Environment Canada has issued a wind and rain warning for Tuesday for the Niagara region.
Strong winds may cause local power outages and flying debris, said a public notice.
Niagara Falls, Welland, St. Catharines and Grimsby are expected to see a significant thunderstorm with rainfall starting this afternoon followed by a heavier downpour in the evening.
EC said the storm is the result of a low pressure system from Colorado combined with an approaching artic cold front is expected to bring a rainfall of 15 to 30 millimetres with the possibility of wind gusts up to 100 km/h early Wednesday morning.
Residents are advised to take safety precautions.