textproduct: Miami - South Florida

KEY MESSAGES

Updated at 658 PM EDT Tue Sep 22 2026

- Scattered to numerous showers and thunderstorms expected today. Rain chances remain elevated the rest of the week. - Heavy downpours from the stronger showers and thunderstorms could lead to localized flooding over the urban and poor drainage areas each day.

SHORT TERM

(Rest of today through Wednesday) Issued at 357 PM EDT Tue Sep 22 2026

Another unsettled day is expected across South Florida today. At the surface, mesoanalysis depicts weak inverted surface troughing over the eastern Gulf and a frail area of low pressure centered a couple hundred miles offshore of the Southeast CONUS, with which a surface boundary is also associated. A faintly apparent pressure gradient is present across our region as we find ourselves nestled between the two aforementioned surface features with a narrow corridor of slightly enhanced southerly winds extending from the Florida Straits northward to South Florida on the westernmost periphery of subtropical ridging. In the upper levels, the same low pressure system that had been affecting us since late last week has since been unraveled with higher heights building into the general vicinity and an axis of shortwave troughing sliding eastward across the southern Appalachians helping stretch it into an elongated trough over the eastern Gulf and several vorticity maxima across and just offshore of the Southeast/Mid-Atantic CONUS. Due to this, we will no longer be influenced by this upper-level perturbation but rather by another one that will be lifting northward into our adjacent Atlantic waters from central Cuba. Preceding this will be a deep moisture surge that is already being observed on both water vapor imagery and mesoanalysis in which our PWATs via a rich southerly moisture transport are increasing by a substantial margin from what was 2.25" in this morning's 12Z MFL sounding to around 2.3" now and possibly to as high as 2.5" later this afternoon across portions of Southeast Florida, which is extremely anomalous for this time of year and close to record territory as per HREF guidance. Forecast soundings can also support this with afternoon profiles indicating a heavily saturated atmospheric column with the intrusion of this deep Caribbean moisture.

With the nagging, multi-day upper-level low now being removed from the picture, notches of low to mid-level vorticity associated with the aforementioned disturbance over Cuba will now, in addition to the plentiful amount of atmospheric moisture and surface destabilization (SBCAPE of 2500-3500 J/Kg) in place, be the primary causes of action for the scattered to numerous showers and thunderstorms that will be developing across mainland South Florida as the rest of the afternoon progresses (widespread PoPs of 50-80%) and, albeit with increasingly lesser coverage, persisting into the evening hours. Bulk shear will generally be less than 10 kts across much of our peninsula, meaning we will again be dealing with slow- moving downpours that could exacerbate the flood concerns we have had to contend with over the past few days (especially across the east coast metros). The latest 12Z LPMM rainfall guidance indicates the potential for isolated portions of South Florida to receive between 2 and as much as 6 inches through 8AM Wednesday morning.

Lowering surface heights across South Florida tomorrow and the northeastward displacement of the surface low offshore of the Southeast CONUS will decrease the local pressure gradient, allowing our winds to be even weaker, albeit still southerly, than today and mainly sea-breeze driven. Plenty of moisture will remain in place (PWATs of 2.2-2.4") with perhaps better upper-level forcing than today with the low to mid-level perturbation continuing to lift northward parallel to the east coast of South Florida. Due to the close proximity of this disturbance, the best instability dynamics appear to be along the east coast which, in combination with our winds turning more westerly aloft in response to the passage of this disturbance, will allow the bulk of our diurnal convection to slowly drift towards and favor our eastern metros (where our highest regional PoPs of 70-90% will reside) as the afternoon progresses and into the evening hours. This is not to say that activity will not still be fairly scattered in nature across the peninsula due to just how saturated our atmospheric column (aided by superficial destabilization) will be. Similar to today, poor environmental parameters aloft tomorrow should keep the potential for strong/severe thunderstorms minuscule; with heavy downpours, localized flooding across our metros, and dangerous cloud-to-ground lightning being the primary concerns.

Due to the widespread coverage of showers and storms both today and tomorrow, high temperatures across South Florida will be restricted to the mid 80s-low 90s with heat index values rising into the low to upper 90s during the early portions of the day before the onset of convection looks to provide areawide relief.

LONG TERM

(Wednesday night through Monday) Issued at 111 AM EDT Tue Sep 22 2026

Late in the week and through this weekend, an upper level trough will dig across the eastern US and enhance across most of the Eastern Seaboard before settling off the New England coast in the western Atlantic. A frontal boundary will push southwards in tandem with the trough strengthening and the front will eventually settle over far southern Florida or the Florida Straits this weekend. As the front stalls, much drier air will advect into Central Florida, but most of this will not make it into South Florida. However, PWATs will still fall to average or below average levels with the lake region seeing the lowest values. With this anticipated less moisture available, shower and thunderstorm coverage is expected to decrease primarily for the lake region. This is reflected with PoPs of 25-40% this weekend near the lake and 50-70% for the southern half of the forecast area. Despite the decrease in PoPs for a lot of the area, the pattern will still remain active and unsettled through the forecast period.

Daily high temperatures each day will continue to reach the upper 80s to near 90 with overnight lows mostly in the low to mid 70s. However, areas near the lake could see temperatures drop into the upper 60s several nights.

AVIATION

(00Z TAFS) Issued at 658 PM EDT Tue Sep 22 2026

Winds will become L/V past sundown and through the overnight period across all of South Florida. Will keep TSRA for a few more hours for all terminals, dropping it to SHRA after 01Z. Winds should be fairly light again at around 5-10 kts on Wednesday out of the southeast after 15/16Z across the east coast terminals and out of the WNW at KAPF. Scattered TSRA after 15Z, persisting through much of the afternoon into the early evening.

MARINE

Issued at 111 AM EDT Tue Sep 22 2026

A gentle southerly flow is expected across the local waters for the next several days with seas of 2 feet or less. Scattered showers and thunderstorms will continue to develop each day, producing locally hazardous winds and seas.

PRELIMINARY POINT TEMPS/POPS

Miami 76 86 76 88 / 60 80 30 70 West Kendall 76 85 75 88 / 60 90 30 70 Opa-Locka 76 86 75 88 / 60 80 30 70 Homestead 76 86 75 89 / 70 90 40 70 Fort Lauderdale 76 86 75 88 / 70 70 30 70 N Ft Lauderdale 77 86 75 88 / 60 70 30 70 Pembroke Pines 75 86 75 88 / 60 70 30 70 West Palm Beach 76 86 75 88 / 50 80 30 70 Boca Raton 75 86 75 88 / 60 70 30 70 Naples 75 88 74 89 / 50 60 30 40

MFL WATCHES/WARNINGS/ADVISORIES

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