Local conservation authorities are warning of flooding, flash flooding and water pooling on the roads.
Both the Saugeen Valley and Ausable Bayfield Conservation Authorities are watching the situation closely after environment Canada issued a rainfall warning for all of Midwestern Ontario.
Both watersheds could see between 75 and 100 millimetres of rain in 48 hours, with locally heavier downpours in areas that are hit with multiple thunderstorms.
The Ausable Bayfield authority says if embedded thunderstorms develop, along with the higher end prediction for rainfall, then widespread flooding is likely, leading to numerous road closures.
There is also a gale warning in effect for the southern Lake Huron Shoreline where winds speeds of 40 to 70 km/h are expected.
Flows in streams and rivers will be higher than normal and minor flooding is possible in low-lying areas that typically flood. There is also the chance heavy downpours could cause flash flooding and water pooling on roadways.
Flows on the larger rivers are not likely to peak until Thursday and Friday. Flows would remain higher than normal through the weekend
County and municipal staff are urged to monitor problem areas and be ready to close roads.
Everyone is urged to stay away from all watercourses including the Lake Huron shoreline where high wave action is expected.
The advisory from the Saugeen Valley Conservation Authority remains in effect until Friday. The advisory from the Ausable Bayfield will remain in effect until Monday, September 27, 2021.
~With files from Kate Stockmann