textproduct: Miami - South Florida

KEY MESSAGES

Updated at 109 AM EDT Sat Jul 18 2026

- Heat indices will range between 105 and 110 degrees through the early evening hours. Take appropriate precautions during extended periods outdoors.

- Scattered to numerous showers and thunderstorms will develop through the evening hours favoring interior and eastern areas of South Florida. - Any thunderstorm will be capable of producing strong wind gusts, frequent lightning, heavy downpours, and small hail.

SHORT TERM

(Rest of today through Saturday) Issued at 219 PM EDT Fri Jul 17 2026

Current water vapor imagery reveals a well defined upper level low over the eastern Gulf waters. This upper level low will continue to retrograde slowly to the southwest during the rest of the afternoon hours. At the surface, high pressure that continues to be centered over the northern Gulf just south of the Louisiana coast is helping induce a westerly sfc flow across South Florida and this will continue to be the case through the rest of the day with a counteracting Atlantic sea breeze slowly trying to push inland as daytime heating continues. The 12Z MFL sounding demonstrates a good amount of drier air in the lower levels, which has been the main storyline through this entire week with the lingering presence of Saharan dust. RAP guidance, however, suggests that our atmospheric column will be moistening throughout the day as moisture transport will be favorably out of the south and PWATs climb to the range of 1.8-2.1". In combination with substantial large-scale forcing due to the nearby upper low over the Gulf, high surface CAPE values of over 3500 J/kg, and a surface flow out of the west/pinned Atlantic sea breeze, we anticipate the development of scattered to numerous showers and thunderstorms this afternoon and evening across the interior and east coast metro areas. This morning's sounding also showed a fairly large DCAPE value of 1163 J/kg in direct association with the Saharan dust we have in place. With steep 0-3km lapse rates expected to steadily rise to 7.5-8.5 degrees C/km during the peak heating of the day, downburst signatures will once again act as the likely and most common hazard with most collapsing cores, producing strong to perhaps locally damaging wind gusts. Given that the dynamics in place are similar to what they have been over the past several days, we cannot omit the possibility of small hail with the relatively modest mid- level lapse rates of around 6 degrees C/km and just marginally favorable, but still fairly weak, flow aloft of around 20 kts. Along with the potential for strong winds and small hail, bursts of heavy rainfall and frequent lightning will also be likely with most of today's cells.

In addition to this convective regime, heat advisories remain in effect through 7 PM EDT this evening for our eastern metros and Collier County with peak heat index values reaching the 105-110 degree range. Make sure to follow all the necessary precautions to protect yourself and those around you from this elevated heat risk.

Sfc flow shifts to more of a south-southeasterly direction across the majority of our region on Saturday as the aforementioned ridge of high pressure over the Gulf continues to retreat to the west, giving way to more of a typical subtropical-high influence. The best forcing with our upper-level low will be mostly located north of our region and over the eastern Gulf waters as the feature will continue to meander over this general vicinity. Similar to this morning, this buoyant mechanism could allow for additional showers and storms across our Gulf coast locales to kick off Saturday. Sufficient regional moisture and marine DMAX will result in showers and storms also coexisting over our Atlantic waters and east coast metros as they ride our sfc flow out of the SSE, in what will be more of a summerlike morning routine. The morning convection will be succeeded by another active afternoon and evening period with plentiful diurnal destabilization and lingering moisture from our upper low leading to scattered shower and storm coverage over the interior and around the Lake Okeechobee region. Concurrently, model guidance hints at yet another intrusion of Saharan dust from the western Caribbean into the southernmost portions of the peninsula given low-level transports being out of the south-southeast on the southeastern flank of our Gulf upper low. As a result, PoPs will be on the lower end of the scale where this dust is most abundant, increasing as we head further north toward the Lake where higher amounts of available moisture will reside and the dust will have less of an impact on convection. Heat will remain an ongoing concern as hazardous heat indices could once again be nearing heat advisory criteria especially over the metro areas. Make sure to limit your time outdoors during the hottest hours of the day, when heat indices are forecast to climb again into the 105-110 degree range.

LONG TERM

(Saturday night through Thursday) Issued at 412 AM EDT Fri Jul 17 2026

Latest long range model solutions keep rain chances in place through early next week with overall model consensus showing a trough and potential associated low lingering around the eastern Gulf and northern Florida. But the air mass across SoFlo seems to begin to rebound from the wet conditions with a gradual decrease in shower activity. Max POPs/Wx coverage on latest NBM are now coming in the 30-40% through much of the work week, with Tuesday as the driest day.

Sea breezes and outflow boundary collisions will remain as the focal points for deeper convection to develop. Therefore, there will be continued good support for stronger, taller storms especially with sea breezes and boundary collisions. Main hazards will be damaging wind gusts, hail, lightning strikes and localized flooding.

Despite the spike in rain and thunderstorms, there should be enough sunshine for keeping max temps in the 90s each day. Heat advisory potential will be explored each day. Limit strenuous outdoor activities and take action when you see symptoms of heat exhaustion and heat stroke. For more on what you can do to prepare for and mitigate heat illness, visit ready.gov/heat.

AVIATION

(06Z TAFS) Issued at 109 AM EDT Sat Jul 18 2026

VFR is generally expected to prevail for the period. SE winds expected around 10-15 kt for the east coast terminals and SSW winds at KAPF in the afternoon. Scattered SHRA will begin to develop after 11-12Z with VCTS likely for a few hours after 15Z as well. Any on site SHRA/TSRA should clear quickly given brisk wind flow. However, this could result in short duration restrictions during the late morning and afternoon hours.

MARINE

Issued at 219 PM EDT Fri Jul 17 2026

Winds will gradually become more southerly across all local waters by Saturday as an area of disturbed weather continues to develop over the northeastern Gulf. Scattered showers and thunderstorms will remain possible across all local waters through the weekend. Seas across the Atlantic waters will remain at 3 feet or less through the weekend while seas across the Gulf waters remain at 2 feet or less. Brief periods of rough seas and gusty winds may accompany any thunderstorm that forms.

PRELIMINARY POINT TEMPS/POPS

Miami 92 80 93 80 / 20 10 30 0 West Kendall 92 77 93 77 / 20 10 30 0 Opa-Locka 93 80 94 80 / 20 10 30 0 Homestead 92 80 93 80 / 20 10 10 0 Fort Lauderdale 91 81 92 81 / 20 20 30 0 N Ft Lauderdale 91 80 92 80 / 20 20 40 0 Pembroke Pines 93 81 95 81 / 20 10 30 0 West Palm Beach 91 78 93 79 / 20 10 50 10 Boca Raton 90 79 91 80 / 20 20 40 10 Naples 90 78 91 80 / 60 40 50 30

MFL WATCHES/WARNINGS/ADVISORIES

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