443 FXUS63 KMKX 250224 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 924 PM CDT Thu Jul 24 2025 .KEY MESSAGES... - Areas of dense fog may form during the overnight given good radiational cooling conditions. - Chances for thunderstorms (30-60%) remains in the forecast for Friday night through Saturday. More chances then return Monday morning through Wednesday. - Heat and humidity returns Sunday through Tuesday. && .UPDATE... Issued 923 PM CDT Thu Jul 24 2025 A weak cold front over central WI will slowly move south across srn WI during the overnight. High pressure will settle over nrn WI by 12Z Fri then shift across the nrn Great Lakes. Dewpoints will remain rather high tnt even after the weak frontal passage. And with some clearing occurring and light winds, expect areas of fog to form during the overnight and last until 13-15Z Fri. Warm and humid conditions with some sunshine is then expected after any fog and stratus dissipate, with more pleasant conditions near the lake via onshore flow. Gehring && .SHORT TERM... Issued 317 PM CDT Thu Jul 24 2025 Tonight through Friday night: Mid-level cloud cover along and ahead of an approaching cold front has kept a lid on heat concerns this afternoon. The hottest conditions are currently over Racine and Kenosha Counties where heat indices are between 90 and 95, and skies have remain clear to mostly sunny for a larger portion of the day. The cold front will continue to sink southeast this afternoon, gradually limiting any remaining concerns for uncomfortable heat. A few showers have festered this morning and into the early afternoon along the cold front and near a remnant MCV from early morning convection over Iowa. Current RAP analysis shows this MCV moving over central WI at this time, with radar showing weak showers and storms pockmarking north central and southwest Wisconsin behind the MCV closer to the surface front. With shower and storm activity favoring the front, this feature should be the focus of any remaining storm activity this afternoon as it slowly move southeast. Given very weak CAPE/Lapse rates over most of the region, strong storms are not anticipated. Tonight, subsidence will move in behind the cold front along with light winds. The cold front won`t feature a particularly great push of dry air behind it, and dew points will remain elevated overnight. With these ingredients, fog is expected to form over most of southern WI overnight. Fog should mix out shortly after daybreak. We`ll remain mostly dry on Friday as high pressure moves in as the cold front stalls over northern IL. While temperatures will cool with highs in the low to mid 80s, dew points will remain elevated, making it feel muggy outside. CMiller && .LONG TERM... Issued 344 PM CDT Thu Jul 24 2025 Saturday through Thursday: Warm advection returns Friday night into Saturday morning as a warm front lifts north toward the state. There are varying solutions regarding how showers and storms will evolve Saturday morning into Saturday night. The GFS, favors a more aggressive solution, giving rain to most of southern Wisconsin through Saturday. Most CAMs and the ECMWF however, show only a glancing blow of rain and storms along the WI/IL border and southeast Wisconsin Saturday morning and early afternoon. Given some of the uncertainty and the frontal position being dictated by shower and storm activity along the stalled front on Friday, we`ll monitor obs and model trends for a bit better agreement Saturday. In any case, a brief lull is expected Saturday evening/Sunday morning as a small area of high pressure moves overhead. The warm front from Saturday will finally lift north late Sunday morning into the afternoon, ushering in a return of the hot and humid air mass. Highs will be in the low 90s, amid dew points in the low 70s. Heat will then linger into Monday as well. Monday into Wednesday, northwest flow aloft around the ridge and wiggles in the flow will then cause multiple chances for storms over the upper midwest into the middle of next week, although it is too early to pinpoint where the best chances will be. CMiller && .AVIATION... Issued 923 PM CDT Thu Jul 24 2025 VFR conditions this evening transitioning to areas of fog and low stratus during early Fri AM across srn WI. Patchy dense fog will be possible along with Cigs below 500 feet. The fog should dissipate by 13-15Z Fri with any MVFR Cigs or lower to dissipate by 17Z. Sct040 cumulus for the afternoon. Shower and storm chances will then increase late Fri nt into Sat. Gehring && .MARINE... Issued 923 PM CDT Thu Jul 24 2025 A weak cold front over northern Lake Michigan will slowly move to far southern Lake Michigan for early morning Friday. Light southwest winds will shift to northeasterly with the frontal passage. With the easing winds and moist airmass behind the front, some marine fog may form tonight. High pressure of 30.1 inches will then briefly pass over the upper Great Lakes through Friday, with light and variable winds over the northern half of the lake, and north winds over the southern half of the lake. Winds will come around to southerly Friday night into Saturday morning as a warm front lifts north over the southern third of Lake Michigan ahead of weak low pressure of 29.8 inches. Showers and thunderstorms are expected to pass over the lake through much of the day as the low pressure system passes by. Winds briefly come around to northwesterly Sunday morning before returning to southerly by the afternoon, following another warm front. Gehring && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSMilwaukee www.twitter.com/NWSMilwaukee www.youtube.com/NWSMilwaukee