813
FXUS62 KKEY 081917
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
317 PM EDT TUE JUL 8 2025
..NEW AVIATION
AVIATION
(18Z TAFS)
ISSUED AT 306 PM EDT TUE JUL 8 2025
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH EYW AND MTH FOR THE
REST OF TODAY AND INTO TONIGHT. WHILE A FEW CLOUDLINES HAVE
ATTEMPTED TO FORM IN THE VICINITY OF THE ISLAND CHAIN, NONE HAVE
DEVELOPED IN SUCH A WAY THAT IMPACTS EITHER TERMINAL YET.
MEANWHILE, A CLUSTER OF THUNDERSTORMS MOVING SOUTHWEST OFF OF
SOUTH FLORIDA POSES SOMEWHAT OF A THREAT TO THE LOWER KEYS IF IT
HOLDS TOGETHER OVER THE NEXT FEW HOURS, BUT LOW CONFIDENCE IN IT
SURVIVING THE TRIP WILL KEEP MENTION OUT OF THE TAFS FOR NOW.
SHORT TERM AMENDMENTS WILL COVER ANY UNEXPECTED DEVELOPMENTS
RELATING TO REIGNITING CLOUD LINES AND THE PREVIOUSLY MENTIONED
THUNDERSTORM CLUSTER. NEAR SURFACE WINDS WILL BE OUT OF THE
NORTHEAST AT 5 TO 10 KNOTS, WITH OCCASIONAL HIGHER GUSTS NEAR 15
KNOTS AT EYW EARLY.
PREVIOUS DISCUSSION
ISSUED AT 1120 AM EDT TUE JUL 8 2025
ANOTHER SUMMER DAY IS UNDERWAY ACROSS THE FLORIDA KEYS. KBYX RADAR
DETECTS A FEW SHOWERS WITH A THUNDERSTORM HERE AND THERE BUBBLING
ALONG OLD OUTFLOW BOUNDARIES IN THE STRAITS OF FLORIDA AND IN THE
GULF WATERS WEST OF THE LOWER KEYS. MEANWHILE, GOES-19 VISIBLE
IMAGERY NOTES CUMULUS CLOUD STREAMERS PROPAGATING SOUTHWEST OFF OF
THE MIDDLE KEYS WITH NOT MUCH ELSE OVER THE ISLAND CHAIN. THIS HAS
ALLOWED FOR A WARM START TO TODAY WITH TEMPERATURES ON LAND ALREADY
READING IN THE MID TO UPPER 80S. MODERATE NORTHEAST TO EAST WINDS
PREVAIL ALONG THE REEF AND UP INTO SOUTH FLORIDA WITH A MAINLAND
SHADOW KEEPING SKIES CLEAR IN OUR GULF WATERS JUST OFF OF
FLORIDA'S WEST COAST. OVERALL, BREEZES ARE SLIGHTLY HIGHER THAN
YESTERDAY WHILE SHOWER COVERAGE HAS SHIFTED MORE TO OUR SOUTHERN
WATERS.
THE SHORT TERM FORECAST FINDS US IN A BIT OF A LULL REGARDING RAIN
CHANCES. NORMALLY, A TYPICAL SUMMER DAY WITH GENTLE TO MODERATE
NORTHEAST BREEZES AND AVERAGE MOISTURE CONTENT WOULD POINT US
TOWARDS CLOUDLINES FORMING ALONG THE ISLAND CHAIN. WHILE THIS
ISN'T ENTIRELY OUT OF THE QUESTION, THERE ARE A FEW FACTORS
WORKING AGAINST IT TODAY. WHILE THIS MORNING'S KKEY SOUNDING DID
OBSERVE A NEAR NORMAL PW VALUE (~1.8 INCHES), CIMSS MIMIC TPW
DEPICTS A SWATH OF RELATIVELY DRY AIR (PW OF ~1.6 INCHES) OVER
THE KEYS BETWEEN A SLUG OF TROPICAL MOISTURE IN THE GULF AND
MOISTURE ASSOCIATED WITH THE INCOMING INVERTED TROUGH CHURNING
THROUGH THE EAST END OF THE BAHAMAS. FURTHERMORE, DRY AIR OBSERVED
JUST ABOVE THE INVERSION AT 900 MB MAY ALSO BE ENTRAINING INTO
POCKETS OF DEVELOPING CONVECTION MAKING ANY DEEP DEVELOPMENT SHORT
LIVED AT BEST. FINALLY, BREEZES ARE A TOUCH HIGHER THAN THE USUAL
NEARLY STATIONARY CLOUDLINE LIKES TO LIVE IN. DESPITE ALL OF THESE
FACTORS WORKING AGAINST RAINFALL, WE STILL ARE OPTING TO SIT ON
THE HIGHER SIDE OF GUIDANCE WITH SLIGHT RAIN CHANCES JUST BELOW
NORMAL FOR THIS TIME OF YEAR. AS THE PREVIOUSLY MENTIONED INVERTED
TROUGH CONTINUES TO SHIFT WEST, RAIN CHANCES WILL GRADUALLY
INCREASE THROUGH TONIGHT AND INTO TOMORROW.
