Environment Canada has issued a severe thunderstorm watch for Southwestern Ontario.
The watch includes London, east and west Middlesex County, Strathroy, Parkhill and Komoka.
The national weather agency says the watch is expected to last from Wednesday afternoon into the evening as the storms move southeast.
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The agency says people can expect wind gusts up to 100 km an hour and hail up to 2 to 3 cm in size.
People are advised to stay indoors in the event of a thunderstorm with the possibility of hail, damaging winds and torrential rainfall.
Environment Canada reports strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles.
It is also recommending people avoid water-related activities which are unsafe due to lightning and violent and sudden gusts of wind over bodies of water.
The Office of the Fire Marshal and Emergency Management recommends that people take cover immediately if threatening weather approaches.
