textproduct: Key West

KEY MESSAGES

- Moisture will linger across the region through midweek, supporting rain and thunderstorm chances.

- The primary threat for any stronger thunderstorms will be dangerous lightning strikes. When thunder roars, go indoors. If on a boat, stay low, or go below.

- Heat index values will range from 100-108 degrees daily, with little relief in the muggy conditions overnight. Know the signs of heat stress, take frequent breaks, and stay hydrated.

DISCUSSION

Issued at 1033 AM EDT Tue Sep 8 2026

The Florida Keys remain in a weak nebulous regime with light and variable winds. This morning's sounding showed a fairly moist and unstable environment, however, we're lacking any organized lift. This has led to pulse activity that go up nearly in place, last on the order of 30 minutes, and then collapsing. Most of the showers and thunderstorms have resided across the Southeast Gulf and Straits of Florida waters. In the last hour or so, there has been a flurry of isolated activity north of the Middle and Upper Keys. Most of this activity is dancing on either side of the island chain but a few select island communities have seen a brief shower pass through.

For the remainder of today, we will continue to have light and variable winds with a chance for showers and thunderstorms, mainly this morning. Relatively drier air will move in later this afternoon and we should see the coverage fall off but not zero. No changes made to the going forecast.

MARINE

Issued at 1033 AM EDT Tue Sep 8 2026

Light and variable winds will persist into this afternoon, along with scattered showers and isolated thunderstorms. Mariners can expect gusty erratic winds in and around showers and thunderstorms, blinding downpours, and bouts of lightning. In addition, conditions are marginally favorable for an isolated waterspout to develop. A waterspout will most likely form beneath the dark, flat base of a building towering cloud, just at the hint of rain.

AVIATION

(15Z TAFS) Issued at 1033 AM EDT Tue Sep 8 2026

VFR conditions will prevail outside of any pesky showers or thunderstorms that manage to pass over the terminals. Expect light and variable winds to persist throughout most of the forecast period.

PREV DISCUSSION

Issued at 400 AM EDT Tue Sep 8 2026

Weak lower level troughing remains across the Florida peninsula this morning. This has contributed to the atmosphere remaining very moist. Last evenings sounding had a precipitable water of 2.25 inches which was above the 90th percentile for the date. There was a sliver of lower level inhibition, but CAPE was more than ample and lower level moisture was quite high. Surface winds and steering flow remain quite weak and often variable.

Over the next few days, the troughing across Florida will wash out as a pressure ridge builds east southeastward off the Atlantic Coast and down along the Gulf coast. As this takes place, variable surface breezes will gradually firm up out of the east. Moisture and instability will remain high, while inhibition limited. This along with the increasing flow should keep shower and thunderstorm chances near to slightly above normal. Seasonable temperatures will continue with highs near 90 and lows in the lower to mid 80s.

The surface ridge will retreat into the Atlantic late in the week and this evening as it shifts down the Florida peninsula. This will tip breezes a bit more southeasterly whilst continuing the usual peaks and lulls. Some drier air may arrive Friday, but will be followed by increased moisture during the weekend.

PRELIMINARY POINT TEMPS/POPS

Key West 92 82 92 82 / 30 30 30 30 Marathon 91 84 91 83 / 40 30 30 50

KEY WATCHES/WARNINGS/ADVISORIES

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