Environment Canada has issued yellow rainfall and wind warnings for the region.
The warnings are in effect for Windsor-Essex and Chatham-Kent.
The weather agency said total rain and freezing rain amounts between 20 to 40 millimeters with locally up to 50 millimeters possible.
Rain will be heavy at times through Sunday afternoon and evening with risk for a few isolated thunderstorms. The rain will ease overnight.
The Essex Region Conservation Authority issued a watershed conditions statement through noon Monday as the rain may causing ponding and possible flooding in low-lying areas and smaller waterways.
Residents are reminded to use caution near watercourses and keep children and pets away.
Strong winds are expected on Monday with southwesterly wind gusts of 80 to 90 km/h possible.
Environment Canada said local utility outages are possible, including damage to roofs, fences, branches or soft shelters is possible.
The winds are expected to ease through Monday evening as they shift around to the northwest, but gusts of 60 km/h to 70 km/h are still likely.