409
FXUS62 KKEY 171507
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1107 AM EDT WED JUN 17 2026
..NEW DISCUSSION, MARINE, AVIATION, PREV DISCUSSION
KEY MESSAGES
- RAIN CHANCES WILL ONLY REACH 10% OVER THE NEXT SEVERAL DAYS.
- CONDITIONS WILL REMAIN SEASONABLY WARM AND MUGGY, BUT WE MAY
SEE HEAT INDEX VALUES ABOVE 105F, PARTICULARLY ALONG THE UPPER
KEYS, THROUGH FRIDAY.
DISCUSSION
ISSUED AT 1035 AM EDT WED JUN 17 2026
A FEW EARLY MORNING SHOWERS HAVE KEPT OUR KBYX RADAR BUSY AS IT
HAS CONTINUED TO DETECT THIS ACTIVITY ACROSS THE NEARSHORE AND
OFFSHORE WATERS ADJACENT TO THE MIDDLE AND UPPER KEYS. MRMS
ESTIMATES ONLY A FEW HUNDREDTHS OF RAIN MAY HAVE FALLEN ALONG
ISLAND COMMUNITIES WHILE THE "HEAVIER" SHOWERS OVER THE DISTANT
FLORIDA STRAITS MAY HAVE PRODUCED UP TO THREE QUARTERS OF AN INCH
FOR OUR LOCAL MARINE LIFE. AS WE ARE TYPING THIS MORNING UPDATE,
THIS SHOWER ACTIVITY IS DIMINISHING QUICKLY, AND WE EXPECT OUR
RADAR TO BE FREE OF ANY SHOWERS WITHIN THE NEXT 30 MINUTES OR SO.
THERE IS NO EVIDENCE OF ANY MEANINGFUL, LARGER SCALE LIFT. IN
FACT, THE SOUTH-SOUTHEASTERLY FLOW MAY LEAD US TO BE SHADOWED BY
CUBA JUST LIKE YESTERDAY. THERE MAY ALSO BE SOME SAHARAN AIR LAYER
(SAL) PLAYING A ROLE HERE AS THERE IS A NOTABLE DRY LAYER AROUND
700MB ON THE KKEY 12Z SOUNDING FROM THIS MORNING. THE INHERITED
FORECAST REFLECTS A 10% CHANCE OF RAIN, MAINLY IN THE MORNING, AND
THIS SEEMS REASONABLE AS THE UPPER KEYS CARRY THAT 10% CHANCE ALL
DAY. THERE MAY BE LESS CUBAN SHADOW INFLUENCE IN THAT PORTION OF
OUR FORECAST AREA.
OF NOTE, SURFACE OBSERVATIONS ARE REPORTING DEW POINTS NEAR 80F
THIS MORNING. THESE ARE VALUES ASSOCIATED WITH EXCEPTIONALLY
MUGGY AIR, AND POINT TO A MODERATE TO HIGH HEAT RISK SINCE THE
HUMAN BODY HAS A MORE DIFFICULT TIME COOLING ITSELF IN THESE
CONDITIONS. ANYONE ENJOYING OUR SHOWER-FREE SKIES TODAY SHOULD
TAKE THIS INTO CONSIDERATION. PREVENT HEAT RELATED ILLNESS BY
WEARING LOOSE, LIGHT COLORED CLOTHING, DRINKING PLENTY OF
HYDRATING BEVERAGES, AND TAKING BREAKS IN THE AIR CONDITIONING.
DISCUSSION
ISSUED AT 357 AM EDT WED JUN 17 2026
THE AFOREMENTIONED RIDGE WILL CONTINUE TO DOMINATE OUR SENSIBLE
WEATHER THROUGH MUCH OF THE NEXT 7 DAYS. DESPITE THE MOISTURE IN
THE LOWEST LEVELS ACROSS THE AREA, WE WILL HAVE TO CONTEND WITH
POCKETS OF DRIER AIR JUST ABOVE THE BOUNDARY LAYER. THIS COMBINED
WITH THE DEEP LAYER SUBSIDENCE, WILL MAKE IT HIGHLY UNLIKELY FOR
SHOWERS OR AN ISOLATED THUNDERSTORM TO GET GOING. THE IMPACTS
INSTEAD WILL BE THE INCREASING HEAT RISK. HEAT INDEX VALUES FOR
TUESDAY REACHED AND EXCEED 100 DEGREES AND IS EXPECTED TO REACH
HIGHER VALUES TODAY THROUGH FRIDAY, ESPECIALLY ACROSS THE UPPER
KEYS.
A QUASI-STATIONARY FRONTAL BOUNDARY THAT LIES ALONG AND NORTH OF
THE NORTH GULF COAST WILL MEANDER SOUTHWARD TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND. THIS WILL ACT TO WEAKEN THE RIDGE AND
LEAD TO SLACKENING WINDS OVER THE WEEKEND. WINDS COULD BRIEFLY GO
LIGHT AND VARIABLE SATURDAY INTO SUNDAY BEFORE THE RIDGE GRADUALLY
RE-BUILDS AND WINDS RETURN SOLIDLY FROM THE EAST AND SOUTHEAST.
MEANWHILE, MOISTURE WILL CONTINUE TO BE LIMITED ALONG WITH LARGE
SCALE SUBSIDENCE HOLDING IN PLACE. THIS WILL KEEP RAIN CHANCES AT
10 PERCENT AT BEST THROUGH THE FORESEEABLE FUTURE.
MARINE
ISSUED AT 1035 AM EDT WED JUN 17 2026
THERE ARE NO WATCHES, WARNINGS, OF ADVISORIES IN EFFECT FOR THE
FLORIDA KEYS LOCAL WATERS. A WEAK HIGH PRESSURE SYSTEM IN THE
CENTRAL NORTH ATLANTIC WILL SUPPORT LIGHT TO GENTLE BREEZES
PERSISTING THROUGH THE REST OF TODAY ACROSS THE FLORIDA KEYS
COASTAL WATERS. THE HIGH WILL BEGIN TO STRENGTHEN TONIGHT,
SUPPORTING SLIGHTLY FRESHENED BREEZES THROUGH THE END OF THE WORK
WEEK. AS A WEAK FRONTAL BOUNDARY APPROACHES THE FLORIDA PENINSULA,
THE HIGH WILL ONCE AGAIN WEAKEN, SUPPORTING A RETURN TO LIGHT TO
GENTLE BREEZES AND POTENTIALLY LIGHT AND VARIABLE BRIEFLY, FOR THE
WEEKEND.
AVIATION
(15Z TAFS)
ISSUED AT 1035 AM EDT WED JUN 17 2026
VFR CONDITIONS WILL PREVAIL AT BOTH ISLAND TERMINALS, BUT
INTERMITTENT OBSERVATIONS OF MVFR CIGS AT MTH ARE POSSIBLE DURING
THE FIRST FEW HOURS OF THE TAF PERIOD DUE TO LINGERING LOWER LEVEL
CLOUDS. MOST OF THIS CLOUD COVER WILL CLEAR OUT AS NEARBY VERY
LIGHT SHOWERS CONTINUE TO DISSIPATE. SURFACE WINDS NEAR 10 KNOTS
WILL PREVAIL OUT OF THE SOUTHEAST.
PREV DISCUSSION
ISSUED AT 1035 AM EDT WED JUN 17 2026
PRELIMINARY POINT TEMPS/POPS
KEY WEST 91 82 91 82 / 0 20 10 0
MARATHON 88 82 89 83 / 10 10 10 0
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...DP
AVIATION/NOWCASTS....DP
DATA ACQUISITION.....DP
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