A flood watch is posted for Windsor-Essex.
Essex Region Conservation Authority says the area has received more than 40mm of rain over the past 24 hours.
The agency says areas of northern Amherstburg and Essex, southern Tecumseh and LaSalle, along with the city of Windsor have received between 40 and 50mm.
More rainfall is expected Wednesday morning leading to possible flooding in low-lying areas and near watercourses.