textproduct: Key West

KEY MESSAGES

- Major coastal flooding will continue across the Keys during the next several tidal cycles. Coastal flooding will gradually decrease later this week, but receding rates may be slow, especially in the Upper Keys.

- A Small Craft Advisory is in effect for the Florida Keys marine zones west of seven mile bridge. Breezes will continue to slacken overnight and become more easterly.

DISCUSSION

Issued at 1035 AM EDT Wed Oct 28 2026

Satellite observations from GOES East, using nighttime microphysics and day cloud phase imagery, identified a thick shield of cloud cover across the Lower and Middle Keys this morning. Sustained north to northeasterly winds were able to supply enough cold air advection to support this shield of cloud cover. While there is sufficient low level moisture for clouds, ALPW products highlight that most of the moisture is trapped below 700 mb. The upper level environment is much drier, an observation supported by this morning's 12Z KKEY sounding. The balloon traveled through a low cloud layer before entering a very dry environment just above 6000 feet. Any showers that manage to form across the Keys waters will be shallow and short-lived.

Conditions across the Keys in the late morning show skies are cleaning. Temperatures along the island chain are in the upper 70s, and as skies clear, highs in the mid 80s are more likely. Breezes are slackening across the island chain as well. The rest of the day is likely to set the stage for weather across the Keys through the work week. Light to gentle northeasterly breezes with a slight chance of showers to bring October to a close.

The major hazard for the Keys will be the ongoing King Tide event. Major saltwater flooding is expected to continue for the lower- lying parts of the Florida Keys tonight. Residents should continue to take precautions to protect vehicles and property from saltwater tonight.

MARINE

Issued at 1035 AM EDT Wed Oct 28 2026

A Small Craft Advisory is in effect for the waters of the Outer Gulf, the Western Florida Straits, and the nearshore waters surrounding the Lower Keys. Small Craft Should Exercise Caution until seas subside for the Eastern Straits of Florida.

From synopsis: a weak area of low pressure will continue to slide westward towards the Keys this afternoon. This will cause breezes to abruptly slacken from east to west. 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

(15Z TAFS) Issued at 1035 AM EDT Wed Oct 28 2026

Northerly winds sustained layers of IFR CIGs across EYW and MTH this morning. Winds are slowly slackening around the island chain, and cloud cover is gradually clearing. While SKC conditions are not expected, VFR conditions are expected to prevail by afternoon hours. Periods of MVFR CIGs due to cloud cover between FL010 and FL020 are possible, but not at sufficient frequency to require a TEMPO.

CLIMATE

On this day in 1957, the daily record low temperature of 60F was recorded in Key West. Temperature records for Key West date back to 1872. Also, on this day in 1957, the daily record low temperature of 56F was recorded in Marathon. This is also tied for the coldest temperature recorded during the month of October. Temperature records for Marathon date back to June 1950.

PRELIMINARY POINT TEMPS/POPS

Key West 84 78 86 79 / 20 20 20 20 Marathon 85 77 86 77 / 20 20 20 20

KEY WATCHES/WARNINGS/ADVISORIES

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

GM...Small Craft Advisory until 5 PM EDT this afternoon for GMZ033>035-044-054-055-074-075.