A severe thunderstorm warning is in effect for the St. Catharines, Grimsby, and Northern Niagara Region.
Meteorologists are tracking a storm that could bring strong winds, heavy rain, and nickel sized hail.
Residents could see 50 mm of rain in that area.
A special weather statement is also in effect for the Niagara Falls and Welland areas. They could see 40 mm of rain and wind gusts up to 70 km/h.