008
FXUS62 KKEY 191935
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
335 PM EDT TUE AUG 19 2025
..NEW AVIATION
AVIATION
(18Z TAFS)
ISSUED AT 335 PM EDT TUE AUG 19 2025
VFR CONDITIONS WILL PREVAIL AT BOTH EYW AND MTH FOR THE REST OF
TODAY AND INTO TONIGHT. STORMS MOVING SOUTH FROM MAINLAND SOUTH
FLORIDA COULD CROSS THE ISLAND CHAIN NEAR MTH THIS EVENING, BUT
UNCERTAINTY IN THE EXACT TIMING AND LOCATION OF THESE SHOWERS WILL
KEEP MENTION OUT OF THE TAFS FOR NOW. NEAR SURFACE WINDS WILL BE
OUT OF THE NORTHWEST AT 5 TO 10 KNOTS, INCREASING TO NEAR 10
KNOTS.
PREVIOUS DISCUSSION
ISSUED AT 1155 AM EDT TUE AUG 19 2025
NOCTURNAL CONVECTION HAS MOSTLY FALLEN APART THIS MORNING LEAVING
THE FLORIDA KEYS AND ITS COASTAL WATERS LARGELY RAIN FREE. KBYX
IS STILL TRACKING ONE SMALL SHOWER IN THE DISTANT STRAITS OFF OF
THE MIDDLE KEYS, BUT GOES-19 VISIBLE IMAGERY NOTES MOSTLY CLEAR
SKIES WITH A FEW FAIR WEATHER CUMULUS STRETCHED ACROSS OUR CWA
OTHERWISE. HURRICANE ERIN IS CURRENTLY EAST OF THE BAHAMAS AND
WHILE IT WILL CONTINUE TO MOVE OFF TO THE NORTHWEST, ITS INFLUENCE
ON OUR WIND FIELD IS OBSERVED ALONG THE REEF WITH GENTLE AND
SOMEWHAT VARIABLE NORTHERLY WINDS. MEANWHILE, TEMPERATURES ALONG
THE ISLAND CHAIN ARE ALREADY NEAR 90 WITH UNFORTUNATE DEWPOINTS UP
TO THE LOWER 80S.
MORE OF THE SAME WEATHER IS EXPECTED IN THE SHORT TERM FORECAST.
CIMSS MIMIC LAYER TPW NOTES THE SAME DRY SLOT IT DID YESTERDAY
OVER SOUTH FLORIDA AND OUR AREA. THIS DRY AIR CAN ALSO BE OBSERVED
IN THE MID LEVELS OF THIS MORNINGS KKEY 12Z SOUNDING AND IS MOSTLY
THE BLAME FOR SUPPRESSED CONVECTIVE DEVELOPMENT TODAY. ONCE AGAIN,
WE WILL BE LOOKING FOR LATE AFTERNOON SEABREEZE CONVECTION FROM
MAINLAND TO FOLLOW NORTHERLY FLOW INTO OUR WATERS. USUALLY THIS
SET UP CAN CAUSE A LOT OF RAIN TO SWEEP THROUGH, BUT CAMS ARE NOT
TOO THRILLED WITH THE SET UP POSSIBLY DUE TO THE UNSEASONABLY DRY
AIR ALOFT. THUS CHANCE POPS ARE HELD FOR NOW. TONIGHT AND INTO
TOMORROW, BREEZES WILL CONTINUE TO FRESHEN OUT OF THE NORTHWEST
AND TURN TO THE WEST. RAIN CHANCES WILL REMAIN NEAR OR ABOVE
NORMAL DUE TO EXCESS MOISTURE FROM ERIN FOR THE NEXT FEW DAYS.
