textproduct: Miami - South Florida

KEY MESSAGES

Updated at 233 AM EDT Fri Sep 11 2026

- Numerous showers and thunderstorms are forecast today, focusing along the east coast this morning before the bulk of activity shifts over southwestern Florida in the PM. Gusty winds and dangerous cloud to ground lightning is possible with any storm. - A moderate risk of rip currents is forecast at Palm Beach County beaches today. - High temperatures will generally rise into the low to mid 90s across South Florida through the upcoming weekend, resulting in widespread Moderate to Major HeatRisk each day.

SHORT TERM

(Today through Saturday) Issued at 233 AM EDT Fri Sep 11 2026

We have noticed a few key features from looking over visible satellite imagery yesterday afternoon. Widespread anvil debris from antecedent thunderstorm activity across much of South Florida is one of them, with the second being a residual outflow boundary (a direct byproduct of t-storm activity that formed outside of Biscayne Bay and pushed through the east coast metro) that has remained practically stationary across our nearshore Atlantic waters. This upper-level cloud cover has resulted in not only cooler temperatures across our east coast observing sites (some stations such as KMIA may have actually already recorded their low temperature yesterday afternoon after being enveloped in this rain-cooled environment) but the formation of a land breeze across our immediate east coast which, for the time being, has allowed individualized showers that have fired up along the aforementioned outflow boundary to stay over our local Atlantic waters. With the prevailing surface flow being out of the east, however, we can anticipate these showers to continue inching closer to the east coast through these early morning hours before eventually falling apart shortly upon moving onshore due to the loss of best nocturnal environmental dynamics over the water and the rather stable boundary layer over mainland South Florida. Mesoanalysis indicates that this lingering outflow boundary will not be persisting over the local waters for much longer, but will continue to act as a short-fuse focus of ascent before easterly flow reestablishes itself and erodes it through daybreak. In addition to this, mid-level water vapor imagery shows plenty of moisture residing around the Lake Okeechobee region and SW Florida in response to a 500-mb perturbation that has been, and still is, lifting through our region since yesterday (and what evidently prompted shower and thunderstorm activity, through amplified forcing aloft, to be a little more widespread in nature). The passage of this upper-level disturbance is not only being noted on mesoanalysis but also on regional ACARS soundings as a localized enhancement and erratic shifts in wind speeds at and around that specific pressure height.

The aforementioned impulse will be ejected to our north and exiting our vicinity as the rest of the day progresses as it rides the western periphery of a mid-level subtropical ridge towards central Florida and eventually into the nearshore Atlantic waters of the Southeast United States, attempting to merge with another shortwave feature crossing the AL/GA region zonally thereafter. At the surface, as previously mentioned, an easterly flow regime is expected to prevail across South Florida at the expense of expansive surface ridging over the subtropical Atlantic. Although we will be losing the primary forcing mechanism aloft with the departure of our mid-level disturbance, anomalously high PWATs, as per HREF guidance, between the 70th and 90th percentiles (equating to 2.0-2.2") combined with ample surface-based instability (3500-4500 J/Kg) building throughout the diurnal cycle should be sufficient to support scattered showers and thunderstorms across mainland South Florida once again. LPMM composite reflectivity shows cells initially firing up during the morning hours along the east coast sea breeze and subsequently becoming more numerous in nature as they push inland towards the interior and SW Florida during the afternoon hours. Rather unimpressive localized dynamics (poor low to mid level lapse rates, warm 500mb temperatures falling within the 50th to 75th percentiles for the date, and weak background flow) should keep the threat of storms reaching strong to severe thresholds low. The atmosphere has been conducive enough over the past few days to pump out sub-SPS wind gusts of anywhere between 20 and 40 mph, and with a similar environment today, should continue to be a potential hazard to be aware of. Heavy rainfall, localized flooding (especially around our Gulf coast locales with the diurnally-induced Gulf sea breeze looking to counteract our prevailing easterly flow) and frequent/dangerous lightning strikes should be the other risks we will have to contend with. HREF shows neighboring probs of 10-30% of rainfall rates exceeding an inch per hour along this pinned Gulf sea breeze.