FORECAST
ISSUED AT 452 AM EDT TUE JUL 8 2025
CIMSS ANALYSIS PRODUCTS HAVE BEEN VERY HELPFUL WHEN IT HAS COME TO
TRYING TO SORT THIS PATTERN OUT. MIMIC LAYER PWAT SHOWS THAT
COMPARATIVELY DRIER AIR WILL PREVAIL FOR AT LEAST TODAY, BUT AN
AREA OF ENHANCED MOISTURE EXISTS OVER THE BAHAMAS AND EASTERN
CUBA. VORTICITY ANALYSIS SHOWS AN ELONGATED AREA OF RELATIVE
VORTICITY AT THE 200 MB LEVEL OVERHEAD, BUT THIS FEATURE IS LOST
AS WE PROGRESS DOWNWARD THROUGH THE ATMOSPHERE, AND IS LIKELY
PLAYING A ROLE IN OUR QUIETER RADAR. HOWEVER, AT THE 500MB AND
700MB LEVELS, WE CAN SEE TWO AREAS OF INTEREST OVER THE BAHAMAS,
AND TO THE SOUTH OF CUBA. WITH THE DEEP LAYER STEERING FLOW
LOOKING A LITTLE KINKY, IT IS HARD TO SAY WHICH ONCE OF THESE
AREAS IS GOING TO POSSIBLY RESULT IN SOME ACTIVE WEATHER. GLOBAL
DETERMINISTIC AND ENSEMBLE GUIDANCE ARE STILL INDICATING THAT ONE
OF THESE AREAS OF CYCLONIC FLOW WILL PUSH ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY, BRINGING AN UPTICK IN MOISTURE AND
AN INCREASE IN POPS. FOR NOW, WE WILL CONTINUE TO ADVERTISE POPS
BETWEEN 30 AND 40 PERCENT FROM WEDNESDAY ONWARD, WITH A PEAK OF 50
PERCENT POPS ON THURSDAY. THE UNCERTAINTY MAINLY STEMS FROM
GUIDANCE STRUGGLING TO REFLECT THIS WAVE AT THE SURFACE, BUT THERE
ARE SOME HINTS OF AN INVERTED TROUGH IN THE LOWER LEVELS OF THE
ATMOSPHERE.
MARINE
ISSUED AT 1120 AM EDT TUE JUL 8 2025
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR
THE COASTAL WATERS OF THE FLORIDA KEY. FROM SYNOPSIS, A BUILDING
ATLANTIC HIGH WILL SUSTAIN GENTLE TO MODERATE BREEZES FOR THE NEXT
FEW DAYS. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE CLOSE TO
NORMAL THROUGH WEDNESDAY, BUT AN EASTERLY WAVE AND VEERING WINDS
MAY GENERATE ELEVATED SHOWER COVERAGE FROM WEDNESDAY EVENING
THROUGH THE END OF THE WEEK.
CLIMATE
ON THIS DAY IN 2023, THE DAILY RECORD HIGH TEMPERATURE OF 97F WAS
RECORDED AT MARATHON. TEMPERATURE RECORDS FOR MARATHON DATE BACK TO
1950.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 81 91 81 91 / 20 30 40 50
MARATHON 81 89 81 89 / 20 30 40 50
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...JAM
AVIATION/NOWCASTS....JAM
DATA ACQUISITION.....JAM
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