textproduct: Key West

KEY MESSAGES

- A Coastal Flood Statement remains in effect for the Lower and Middle Keys, with minor saltwater flooding possible, especially around the time of high tide.

- Expect elevated rain and thunder chances for Friday afternoon through Saturday evening,

- A swath of Saharan dry air will push across the Keys for the second half of the weekend, lasting through early next week.

DISCUSSION

Issued at 400 AM EDT Fri Aug 14 2026 Surface wind and pressure analysis places an expansive high pressure system centered in the vicinity of the Azores in the North Atlantic, which continues to strengthen and build westward. The axis of the ridge is bisecting the Florida Space Coast. Meanwhile, lower tropospheric vorticity analysis places an inverted trough in the vicinity of eastern Cuba and the island of Hispaniola. Finally, satellite-derived layer- and atmospheric- integrated precipitable water products are highlighting a postively-tilted, discernible moisture surge extending from Andros Island northeastward to the central Bahamas. Locally, earlier convection associated with a broken cloud line over portions of the Lower Keys has since waned, with local KBYX Doppler radar now only detecting isolated showers across the Keys marine zones. Land- based surface observations are sampling temperatures in the balmy mid 80s at this early Friday morning hour.

Overall, with a noticeable increase in forcing and steering flow, the Florida Keys will quickly move from a mesoscale regime to a synoptic-scale forced regime later today through the weekend. The aforementioned moisture surge, coincident with the inverted trough to its southwest, will progress westward today. Meanwhile, at the surface, the high pressure system will continue to build westward towards the Florida Peninsula, supporting freshening east to southeast breezes. Composting these features will result in a wetter and more thundery pattern beginning later this afternoon, continuing through at least Saturday morning. Forecast soundings do indicate a bit of inhibition to overcome, which will continued to be monitored, as it may limit more widespread and stronger thunderstorms across the Keys for these periods.

Thereafter, there is high confidence that a strong Saharan dust layer (a bit unusual for this late in August) will propagate westward towards the Keys by sometime late Saturday afternoon or early Sunday evening. While this will tend to shut down any shower and thunderstorm activity thereafter for several days, we will need to monitor the leading edge of this dust plume. The leading edge is analogous to a classic Mid-west dry line, with a discernible line of deep convective thunderstorms often occurring as the plume pushes through the Keys.

In terms of the tropics, although the National Hurricane Center is monitoring two possible areas in the Main Development Region of the Tropical Atlantic, chances for development of both systems continues to wane. Regardless of development, neither system is expected to provide impacts to the Keys at this time.

MARINE

Issued at 400 AM EDT Fri Aug 14 2026 A Coastal Flood Statement remains in effect for the Lower and Middle Keys, with minor saltwater flooding possible around the time of high tide late this morning through the early afternoon hours. Boaters can expect less clearance under fixed bridges, especially around the time of the high tide. Tide anomalies will decrease over the weekend. From synopsis, high pressure in the central North Atlantic will strengthen and build westward for the next several days. With the associated ridge axis located north of the Florida Keys, this will support gentle to moderate east to southeast breezes for the marine zones through Sunday night. A weak frontal boundary will stall over the Florida Peninsula for early next week. This will disrupt the ridge's influence on the Keys coastal waters. Breezes will respond, becoming light to gentle.

AVIATION

(06Z TAFS) Issued at 400 AM EDT Fri Aug 14 2026 VFR conditions will prevail at both island terminals through at least 14/18z, with only isolated vicinity showers and thunderstorms expected. A moisture surge from the east thereafter will support increased rain and thunder chances for the second half of the TAF period. Due to the scattered nature and the uncertainty in exact timing, have included a general mention of VCSH for now, first at MTH, then at EYW, with more specific impacts to VISs and CIGs to be nailed out in later TAF issuances.

PRELIMINARY POINT TEMPS/POPS

Key West 91 81 91 82 / 20 50 40 10 Marathon 89 82 89 83 / 30 50 40 10

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...None.