Environment Canada issued a special weather statement Monday, May 14/2018, calling for significant rainfall overnight for South Niagara which will continue into Tuesday morning.
“A weather system moving along the line of a warm front over northern Ohio will affect Southern Ontario near midnight with a significant rain fall,” the statement said. “Showers and embedded thunderstorms will soak the region tonight into Tuesday as the front tries to get closer to the area. A widespread rainfall of 20 to 40 mm is expected from this round of precipitation.”
“Total rainfall amounts of 50 millimetres or more are quite possible in a few localities that receive a thunderstorm or two tonight into Tuesday,” the statement said.
The rainfall is expected to end Tuesday afternoon as the weather front is pushed back south.
The statement also says “Motorists should be prepared for ponding of water on poorly drained sections of roads, and low visibility in heavy downpours.”