textproduct: Key West

KEY MESSAGES

- Measurable rain chances will stay low for each forecast period through this weekend, generally at 20% or less.

- Conditions will remain seasonably warm and muggy.

- There will be little relief in the warm temperatures overnight, with minimum temperatures near record values in the lower to mid 80s for most communities.

DISCUSSION

Issued at 1120 PM EDT Tue Jun 23 2026 An upper-level composite analysis this evening indicates that the Florida Keys and adjacent coastal waters are beneath the far eastern flank of a deep layer mean anticyclone centered over the Rio Grande Valley. A deep layer of very light winds was sampled by the Key West evening radiosonde balloon, along with a fairly deep layer of very dry air from about 2000-20000 feet above ground. Animations of satellite-derived precipitable water and University of Wisconsin CIMSS Saharan Air Layer Tracking Product images indicate that the current very dry air aloft is associated with a remnant narrow SAL plume. A deeper moist layer is just upstream over the Bahamas and eastern Cuba. Key West radiosonde balloon winds were generally easterly in the lower-mid troposphere and west-northwesterly in the upper troposphere. The thermodynamic stratification was moderately unstable, but with significant convective inhibition energy based at low altitudes. Weakly difluent flow in the boundary layer is facilitating quick dissipation of transient outflow boundaries from nearby land-based convective cells.

Current air temperatures in most Keys island communities are in the mid 80s, with dewpoint temperatures in the mid 70s, and heat indices in the lower to mid 90s. Winds were ESE 5-10 mph over land and ESE 5-10 knots over water. Latest Key West Doppler radar scans show no precipitation echoes across the service area, not surprising given the very dry air at low and mid levels.

Current forecasts for overnight are in no need of adjustment. Shower and thunderstorm chances should increase after about 0300 EDT as a deeper moist layer moves in from the east-southeast. However, cell coverage should still remain isolated.

MARINE

Issued at 1120 PM EDT Tue Jun 23 2026 No watches, warnings, or advisories are in effect for Florida Keys coastal waters zones. Currently, ESE winds of 5-10 knots prevail, with seas ranging 1-3 feet. Similar conditions are expected overnight through Wednesday, with a slight uptick in both wind speeds and wave heights expected during the Wednesday night-Friday time frame. Shower and thunderstorm coverage, which is nil at the moment, should increase a bit after midnight as a deeper plume of moisture moves in from the east and southeast.

AVIATION

(00Z TAFS) Issued at 1120 PM EDT Tue Jun 23 2026 Through 24/24Z, prevailing VFR conditions are expected at both EYW and MTH. Although a brief sub-VFR episode from a transient rain shower is not impossible, the probability is too low for inclusion in the TAFs.

KEY WATCHES/WARNINGS/ADVISORIES

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