textproduct: Key West

KEY MESSAGES

- Light to gentle southeasterly winds will prevail through the remainder of the day.

- A more active weather pattern will develop for the new work week with higher chances for showers and thunderstorms.

- Highest rain chances are expected to occur late Tuesday into Wednesday.

AVIATION

(18Z TAFS) Issued at 127 PM EDT Sun Aug 2 2026 VFR conditions are generally expected throughout the period but there is some potential for scattered SHRA tonight into Monday morning. However, if any shower activity does develop, it will be brief and overall forecast confidence in its development was not high enough to include in the most recent TAF issuance. Otherwise, surface winds will remain out of the SE at 5-10 kts through tonight and could slowly start to shift to the SW by the end of the period.

DISCUSSION

Issued at 1044 AM EDT Sun Aug 2 2026 KBYX radar imagery is showing widely scattered showers and occasional thunderstorms primarily north of the Island Chain with precipitation activity drifting to the NNW along the western flank of Atlantic high pressure. This activity has been a result of speed convergence in the southeasterly low-level flow regime and a highly unstable environment per the latest 12Z KEY RAOB, which calculated a SBCAPE value near 4000 J/kg with minimal to no inhibition. While these parameters would ultimately be favorable for continued convective activity through the remainder of the day, the gradually veering low-level wind profile has brought the Cuban shadow effect into play and this can be clearly seen in recent GOES-19 visibility satellite imagery. The recent satellite imagery shows a narrow band of cumulus quickly drifting northward across the Straits and approaching the reef with all the precipitation activity ahead of this feature as to be expected. Since the air mass is noticeably drier behind this band of cumulus, rain chances for the remainder of the day across the Florida Keys should be on the limited side depending on how far north this feature spreads, with most hi-res guidance in agreement that there should be a lull in activity by late afternoon or early evening. However, the forecast challenge thereafter will be whether or not convection from Cuba will spread an outflow boundary that ignites additional activity across the Straits and given this potential scenario, PoPs of 30-35% will be in place area-wide overnight and we will be monitoring conditions closely regarding the evolution of this. Otherwise, heat indices are already in the low 100s and could reach around 106 or slightly higher depending on how much clearing occurs in the wake of the downsloping influence from Cuba.

MARINE

Issued at 541 PM EDT Sat Aug 1 2026 No watches, warnings, or advisories are currently in effect for the Florida Keys waters. Light to gentle breezes will continue into early next week with some occasional periods of gentle to moderate. In addition, rain chances will also be increasing for the new work week as deeper moisture spreads into the region ahead of a frontal boundary approaching northern Florida. As chances for showers and thunderstorms increase next week, mariners can expect higher winds and seas near this activity.

PREV DISCUSSION

Issued at 541 AM EDT Sun Aug 2 2026 The showers and thunderstorms observed in the Straits of Florida earlier this morning have all fizzled out leaving only a few very light showers in its wake. Beyond that, KBYX is not detecting any activity. Temperatures across the island chain are in the mid 80s with dew points in the mid 70s making for another muggy summer morning. Along the Reef, marine locations are recording east to southeast winds of 5 to 10 knots. For today, shower development is possible but just slight chances are advertised for the day. Variable and light winds will becoming mostly southeasterly after sunrise and slightly freshen to 5 to 10 knots.

Through next week the western periphery of the Atlantic subtropical ridge will remain the dominate feature. This will support generally light to moderate east to southeast breezes and bring an influx of moisture to our area. With sufficient precipitable water values we can expect higher rain chances peaking on Tuesday night through Thursday night. Cloud lines will be possible with the southeasterly winds as well causing showers and potential waterspouts as well. Outside of higher chances of convection breezes will be steady at light to moderate throughout the week. Going into next weekend rain chances will return to near normal for early August.

KEY WATCHES/WARNINGS/ADVISORIES

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