textproduct: Key West

KEY MESSAGES

- A Saharan Air Layer is moving across the Florida Keys and will keep rain chances down today.

- Heat will be the primary weather concern this week. Heat indices may creep towards 110 before the weekend.

- Shower coverage is expected to increase at the end of the week while a low in the upper atmosphere tracks westward across the Keys.

DISCUSSION

Issued at 1215 AM EDT Thu Jul 9 2026

Quiet weather continues across the Keys this morning. A narrow but healthy surface through lower level Atlantic ridge stretches westward across Central Florida and is driving breezy east to southeasterly flow across the Keys. This flow is holding up temperatures and current readings are in the mid to upper 80s with dew points in the mid to upper 70s. While this evenings sounding indicated a precipitable water not to far from normal at 1.67 inches, there was a robust subsidence inversion based just above 900 mb with a good slug of dry air. This has kept shower activity down to essentially non existent across our forecast area.

A cut off upper low is currently creeping its way westward through the central Bahamas and has produced a weak lower level reflection that is beginning to move across Cuba. While today will remain dry, the weak trough will push through our area beginning tonight. This will wipe out the stable and dry layer holding showers at bay. Expect a slight to low chance for showers and thunderstorms beginning tonight. East to southeasterly breezes will remain moderate to fresh, peaking in the evening and early night hours and lulling slightly during the day. This will continue to drive slightly above normal temperatures with highs near 90, lows in the mid 80s, and dew points holding in the mid to upper 70s.

The previously mentioned upper low will contribute to yet another lower level trough heading into the weekend. This will keep at least a low chance for showers and thunderstorms. Thereafter, much drier and more stable lower levels is expected to sweep in. As a result, rain chances will be slight or less from later in the weekend and well into next week.

MARINE

Issued at 1215 AM EDT Thu Jul 9 2026

A robust Atlantic surface ridge will stretch across Central Florida over the next few days and result in moderate to fresh east to southeasterly breezes. Winds will tend to peak in the late evening hours and lull slightly during the day. At least marine cautions will be required for most of our waters through this stretch. For this weekend and into next week, winds will slowly trend downwards as the ridge retreats eastward and weakens slightly.

AVIATION

(00Z TAFS) Issued at 1215 AM EDT Thu Jul 9 2026

VFR conditions will prevail at the island terminals today. Surface winds will be moderate to fresh out of the east to southeast.

PRELIMINARY POINT TEMPS/POPS

Key West 91 83 91 83 / 0 20 30 30 Marathon 90 83 90 83 / 0 30 30 40

KEY WATCHES/WARNINGS/ADVISORIES

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