631
FXUS62 KKEY 271604
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1204 PM EDT MON JUL 27 2026
..NEW DISCUSSION, MARINE, AVIATION, PREV DISCUSSION
KEY MESSAGES
- PEAK RAIN AND THUNDER CHANCES ARE EXPECTED TODAY WITH DECREASING
RAIN CHANCES EXPECTED FOR TONIGHT, THOUGH STILL ABOVE NORMAL AS
THE ACTIVE PATTERN CONTINUES.
- LIGHT TO GENTLE WEST TO NORTHWEST BREEZES EXPECTED THIS MORNING
BECOMING MAINLY WESTERLY THIS AFTERNOON AND TONIGHT.
- HEAT INDICES MAY APPROACH 105 TO 110 DEGREES EACH AFTERNOON FOR
SOME FLORIDA KEYS ISLAND COMMUNITIES, ESPECIALLY IN THE UPPER
KEYS.
DISCUSSION
ISSUED AT 1200 PM EDT MON JUL 27 2026
IT HAS BEEN A BUSY MORNING ACROSS THE FLORIDA KEYS AS WEATHER
REMAINS UNSETTLED! DEEP TROUGHING HAS PROVIDED UPPER LEVEL SUPPORT
FOR SHOWERS AND THUNDERSTORMS THIS MORNING, WITH MANY WAKING UP
JUST BEFORE SUNRISE THANKS TO THE ROLLING THUNDER. CIMSS MEAN
LAYER ANALYSIS SHOWS THE TROUGH AXIS JUST BARELY TO OUR EAST, SO
WE ARE STILL IN THE THICK OF IT WITH RESPECT TO THE VERTICAL
PROFILE PROVIDING SUPPORT. OUR 12Z KKEY SOUNDING FROM THIS MORNING
COMES WITH THE CAVEAT THAT IT LIKELY INTERCEPTED AN OUTFLOW
BOUNDARY NEAR THE SURFACE, SO SOME OF THE VALUES CALCULATED MAY
NOT NECESSARILY BE REPRESENTATIVE OF THE AREA. WITH THAT BEING
SAID, AN EXCEPTIONALLY WET PROFILE WAS SAMPLED WITH A PWAT VALUE
OF 2.31", WHICH IS THREE HUNDREDTHS GREATER THAN THE DAILY MAXIMUM
VALUE OF 2.28". MRMS 3-HOUR RADAR DERIVED RAINFALL ACCUMULATIONS
HIGHLIGHT THE MIDDLE KEYS WHERE A SLOW-MOVING LINE OF
THUNDERSTORMS THIS AFTERNOON MAY HAVE PRODUCED UP TO AN INCH OF
RAINFALL. THE MOST EFFICIENT SHOWERS STAYED OFFSHORE WHERE OUR
LOCAL MARINE LIFE MAY HAVE ENJOYED UP TO 2 TO 3 INCHES OF
RAINFALL.
WITH THE ENVIRONMENT STILL PRIMED FOR MORE ACTIVITY, AND WHILE THE
TROUGH AXIS SLOWLY CRAWLS EASTWARD, THINGS SHOULD KEEP UP FOR THE
NEXT FEW HOURS BEFORE GRADUALLY WANING. NO CHANGES ARE NEEDED TO
THE INHERITED FORECAST.