Rinse and repeat on Saturday, although there will be a few minor, and we really mean minor, changes to the upper-level pattern. Surface ridging will remain in place across the subtropical Atlantic, keeping our easterly flow set in stone. Barely aloft at around the 850-mb height level, a weak impulse which will be located around eastern Cuba on Friday will be steadily riding the southwestern periphery of another coinciding ridge at the same isobaric height and reaching our general vicinity to kick off the weekend. This, according to the National Blend of Models (NBM), will bring a modest moisture surge to our region along with some coincident forcing. PWATs are forecast to rise ever so slightly to the 2.1-2.3" range and, in addition to the introduction of the aforementioned shortwave, will result in a corresponding uptick in regional PoPs to around the 70-90% range, up from 60-80% on Friday. Routine summertime pattern in the sense that showers and storms will be residing over the local waters (and briefly pushing onshore) during the overnight hours when and where cyclical instability will be highest, followed by an increase in such activity over the mainland during the afternoon period. With easterly flow, convection will look to once again favor the western half of South Florida during peak heating of the day. Though with a slightly veering flow in the lowest 3 km of the atmosphere from southeasterly today to southerly on Saturday due to a small westward shift in our low to mid level subtropical ridge, it is possible we get the interior and eastern metros more involved than Friday with the elevated amounts of moisture and forcing simply bolstering a higher coverage of overall storms. With a fairly similar mesoscale setup expected with respect to our prevailing easterly flow and emerging Gulf sea breeze, these counteracting features could present a localized flood risk from nearly stationary/boundary-derived cells over surrounding areas. Forecast soundings and overall unamusing dynamics suggest the severe threat will once again be minuscule, with gusty and erratic winds, frequent lightning, and indubitably heavy downpours being the main hazards in and around the strongest thunderstorms.

High temperatures will look to climb into the low to mid 90s both today and Saturday with max apparent temps generally in the 100-105F range. Wherever convection fails to traverse early in the day along our coastal metro areas is where the heat will be able to build quickest after daybreak. However, look for more widespread relief later in the day as both showers/thunderstorms and upper-level cloud canopies increase in areal coverage.

LONG TERM

(Saturday night through Thursday) Issued at 233 AM EDT Fri Sep 11 2026

Easterly flow and high pressure will be two meteorological commonalities that we will continue to message into the foreseeable future. At the surface, erratically structured yet apparent Atlantic ridging will be the focal point behind our easterly wind late this weekend and at least into early next week. By Tuesday and beyond, models have been consistent in showing a strengthening of these surface easterlies as the aforementioned subtropical ridging shifts eastward toward the central subtropics far enough away from South Florida to lose its local influence. At the same time, anomalously strong surface ridging will work its way from west to east across the northern tier of the CONUS and toward New England and Atlantic Canada from late this weekend into upcoming work week. ECMWF ensemble data shows mean 1000-mb geopotential heights between the 90th and 97th percentiles for climatology expanding well to the south and west of the primary ridge axis into the southwest Atlantic waters and just north of South Florida, which will help induce a stronger onshore flow across our region within the 5-7 day time frame. Coincident to this strong surface ridge will be an even more impressive upper-level anticyclonic pattern over the southeast/Mid- Atlantic US, where ECMWF ensemble forecasts are depicting 500-mb geopotential heights to be at the maximum percentiles for climatology through much of next week. With this abnormally strong feature overhead, we can expect any surface-based fronts and the overall storm track associated with the polar jet stream to stay well displaced to our north over the northern United States.

All the while, we are also monitoring evolving deterministic model trends with respect to the potential intrusion of Saharan dust during the latter half of the weekend and into next week, but mainly next week. NASA GEOS Dust Extinction Aerosol forecast shows a deep Saharan Air Layer (SAL) approaching the nearshore waters of South Florida on Sunday, but mostly staying to our south over the Keys and Florida Straits because of the aforementioned record-strong ridging aloft over the SE CONUS. It is not until Tuesday that models start to become a little more insistent on this dust actually penetrating our atmospheric column, with the NBM showing a reduction in PWATs to at or just below 2" (roughly between the 50th and 70th percentiles) on days 5-7 and forecast soundings displaying larger dew points depressions.

