Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
002 FXUS63 KMKX 050505 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1205 AM CDT Sat Sep 5 2026 .KEY MESSAGES... - Fog is expected to develop across southern WI through this morning with some dense fog possible, especially for low- lying areas and along the lakeshore through the morning. - Milder temps and drier, less humid conditions this weekend and Labor Day with daytime highs int the 70s and low 80s and nightly temps falling into the upper 50s to low 60s. - Warmer temps and humidity return Tuesday and Wednesday with the next chances for shower and thunderstorms. && .SHORT TERM... Issued 1201 AM CDT Sat Sep 5 2026 Today through Sunday night: Outside of an isolated pop-up shower toward the WI/IL border, mostly dry into the morning. Otherwise, we continue to see a weak cold front continue push its way southward through the morning enhanced by the easterly flow from high pressure. Light winds and elevated surface moisture from recent rainfall behind the front will set the stage for fog development across the area through the morning. Expect pretty widespread coverage with visibilities of 1-3sm, but also could see pockets of dense fog at times, especially for low-lying areas and river valleys. Do not know if and how widespread the dense fog may get, but will continue to monitor and see if a advisory may be warranted. Nonetheless, the fog is expected to continue through the morning, but gradually lift by mid to late morning with some lower clouds lagging behind by an hour or two. Expect drier, not as humid, and milder conditions by this afternoon as upper-level ridge begins to build across the Upper Midwest. This will allow light easterly flow off of Lake Michigan to become more prevalent across southern WI as high pressure builds into the Great Lakes region from Canada through the afternoon and evening. As a result temps in the upper 70s toward the lake and to lower 80s inland toward southwestern WI expected this afternoon. Cooler conditions are expected overnight with lows dipping into the upper 50s to low 60s. This high pressure and drier pattern will remain in place through the remainder of the holiday weekend with similar temps and drier conditions for Sunday along with less humidity. Wagner && .LONG TERM... Issued 1201 AM CDT Sat Sep 5 2026 Monday through Friday: Influence from the upper-level ridge and surface high pressure over the Great Lakes will continue trough the holiday as it will be reinforced by an additional area of high pressure building down. Predominately easterly flow off of Lake Michigan will help keep a couple of degree cooler than what we have been seeing along with less humidity. Highs for Labor Day are looking to top off in the upper 70s to low 80s. Then influence from the high pressure wanes into Tuesday as the upper-level ridge axis slides eastward while and upper-level trough lifts across the Upper Midwest. This pattern shift is expected to bring more southerly flow to southern WI along with low-level WAA, moisture advection, and temps warming back into the 80s for Tuesday into Wednesday. This will also be the next window for increased shower and storm chances across the area as it brings a surface low across Manitoba/Ontario with a cold front drifting across the Upper Midwest later Tuesday into Wednesday. However, the better upper- level dynamics look to remain to the north closer tied to the trough/low itself, the low-level forcing from the front along with some WAA and signs of a LLJ are looking to be enough for the increased PoP chances later Tuesday into Wednesday. Then behind the midweek system, the pattern is trending more benign with zonal upper-level flow and high pressure building across the region for the end of the week. Wagner && .AVIATION... Issued 1201 AM CDT Sat Sep 5 2026 Light winds and recent rainfall will result in conditions favorable for fog development across southern WI tonight through this morning. Expecting widespread lower visibilities of 1-3sm, and even lower for low-lying terminals and river valleys that may see pockets of dense fog at times through daybreak. Accompanying the fog will also be lower ceilings ranging from MVFR to LIFR. Expect these lower visibility conditions to improve later in the morning with some the lower ceilings lagging a bit behind the visibility. Otherwise, high pressure will build across the Great Lakes through the day and will influence the pattern over southern WI through the remainder of the weekend with prevailing light easterly winds. Wagner && .MARINE... Issued 1201 AM CDT Sat Sep 5 2026 Light winds over Lake Michigan will shift east-northeasterly overnight into Saturday morning a cold front gradually slides southward. Areas of dense fog may form over central and southern Lake Michigan after the frontal passage and continue through Saturday morning. Then high pressure builds over the Great Lakes from Ontario through the weekend and will bring modest northeast winds through Saturday, especially for central and southern Lake Michigan. Winds eventually weaken and become more light and variable for Sunday and Monday as an additional high pressure slowly reinforces the high pressure over the Great Lakes. Wagner && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, X, and YouTube at: www.facebook.com/NWSMilwaukee www.x.com/NWSMilwaukee www.youtube.com/NWSMilwaukee