textproduct: Key West

DISCUSSION

Issued at 200 PM EDT Tue Oct 27 2026 Satellite-derived vorticity analysis continues to place a stubborn weak area of low pressure centered directly over the Bahama Islands. The Florida Keys remain entrenched in a very tight moisture gradient, with much of the Florida Keys remaining under the continental influence of very-dry mid-level air, sampled in the 12z sounding at KEY, which is also distinctly evident in 850-700 mb APLW satellite products. Local Doppler radars highlight the tight gradient as well, with virtually all shower activity along the western edge of the moisture gradient, extending along a line from the Straits of Florida south of the Middle Keys northeastward to the Upper Keys. Showers continue to be quite light closest to the island chain, with most communities in the Upper Keys only receiving up to one tenth of an inch of rainfall in the past twenty four hours based on MRMS analyses. With continued north to northeast breezes, temperatures remain a few degrees below all available numerical weather prediction guidance, only hovering near 80F at this early afternoon hour.

A bit of a difficult forecast for tonight through tomorrow. Mean low-level easterlies in the flow around a high pressure near the Azores should slide the aforementioned surface low pressure system westward towards the Keys over the next 24 hours. This should also advect a weak nudge of increased mid-level moisture, and forecast soundings reflect this. With that said, the low pressure system will remain weak, with little surface convergence associated with it. Given all of these factors, currently forecasting light scattered showers in the Upper Keys to slowly propagate further westward, mainly late tonight and during the day tomorrow, but may also possibly lingering into Tuesday. Rainfall amounts for any shower activity should continue to be mainly light.

Another high pressure system is expected to build over the Eastern Seaboard late this week and into the weekend, supporting light to gentle northeast to easterlies. Seasonable conditions look to return for theses periods through early next week, with highs generally in the lower to mid 80s, lows in the lower upper 70s, and seasonable rain chances (around 20%).

In terms of tides, peak high tides should occur tonight through Thursday night, with similar to, or a few inches higher, than what was observed last night. While tides will begin to recede thereafter, this may be a very slow process, especially for the Upper Keys. After the Coastal Flood Warnings are able to be cancelled later this week, additional Coastal Flood Statements or Advisories may be required through much of the weekend.

MARINE

Issued at 200 PM EDT Tue Oct 27 2026 A Small Craft Advisory is in effect for all Florida Keys marine zones. From synopsis, a tight pressure gradient between high pressure over the Eastern Seaboard and a low pressure system near the Bahamas will support strong breezes tonight. As the low slides eastward towards the Keys, breezes will abruptly slacken on Wednesday. The low will slide into the central Gulf and weaken later this week, as another high pressure system takes over the pressure field through the weekend. This will support light to gentle northeast to east breezes through Sunday night.

AVIATION

(00Z TAFS) Issued at 738 PM EDT Tue Oct 27 2026 VFR conditions are expected to prevail at EYW through this TAF period. At MTH, MVFR ceilings on the west side of a weak surface low may reach the terminal this evening in addition to VCSH as the low shifts to the west. VFR ceilings should then return to MTH ~09-10Z, but a SCT deck will remain around 3kft. Winds will gradually decrease overnight with north-northeasterly breezes around 8 to 12 kts and occasional gusts of 15-18 kts. Gusts should diminish by sunrise tomorrow.

PRELIMINARY POINT TEMPS/POPS

Key West 76 83 77 85 / 20 40 30 20 Marathon 77 84 77 85 / 20 40 30 20

KEY WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Warning until 5 AM EDT Wednesday for FLZ076>078.

GM...Small Craft Advisory until 5 AM EDT Wednesday for GMZ031>035- 042>044-052>055-072>075.