textproduct: Key West

KEY MESSAGES

- Measurable rain chances will remain low through today through early next week, at generally 10% or less.

- Conditions will remain seasonably warm and muggy, but we may see heat index values above 105F, particularly along the Upper Keys, through Sunday.

- A pocket of Saharan Air currently near and north of Hispaniola will slowly move west across our area starting Monday and could linger through Wednesday.

DISCUSSION

Issued at 444 AM EDT Sun Jun 21 2026

It was another relatively active night across the waters north of the island chain. A residual boundary that likely originated from a cloud line attempting to develop yesterday afternoon, briefly came to life across the Lower Keys. Unfortunately, the single shower that developed fell apart before reaching Key West. However, it did manage to produce around a quarter of an inch of rainfall at the Boca Chica Naval Air Station before it dissipated. Convection remains ongoing this hour but lies just northwest and west of Key West between Smith Shoal Light and the Dry Tortugas. Since the shower did not reach Key West International Airport, and we do not see temperatures fall below 83 degrees before midnight, a new warm low temperature record could be set or tied.

Today will be similar to yesterday in the sense that morning convection will wither shortly after sunrise. Then eyes will turn to the southern Mainland where convection will fire in the afternoon and once again drift over the Upper Keys and the waters north of the island chain. In addition, we may have a long enough period of northeast to east winds in the 850-700 mb layer which may be just enough for a late day cloud line to try and take shape. The atmosphere set- up will also be similar and any showers or thunderstorms that collapse as they enter our waters could be quite frisky. This will lead to locally confused seas and higher winds.

Meanwhile, lurking just north of Hispaniola and Puerto Rico is a decent slug of Saharan Air. This will slowly move in starting late tonight into Monday and linger through Wednesday. The leading edge could provide a slight chance of showers and thunderstorms before the drier, more stable air shuts down most of our prospects for precipitation. Temperatures through the next seven days will hardly budge, however, the introduction of the drier Saharan Air may afford us a somewhat, albeit slight reduction in dew points.

MARINE

Issued at 444 AM EDT Sun Jun 21 2026

Convection remains ongoing across mainly the waters north and northwest of the Lower Keys. This activity is expected to diminish over the next several hours. As we go into the afternoon, convection across the southern Mainland will fire and drift southward across the Upper Keys, Florida Bay, and extreme southeast Gulf waters. The storms will have the potential to collapse and eject locally stronger winds and confused seas. Outside of convection, breezes will tend to be east to southeast and generally light to gentle through Wednesday. The exception will be the Straits of Florida where periods of gentle to moderate breezes can be expected. A broad high currently centered over the Florida Peninsula, is expected to gradually build starting Thursday with a period of freshening breezes possible.

AVIATION

(06Z TAFS) Issued at 444 AM EDT Sun Jun 21 2026

Convection northwest of the EYW terminal will quickly diminish and move further to the west within the next couple of hours. We will be watching for a potential late afternoon cloud line that may develop, especially across the MTH terminal. Confidence is too low to include mentions of either VCSH or VCTS at this time. This will be assessed further with future amendments.

KEY WATCHES/WARNINGS/ADVISORIES

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