Environment Canada has issued a special weather statement for London and the surrounding area, warning heavy amounts of rain could fall overnight throughout the region.
The national weather agency says a weather system will move in from Northern Ohio, and will bring significant amounts of rain to Southern Ontario, starting around midnight. The system is also expected to bring thunderstorms with it.
20 to 40 mm rainfall is expected overnight, with the possibility of 50 mm or more in a few localities.
They estimate the precipitation will come to an end on Tuesday afternoon, but are warning motorists to drive carefully on roadways, as they say small ponds of water will form on poorly drained sections of roads, while the rain will cause low visibility.
The statement is in effect for London, Parkhill, Strathroy, Komoka and Middlesex County.