textproduct: Miami - South Florida

KEY MESSAGES

Updated at 652 PM EDT Wed Aug 19 2026 - Record heat possible again today. A Heat Advisory is in effect for all of South FL.

- Scattered thunderstorms expected late in the day. Storm chances increase for the end of the week through the weekend.

UPDATE

Issued at 448 PM EDT Wed Aug 19 2026

After a stretch of clear skies and anomalously dry conditions, a gradual moistening trend is underway across South Florida. The 12Z MFL and ACARS soundings show PWAT values modestly higher than yesterday, though they remain below climatological normals for mid- August. A stout temperature inversion near 850 mb, alongside lingering mid-level dry air, helped delay convective initiation along the Atlantic sea breeze this afternoon. However, scattered showers and thunderstorms are developing mainly over the interior sections and these storms could drift back towards the east coast metro areas through the early evening hours. Dangerous heat indices will also remain in place through the early evening hours area wide. Overnight lows will remain a few degrees above normal, generally in the mid 70s across interior locations and upper 70s to lower 80s across urban and coastal areas. Hot and humid conditions will persist through the remainder of the work week, with maximum heat indices likely reaching 105-110F each day.

SHORT TERM

(Today through Thursday) Issued at 103 AM EDT Wed Aug 19 2026

After a history making day in Miami on Tuesday with the high temp hitting 100, it's not time to let the guard down, as the heat will be a major factor again today. Surface high pressure will remain over the central Gulf today and Thursday, while the upper level ridge begins to break down over the region as a trough starts to dig into the eastern US. Global models are still hinting at a weak mid/upper level low over the northeastern Gulf over the next couple of days.

Today will start out dry across South FL, however low level moisture will slowly start increasing as the day progresses as the higher concentrations of Saharan dust finally get shunted south of the area. PWAT values of 1.8-1.9 inches are expected by late afternoon. The east coast sea-breeze will take its time to begin pushing inland but by mid afternoon should be making it's way through the metro. Some scattered thunderstorms are expected late in the day along the breeze. The heat will continue to be the main story today though. With west to northwest flow over the area through at least early afternoon, high temps will easily reach the mid to upper 90s. While the mean forecast high for Miami is around 97, the latest NBM probs once again have about a 10% chance of reaching 100 at the airport, so definitely not out of the realm of possibility that Miami does it for the second day in a row. The timing of the sea-breeze making it to the airport will likely be the determining factor. Heat indices this afternoon will reach 105-112, so yet another Heat Advisory will be in place for all of South FL from 11 AM to 7 PM.

Convection will likely linger for several hours after dark until fully dissipating and skies begin to start clearing overnight. Low temps tonight remain mild ranging from the middle 70s over inland south FL to lower 80s near the coasts.

Moisture further increases on Thursday with forecast soundings showing PWAT values of around 2 inches. Latest hi-res guidance is in fairly good agreement of convection getting an earlier start in the afternoon, with scattered to numerous thunderstorms from mid afternoon through early evening. With the anticipated earlier start to convection that should help temps stay a tad lower on Thursday, albeit still above normal. Expecting highs in the low to mid 90s across the metro, and mid to upper 90s over inland South FL. Heat indices will still reach 105-110 by early afternoon before rain starts to cool some areas down, so additional heat headlines may be needed.

LONG TERM

(Thursday night through Tuesday) Issued at 103 AM EDT Wed Aug 19 2026

The extended period will see a much needed return to a more typical summertime pattern. An upper level ridge will be anchored over the western US while the eastern US will remain under the influence of a trough. Surface high pressure will remain over the Gulf this weekend into early next week. Expect mainly diurnally driven sea-breeze convection each day with seasonable PoPs (40-60%) favoring the afternoon and early evening hours, and then widely scattered coastal showers during the overnight period.

Temperatures will remain above normal through the weekend and into early next week. Max heat indices will remain around advisory criteria each day, so additional heat headlines will remain possible.

AVIATION

(00Z TAFS) Issued at 652 PM EDT Wed Aug 19 2026

Mainly VFR conditions will prevail through the forecast period. Scattered showers and thunderstorms drifting towards the east coast metro will dissipate after sunset. L/V winds overnight will increase out of the SE after 15Z at east coast terminals. Scattered showers and storms will once again be possible along sea breeze boundaries after 20Z. At KAPF, WNW winds will gradually decrease overnight, then increase again out of the west after 16Z.

MARINE

Issued at 103 AM EDT Wed Aug 19 2026

Moderate west to northwest breeze across the Gulf waters today, with gentle to moderate southerly winds across the Atlantic. Seas generally 2 ft or less. Scattered thunderstorms are possible late in the day which may result in locally hazardous winds and seas.

CLIMATE

Issued at 103 AM EDT Wed Aug 19 2026

Record high temperatures are possible Wednesday. Here are the current records for Wednesday:

WED(YEAR)

MIA 96 (1909) FLL 97 (1952) DJT 97 (1938)

PRELIMINARY POINT TEMPS/POPS

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

MFL WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory until 7 PM EDT this evening for FLZ063-066>070-075- 168.

Extreme Heat Warning until 7 PM EDT this evening for FLZ071>074- 172>174.

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