textproduct: Key West

KEY MESSAGES

- Coastal flooding will continue to gradually decrease over the weekend, but receding rates will be slow, especially in the Upper Keys.

- A wet, stormy period will continue through tomorrow. Locally heavy rainfall, especially when coincident with high tides, will exacerbate coastal flooding hazards.

- Much drier conditions are expected for Tuesday through the remainder of the work week.

DISCUSSION

Issued at 1025 AM EST Sun Nov 1 2026 Shower activity went from thunderstorms near the Dry Tortugas and southwest of Floyd's Wall before sunrise to a suite of ongoing thunderstorms surrounding the Lower Keys. Long lasting thunderstorms prevented the release of the morning KKEY sounding, and one particular thunderstorm generated a copious amount of lightning southeast of Key West. Showers were also slow moving and had a tendency to backbuild. Over the course of three hours, anywhere from 2 to 5 inches of rainfall accumulated from eastern Key West to Big Coppitt Key. The atmosphere ended up being too saturated to observe hazardous gusts from even the most vigorous thunderstorms. The heaviest showers have begun to dissipate around the Lower Keys as of the late morning showers.

What exactly happened this morning? Last night, breezes freshened to moderate to fresh across the northern waters of the Florida Keys. Shortly before thunderstorms started to develop en masse, anemometers along the reef sampled breezes that began to shift southerly and slacken. High resolution models showed a similar trend. That slight shift provided enough lift for the observed thunderstorms. The slackening breezes occurred at about the same time as a high pressure system over New England began to weaken and and upper altitude trough moved further into the Gulf. Showers that otherwise would have struggled to reach 40 to 50 kft received dynamical support aloft due to the nearby trough.

What does the afternoon look like across the Keys? For the Lower and Middle Keys, the extent of heavy rainfall used up the vast majority of the instability in the atmosphere. The high pressure over New England is also on track to slip into the Atlantic, would would weaken the pressure gradient across the Keys. The source of low level lift would theoretically shift towards the Upper Keys, which were spared the heaviest rainfall this morning. As always with the atmosphere, this is not a guarantee. The atmosphere very well may destabilize faster than expected across the Lower Keys, or the lift required to sustain long lasting showers may not materialize over the Upper Keys. Either way, keep watching the radar to see where additional rainfall flares up across the Keys, and keeping an umbrella handy would be a good idea.

MARINE

Issued at 1025 AM EST Sun Nov 1 2026 Small Craft Should Exercise Caution headlines are in effect for the eastern portions of Hawk Channel and the Florida Straits. Otherwise, there are no watches, warnings, or advisories in effect for the local waters. However, an increase in shower and thunderstorms activity throughout this afternoon and tonight will result in localized hazardous marine conditions including gusty and erratic strong winds, confused seas, and occasional lightning strikes.

From synopsis: a broad area of high pressure over the eastern United States continues to sustain gentle to moderate breezes across the Florida Keys waters this weekend. Occasionally, fresh breezes are possible. Small Craft Should Exercise Caution headlines are in effect for the eastern portions of Hawk Channel and the Florida Straits. Stronger winds along the east coast will also generate an elevated northerly swell for the waters south of the Upper Keys. Shower chances will continue to remain high through Monday due to broad wind convergence across the Keys. Breezes are on track to slacken during the middle of the week as drier air moves into the Keys.

AVIATION

(15Z TAFS) Issued at 1025 AM EST Sun Nov 1 2026 Heavy TSRA developed in the vicinity of EYW this morning. Additional TSRA were able to form near MTH after sunrise. Gusts over 20 knots were observed, but are becoming less likely. Breezes are expected to remain below 10 knots near both terminals, but winds will be more variable near SHRA. While VFR conditions are expected to prevail, nearby SHRA and TSRA could cause MVFR to IFR conditions.

CLIMATE

On this day in Keys Weather History, in 2005, 4.14" of rain fell in Key West in the early morning hours. With streets and storm drains clogged with debris only a week after Hurricane Wilma, the heavy rain caused significant flooding throughout the city. Precipitation records for Key West date back to 1871.

PRELIMINARY POINT TEMPS/POPS

Key West 83 75 83 76 / 80 70 50 30 Marathon 84 76 83 77 / 70 70 50 30

KEY WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 5 AM EST Monday for Flies>078.

GM...None.