The Wednesday forecast in London, Ont., has prompted a severe thunderstorm watch from Environment Canada.
“Conditions will become favourable for the development of severe thunderstorms beginning in the afternoon,” said an alert from the national weather agency.
The watch covers London, Parkhill and eastern Middlesex County.
Forecasters warn of wind gusts up to 100 km/h, nickel-sized hail and localized bouts of heavy rain. There is also a risk of a tornado, according to Environment Canada.
If the storms do arrive, they are expected to last into the evening.
Environment Canada is continuing to monitor the weather system as it develops.