Area Forecast Discussion
Issued by NWS Miami, FL
Issued by NWS Miami, FL
526 FXUS62 KMFL 122333 AFDMFL Area Forecast Discussion National Weather Service Miami FL 733 PM EDT Wed Aug 12 2026 ...New AVIATION... .KEY MESSAGES... Updated at 728 PM EDT Wed Aug 12 2026 - A Heat Advisory is in effect today for all of South Florida. - Heat remains the primary hazard through next week. - Highest rain chances today, Thursday, and Saturday. && .SYNOPSIS... Issued at 300 PM EDT Wed Aug 12 2026 Overall pattern this afternoon continues to exhibit a split subtropical high with one center over the northern Gulf and another over the central subtropical Atlantic. In between these two highs, the base of the eastern North American longwave trough extends over the western Atlantic and northern Bahamas, placing South Florida in the "weakness" between the two highs and light winds of a northerly component in the low and mid levels. Models show minor mid-level troughs sliding southward over the peninsula today and Thursday on the eastern flank of the Gulf high. Model consensus shows the Gulf and subtropical Atlantic highs re- connecting near/over the Florida peninsula by the end of the week and upcoming weekend as the eastern North American trough lifts out. Deep layered easterly winds will return to our area in response to the building high. The fractured poleward end of a tropical wave currently over Hispaniola and the far SE Bahamas is expected to move across the Straits of Florida and southern Florida peninsula Friday night and Saturday. Along and behind the wave, the northern fringe of a Saharan Air Layer (SAL) will likely spread into South Florida and linger into early next week. && .SHORT TERM... (Rest of today through Thursday) Issued at 300 PM EDT Wed Aug 12 2026 The light northerly flow over the area early this afternoon is helping to focus convective initiation along the seabreezes, with cells drifting south along the inland-penentrating seabreezes. The focus the remainder of this afternoon for showers and thunderstorms will be over the interior peninsula and far-outlying suburbs of both coasts where PoPs this afternoon range from 50-80%, although outflows spreading out from convective clusters could trigger a few storms over the metro areas later this afternoon and early this evening. ACARS-sampled seasonably high precipitable water (PWAT) values, residual dry mid level air, and forecast DCAPE values around 1200-1300 j/kg could result in locally strong downdrafts with any of the storms this afternoon. This pattern changes little on Thursday with a similar pattern of convective initiation and coverage. The only notable difference is a slightly more easterly component to the steering winds on Thursday which shift the highest PoPs of 60-70% westward over inland Collier and Mainland Monroe counties. Elsewhere, Thursday`s PoPs range from 40-50% over SW Florida to 30-40% over most of SE Florida. Heat index values in the 105-110F range area-wide this afternoon appears to be verifying the heat advisory today, as dewpoints in the mid to upper 70s are combining with air temperatures in the lower to mid 90s over the metro areas and upper 90s over the interior. Low level thickness values don`t appear to be as high on Thursday compared to today, which may cut down slightly on the heat index. Nevertheless, no substantial changes in temperature impacts are expected with HeatRisk remaining in the Major range over the western SE Florida and eastern SW Florida suburbs. && .LONG TERM... (Thursday night through next Tuesday) Issued at 300 PM EDT Wed Aug 12 2026 A slightly drier air mass briefly moves into the region on Friday, but it will be short lived as the axis of higher moisture is expected to arrive Friday night and Saturday in association with the tropical wave. This is reflected in PoPs jumping up into the 30-50% range over SE Florida Friday night/Saturday morning, then 60-80% over interior and SW Florida Saturday afternoon as the wave moves west and E/SE wind flow steers convection away from the east coast and towards the west coast. A few of these thunderstorms on Saturday could be rather strong as the SAL layer superimposed on the higher moisture at low levels could steepen lapse rates just enough. The tropical wave will be west of the area by Saturday night, which will open the door for a larger SAL to move into the region on Sunday. Model consensus PWATs impressively drop to the 1.4-1.6 inch range on Sunday which is the lowest 10th percentile for mid- August. Therefore, PoPs are essentially less than 10% area-wide on Sunday, which of course is quite rare for this time of year. PWATs modestly increase Monday and Tuesday to about the 30 to 40th percentile, which supports PoPs in the 30-50% which are still a little below seasonal norms. Aside from a slight decrease in temperatures on Saturday due to increased cloud cover and precipitation, temperatures and heat index will remain high enough for the possibility of heat advisory conditions to continue. The hottest temperatures of the long term period are expected on Sunday when the lowest PoPs should coincide with warmer temperatures aloft, resulting in highs in the mid to upper 90s over most of South Florida. Some dry air could mix down to the surface and lower dewpoints just enough to preclude a widespread significant heat episode, but temperatures should still be high enough for moderate to major HeatRisk. && .AVIATION... (00Z TAFS) Issued at 728 PM EDT Wed Aug 12 2026 Lingering SHRA/TSRA near MIA/FLL area terminals through 01z as storms move slowly south. This activity will gradually dissipate after 01z, with VFR expected for the remainder of the night. Repeat pattern expected Thursday with SHRA/TSRA developing after 18z and move S/SW along the seabreezes. These will likely come close enough to the terminals to warrant a PROB30 TSRA with MVFR conditions for the last 6 hours of the forecast period. Winds light except for seabreezes in the 8-12 knot range after 18z. && .MARINE... Issued at 200 AM EDT Wed Aug 12 2026 Light winds and low seas are expected through the week. Daily wind increases to around 10 knots are expected in the seabreeze zone, as well as a light chop. Shower and thunderstorm activity will remain fairly isolated and mostly limited to the morning hours for the east coast and the evening for the Gulf. && .PRELIMINARY POINT TEMPS/POPS... Miami 79 92 81 93 / 10 40 10 10 West Kendall 77 92 77 93 / 10 40 10 10 Opa-Locka 80 93 81 93 / 10 40 10 10 Homestead 77 92 80 93 / 10 30 10 10 Fort Lauderdale 80 91 80 91 / 10 30 10 10 N Ft Lauderdale 80 92 81 92 / 10 40 10 10 Pembroke Pines 80 92 81 93 / 10 40 10 10 West Palm Beach 78 93 79 93 / 10 40 10 10 Boca Raton 79 91 80 91 / 10 40 10 10 Naples 78 92 77 93 / 10 40 20 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && $$ SHORT TERM...Molleda LONG TERM....Molleda AVIATION...Molleda