370
FXUS62 KKEY 131549
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1149 AM EDT SAT SEP 13 2025
..NEW DISCUSSION, MARINE, AVIATION
DISCUSSION
ISSUED AT 1147 AM EDT SAT SEP 13 2025
A RELATIVELY QUIET MORNING CONTINUES ON FOR THE FLORIDA KEYS AFTER
LAST NIGHT'S ACTIVE PERIOD. SURPRISINGLY, PARTLY CLOUDY SKIES ARE
OBSERVED ON GOES-19 VISIBLE IMAGERY AS CLOUD DEBRIS FROM LAST
NIGHT'S MESOSCALE CONVECTIVE SYSTEM (MCS) SHIFTS OVER THE BAHAMAS
AND OUT OF OUR WATERS. MEANWHILE, SOME HIGH CLOUDS ARE STILL
PRESENT DUE TO PERSISTENT SHOWERS IN THE DISTANT STRAITS OF
FLORIDA, BUT ARE QUICKLY DETERIORATING. KBYX RADAR ALSO DETECTS
SOME SHOWERS PERCOLATING ALONG BOUNDARIES EXTENDING THROUGH THE
DEEP GULF WATERS AND OVER ACROSS THE MIDDLE KEYS, THOUGH LIGHTNING
HAS BEEN MORE ABSENT THEN NOT. AS THIS BOUNDARY PUSHED OVER THE
UPPER AND MIDDLE KEYS, GENTLE NORTHEAST BREEZES BACKED TO THE
NORTH ACROSS OUR EASTERN OFFSHORE OBSERVATION STATIONS ALONG THE
REEF. A SIMILAR SEPARATION OF TEMPERATURE VALUES IS ALSO SEEN ON
LAND AS OBSERVATIONS ON THE UPPER KEYS ARE READING IN AT AROUND 81
DEGREES WITH THE REST OF THE ISLAND CHAIN BEING A FEW DEGREES
HIGHER. DEWPOINTS ARE STILL FLOATING ABOUT THE MID 70S.
UNCERTAINTY PREVAILS IN THE SHORT TERM FORECAST PERIOD AS A FEW
ENVIRONMENTAL FEATURES ARE PRESENTING DIFFERENTLY THAN ORIGINALLY
EXPECTED. THE FRONT THAT HAD BEEN ROOTED OVER MAINALND FLORIDA FOR
SO LONG HAS SUNK SOUTH OVER OUR WATERS TOWARDS CUBA TAKING AWAY A
POSSIBLE SOURCE OF SYNOPTIC LIFT. MEANWHILE, THE UPPER LEVEL
TROUGH AXIS IS STILL NOSED OVER THE YUCATAN PENINSULA DISPLACING
UPPER LEVEL SUPPORT FOR CONVECTIVE DEVELOPMENT OUT TOWARDS THE
BAHAMAS RATHER THAN ENCOMPASSING OUR WATERS. THE MOST SURPRISING
FEATURE IS DRIER AIR DESCENDING ALONG THE WEST COAST OF FLORIDA.
WHILE THIS MORNING'S KKEY 12Z SOUNDING WAS NOT PARTICULARLY DRY,
A LAND SHADOW IS PRESENT OFF OF THE SOUTHWEST COAST OF MAINALND.
TBW'S 12Z SOUNDING IS IS QUITE DRY THIS MORNING ABOVE THE SURFACE
WITH NORTHERLY WINDS ADVECTING MORE DRY AIR NEAR THE LOWER LEVELS
AND PUSHING IT DOWN THE COASTLINE. THESE FACTORS PLUS THE FACT
THAT THE OVERNIGHT MCS ARRIVED WHEN IT DID, EXPLAINS THE LULL IN
ACTIVITY WE ARE CURRENTLY OBSERVING. THAT BEING SAID, SOME
CONVECTION IS STILL TRYING TO BUBBLE IN THE GULF, PARTICULARLY
ALONG BOUNDARIES LOCATED OUTSIDE OF THE PATH OF THE OLD MCS. WILL
KEEP POPS WHERE THEY ARE WITH THE HIGH END OF GUIDANCE AS THERE
ARE CERTAINLY ENOUGH INGREDIENTS AROUND FOR WET SEASON TO DO ITS
THING BEFORE DRIER AIR FULLY SEEPS IN.
MARINE
ISSUED AT 1147 AM EDT SAT SEP 13 2025
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR
THE COASTAL WATERS OF THE FLORIDA KEYS. FROM SYNOPSIS, A WEAK
FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF THE FLORIDA KEYS
COASTAL WATERS OVER THE NEXT SEVERAL DAYS. WEAK UNDULATIONS OF
THIS FEATURE, INTERACTING WITH HIGH PRESSURE TO ITS IMMEDIATE
NORTH, WILL RESULT IN A LOW CONFIDENCE FORECAST FOR WINDS AND RAIN
CHANCES. GENTLE TO MODERATE NORTHEAST TO EAST BREEZES ARE
EXPECTED TO BUILD IN BY TUESDAY OR WEDNESDAY, AS THE AXIS OF THE
HIGH PRESSURE FINALLY IS ABLE TO SPREAD DOWN CLOSER TO THE KEYS
MARINE ZONES.
AVIATION
(15Z TAFS)
ISSUED AT 1147 AM EDT SAT SEP 13 2025
VFR CONDITIONS ARE EXPECTED AT BOTH EYW AND MTH TODAY. WHILE
SHOWERS AND THUNDERSTORMS CANNOT BE RULED OUT, LOW CONFIDENCE IN
THE EXACT TIMING OR LOCATION OF THEIR FORMATION WILL LEAVE A
GENERAL VCSH IN FOR NOW, WITH AMENDMENTS SUBMITTED AS NEEDED. NEAR
SURFACE WINDS WILL BE GENERALLY OUT OF THE NORTH AT 5 TO 10
KNOTS.
CLIMATE
IN 2024, THE DAILY RECORD WARM LOW TEMPERATURE OF 87F WAS RECORDED
IN KEY WEST. THIS ALSO RANKS AS THE WARMEST LOW TEMPERATURE EVER
RECORDED IN SEPTEMBER. TEMPERATURE RECORDS FOR KEY WEST DATE BACK TO
1872.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 88 78 89 79 / 60 50 40 40
MARATHON 87 78 88 79 / 60 50 40 40
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...JAM
AVIATION/NOWCASTS....JAM
DATA ACQUISITION.....JAM
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