Southern Ontario: Thunderstorm Outlook for Sunday, September 12, 2021

Forecast Discussion

Scattered thunderstorms are expected to develop across parts of Southwestern Ontario and into the Golden Horseshoe during the afternoon and evening on Sunday. The environment is favourable for a few of these storms to reach severe levels with damaging wind gusts as the main threat along with small to medium sized hail and heavy downpours. An isolated tornado can’t be ruled out either, but the risk isn’t particularly strong. The strongest risk zone extends from Southern Lake Huron, through London and along the Northern Lake Erie shoreline. Current weather guidances show strong cells developing over Michigan during the afternoon and track into the Sarnia and Grand Bend area by the late afternoon. It’s should be fairly quiet for those north of Lake Simcoe with the thunderstorm risk contained to the southern part of our region. The storm risk should come to an end by midnight.