textproduct: Key West

KEY MESSAGES

- Light to gentle winds will continue through this tonight.

- A more active weather pattern will develop with higher chances for showers and thunderstorms starting on Tuesday.

- Highest rain chances are expected to occur late Tuesday into Wednesday with a brief lull, followed by another round of higher chances for the end of the week.

AVIATION

(18Z TAFS) Issued at 146 PM EDT Mon Aug 3 2026 VFR conditions will prevail through the remainder of the day with SW surface winds at 5-10 kts through this evening, but winds will shift to the SE overnight into Tuesday. In addition, scattered SHRA/TSRA could also occur tonight into Tuesday morning, which could mainly form due to activity sliding southward from the FL mainland or activity approaching the Keys from Cuba. However, confidence in overall precipitation timing and coverage was too low to include in latest TAF issuance at this time.

DISCUSSION

Issued at 1052 AM EDT Mon Aug 3 2026 Other than shower activity in the offshore Gulf waters, the majority of the KEY CWA is dry at this time. The latest 12Z KEY RAOB reveals the reasoning for this as a low-level southerly flow was measured in the boundary layer, which is providing a Cuban shadow influence and this is further verified by recent GOES-19 satellite imagery showing a northward advancing cumulus field dissipating quickly as it spreads offshore of the northern Cuban coastline. While this is acting as a drying mechanism for the time being, forecast soundings do show a gradually veering profile throughout the day in the low levels, which combined with a gradual decrease in wind speeds, may allow for the development of a reverse cloud line across portions of the island chain and this could be one source of precipitation development later today. However, given the low-level dry air in place, further enhanced by the Cuban shadow, and mean wind speeds around 10 kts through the 1000-700mb layer, this scenario is of low confidence at this point. As a result, the main update this morning was to make a slight downward adjustment with PoPs, which now puts the majority of the KEY CWA in the slight category (15-24%).

While the Cuban influence has had a role thus far today in keeping things on the drier side, conditions will need to be monitored closely this evening and overnight as there are two potential areas where higher rain chances could occur. The first is around Florida Bay and Upper Keys where convection across the SEFL mainland may produce outflow boundaries that yield development, which could then linger past midnight. Similarly, convection is expected to erupt across Cuba this evening and may be able to propagate across the Straits or produce outflows that ignite additional convection, which ultimately could drift across the Island Chain. PoPs reflect these potential scenarios for tonight with widespread chance (30%-40%) values forecast area- wide. As a result, we will be keeping a close watch on the convective evolution of this throughout the day should additional forecast updates be needed and possibly short-fused marine warnings.

MARINE

Issued at 508 AM EDT Mon Aug 3 2026 No watches, warnings, or advisories are currently in effect for the Florida Keys waters. From synopsis, light to gentle breezes will continue to be in place through Tuesday before wind speeds increase to the gentle to moderate range for mid to late week as a southeasterly flow patters develops. In addition, rain chances will also be increasing by Tuesday night as deeper moisture spreads into the region ahead of a frontal boundary approaching northern Florida. As chances for showers and thunderstorms increase, mariners can expect higher winds and seas near this activity.

KEY WATCHES/WARNINGS/ADVISORIES

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