textproduct: Key West

KEY MESSAGES

- Chance of showers and thunderstorms continues through tonight and tomorrow with possible afternoon cloud line development. - Mainly light to gentle broadly easterly breezes will continue through the first half of the week.

- Increased moisture content, associated with The Remnants of tropical system Dolly, may bring a period of enhanced rain chances by Thursday and Friday.

DISCUSSION

Issued at 1001 PM EDT Tue Sep 1 2026

This evening, outflow from decaying thunderstorms over south Florida generated isolated to scattered showers and thunderstorms across our nearshore and coastal waters, especially in the Florida Bay and near the Middle to Upper Keys. This activity has remained below warning criteria with vicinity marine observation sites, such as the weatherflow stations at Carysfort Reef Light and Alligator Reef Light, measuring thunderstorm wind gusts near 25 knots. On KBYX radar, multiple outflow boundaries continue to meander across the Gulfside waters surrounding the Lower to Middle Keys and in the Florida Straits, occasionally triggering a brief shower or storm. Most of the activity will gradually wane through the overnight hours, but moisture content remains very high across the area. PWATs on the 00Z KKEY RAOB measured above the 90th percentile, even approaching the max value for the day. It won't take much for one of these mesoscale boundaries to trigger activity, so will maintain Slight Chance to Chance PoPs in the forecast for tonight. Although the large scale pattern continues to be dominated by expansive ridging over the Southeastern CONUS and Central Atlantic, surface analysis reveals a low amplitude trough over Florida, particularly noticeable in the lower-levels. Weak cyclonic flow in combination with the high moisture content will promote chances for showers and thunderstorms again tomorrow, likely in a similar fashion to today with thunderstorm outflow propagating south from the Florida mainland, contributing to activity in our coastal waters north of the Island Chain. Light easterly to east-southeasterly breezes are expected tomorrow, variable at times during the afternoon, and island cloud line formation remains a possibility once again which could lead to waterspout development. Otherwise, it's a muggy night with temperature readings currently in the mid 80s and dewpoints in the mid 70s. Seasonable but warm conditions are expected tomorrow with highs in the lower 90s and dewpoints in the mid to upper 70s resulting in another day of 104-108 degree heat indices.

MARINE

Issued at 1001 PM EDT Tue Sep 1 2026

A few showers and the occasional thunderstorm continue to persist along a southward moving outflow boundary in the southeastern Gulf. This activity has been producing occasional wind gusts near 20 knots. Otherwise, generally light, northeasterly breezes are expected to continue for the next few hours, becoming easterly then east-southeasterly by the morning hours. From synopsis, the western periphery of an Atlantic high remains in control of the Keys for the next several days. Therefore, expect continued peaking and lulling breezes. The direction will also vary over the next few days with east to southeasterly breezes overnight and in the morning becoming northeast to east breezes late afternoon and evening. In addition, the overall flow will keep deep moisture in place across the region with daily chances of showers and thunderstorms. Locally hazardous winds and seas are expected in the vicinity of thunderstorm activity.

AVIATION

(00Z TAFS) Issued at 1001 PM EDT Tue Sep 1 2026

VFR conditions are expected to persist through a majority of this TAF cycle. However, atmospheric moisture content remains very high, and multiple outflow boundaries continue to meander in the vicinity of both terminals, so brief periods of SHRA/TSRA may occur. For now, introduced a PROB30 for TSRA at KEYW to account for morning convection which is being depicted by the latest hi- res model guidance. Overall flow is weak across the region, but continues to be influenced by the western periphery of an Atlantic surface ridge which will promote light, E to ESE sfc winds, VRB at times during the day.

KEY WATCHES/WARNINGS/ADVISORIES

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