE OF SHOWERS ARE FORECAST TO
SHIFT SOUTHWESTERLY BUT REMAIN NEAR 10 KNOTS. A LULL IN VCSH IS
FORECAST OVERNIGHT WITH SHOWER COVERAGE INCREASING ONCE MORE
BEFORE SUNRISE. STAY TUNED FOR ADDITIONAL AMENDMENTS.
PREV DISCUSSION
ISSUED AT 1009 AM EDT WED SEP 3 2025
DRENCHED WOULD BE AN APT WORD TO DESCRIBE THE ENVIRONMENT AROUND
THE FLORIDA KEYS. THE BROAD ENVIRONMENTAL PATTERN THAT DIRECTED
DEEP LAYERS OF MOIST TROPICAL WATER ACROSS THE FLORIDA KEYS SHOWS
NO SIGNS OF STOPPING. THE MORNING KKEY RADIOSONDE SAMPLED A PWAT
OF 2.46", A NEW DAILY RECORD. WESTERLY WINDS ARE DIRECTING
UNTAPPED GULF MOISTURE AND HEAT ACROSS THE GULF AND CARIBBEAN INTO
A SYNOPTIC NEAR-STATIONARY BOUNDARY ACROSS SOUTHERN FLORIDA. THE
WEATHER PREDICTION CENTER PUT THE FLORIDA KEYS UNDER A MARGINAL
RISK (LEVEL 1 OF 4) FOR EXCESSIVE RAINFALL TODAY. CONSIDERING THE
KKEY RAIN GAUGE SAMPLED ALMOST AN INCH OF RAIN YESTERDAY, MAKES
PERFECT SENSE.
OUTSIDE OF SHOWERS, WHICH IS A BIT OF A RARITY TODAY, BREEZES
ARE RATHER PERSISTENT GENTLE TO MODERATE WESTERLIES. COPIOUS
AMOUNTS OF MOISTURE AND CLOUD COVER WILL KEEP TEMPERATURES
BELOW NORMAL FOR THE REST OF THE AFTERNOON. SHOWER ACTIVITY IS
EXPECTED TO DIMINISH TONIGHT FOLLOWING THIS AFTERNOON'S BOUTS OF
RAINFALL. HOWEVER, THE OVERALL ENVIRONMENTAL PATTERN IS NOT
FORECAST TO BREAK UNTIL SATURDAY, SO EXPECT YET MORE ROUNDS OF
SHOWERS TOMORROW.
DISCUSSION
ISSUED AT 450 AM EDT WED SEP 3 2025
THIS WET WEATHER PATTERN HAS BEEN IN PLACE ACROSS THE KEYS FOR
SEVERAL DAYS NOW AND THAT DOES NOT LOOK TO CHANGE ANYTIME SOON. A
STATIONARY FRONT FINDS ITSELF PARKED OVER SOUTH FLORIDA AND THE
FLORIDA KEYS THIS MORNING WITH A BROAD ASSOCIATED SURFACE LOW
ANALYZED SOMEWHERE NORTH OF THE BAHAMAS. MID TO UPPER LEVEL TROUGHING
ACROSS EASTERN CONUS ALONG WITH THIS SURFACE LOW WILL CONTINUE TO
PROMOTE WESTERLY BREEZES ACROSS MUCH OF OUR VERTICAL WIND PROFILE
SIMILAR TO WHAT WAS RECORDED IN YESTERDAY EVENING'S 00Z KKEY
BALLOON SOUNDING. LOOKING AT THE GULF IN CIMSS MIMIC TPW, HIGH PW
VALUES INDICATING ROBUST MOISTURE ARE FOUND NOT ONLY OVER OUR
AREA, BUT ALSO UPSTREAM IN THE GULF WATERS. THIS WILL HELP KEEP PW
VALUES CLOSE TO IF NOT BREACHING THE 90TH PERCENTILE OVER THE
NEXT FEW DAYS OR SO. WARM TEMPERATURES PROMOTING SEASONAL
INSTABILITY WITH A HIGH RESERVE OF MOISTURE ADVECTING OVER A
SYNOPTIC BOUNDARY IS A SLAM DUNK FOR HIGH RAIN CHANCES ALONG WITH
A MARGINAL RISK (LEVEL 1 OF 4) FOR EXCESSIVE RAINFALL (VIA THE
WEATHER PREDICTION CENTER) THROUGHOUT THE SHORT TERM.
