Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
525 FXUS63 KMKX 070003 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 703 PM CDT Sun Sep 6 2026 .KEY MESSAGES... - Mild and pleasant weather continues through Labor Day. - Patchy dense fog expected in low-lying areas of southwestern Wisconsin tonight into early Monday morning. - A Moderate to High Swim Risk may develop for Lake MI beaches in Sheboygan and Ozaukee Counties for Tue-Tue evening. - Warmer temps and higher humidity returns for Tue-Wed. There are 40-60% chances for showers on Tuesday mainly well north and west of the MKE metro area, followed by 60-90% chances for showers and thunderstorms Tuesday night, lingering into Wed AM. && .UPDATE... Issued 704 PM CDT Sun Sep 6 2026 High clouds will remain through tonight, with patchy dense fog developing again late tonight into early Monday morning as temperatures cool into the mid-60s and winds become calm. Otherwise, forecast remains on track. MH && .SHORT TERM... Issued 203 PM CDT Sun Sep 6 2026 Tonight through Wednesday: Low level instability has resulted in broken cumulus development well inland from the lake that will thin through the afternoon. Otherwise another warm and pleasant day. High pressure over the nrn Great Lakes will shift to the lower Great Lakes for Labor Day and continue to support warm and pleasant conditions. Some daytime camels can be expected but mid to high clouds may also stream in from the west via a weakening upper trough within a larger scale upper ridge. The upper ridge to the west will then drift ewd across the wrn Great Lakes into Mon nt then flatten as it moves to the east on Tue. Weak low to mid level warm, moist advection can be expected while PWATs rise to 1.8-2.0 inches late in the day. The CAMs suggest a weakening MCS will move into south central WI from wrn WI in the morning and continue to weaken as it attempts to move into se WI in the afternoon. Only mid level saturation and high based instability is expected. 40-60% chances for showers are forecast on Tue mainly well north and west of the MKE metro area, including the Madison area. The main moisture plume and slightly better mid level lapse rates will then shift into srn WI Tue nt ahead of the approaching weak cold front that trails from strong low pressure over far nrn Ontario or Hudson Bay. MUCAPE will still remain limited but lift and moisture will still support shower and storm chances of 60-90%, with some showers and storms lingering into Wed AM. It is possible the showers and storms could develop to the west over IA where an effective warm front will stall with the convective activity then moving east into nrn IL and possibly srn WI. Overall the severe thunderstorm threat looks very low with possibly more of a heavy rain and urban and small stream flooding potential, albeit still low at this time. Gehring && .LONG TERM... Issued 203 PM CDT Sun Sep 6 2026 Wednesday night through Sunday: The weak cold front will then pass on Wed followed by a sfc ridge and pleasant conditions on Thu. Sly winds and warm, moist advection will return by the end of the week with an approaching sfc trough from the west. More substantial cyclogenesis is possible on Sunday to the west. There are 20-40 percent chances for showers and storms Fri nt-Sun at this time. Gehring && .AVIATION... Issued 704 PM CDT Sun Sep 6 2026 High clouds around 25,000 ft will continue throughout tonight, with patchy dense fog in low-lying areas developing late tonight into early Monday morning in southwestern Wisconsin. Generally easterly winds are expected through sunset, becoming mostly calm to light and variable overnight. Winds shift to southeasterly and become steady into Monday, with high clouds lingering and a few diurnal cumulus around 4000 ft developing Monday afternoon. Monday night, southeasterly winds continue and scattered high clouds remain. MH && .MARINE... Issued 203 PM CDT Sun Sep 6 2026 High pressure around 30.2 inches over the northern Great Lakes today, shifting to the lower Great Lakes for Monday. Light and variable winds are forecast through this period. Increasing south to southwest winds are forecast for Tuesday into Wednesday, shifting west to northwest Wednesday night into Thursday, as a cold front moves toward and through the region. Cannot rule out a few isolated gales on Wednesday across far northern Lake Michigan. A Small Craft Advisory will likely be needed Tuesday and Tuesday evening north of Port Washington for breezy south winds and high waves. Gehring && .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