Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
183 FXUS63 KMKX 301947 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 247 PM CDT Sat Aug 30 2025 .KEY MESSAGES... - Patchy fog along and west of the Kettle Moraine, with areas north and west of Madison seeing potential for more widespread fog (40% chance) and locally dense pockets of fog. - Dry conditions with a gradual warming trend through early next week. - Next shower and thunderstorm chances (60-75%) return to the forecast Wednesday into Thursday. && .SHORT TERM... Issued 247 PM CDT Sat Aug 30 2025 Tonight through Sunday night: Broken diurnal cumulus clouds have developed across the entirety of southern Wisconsin this afternoon, with most areas seeing this cumulus activity diminish by sunset and clear skies prevailing under high pressure overnight. Model differences in dewpoint forecast remain high (generally seeing output between 47 and 54 degrees), especially along and east of the Kettle Moraine. Therefore, confidence in fog development in those regions remains low. Low-lying areas and known cool spots may still be able to develop ground fog, especially since temperatures will be able to fall rapidly under clear skies. Farther west, higher confidence exists in dewpoints above 50 degrees overnight; and correspondingly higher confidence exists in fog development across the area. Areas north and west of MSN stand the best chance of seeing widespread fog, with locally dense fog still possible. Will monitor conditions through this evening in case headlines are needed. Temperatures recover into the upper 70s on Sunday as high pressure lingers and light winds allow for rapid heating at the surface during the day. Drier conditions are seen in models, but diurnal cumulus are still possible. Overnight Sunday, temperatures will fall quickly to around 50 degrees, allowing for patchy fog to develop in low lying areas under clear skies and high pressure once again. MH && .LONG TERM... Issued 247 PM CDT Sat Aug 30 2025 Monday through Saturday: Dry conditions continue through Monday, with patchy fog burning off quickly after sunrise. High pressure remains dominant over the region into Tuesday, allowing for continued slow warming trends. Patchy fog is possible again Monday night. Going into Tuesday, a low pressure system circulating over the central Plains into the Lower Mississippi Valley may phase with a low pressure system propagating southeastward through the Canadian Prairies, allowing for southwesterly winds to become established over southern Wisconsin by Tuesday afternoon. Temperatures may rise into the low 80s, especially in the downsloping regions of the Kettle Moraine. Increasing clouds Tuesday evening, with the primary cold front holding off until Wednesday morning (GFS remains the fastest solution with overnight Tuesday, but is trending later with the most recent runs). MUCAPE ahead of and along the front is currently forecast to be around 500 J/kg, with the better shear profiles behind the front. Current expectations, unless the front slows down even farther and comes through southeastern Wisconsin Wednesday afternoon, expecting any convection to be generally weak with lightning as the primary hazard. Precipitation, however, is likely (60-75% chance). A return to northwesterly winds is expected Wednesday night into Thursday behind the front as the Canadian low pressure system occludes over southern Ontario. Winds are expected to be quite gusty, bringing in much cooler than normal temperatures. Expect lows in the 40s Wednesday and Thursday, with highs near 60 degrees on Thursday and Friday. Additional waves of precipitation are possible (10-20% chance) Thursday into Friday as shortwaves wrap around the back side of the low. Conditions improve into Saturday as low pressure finally lifts into the Hudson Bay and eastward. Expect highs near 70 degrees with clearing skies. MH && .AVIATION... Issued 247 PM CDT Sat Aug 30 2025 VFR conditions and light easterly winds expected through the remainder of today, with brief gusts along the lake breeze this afternoon. Diurnal cumulus deck will dissipate into tonight, with patchy fog potential late tonight into early Sunday morning along and west of the Kettle Moraine. Best chances for 2-5 SM visibility are from MSN westward, with locally dense fog possible (quarter mile visibility) primarily north and west of MSN. Trends will be monitored overnight and adjustments made accordingly. Fog will burn off shortly after sunrise on Sunday, with light southeasterly winds developing again, as well as scattered diurnal cumulus around 4000 ft. Light and variable to calm winds with patchy fog is once again possible Sunday night. MH && .MARINE... Issued 247 PM CDT Sat Aug 30 2025 High pressure will remain over the Great Lakes region through Monday, keeping winds light and variable across Lake Michigan. Tuesday, low pressure crossing southern Ontario will bring increasing south-southwesterly winds into Wednesday morning. A cold front associated with this low pressure system will bring a broken line of thunderstorms to the lake, with some producing strong wind gusts, Wednesday into Wednesday evening. Behind this cold front, expect west-northwesterly winds with gusts around 30 kt. Isolated gales are possible, and trends will be monitored with future updates to assess gale potential. Regardless of gale potential, winds and waves in the nearshore waters will likely reach Small Craft Advisory conditions. Winds continue through Thursday. Northern portions of Lake Michigan will continue to see showers into Thursday as well, and waterspouts may be added in future forecast updates if pattern remains favorable. MH && .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