UNFORTUNATELY, THIS PATTERN WILL LINGER AROUND INTO THE END OF THE
WEEK RESULTING IN MULTIPLE DAYS IN AN ENVIRONMENT CAPABLE OF
PRODUCING POTENTIALLY HEAVY, FLOODING RAINS AT TIMES. THE WIND
FORECAST IS A LITTLE MORE MURKY AS THE FUTURE LOCATION OF THE
BROAD SURFACE LOW IS SOMEWHAT UNCERTAIN. RECENT GUIDANCE HAS IT
OPENING UP INTO A BROAD TROUGH AS IT SHIFTS NORTHEAST THROUGHOUT
TODAY, THUS RESULTING IN A SOMEWHAT LIGHTER FLOW THAN PREVIOUS
RUNS. THAT BEING SAID, A MODERATE TO FRESH WESTERLY SURGE WILL
STILL BE IN THE CARDS ON THE DAILY DEPENDING ON THE ALLOWANCE OF
DAYTIME HEATING ON MAINLAND AND BEHAVIOR OF THE LOW.
WE LOOK TO FINALLY BREAK FREE OF THIS PATTERN SATURDAY AS THE MID
TO UPPER LEVEL TROUGHING AND THE SURFACE LOW EXIT TO THE
NORTHEAST. THIS WILL ALLOW WEAK RIDGING TO SLIDE BACK INTO THE
AREA WITH WINDS GRADUALLY FLIPPING BACK AROUND TO A CLOSER TO
NORMAL SOUTHEASTERLY WIND DIRECTION. WHILE THE BIG PLAYERS FOR
HEAVY RAINFALL WILL BE OUT OF THE PICTURE, ANOTHER UNDULATION OF
MOISTURE LOOKS TO SETTLE IN FROM THE EAST KEEPING RAIN CHANCES
JUST ABOVE NORMAL INTO NEXT WEEK.
MARINE
ISSUED AT 1009 AM EDT WED SEP 3 2025
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR
THE COASTAL WATERS OF THE FLORIDA KEYS. FROM SYNOPSIS, A BROAD
SURFACE LOW ALONG A STATIONARY FRONT STRETCHING FROM THE GULF
EASTWARD TO THE FLORIDA PENINSULA WILL MAINTAIN WEST TO NORTHWEST
WINDS ACROSS THE KEYS MARINE ZONES TONIGHT. THE FRONT WILL REMAIN
ROOTED IN PLACE THROUGH THE NEXT FEW DAYS, WHILE THE LOW MEANDERS
NORTHEAST INTO THE WESTERN NORTH ATLANTIC PROMOTING SOUTHWEST TO
WEST BREEZES THROUGHOUT THE WEEK. ABUNDANT MOISTURE WILL PROMOTE
ABOVE NORMAL RAIN AND THUNDER CHANCES THROUGH THE END OF THE WORK
WEEK.
CLIMATE
ON THIS DAY IN KEYS WEATHER HISTORY IN 2007, THE DAILY RECORD HIGH
TEMPERATURE OF 95F WAS RECORDED IN KEY WEST. THIS IS ALSO TIED FOR
THE WARMEST TEMPERATURE EVER RECORDED IN SEPTEMBER. TEMPERATURE
RECORDS FOR KEY WEST DATE BACK TO 1872.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 79 91 80 91 / 80 80 70 70
MARATHON 79 89 80 89 / 80 80 80 80
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....AP
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