Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
715 FXUS63 KMKX 071141 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 641 AM CDT Mon Sep 7 2026 .KEY MESSAGES... - Moderate to high swim risk conditions may develop for Lake MI beaches in Sheboygan and Ozaukee Counties Tuesday into Tuesday night. - Showers and storms are expected to develop as warmer, more humid air moves in Tuesday into Tuesday night. These storms will be capable of producing heavy rain and lightning. A few may become capable of producing damaging winds, but confidence is not high at this time. - Chances for on-and-off thunderstorms return to the forecast Friday night through early next week. && .UPDATE... Issued 640 AM CDT Mon Sep 7 2026 Scattered high-altitude clouds have prevented much of the anticipated fog from forming early this morning. A few patches evident on regional METARS, but seems to be hyper-localized to low-lying marshy areas and river valleys. Otherwise, no changes to the short-term or extended forecast. Sheppard && .SHORT TERM... Issued 1213 AM CDT Mon Sep 7 2026 Today and Tonight: Patchy dense fog in low-lying areas is expected in southwestern Wisconsin through sunrise, burning off shortly thereafter. Light and variable winds will become southeasterly and steady as low pressure propagates northeastward through the northern Plains. High clouds and some diurnal cumulus will keep temperatures in the upper 70s to around 80 degrees through the afternoon. High clouds will linger through the overnight hours tonight, with southeasterly winds continuing to mix the boundary layer and keeping fog from developing. A few isolated showers may develop in southwestern Wisconsin by early Tuesday morning. MH && .LONG TERM... Issued 1213 AM CDT Mon Sep 7 2026 Tuesday through Monday: Low pressure deepens in the Canadian Prairies on Tuesday, with broad, strengthening WAA in all levels. Frontogenesis at the low levels will allow for precipitation development across southwestern to central Wisconsin, spreading eastward through the afternoon. PWATs around 2 inches combined with mid-level MUCAPE in the 400-700 J/kg range and a broad area of lift, heavy rain becomes a threat going into the afternoon and overnight hours. West to east bulk shear of 35 to 40 kt and 850 mb LLJ nosing into northern Illinois overnight may allow for a period of storm intensification. The primary hazard looks to be urban and small stream flooding, but cannot rule out brief downburst activity due to precipitation loading. Southwesterly winds gusting between 20 and 25 mph are expected even outside of storms as low pressure continues to deepen. With gusty winds and building waves Tuesday into Tuesday night, a moderate to high swim risk will also develop in Ozaukee and Sheboygan County Lake Michigan beaches. Low pressure lifts into the Hudson Bay Wednesday morning, the last waves of rain and storms will progress southeastward out of Wisconsin. The cold front will finally work its way through Wednesday afternoon, bringing an end to any further thunderstorm activity. Northwesterly winds develop after storms exit, with temperatures falling into the low 70s quickly after the frontal passage. High pressure will build through the northern Plains into the central Plains Wednesday afternoon through Wednesday night, bringing cool and dry conditions with lows in the 50s Wednesday night and highs in the mid-70s Thursday. High pressure gradually propagates eastward through the Ohio Valley through Friday, keeping conditions dry and highs in the upper 70s. An active pattern returns into the weekend as multiple shortwaves swing southeastward through southern Canada and interact with lee cyclogenesis in the central to northern Great Plains. On and off periods of thunderstorms are expected, with some potential for severe weather if ingredients come together at the right time. Active pattern continues into early next week. MH && .AVIATION... Issued 640 AM CDT Mon Sep 7 2026 A few patches of fog across southern WI early this morning, should burn off over the next hour from now leaving completely dry weather and VFR for the entire rest of the TAF period. Light southeast winds develop today, then turn south and accelerate into Tuesday. Sheppard && .MARINE... Issued 1213 AM CDT Mon Sep 7 2026 High pressure around 30.2 inches will allow for light and variable winds through tonight. Meanwhile, low pressure around 29.8 inches over the northern High Plains this morning will deepen to 29.5 inches as it lifts northward through the Canadian Prairies into Tuesday morning. This will allow for gradually increasing southeasterly winds late tonight through Tuesday. Gusts around 30 kt are expected across the northern half Tuesday afternoon through Tuesday night. Gusty winds and rising waves may create Small Craft Advisory conditions in the nearshore waters north of Milwaukee in southern Wisconsin. As low pressure enters the Hudson Bay Tuesday night, winds shift southwesterly, then westerly on Wednesday as a cold front pushes southeastward through the Lake. Winds become northwesterly behind the front, gradually weakening through Thursday and Thursday night. Winds shift to southerly again and increase into Friday as low pressure develops in the northern Plains. 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