As we wrap up the weekend and head into the following work week preceding the arrival of the SAL, PWATs are forecast to remain generally within the 2.0-2.3" range (80th-95th percentiles) across South Florida which, in addition to abundant surface-based CAPE during each diurnal cycle and the easterly flow regime we will have in place, will continue to support the development of scattered to numerous showers and thunderstorms during the afternoon and early evening hours with the highest coverage forecast to be over the western half of the peninsula. Main concerns will be dangerous cloud- to-ground lighting, gusty and erratic winds, and heavy rainfall that could lead to localized flooding in and around the Naples metro with the impending Gulf sea breeze pushing inland every afternoon and working to counteract our prevailing easterly flow. PoPs are lowered for the latter half of this long-term forecast from Tuesday and beyond with the potential intrusion of Saharan dust, to which the extent of regional shower and thunderstorm coverage across South Florida is still to be determined.

Typical South Florida heat sticks around through the upcoming weekend and into next week, with highs consistently reaching the low to mid 90s each afternoon and maximum apparent/feels-like temperatures in the 100-105F range (with isolated higher values of 106-107F). Make sure to take the proper precautions to protect yourself and those around you from these elevated temperatures, especially if spending extended periods of time outdoors.

AVIATION

(06Z TAFS) Issued at 141 AM EDT Fri Sep 11 2026

SHRA/TSRA is forecast to develop and become numerous across the region today, initially focusing along the east coast of South Florida this AM before shifting westward as the day progresses. Sub-MVFG cigs/vis and gusty erratic wind shifts is possible at any terminal that is impacted by SHRA/TSRA or resultant sprawling outflow. L/V winds at daybreak will enhance out of a SErly direction across the region before a gulf breeze pushes onshore at KAPF between 17-19z. TEMPOs and short fused amendments may be needed with future TAF forecasts as timing and coverage confidence increases.

MARINE

Issued at 233 AM EDT Fri Sep 11 2026

Gentle to moderate southeasterly winds will prevail across the South Florida local waters through the upcoming weekend and into the start of next week. Daily showers and thunderstorms developing or moving over the waters could produce dangerous lightning, gusty and erratic winds leading to periods of perturbed seas, and sudden reductions in visibility within pockets of heavy rain. Wave heights in the Atlantic will range between 1-3 feet through the first half of the weekend, lowering to 1-2 feet for the latter half of the weekend and into early next week as northeasterly swell subsides. Seas across the nearshore waters of the Gulf will remain below 2 feet through the weekend. Deteriorating marine conditions i.e increasing wave heights will be something to monitor with a stronger surface flow in place as we approach the middle of next week.

BEACHES

Issued at 233 AM EDT Fri Sep 11 2026

The combination of a lingering northeasterly swell and onshore surface winds will result in a moderate risk of rip currents at Palm Beach County beaches today. King Tides should not be much of a concern through the upcoming weekend as none of our coastal gauges are forecast to reach minor flood stage. With a strengthening easterly flow from the middle of next week and onward, there is increasing confidence that the risk of rip currents will be on the rise for our east coast beaches (Palm Beach, Broward, and Miami- Dade) with probabilistic guidance showing rip probs exceeding 25% (moderate risk) and approaching or reaching 50% (high risk).

PRELIMINARY POINT TEMPS/POPS

Miami 90 80 90 79 / 50 30 80 30 West Kendall 89 79 90 78 / 50 30 70 20 Opa-Locka 90 81 90 80 / 50 30 80 20 Homestead 90 79 90 78 / 50 30 70 30 Fort Lauderdale 89 80 90 79 / 60 30 80 30 N Ft Lauderdale 90 80 91 79 / 60 30 80 30 Pembroke Pines 90 81 90 78 / 50 30 80 20 West Palm Beach 91 79 91 78 / 50 30 80 20 Boca Raton 90 79 90 78 / 60 30 80 30 Naples 91 77 91 77 / 70 20 70 30

MFL WATCHES/WARNINGS/ADVISORIES

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