FORECAST
ISSUED AT 339 AM EDT TUE AUG 19 2025
AS OF 5 AM EDT, ERIN WAS LOCATED ROUGHLY 630 MILES TO THE ENE OF
KEY WEST. THE SYSTEM LOOKS PRETTY LARGE ON SATELLITE, AND WE CAN
SEE SOME OF THE HIGHER CIRRUS CLOUDS ACROSS OUR FORECAST AREA ARE
FROM THE "EXHAUST" OF ERIN. THE CURRENT FORECAST HAS THE SYSTEM
TURNING TO THE NORTH TODAY. AS ERIN PASSES WELL TO OUR EAST,
MOISTURE WILL ADVECT FROM THE NORTH AND SHOWERS AND THUNDERSTORMS
COULD BE MORE EFFICIENT AT PRODUCING HEAVIER SHOWERS. WITH THE
FAIRLY SLOW MOVEMENT THE SYSTEM HAS, MOISTURE WILL BE ABLE TO SORT
OF "BUILD UP" IN THE VERTICAL PROFILE, AND IT IS POSSIBLE THAT
THE 30 PERCENT CHANCE OF RAINFALL WE HAVE ADVERTISED, SPECIFICALLY
FOR WEDNESDAY, MAY BE A LITTLE TOO LOW. REGARDLESS, THE NEXT
COUPLE OF DAYS HAVE THE OPPORTUNITY TO BE A LITTLE WETTER AND A
LITTLE CLOUDIER THAN WE THINK RIGHT NOW, IT JUST DEPENDS ON ERIN'S
MOTION.
ONCE ERIN PUSHES FAR ENOUGH NORTHWARD, POSSIBLY FROM THURSDAY
AFTERNOON AND ONWARD, RIDGING WILL BE ABLE TO BUILD BACK IN.
GUIDANCE IS SUGGESTING SUBSTANTIALLY DRY AIR ABOVE 850MB, SO OUR
MOISTURE SOURCE FOR ANY ACTIVITY WILL BE VERY SHALLOW. EVEN THOUGH
SHOWERS WILL STILL BE POSSIBLE, SINCE IT IS AUGUST IN FLORIDA, A
SHALLOW MOISTURE SOURCE MEANS THEY WILL LIKELY BE SHORT LIVED AND
UNABLE TO BUILD INTO THUNDERSTORMS. THE BOTTOM LINE IS THAT
WEATHER CONDITIONS SHOULD FEEL MORE NORMAL ONCE ERIN PUSHES AWAY,
BUT YOU MAY WANT TO KEEP AN UMBRELLA CLOSE UNTIL THEN.
MARINE
ISSUED AT 251 PM EDT TUE AUG 19 2025
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR
THE COASTAL WATERS OF THE FLORIDA KEYS. FROM SYNOPSIS, HURRICANE
ERIN WILL CONTINUE TO TURN DUE NORTHWARD OVER THE OPEN ATLANTIC
GOING INTO TONIGHT. THE INCREASINGLY EXPANSIVE CIRCULATION OF ERIN
WILL RESULT IN A TRANSITION FROM LIGHT TO GENTLE NORTHERLY
BREEZES ACROSS FLORIDA KEYS COASTAL WATERS OVERNIGHT, TO GENTLE TO
MODERATE NORTHWEST BREEZES TUESDAY AND MODERATE TO FRESH WESTERLY
BREEZES ON WEDNESDAY. A SLIGHT SWELL FROM THE NORTH WILL LEAD TO
ELEVATED SEAS IN EASTERN PORTIONS OF THE FLORIDA STRAITS AND HAWK
CHANNEL. AS HURRICANE ERIN MIGRATES FARTHER AWAY TOWARD THE NORTH
AND NORTHEAST, A WEAK SUBTROPICAL HIGH PRESSURE RIDGE WILL SETTLE
OVER FLORIDA KEYS COASTAL WATERS, RESULTING IN A LIGHTER WIND
PATTERN THURSDAY THROUGH SATURDAY.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 83 93 82 92 / 30 30 30 30
MARATHON 82 91 83 91 / 30 30 30 30
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...JAM
AVIATION/NOWCASTS....JAM
DATA ACQUISITION.....JAM
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