textproduct: Miami - South Florida

KEY MESSAGES

Updated at 647 PM EDT Sun Sep 13 2026

- Scattered showers and thunderstorms focus mainly across interior South Florida today with a few extending towards the coasts. Frequent lightning, heavy rain and gusty winds will be possible with any storms. - High temperatures will generally rise into the low to mid 90s across South FL each day, resulting in widespread Moderate to Major HeatRisk.

UPDATE

Issued at 109 PM EDT Sun Sep 13 2026

Scattered convection developed early this afternoon across SW FL, and an outflow boundary is racing towards the SE FL metro so expect additional convection to spread eastward as the afternoon progresses. Could be an isolated urban/poor drainage threat across the east coast metro today, especially with the sea-breeze pinned near the coast. Overall the previous forecast remains on track. Only minor change made was to add some patchy fog over inland south FL early Monday morning with light winds and clear skies expected over the interior. Some of the hi-res models have picked up on the fog potential as well.

SHORT TERM

(Today through Monday) Issued at 227 AM EDT Sun Sep 13 2026

A substantial ridge of high pressure remains parked across the south- central and southeast U.S. that has resulted in many locations across the Deep South reaching triple digits for ambient high temperatures. Another feature of interest identified on latest guidance is a tropical upper tropospheric trough (TUTT) located over the Caribbean. This will be a feature to monitor into mid-week, but is not expected to play an impactful role in the local weather at least until mid-week. The high pressure over the Southeast states will create a week flow pattern throughout the atmospheric column, which should allow the afternoon sea breezes to advance inland and collide over the interior regions of South Florida. Deep moisture remains present across the area through the short term, so expect afternoon showers and thunderstorms to increase in coverage with the highest chances being for interior locations where the sea breezes and other boundaries merge (70-80% PoPs). PoPs will still be elevated closer to the coasts and metros as well, but will be in the 50-60% range and likely a result of initial convection as the circulations develop and/or late day outflow boundary development. Primary concerns will be frequent lightning, stronger wind gusts below severe levels, and heavy downpours.

Total QPF is not expected to result in more than 0.5-1.5", but it is worth mentioning that the HREF LPMM does show potential for highly localized pockets to receive 5-7" of rain today. Therefore, localized flooding cannot be ruled out but it is still highly unlikely and the highest risk for this will be over the Everglades. High temperatures generally remain in the upper 80s to low 90s with overnight lows in the mid to upper 70s.

LONG TERM

(Monday night through Saturday) Issued at 227 AM EDT Sun Sep 13 2026

Strong surface ridging will set up across the Eastern Seaboard towards the middle of this week. Aloft, an even stronger ridge that could be at or near all-time records with respect to 500-mb height anomalies will be building over the eastern US. With this setup, there is increasing confidence that jet stream dynamics will cause a pronounced cut-off low to form off the mainstream flow of an upper- level near eastern Canada. Guidance continues to hint at this trough dropping southward underneath the potent ridge across the Eastern Seaboard and approach South Florida mid-week around the Wednesday night to Thursday time frame. This low also appears to "absorb" the previous TUTT low over the Caribbean as it eventually advects across the Florida Peninsula.

It remains too early to tell what exact impacts could occur from this low advecting across the area late in the week, but in general it will provide extra forcing for ascent that will be able to produce widespread showers and thunderstorms under a deep moisture presence (PWATs over 2.0"). As conditions evolve over the next few days, details will become more clear and communicated. As of now, we can expect numerous showers and thunderstorms each day with risks for heavy rainfall resulting in flooding. High temperatures each day will continue to be in the upper 80s to low 90s.

AVIATION

(00Z TAFS) Issued at 647 PM EDT Sun Sep 13 2026

Scattered convection will come to an end over the next few hours and then mostly quiet conditions overnight with light and variable winds. Sea breeze will take awhile to kick in on Monday but winds should become ESE around 10 kts after 18Z across the east coast metro with a westerly Gulf breeze at APF. Scattered thunderstorms during the afternoon and early evening will favor interior and SW FL.

MARINE

Issued at 227 AM EDT Sun Sep 13 2026

A light to gentle and generally variable wind flow is expected across the local waters today and into early this week. This flow will eventually increase to near hazardous levels out of an easterly to northeast direction as a disturbance approaches from the northeast. Seas will remain 1-2 feet or less today and into early this week. Scattered showers and storms remain likely each day, primarily in the early morning and late night hours over the waters and can result in locally hazardous winds and seas.

PRELIMINARY POINT TEMPS/POPS

Miami 78 90 79 90 / 10 30 20 70 West Kendall 75 90 76 90 / 10 40 20 70 Opa-Locka 78 91 78 90 / 10 40 20 70 Homestead 77 90 78 90 / 10 30 20 60 Fort Lauderdale 78 90 80 90 / 10 30 30 70 N Ft Lauderdale 78 91 79 90 / 10 30 30 70 Pembroke Pines 77 90 78 90 / 10 30 20 70 West Palm Beach 76 91 79 91 / 10 40 40 80 Boca Raton 77 90 79 90 / 10 30 30 70 Naples 76 91 76 92 / 20 50 40 80

MFL WATCHES/WARNINGS/ADVISORIES

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