124
FXUS62 KKEY 100231
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1031 PM EDT SUN AUG 9 2026
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
- GENTLE TO MODERATE BROADLY E-SE BREEZES WILL PREVAIL, PEAKING
OVERNIGHT AND LULLING DURING THE DAY, EXCEPT MODERATE TO FRESH
BREEZES FOR HAWK CHANNEL AND THE STRAITS OF FLORIDA OVERNIGHT.
- RAIN AND THUNDER CHANCES REMAIN SLIGHTLY ABOVE NORMAL FOR
OVERNIGHT WITH NEAR TO BELOW NORMAL SHOWER AND THUNDER CHANCES
STARTING TOMORROW.
DISCUSSION
ISSUED AT 1030 PM EDT SUN AUG 9 2026
CIMSS PRODUCTS SHOWS MEAN LAYER RIDGING ACROSS THE WESTERN NORTH
ATLANTIC. THE WESTERN PERIPHERY OF THIS RIDGE EXTENDS WESTWARD
OVER FLORIDA AND THE KEYS. MARINE OBSERVATION PLATFORMS
SURROUNDING THE ISLAND CHAIN ARE RECORDING EAST TO SOUTHEAST
BREEZES NEAR 15 KNOTS AS A RESULT. KBYX RADAR DETECTED SOME
ISOLATED SHOWERS AND THUNDERSTORMS EARLIER WHICH IMPACTED PARTS OF
THE ISLAND CHAIN. RADAR WAS QUIET FOR A FEW HOURS UNTIL RECENTLY
WHEN ISOLATED SHOWERS AND THUNDERSTORMS REDEVELOPED ACROSS
PORTIONS OF THE WESTER DISTANT STRAITS OF FLORIDA. GOES 19 TOTAL
PRECIPITABLE WATER (TPW) PRODUCTS SHOWS A PLUME OF 1.5 TO 2 INCH
PWATS ESTIMATED TO BE MOVING THROUGH THE KEYS CURRENTLY. HOWEVER,
MUCH DRIER AIR IS LURKING NOT TOO FAR AWAY WITH ESTIMATED PWATS OF
1.2 TO 1.3 INCHES APPROACHING THE CAY SAL BANK. GOES 19 NIGHTTIME
MICROPHYSICS IMAGERY SHOWS MAINLY PARTLY CLOUDY SKIES ACROSS THE
KEYS WITH MAINLY LOW LEVEL CUMULUS. TEMPERATURES ALONG THE ISLAND
CHAIN ARE IN THE MID 80S AND DEW POINTS ARE IN THE MID TO UPPER
70S.
SHORT TERM FORECAST
THE 00Z EVENING SOUNDING SHOWS A VERY MOIST AND UNSTABLE
ATMOSPHERIC PROFILE. INSTABILITY WAS MEASURED QUITE HIGH WITH
CAPE VALUES BETWEEN 3000-3500 J/KG. THE PWAT VALUE MEASURED ALSO
CAME IN QUITE HIGH AT 2.05 INCHES. THIS IS JUST ABOVE THE 75TH
PERCENTILE FOR THE DATE. THE WIND PROFILE IS MAINLY EASTERLY WITH
SOME SLIGHT VEERING WITH 080 DEGREES AROUND 1000 FT TO 120
DEGREES AT 3000 FT. OVERALL, CURRENT THINKING FOR THE OVERNIGHT IS
THAT ANY CONVECTION THAT CAN GET GOING MOST LIKELY WILL BE ABLE
TO BECOME A THUNDERSTORM DUE TO ALL THE INSTABILITY. ALSO, GOES 19
TOTAL PRECIPITABLE WATER AS MENTIONED ABOVE IN THE DISCUSSION
SHOWS A PLUME OF MUCH DRIER AIR MOVING INTO THE KEYS. THIS IS ALSO
BELIEVED TO BE THE LEADING EDGE TO THE SAHARAN AIR LAYER (SAL)
THAT IS EXPECTED TO MOVE IN FOR THE NEXT SEVERAL DAYS. USUALLY THE
LEADING EDGE TO THESE MOISTURE FRONTS CAN ACT AS A CATALYST TO
GET SOME MORE ROBUST CONVECTION. THE BEST CHANCES FOR THE ACTIVITY
OVERNIGHT APPEAR TO BE ACROSS THE WESTERN PORTIONS OF THE KEYS,
ESPECIALLY THE LOWER KEYS WESTWARD. OTHER THAN THAT, THE ONLY
CATALYST THAT MAY SPARK ACTIVITY WOULD BE SPEED CONVERGENCE WITH
PERHAPS A LITTLE BIT OF DIRECTIONAL CONVERGENCE, ESPECIALLY LATER
IN THE NIGHT.
MARINE
ISSUED AT 1030 PM EDT SUN AUG 9 2026
SMALL CRAFT SHOULD EXERCISE CAUTION (SCEC) FOR INCREASING WINDS
IS HEADLINED FOR HAWK CHANNEL AND THE STRAITS OF FLORIDA
OVERNIGHT. THERE ARE CURRENTLY NO WATCHES, WARNINGS, OR ADVISORIES
IN EFFECT ACROSS THE FLORIDA KEYS COASTAL WATERS. FROM SYNOPSIS,
RIDGING WILL GRADUALLY BUILD IN ACROSS THE REGION, AND WILL
MAINTAIN GENTLE TO MODERATE EASTERLY TO SOUTHEASTERLY BREEZES ON
OUR WATERS. MARINE CAUTION HEADLINES WILL BE IN PLACE FOR HAWK
CHANNEL AND THE FLORIDA STRAITS DUE TO A BRIEF PERIOD OF
FRESHENING BREEZES OVERNIGHT. HOWEVER, WINDS WILL TREND SLIGHTLY
DOWNWARDS HEADING TOWARDS MID WEEK AS THE RIDGE SETTLES SOUTHWARD
ACROSS CENTRAL FLORIDA. EXPECT SWINGS IN WIND SPEEDS, GENERALLY
LULLING DURING THE DAY AND PEAKING OVERNIGHT. SHOWER AND THUNDER
CHANCES WILL BE NEAR TO BELOW NORMAL THROUGH THE FORECAST.
AVIATION
(00Z TAFS)
ISSUED AT 1030 PM EDT SUN AUG 9 2026
VFR CONDITIONS ARE EXPECTED TO PERSIST AT BOTH EYW AND MTH
TERMINALS THROUGH THE TAF PERIOD. NEAR SURFACE WINDS WILL REMAIN
EAST TO SOUTHEAST THROUGH THE PERIOD. THERE MAY BE A PASSING
SHOWER OR STORM OVERNIGHT INTO THE EARLY MORNING ON MONDAY, THOUGH
THIS IS A LOW RISK. THEREFORE, VCSH WAS NOT INCLUDED IN THE TAF.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 92 83 92 83 / 30 40 20 10
MARATHON 90 84 90 84 / 30 30 20 10
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...MJV
AVIATION/NOWCASTS....MJV
DATA ACQUISITION.....AJP
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