DISCUSSION
ISSUED AT 445 AM EDT MON JUL 27 2026
SURFACE TROUGHING WILL REMAIN ACROSS THE EASTERN SEABOARD AND THE
WESTERN NORTH ATLANTIC TODAY AND TONIGHT, AND WILL KEEP MOISTURE
LOCKED IN ACROSS THE AREA. SLIGHTLY DRIER AIR WILL MOVE IN LATE
TONIGHT, RESULTING IN RAIN CHANCES DROPPING TO SLIGHTLY ABOVE
NORMAL (40%). ANOTHER TROUGH IS EXPECTED TO SWING DOWN FROM
CANADA SLIDING ACROSS THE GREAT LAKES, NORTHEAST, AND MID-
ATLANTIC. THIS WILL REINFORCE THE CURRENT TROUGHING ALREADY IN
PLACE. AT THE SURFACE, A FRONTAL BOUNDARY WILL REMAIN DRAPED
ACROSS NORTH FLORIDA AND GEORGIA FOR THE NEXT SEVERAL DAYS. THIS
IS QUITE UNUSUAL FOR THIS TIME OF THE YEAR. DUE TO THIS, IT WILL
KEEP A FAIRLY UNSETTLED PATTERN ACROSS NORTH TO CENTRAL FLORIDA AS
THE MOISTURE FOCUSES ACROSS THIS AREA. DRIER AIR IS EXPECTED TO
MOVE INTO THE KEYS DUE TO THE RIDGE ACROSS THE ATLANTIC LEADING TO
DECREASING RAIN CHANCES. THE HEAT WILL BECOME THE MAIN STORY
AGAIN ESPECIALLY FROM MID WEEK ONWARD. DAYTIME HIGHS WILL BE IN
THE LOWER 90S AND OVERNIGHT LOWS IN THE LOWER 80S WITH SOME MID
80S FROM MID TO LATE WEEK. DEW POINTS IN THE MID TO UPPER 70S WILL
LEAD TO HEAT INDEX VALUES OF 105 TO 110 DEGREES.
BREEZES WILL FRESHEN TO GENTLE TO MODERATE AS THE HIGH ACROSS THE
ATLANTIC AND THE FRONT ACROSS FLORIDA ACT IN TANDEM WITH ONE
ANOTHER LEADING TO AN INCREASED PRESSURE GRADIENT, ESPECIALLY FOR
MID WEEK. AFTER MID WEEK, THE GRADIENT RELAXES SOME AND BREEZES
RELAX BACK TO LIGHT TO GENTLE.
MARINE
ISSUED AT 1200 PM EDT MON JUL 27 2026
WIDELY SPREAD SHOWERS WITH EMBEDDED THUNDERSTORMS WILL LEAD TO
LOCALLY STRONGER WINDS AND HIGHER SEAS/ROUGHER WATERS AT TIMES
ACROSS VIRTUALLY ALL OF OUR MARINE ZONES TODAY. THE STRONGEST
ACTIVITY WILL BE CAPABLE OF PRODUCING GUSTY AND ERRATIC WINDS OF
25 TO 30 KNOTS, BLINDING DOWNPOURS, AND FREQUENT LIGHTNING
STRIKES. OTHERWISE, ACTIVITY SHOULD VERY GRADUALLY DIMINISH AS THE
ENVIRONMENT BECOMES WORKED OVER. OUTSIDE OF THIS ACTIVITY,
GENERALLY LIGHT TO MODERATE WEST TO NORTHWEST BREEZES WILL BACK TO
THE SOUTHWEST TO WEST TONIGHT WITH A 40 PERCENT CHANCE OF SHOWERS
AND THUNDERSTORMS.
AVIATION
(15Z TAFS)
ISSUED AT 1200 PM EDT MON JUL 27 2026
UNSETTLED WEATHER WILL LEAD TO PERIOD OF MVFR CIGS THROUGHOUT THE
TAF PERIOD, BUT BACKGROUND VFR CONDITIONS SHOULD PREVAIL.
ISOLATED POCKETS OF STRONGER SHOWERS AND THUNDERSTORMS WILL
CONTINUE TO MOVE THROUGH THE AREA, AND COULD BRING VERY INFREQUENT
AND SHORT LIVED IFR TO LIFR CONDITIONS. DUE TO THE LOW CONFIDENCE
REGARDING WHEN, AND IF, THESE CATEGORICAL CHANGES WILL OCCUR,
OPTING TO KEEP THE PREVAILING TAFS VFR WITH VCSH, AND WILL ADJUST
FOR SIGNIFICANT IMPACTS IF NEEDED.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 89 82 90 82 / 60 30 40 20
MARATHON 89 81 91 82 / 70 50 50 20
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...DP
AVIATION/NOWCASTS....DP
DATA ACQUISITION.....DP
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