Wisconsin Weather Update: Flash flood warning for parts of southeast Wisconsin; stormy conditions expected through the week; check forecast

A flash flood warning has been issued for parts of southeast Wisconsin on August 9 and August 10, 2025, according to the National Weather Service (NWS). The latest flood warning for southern Washington County and southern Ozaukee County is in place till 5:30 AM as the heavy rain slowly drifts north. A separate warning is also in effect till 5 AM for Eastern Waukesha County and Milwaukee County. The NWS updated this warning to "considerable," due to the impact the heavy rain and flooding are already having on the area.

People have been advised not to drive on roads that seem to be flooded. Most deaths due to floods occur in vehicles. In some areas across the metro, rainfall in the past 24 hours has surpassed 6 inches. There are chances of thunderstorms accompanied by rainfall and fog in Mosinee (KCWA) in Marathon County till Monday (August 11, 2025). Central Wisconsin Airport (KCWA) is located about 3 miles southeast of Mosinee. The NWS has predicted slight chances of storms on Tuesday (August 12, 2025) with sunny skies. The weather is likely to remain clear and sunny till Wednesday (August 13, 2025).

Later in the week, the weather is expected to turn stormy again, with conditions alternating between cloudy and sunny through Saturday (August 16, 2025). Meanwhile, in Chicago and Houston, several parts are set to witness thunderstorms and rainfall starting Sunday night (August 10, 2025) and mostly till Thursday (August 14, 2025). The weather service has issued a weather alert in Chicago signalling thunderstorm risk and torrential rainfall.


There are chances of thunderstorms in Chicago starting Sunday night (August 10, 2025), and the stormy conditions are likely to prevail till Tuesday night (August 12, 2025). According to the NWS, the conditions will become sunny and clear from Thursday and will remain the same throughout the week.

The NWS has said that there are chances of elevated thunderstorm risk with an associated Level 2 of 5 damaging wind risk up to 60 mph. There is also an elevated flooding risk. Scattered thunderstorms are expected northwest of Interstate 55 tonight. A few of these thunderstorms may be strong to severe, with locally damaging winds being the primary severe weather threat, NWS said in its alert.

“Torrential rain will also be possible with these thunderstorms, which may allow for localized flash flooding. The highest risk of flooding appears to be across far northern Illinois, along and north of Interstate 90, where thunderstorms may move over the same areas overnight,” the alert further stated.