301
FXUS62 KKEY 180734
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
334 AM EDT FRI JUL 18 2025
..NEW DISCUSSION, MARINE, AVIATION
DISCUSSION
ISSUED AT 330 AM EDT FRI JUL 18 2025
ANALYSIS DERIVED FROM SATELLITE-MEASURED UPPER-TROPOSPHERIC
VORTICITY AND WINDS PLACES A TUTT CELL VIRTUALLY DIRECTLY OVER
THE FLORIDA KEYS AT THIS EARLY FRIDAY MORNING HOUR. BELOW THIS
FEATURE, THE 00Z EVENING SOUNDING AT KEY SAMPLED RISING
GEOPOTENTIAL HEIGHTS, SUGGESTING STRONG LOW- AND MID-LEVEL RIDGING
IS BEGINNING TO ENFOLD FOR THE KEYS AND ADJACENT COASTAL WATERS.
THE EVENING SOUNDING ALSO SAMPLED MODEST SURFACE TO 3 KM LAPSE
RATES, AS WELL AS GENERAL DRYING IN THE 900-400 MB ISOBARIC LAYER.
KBYX RADAR HAS BEEN RELATIVELY QUIET OVERNIGHT, WITH ONLY
ISOLATED SHOWERS AND BRIEF THUNDERSTORMS BEING DETECTED ACROSS
THE ENTIRE CWA. FRESHENED EAST TO SOUTHEASTERLY BREEZES,
ASSOCIATED WITH THE LOW- LEVEL RIDGE STRENGTHENING AND BUILDING
WESTWARD, HAVE PREVENTED MOST COMMUNITIES FROM COOLING MUCH
OVERNIGHT, WITH LAND-BASED SURFACE OBSERVATIONS READING IN THE
LOWER TO MID 80S, AND DEWPOINTS IN THE MID TO UPPER 70S.
CONFIDENCE IN THE FORECAST FOR TODAY THROUGH THE WEEKEND IS RATHER
HIGH, WITH THE RIDGING UNDERNEATH THE TUTT CELL AS WELL AS A
DRYING MOISTURE PROFILE BELOW 500 MB SUGGESTING SLIGHT RAIN AND
THUNDER CHANCES AT BEST. THEREAFTER, ENSEMBLE NUMERICAL WEATHER
PREDICTION GUIDANCE SUGGEST THE SYNOPTIC PATTERN MAY GET A BIT
MORE INTERESTING. A FRONTAL BOUNDARY STRETCHING FROM THE MIDWEST
NORTHEASTWARD TOWARDS THE OHIO VALLEY WILL PROGRESS EASTWARD OVER
THE NEXT SEVERAL DAYS, BEFORE LIKELY STALLING SOMEWHERE OFF THE
COAST OF THE SOUTHEAST LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
THERE IS CERTAINLY SOME ENSEMBLE SUPPORT (PARTICULARLY IN THE GEFS
AND GEPS MEMBER AND MEAN PRODUCTS) SUGGESTING POSSIBLE WEAK
CYCLOGENESIS ALONG THIS FRONT, WITH THE FEATURE THEN DIVING
SOUTHWESTWARD TOWARDS THE FLORIDA PENINSULA OR THE EASTERN GULF
MONDAY THROUGH WEDNESDAY. FORECAST SOUNDINGS DEPICT A WINDOW OF
LOWER TROPOSPHERIC MOISTENING, ALONG WITH A VEERED LOW-LEVEL WIND
PROFILE, CONTINUING TO SUPPORT A SEVERAL FORECAST PERIOD WINDOW
FOR ELEVATED SHOWER AND THUNDERSTORM ACTIVITY.
OVERALL, GIVEN MODEL- TO-MODEL AND RUN- TO- RUN CONSISTENCY OVER
THE PAST TWENTY- FOUR HOURS, MINIMAL CHANGES WERE MADE TO THE
PREVIOUS ONCE- PER- DAY FULL FORECAST CYCLE AT KEY TONIGHT.
MARINE
ISSUED AT 330 AM EDT FRI JUL 18 2025
SMALL CRAFT SHOULD EXERCISE CAUTION HEADLINES POSTED FOR ALL OF
THE FLORIDA KEYS MARINE ZONES UNTIL WINDS DECREASE, EXCEPT THE
OFFSHORE SOUTHEASTERN GULF. FROM SYNOPSIS, A STRONG AREA OF HIGH
PRESSURE WILL CONTINUE TO BUILD WESTWARD ACROSS THE NORTH ATLANTIC
TOWARDS THE FLORIDA PENINSULA, SUPPORTING FRESHENING EAST TO
SOUTHEAST BREEZES OVER THE NEXT SEVERAL DAYS. AS A SECOND, WEAK
AREA OF HIGH PRESSURE BUILDS OVER THE EASTERN GULF FOR THE SECOND
HALF OF THE WEEKEND THROUGH EARLY NEXT WEEK, EAST TO SOUTHEAST
BREEZES WILL SLACKEN, BECOMING LIGHT TO GENTLE.
AVIATION
(06Z TAFS)
ISSUED AT 330 AM EDT FRI JUL 18 2025
VFR WEATHER WILL PREVAIL AT BOTH EYW AND MTH DURING THE 06Z TAF
PERIOD. ISOLATED SHOWERS CANNOT BE RULED OUT, BUT ARE NOT
SUFFICIENT TO REQUIRE VCSH OR A TEMPO IN THE TAF. WINDS ARE
FORECAST TO SLACKEN SLIGHTLY DURING THE DAY AND BACK TOWARDS THE
EAST NORTHEAST.
CLIMATE
ON THIS DAY IN 2023, THE DAILY RECORD WARM LOW TEMPERATURE OF 87F
WAS RECORDED AT KEY WEST AND MARATHON. THIS MEASUREMENT TIED FOR THE
WARMEST LOW TEMPERATURE EVER RECORDED IN JULY BOTH BOTH KEY WEST AND
MARATHON. TEMPERATURE RECORDS FOR KEY WEST DATE BACK TO 1872, AND
TEMPERATURE RECORDS FOR MARATHON DATE BACK TO 1950.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 90 82 90 82 / 30 30 20 20
MARATHON 90 82 89 82 / 20 20 20 20
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...BT
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....AJP/BT
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