textproduct: Key West

KEY MESSAGES

- Gentle to moderate southeast to south breezes are expected across Florida Keys coastal waters for the next few days peaking overnight and lulling during the day.

- Heat indices may approach 108 to 110 degrees each afternoon for some Florida Keys island communities.

- Saharan Air Layer plumes will transit the area over the next several days, limiting rain and thunder chances.

FORECAST

The big elephant in the room will be Invest 91L for the next few days. The National Hurricane Center (NHC) currently highlights this system across the northern Gulf with a medium (60%) chance of tropical development through 48 hours and 7 days. The system poses no risk to the Florida Keys. Ridging will continue to be the name of the game going forward for the next week or more for the Keys. Moisture undulations will occasionally slide through the Keys resulting in slight chances of showers and thunderstorms. The timing on this appears to be one round this morning with another round this evening. Model guidance seems to be more bullish on the activity this evening, therefore, chances of showers with a slight chance of thunderstorms is in the forecast for tonight. Some guidance is pointing to convection forming either over or just north of Cuba and then racing northward towards the Island Chain, especially the Lower Keys. Any showers and storms this evening will be capable of heavy downpours, gusty winds, and occasional lightning strikes. Outside of that, continued seasonably warm conditions will continue with highs near 90 degrees and overnight lows in the lower to mid 80s. There is the potential for highs to reach the lower 90s this week which will push the heat index values up to 105 to 110 degrees. However, heat Advisories are not being considered at this time.

The Atlantic ridge will continue to dominate the pattern across the Keys resulting in peaking and lulling breezes mainly out of the southeast to south for at least the first half of the week before becoming more east to southeast for mid to late week and beyond.

MARINE

Issued at 440 AM EDT Sun Jul 19 2026 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, a broad area of low pressure over the eastern Gulf of America will shift northward through Monday, with prevailing gentle to moderate south to southeasterly breezes across Florida Keys coastal waters. An Atlantic high pressure ridge will extend to the Florida Peninsula for the next several days. Gentle southeasterly breezes are expected to prevail across Keys coastal waters Monday night through Thursday, with overnight surges and afternoon lulls.

AVIATION

(06Z TAFS) Issued at 440 AM EDT Sun Jul 19 2026 VFR conditions are expected to prevail at both EYW and MTH terminals through the TAF period. Near surface winds will remain southeast to south through the period. Slight chances for showers and thunderstorms remain in the forecast with the best chance times being this morning and again this evening. Due to the timing and placement uncertainty, VCSH was left out of the TAF for now.

CLIMATE

On this day in 2024, the daily record warm low temperature of 85F was recorded at both Key West and Marathon. Temperature records for Key West date back to 1872 and Marathon date back to 1951.

PRELIMINARY POINT TEMPS/POPS

Key West 90 84 91 84 / 20 30 10 0 Marathon 90 83 91 83 / 20 30 10 0

KEY WATCHES/WARNINGS/ADVISORIES

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