textproduct: Key West

KEY MESSAGES

- A moisture surge will support elevated rain and thunder chances through the Labor Day holiday weekend.

- 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 indices will approach the mid 100s daily, with little relief in the muggy conditions overnight. Know the signs of heat stress, take frequent breaks, and stay hydrated.

DISCUSSION

Issued at 452 AM EDT Sat Sep 5 2026 Busy night for KBYX radar as scattered showers and thunderstorms throughout the coastal waters move westerly and moisture continues to push in from the east. MIMIC Precipitable Water shows a majority of our CWA with around 2.3 inches of PWAT and in the easterly waters areas of 2.6 inches! Temperatures across the island chain are in the mid 80s making for little relief from our day time temperatures overnight. Nighttime Microphysics shows that outside of convective locations, skies are mostly clear to partly cloudy. Along the Reef, marine locations are reporting southeasterly winds near 10 knots. While ample deep tropical moisture continues to dominate our area, scattered showers and thunderstorms are expected to persist throughout our area today and tonight resulting in 50% PoPs in the forecast. Seasonally warm temperatures of near 90F will occur again today resulting in heat indices approaching the mid 100s. Breezes will be light and southeast to southerly therefore a mid afternoon cloud line is possible that could produce waterspout activity.

This weekend, a large trough on the east coast will contribute to mid level heights falling across the Southeast and Florida increasing a more favorable environment for convection, resulting in more shower coverage for our area. Along with deep tropical moisture lingering, shower chances remain elevated through early next week. Mid week, a ridge over the central US will expand eastward welcoming back a high pressure pattern. This along with lower moisture content giving us a break from elevated rain chances through the end of the week.

MARINE

Issued at 452 AM EDT Sat Sep 5 2026 No watches, warnings, or advisories are currently in effect for the Florida Keys. From synopsis, Light to gentle southeast breezes will prevail through mid week as weak steering flow persists across the region, thereafter breezes will freshen to gentle to moderate as high pressure builds in. Waves of low- level moisture pushing across the Keys will support elevated rain and thunder chances through Sunday, possibly returning to near normal by mid week.

AVIATION

(06Z TAFS) Issued at 452 AM EDT Sat Sep 5 2026 VFR conditions are expected to prevail at both EYW and MTH through the TAF period. Although, deep tropical moisture will support scattered showers and thunderstorms that could pass over both terminals resulting in lowe ceilings and visibilities. TEMPOs will be included if direct impacts are expected and VCSH will prevail. Near surface winds will be southeasterly at 5 to 10 knots outside of convection.

KEY WATCHES/WARNINGS/ADVISORIES

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