textproduct: Key West

KEY MESSAGES

- High moisture content across the region will support daily chances for showers and thunderstorms through the weekend.

- Temperatures will be seasonably warm, with highs near 90, and lows in the lower 80s.

DISCUSSION

Issued at 943 PM EDT Thu Sep 3 2026

Latest CIMMS products indicate the Florida Keys is situated within the subsident side of an inverted low to mid-level shortwave trough which is centered over the Central Gulf extending north towards the Gulf Coast region. Other than a few localized thunderstorms which developed along a last minute broken cloud line north of the Lower Keys earlier this evening, much of our surrounding waters have been free of shower and thunderstorm activity. This is partly due to the Cuban shadow brought on by south-southwesterly sfc to low-level winds earlier today. This wind direction has not been resolved well by recent model runs, but marine obs are indicating that winds are gradually becoming south-southeasterly again which was expected. This should also help reduce the haze that originated in Cuba and has made its way across the Straits of Florida, settling over the Lower Keys. MIMIC TWP imagery shows a plume of higher moisture content currently situated over Andros Island and the northern Bahamas. This moisture will advect towards our waters through the night, so we could begin to see some redevelopment in the distant Straits where I have maintained Chance PoPs. Hi-res guidance suggest further development will occur across the area during the day tomorrow as the moisture overspreads the area, especially for the Middle to Upper Keys and surrounding coastal waters. I slightly expanded the region of Likely PoPs for the eastern Florida Straits, Florida Bay, and Upper Keys, but no mentionable changes were made beyond that. Light to gentle easterly breezes are expected to return during the day tomorrow with highs ranging from the upper 80s to lower 90s.

MARINE

Issued at 943 PM EDT Thu Sep 3 2026

No watches, warnings, or advisories are currently in effect for the Florida Keys waters. Recent marine obs indicate that light breezes are shifting and taking on more of a south to southeasterly heading this evening. From synopsis, the western periphery of a weak North Atlantic high will remain in loose control of the Keys coastal waters for the next several days. Light to gentle east to southeast breezes overnight through morning will become light and variable at times during the afternoon and evenings. In addition, the overall flow will keep low-level moisture in place across the region, with seasonally normal rain and thunder chances.

AVIATION

(00Z TAFS) Issued at 943 PM EDT Thu Sep 3 2026

HZ originating from Cuba is being swept north through the southerly winds and causing reduced visibility at EYW. Winds are forecast to become southeasterly through the overnight hours, and this should allow visibilities to improve. Beyond that, aviation impacts are not expected for at least the next several hours at MTH, with improvement expected at EYW soon. A region of higher moisture over the Bahamas is forecast to advect across the area tomorrow morning, and hi-res guidance is indicating shower and thunderstorm redevelopment along the leading edge of that moisture surge. Introduced a PROB30 for TSRA at MTH followed by EYW around midday. Adjustments and TEMPOs may become necessary as we get a better handle on the spatial scale and timing of development.

PRELIMINARY POINT TEMPS/POPS

Key West 82 92 81 92 / 20 40 40 40 Marathon 83 90 82 90 / 20 40 40 40

KEY WATCHES/WARNINGS/ADVISORIES

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