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.

MARINE

Issued at 349 PM EDT Tue Sep 8 2026

From synopsis: The Florida Keys coastal waters will initially remain in a broad nebulous pressure pattern this evening, leading to light and variable winds. By early Wednesday, western extent of the Atlantic Ridge will begin building in, allowing breezes to become more easterly and freshen to gentle to moderate. Waves of low- level moisture pushing across the Keys will support elevated rain and thunder chances through Tuesday, possibly returning to near normal by mid week.

AVIATION

(18Z TAFS) Issued at 349 PM EDT Tue Sep 8 2026

Convection is generally on the downward trend and expecting VFR conditions for the rest of the afternoon and into the evening. There is a chance of showers and possibly thunderstorms developing after midnight but confidence on exact timing remains low. Will leave mentions of VCSH or VCTS for future amendments.

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.

KEY WATCHES/WARNINGS/ADVISORIES

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