textproduct: Key West

KEY MESSAGES

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

- The Remnants of Dolly remain near Puerto Rico and the Virgin Islands and may bring a period of much higher rain chances by the middle of the week.

UPDATE

Issued at 1135 AM EDT Mon Aug 31 2026 It has been a much quieter morning than this past weekend as some drier air has filtered in aloft, which has been mostly due to the influence of upper-level ridging from the SW Atlantic, which will gradually merge with a strong central CONUS ridge throughout the day. Despite the influence of this feature, there have been a few isolated showers attempt to develop but quickly dissipate as updrafts encounter some of the drier air aloft. However, one source of initiation that may occur today and has not been a factor in recent days is the potential for a cloud line to develop. While the low-level flow is not projected to align in a completely ideal direction, the boundary layer flow is rather weak and based on the 12Z KEY RAOB, surface moisture is excellent with a moist profile from the surface to 950 mb. These factors favor a much higher cloud line signal with showers and storms likely to remain near the Island Chain as opposed to displaced given the lighter flow in place. Given our most recent waterspout index was calculated at 26%, also can't rule out some waterspout potential if surface spin develops in the vicinity of towering cumulus. Any cloud line activity that develops should fade by the evening but additional development may occur as outflow boundaries from SWFL convection spread potentially spread southward into portions of the area this evening, particularly the Upper Keys and adjacent marine areas. Otherwise, highs are expected to reach around 90 this afternoon with heat indices peaking around from 105-107 in most areas.

FORECAST

Ever so slightly drier air has moved into the Keys early this morning. Therefore, while we still expect showers and thunderstorms, we don't expect the activity to be as widespread for today and tonight. Therefore, PoPs were lowered slightly to 30% for this frame. The theme remains the overall same though with an Atlantic ridge continuing to extend its western periphery into the Keys. Global and numerical model guidance remain in agreement through at least Tuesday night for a slightly drier period from today through Tuesday night. The PoPs are as follows 30% tonight, 40% Tuesday, and 30% for Tuesday night. Also, with a slightly lighter wind regime today, there is the potential that a cloud line may try to develop during the afternoon, though, this is low confidence at this time. It may happen again Tuesday afternoon as well.

With that said, the forecast for mid to late week while still looking interesting isn't looking as favorable as it did before. Global and numerical guidance virtually show the Remnants of Dolly totally fizzling out as it moves into Cuba. However, the northern fringe of the moisture associated with it may graze the Keys Wednesday/Thursday time frame. The remnants and its moisture will continue moving west northwest gliding along the northern fringe of Hispaniola and eventually moving right into the eastern side of Cuba. It appears that the northern fringe of the moisture associated with Dolly reaches the Keys sometime Wednesday and continues to affect the region through Thursday/Thursday night before continuing northwestward into the Gulf. Therefore, likely Pops are in the forecast for this time frame at 60%. It turns out the main takeaway for this time frame will be to potentially expect slightly friskier showers and thunderstorms and an increase in cloud cover.

Behind the remnants of Dolly, moisture will remain, just not as deep as the mid to late week time frame. Rain chances return back to chances (40-50%), though, still remain elevated for late week and into the holiday weekend. After all, it is September at this point.

The Keys remain on the western periphery of the Atlantic ridge through much of the week. This will continue to yield to peaking and lulling breezes through the middle part of this week. However, the wind direction will also follow suit with east to southeast breezes during the early morning to early afternoon hours followed by northeast to east breezes in the mid to late afternoon into the early overnight hours. Breezes will stabilize a little bit more towards the end of the week with mainly east to southeast light to gentle breezes anticipated. Daytime highs will continue to be near 90 degrees with overnight lows in the lower to mid 80s, cooler in and near shower and storms. Dew points will remain soupy in the mid to upper 70s. September starts in less than 24 hours and Florida will continue to live up to its name for this time of year with daily rain chances.

TROPICS: The National Hurricane Center (NHC) continues to monitor two areas for potential tropical cyclone development. The first is near Puerto Rico and the Virgin Islands (Remnants of Dolly) which has a low or near 0 percent chance of development through 48 hours and a low or 20 percent chance of development through the next 7 days. The second area being watched for tropical cyclone development is currently in the Northern Gulf of America (Invest 97L). This system has a high or 705 chance of tropical development through both the next 48 hours and 7 days. Both of these systems currently pose no threat to the Florida Keys, though, Dolly's remnants may very well bring an increase in rain chances to the Keys.

MARINE

Issued at 1135 AM EDT Mon Aug 31 2026 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. 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 shift over the next few days with east to southeasterly breezes overnight and in the morning with 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

(18Z TAFS) Issued at 138 PM EDT Mon Aug 31 2026 Brief light to moderate SHRA may occur through this evening across portions of the Island Chain due to the development of a cloud line, which may result in brief flight restrictions at times. Other than the potential for a few showers through the remainder of the day, VFR conditions are expected to prevail with surface winds out of the E around 5 kts through this evening, gradually shifting to the ESE overnight into Tuesday morning. Some additional SHRA/TSRA could form late Tuesday morning into the afternoon, but confidence in overall coverage is low at this time so this was not included in the recent TAF issuance.

KEY WATCHES/WARNINGS/ADVISORIES

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