874
FXUS62 KKEY 201947
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
347 PM EDT WED AUG 20 2025
..NEW AVIATION
AVIATION
(18Z TAFS)
ISSUED AT 345 PM EDT WED AUG 20 2025
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH EYW AND MTH FOR THE
REST OF TODAY AND INTO TONIGHT. SCATTERED SHOWERS ALONG WITH A FEW
THUNDERSTORMS ARE PUSHING TOWARDS THE ISLAND CHAIN FROM THE GULF.
WHILE THEY SEEM TO BE LOSING MOMENTUM, INCLUDED VCSH AS A FIRST
GUST FOR TIMING WHEN THEY MAKE IT IN THE VICINITY OF EITHER
TERMINAL IF THEY MAKE IT. NEAR SURFACE WINDS WILL GENERALLY BE OUT
OF THE WEST AT 6 TO 11 KNOTS.
PREVIOUS DISCUSSION
ISSUED AT 1120 AM EDT WED AUG 20 2025
DESPITE HURRICANE ERIN SPIRALING NORTH AWAY FROM THE KEYS ALONG
THE SOUTH END OF THE EASTERN SEABOARD, FAIR WEATHER CONDITIONS ARE
OBSERVED ACROSS THE FLORIDA KEYS THIS MORNING. MOSTLY CLEAR SKIES
ARE SEEN ACROSS THE ISLAND CHAIN WITH ONLY A FEW PATCHES OF
SHALLOW CUMULUS NOW DEVELOPING ABOVE. MEANWHILE, KBYX RADAR
DETECTS SHOWERS AND OCCASIONALLY A THUNDERSTORM OR TWO PULSING
ALONG BOUNDARIES IN THE STRAITS OF FLORIDA AND JUST OUTSIDE OUR
NORTHERNMOST GULF WATERS OFF SOUTH FLORIDA'S WEST COAST.
TEMPERATURES ARE IN A SIMILAR PLACE TO YESTERDAY WITH VALUES IN
THE UPPER 80S TO NEAR 90. DEWPOINTS HAVE DIPPED A FEW DEGREES BACK
DOWN INTO THE UPPER 70S AFTER LAST NIGHT'S CONVECTIVE BURST.
MEANWHILE, LIGHT TO GENTLE WEST TO NORTHWEST BREEZES ARE
STUBBORNLY PERSISTING ALONG THE REEF.
CURRENT CONDITIONS ARE NOT EXACTLY WHAT WE EXPECTED THEY WOULD BE
AT A FEW PACKAGES AGO. DESPITE ERIN'S WIND FIELD EXPANSION,
BREEZES ACROSS THE KEYS ARE STILL UNDERPERFORMING A TOUCH. THIS
COULD BE FOR ANY NUMBER OF FACTORS, BUT FOR NOW WE ARE CHALKING IT
UP TO WIND FIELD VARIABILITY RESULTING IN A BIT OF A DELAY
OVERALL AS WINDS ARE STILL FORECAST TO FRESHEN THROUGHOUT TODAY.
DESPITE THE UNUSUAL WIND DIRECTION FOR THIS TIME OF YEAR, RAIN
CHANCES CONTINUE TO CLOCK IN AROUND NORMAL. A HANDFUL OF
BOUNDARIES ACROSS OUR CWA HAVE SHOWN MILD PROFICIENCY IN
GENERATING PULSE CONVECTION THIS MORNING AND A KICK TO OUR WIND
SPEEDS SHOULD ALSO GENERATE SOME LOCAL SPEED CONVERGENCE. HOWEVER,
THIS MORNING'S KKEY SOUNDING STILL LOOKS FAIRLY DRY FOR THIS TIME
OF YEAR WITH A PW VALUE OF 1.67 INCHES, JUST BELOW THE 25TH
PERCENTILE. RECENT CAMS ARE THUS UNCERTAIN WITH THE AMOUNT OF
TOTAL SHOWER COVERAGE POSSIBLE THROUGHOUT THIS AFTERNOON. WITH
THESE FACTORS WORKING AGAINST EACH OTHER, OPTED TO KEEP CHANCE
POPS OVERALL WITH A REEVALUATION OF CONDITIONS LATER THIS
AFTERNOON AS NEEDED.
FORECAST
ISSUED AT 337 AM EDT WED AUG 20 2025
HURRICANE ERIN IS STILL WELL TO OUR NORTHEAST THIS MORNING,
APPROXIMATELY 600 MILES NORTHEAST OF KEY WEST AS OF 4 AM EDT, AND
THE SYSTEM IS CONTINUING TO FOLLOW ITS NORTHWARD TRACK. AS THE
SYSTEM MOVES FARTHER AWAY, HIGHER PRESSURE WILL BUILD IN ITS
PLACE. MEAN LAYER FLOW WILL SHIFT TO THE WEST AND SOUTHWEST BY
WEDNESDAY NIGHT OR THURSDAY, BUT THERE IS SOME LOWER CONFIDENCE
WITH REGARD TO WHETHER OR NOT WE CAN GET A REVERSE CLOUDLINE TO
SET UP DURING THE DAYTIME. THE GFS IS RESOLVING SOME UNUSUALLY
DRY AIR CONSIDERING THE TIME OF YEAR, HOW HOT IT HAS BEEN, AND HOW
MUCH WATER THE AIR MASS WILL SIT OVER. ON THE OTHER HAND, EC
SUGGESTS ENOUGH MOISTURE MAY LINGER IN THE LOWER LEVELS THROUGH
THE REST OF THE WEEK, AND THAT MOISTURE COULD SUPPORT CLOUDLINE
DEVELOPMENT. DUE TO THE SMALL SCALE NATURE OF OUR LOCAL
CLOUDLINES, THIS IS SOMETHING THAT GLOBAL GUIDANCE WILL NOT
RESOLVE CLEARLY.
OTHERWISE, AS WE APPROACH THE END OF THE WEEK AND HEAD INTO THE
WEEKEND, THE HIGH PRESSURE TRANSVERSING THE AREA WILL ENCOURAGE A
LACK OF CLOUD COVER AND NEARLY STAGNANT AIR. ANY BREEZES WE DO
SUSTAIN WILL BE LIGHT TO GENTLE, SO DON'T EXPECT TOO MUCH RELIEF
FROM THE AUGUST HEAT. RAINFALL CHANCES WILL REMAIN NEAR NORMAL FOR
THE TIME OF YEAR, BUT WITHOUT A SYNOPTIC LIFTING MECHANISM IN
PLACE, WE WILL DEPEND ON MESOSCALE FEATURES (SUCH AS OUTFLOWS FROM
MAINLAND CONVECTION) TO TRIGGER OUT OWN ACTIVITY.
MARINE
ISSUED AT 345 PM EDT WED AUG 20 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 FOLLOW A MAINLY NORTHERLY TRACK ALONG THE
EASTERN SEABOARD. THE INCREASINGLY EXPANSIVE CIRCULATION OF ERIN
WILL RESULT IN A TRANSITION FROM LIGHT TO GENTLE VARIABLE BREEZES
EARLY THIS MORNING TO GENTLE TO MODERATE NORTHWEST BREEZES INTO
TONIGHT. A SLIGHT SWELL FROM THE NORTH WILL LEAD TO ELEVATED SEAS
IN EASTERN PORTIONS OF THE FLORIDA STRAITS. 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 82 92 82 93 / 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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