textproduct: Key West

KEY MESSAGES

- High chance for showers and thunderstorms this afternoon and evening as a low level trough moves into the area.

- Heat will be the primary weather concern over the next seven days. Heat indices may creep towards 110 beginning this weekend.

- A Saharan Air Layer will begin spreading across the Keys later this weekend into next week, keeping rain and thunder chances slight at best.

DISCUSSION

Issued at 117 AM EDT Fri Jul 10 2026

A wetter stretch has begun to move across the Keys area this evening. This is due to an upper level low over the central Bahamas driving a couple of weak lower level troughs and associated increase in moisture and instability. The first round is working its way across the Keys tonight. A squall recently moved through the Lower Keys and further activity is congealing off the Middle and Upper Keys. Otherwise, moderate to fresh breezes are being driven by a narrow but healthy Atlantic ridge reaching westward across Central Florida and along the Gulf Coast. This is keeping temperatures slightly above normal with highs near 90, lows in the mid 80s and dew points in the mid to upper 70s.

The second trough will be carried westward ahead of the responsible upper level low through today and tonight. All guidance is pointing to at least one round of vigorous showers and thunderstorms sweeping through the forecast area from this afternoon into this evening. Hence, mid to high chance pops are being advertised. There is a good chance PoPs may be raised further in the next forecast cycle. Synoptically speaking, the ridge will remain across Central Florida, keeping east to southeasterly breezes moderate to fresh across the Key. Outside of convective influences, temperatures will continue above normal with highs with little to no day to day trend evident.

All guidance points to much drier lower level invading the area beginning saturday as a Saharan Air Layer moves in. Expect increasing low level inhibition and precipitable water falling to near 1.5 inches. As a result, rain chances will slip to slim or lower this weekend through early next week. The Atlantic ridge will weaken and become poorly defined through the first half of the week, allowing winds to trend slowly downwards. Surface temps and moisture will remain nearly unchanged through this period.

MARINE

Issued at 117 AM EDT Fri Jul 10 2026

An Atlantic surface ridge stretches across Central Florida and is maintaining moderate to fresh east to southeasterly breezes across Keys waters this morning. Winds will continue to wax and wane over the next couple of days, generally peaking in the evening and lulling during the day. Broad lower level troughing will lumber its way westward across our area today and tonight. This is setting the table for more rounds of convection, particularly this afternoon into evening. Mariners can expect a round or two of strong gusty winds, and possibly heavy downpours, and frequent lightning strikes. Rain and thunder chances will drop significantly this weekend in to next week as the trough washes out and much drier low levels invade the area.

AVIATION

(06Z TAFS) Issued at 117 AM EDT Fri Jul 10 2026

VFR conditions will prevail at the island terminals today. With that said, convective chances increase sharply to high chance later this afternoon and evening. These may deliver gusty winds and short spells of sub VFR conditions. Outside of convection, breezes will be mostly moderate out of the east to southeast.

PRELIMINARY POINT TEMPS/POPS

Key West 92 83 93 83 / 50 40 10 0 Marathon 90 83 90 84 / 50 30 10 0

KEY WATCHES/WARNINGS/ADVISORIES

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