textproduct: Miami - South Florida

KEY MESSAGES

Updated at 1252 PM EDT Thu May 21 2026

- A high risk of rip currents will continue across the Atlantic Coast beaches through this evening.

- Scattered showers and thunderstorms will be possible across SW Florida once again this afternoon.

- Heat indices will rise into the upper 90s and lower 100s across most areas each afternoon through the end of the week.

SHORT TERM

(Today through Friday) Issued at 230 AM EDT Thu May 21 2026

The pattern will remain generally unchanged today, with an upper level ridge extending across the Gulf and over the peninsula and an upper level low meandering over the western Atlantic waters. Near the surface, an area of high pressure will remain in place over the western Atlantic waters, extending over the peninsula. This setup will help promote robust easterly flow across South Florida during this period, while also maintaining some moisture advection near the surface. However, overnight observations from the 00Z MFL sounding and ACARS flights at KMIA show a pocket of drier air intruding near the mid-levels. Water vapor imagery suggests this is dry air being pulled southward along the western periphery of the upper level low currently east of the Bahamas, and model guidance supports a continuation of this phenomenon today. In fact, most modeled PWATs within the ensemble guidance envelope are trending near to below average for this time of year, really highlighting the shift from conditions earlier in the week. This upper level low is forecast to remain in the area before departing eastward on Friday, allowing for ridging to become more established.

With prevailing easterly flow and some low-level moisture still in place, chances for showers and thunderstorms will remain on the forecast, especially along the sea breeze boundaries over interior/southwest FL each day. However, with drier air aloft and weak forcing and steering, any activity that develops should be transient and sub-severe in nature, with occasional lightning and some gusty winds the main impacts. Some spots could get half an inch to an inch of rain, but otherwise the risk of localized flooding remains low at this time.

Temperatures each day will continue to rise into the upper 80s (along the East Coast) and up into the mid 90s (across southwest FL), with heat indices peaking in the mid 90s across the East Coast, and up into the triple digits across southwest FL. Warm overnight temperatures, especially across the East Coast, will impede much in the way of relief, especially for any vulnerable communities.

LONG TERM

(Friday night through Wednesday) Issued at 230 AM EDT Thu May 21 2026

The rinse and repeat pattern will continue into the extended period, with upper level ridging extending across the Gulf and over the peninsula. Near the surface, an area of high pressure will remain in place over the western Atlantic waters, extending over the peninsula. This setup will help promote robust easterly flow across South Florida during this period, while also maintaining healthy moisture advection along the atmospheric column. Ensemble guidance places PWAT values during the period solidly near the climatological normals for this time of year (1.5-1.7 inches) while model soundings show this moisture permeating the whole column.

With prevailing easterly flow and ample moisture in place, chances for showers and thunderstorms will remain on the forecast over the weekend and into next week, especially along the sea breeze boundaries each afternoon. Although some isolated activity will likely develop over the East Coast metro early each afternoon, the better chances (in the 50-70% range) will be spread out across southwest Florida and the interior where the sea breezes are forecast to meet each day.

Temperatures each day will continue to rise into the upper 80s (along the East Coast) and up into the mid 90s (across southwest FL), although some of the shower activity could help provide some brief, localized relief and help temper conditions. Overnight lows also look to remain elevated through the period.

AVIATION

(18Z TAFS) Issued at 1252 PM EDT Thu May 21 2026

A few showers may impact east coast sites over the next couple of hours, however more numerous showers and storms are expected to develop across Southwest Florida this afternoon and evening. Generally easterly flow prevails with a Gulf breeze likely at APF.

MARINE

Issued at 230 AM EDT Thu May 21 2026

Generally benign boating conditions will prevail as a light to moderate easterly breeze persists across the local waters. Isolated to scattered showers will be possible each day, but will favor the Gulf waters under this easterly wind regime. Gustier winds and rough seas are possible in and around thunderstorm activity.

BEACHES

Issued at 230 AM EDT Thu May 21 2026

Strong onshore flow will continue to promote a high risk of rip currents across the Atlantic coastline through this evening.

PRELIMINARY POINT TEMPS/POPS

Miami 78 89 79 89 / 10 20 10 20 West Kendall 76 90 76 90 / 10 20 10 20 Opa-Locka 78 90 78 90 / 10 20 10 20 Homestead 78 89 78 90 / 10 20 10 20 Fort Lauderdale 79 87 80 88 / 10 20 10 20 N Ft Lauderdale 79 87 79 87 / 10 20 10 20 Pembroke Pines 79 91 79 91 / 10 20 10 20 West Palm Beach 79 88 80 88 / 0 10 10 20 Boca Raton 80 87 81 88 / 10 20 10 20 Naples 76 91 76 91 / 30 40 10 50

MFL WATCHES/WARNINGS/ADVISORIES

FL...High Rip Current Risk through Friday evening for FLZ168-172-173.

AM...None. GM...None.