textproduct: Key West

KEY MESSAGES

- Very warm and humid conditions over the next few days will lead to a moderate risk of heat illness with periods of major risk conditions possible. - Quick moving showers and storms may bring bursts of heavy rainfall, reduced visibility, and gusty winds.

- Gentle to moderate easterly breezes will continue for the next several days peaking in the evenings and overnight and decreasing in intensity during the afternoon hours.

DISCUSSION

Issued at 1010 PM EDT Wed May 20 2026 Another warm and muggy May evening is unfolding across the Florida Keys. Dew points along the island chain are holding steady in the lower to mid 70s. Radar scans from KBYX are highlighting disorganized showers over the eastern Florida Straits, but otherwise shower coverage remains sparse. GOES-East water vapor imagery is struggling to highlight cloud cover across the nearshore and offshore waters, though debris cirrus clouds are transiting across the Middle to Upper Keys. However, per the KKEY evening sounding, the overall PWAT values are nearly the same. Moisture amounts remain heavily concentrated in the lower atmosphere with a drier layer in the upper atmosphere. Enough instability exists across the Keys, but a source of lift is absent.

Synoptically, the environment is still defined by the broad Atlantic high. However, the pressure gradient is mitigated by a weak surface trough off of the eastern coast of Florida. That would be the surface reflection of a cutoff low in the upper atmosphere. What does this mean tonight and tomorrow? First, wind speeds are a bit lower across the Keys than we would otherwise observe in this weather pattern. This also means the trend of slightly weaker winds during the day, thanks to the heat low that develops over south Florida, will continue. Persistence best defines the forecast for the next few days. It will take a few more days to see a change in the weather pattern.

MARINE

Issued at 1010 PM EDT Wed May 20 2026 No watches, warnings, or advisories are in effect across the Florida Keys waters. From synopsis, gentle to moderate east to southeasterly breezes persist across Florida Keys waters. There is high confidence that, in this current weather pattern, a diurnal trend in wind speeds reaching a lull during the day and a peak during the evening will remain in place. Expect rain and thunderstorm chances to return to near normal by the weekend.

AVIATION

(00Z TAFS) Issued at 1010 PM EDT Wed May 20 2026 VFR conditions will prevail at both EYW and MTh for the upcoming TAF period. While ceilings are unlikely, cloud cover between FL020 and FL030 can be observed near the terminals. Shower chances are expected to trend upwards after 06Z.

CLIMATE

On this day in 1932, the daily record rainfall of 3.83 inches was recorded in Key West. Rainfall records for Key West date back to 1871.

On this day in 2024, the daily record rainfall of 7.08" was recorded in Marathon. This also ranks as the wettest day ever recorded in May. Rainfall records for Marathon date back to June 1950.

PRELIMINARY POINT TEMPS/POPS

Key West 81 91 81 91 / 20 20 20 10 Marathon 80 87 80 87 / 20 20 20 20

KEY WATCHES/WARNINGS/ADVISORIES

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