textproduct: Key West

KEY MESSAGES

-Cooler and drier conditions will continue over the next couple of days, with warmer temperatures expected for the end of the week and the weekend.

-Bouts of breezy to windy conditions will continue through Wednesday night.

-Dry conditions expected tonight thorugh Wednesday, with increasing rain chances for Wednesday night and Thursday.

DISCUSSION

Issued at 1030 PM EST Mon Jan 19 2026 The 00z evening sounding at KEY sampled a dry-adiabatically, well-mixed layer from the surface up to around the 925 isobaric surface. The layer characterized by constant potential temperature is then capped by a thermodynamically-stable layer just above, albeit saturated. GOES-19 nighttime microphysics imagery supports this saturdated layer between 925-830 mb, with a relatively thick stratus deck advecting westward towards the Keys over the past several hours. Owed to nocturnal trapping of outgoing longwave radiation, temperatures have actually risen a few degrees since this evening, with available land-based surface observations indicating temperatures in the lower 60s at this hour.

Tonight will be characterized by generally mostly cloudy skies and nil rain chances. Temperatures will likely drop only a few degrees overnight in the Middle and Upper Keys, mainly toward sunrise. In the Upper Keys, the drop will be more noticeable owed to drainage from the South Florida Mainland in the mean fresh to strong northerlies. No changes proposed for this late evening update cycle.

MARINE

Issued at 1030 PM EST Mon Jan 19 2026 A Small Craft Advisory remains in effect for all Florida Keys marine zones. From synopsis, an expansive high pressure system will move across the eastern United States over the next several days, leading to a strengthening pressure gradient. This will continue to promote bouts of fresh to strong breezes throughout the work week. The high will move out into the western North Atlantic mid- late week while weakening. This will support slackening breezes for Friday night and Saturday.

AVIATION

(00Z TAFS) Issued at 1030 PM EST Mon Jan 19 2026 Bouts of MVFR CIGs will occur in the vicinity of both terminals through at least 12z Tuesday morning. Despite the bouts of MVFR CIGs, confidence is high in nil rain chances at the terminals. Clearing conditions, with VFR conditions, are then expected through the end of the TAF period. Near-surface winds will remain out of the north to northeast, slowly veering to the northeast. Winds will occasionally gust to near 25 knots overnight, with frequent gusts to near 20 knots continuing on Tuesday.

PRELIMINARY POINT TEMPS/POPS

Key West 59 72 65 76 / 0 0 0 10 Marathon 59 71 65 77 / 0 0 0 10

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...Small Craft Advisory until 11 AM EST Tuesday for GMZ031>035- 042>044-052>055-072>075.