Southern Ontario: Thunderstorm Outlook for Tuesday, July 20, 2021

Forecast Discussion

Thunderstorm development is possible across Southern Ontario during the afternoon and evening on Tuesday. A few of these storms could beomce severe in a zone stretching from Owen Sound to Lake Simcoe and along the northern shoreline of Lake Ontario. Large hail, damaging wind gusts and heavy rainfall will be the main threats with these storms although an isolated tornado can’t be ruled out.

Right now, the tornado risk isn’t clear so we’re waiting until the next forecast update to pinpoint any tornado risk if it still exsits. As we get closer to the event the isolated severe risk zone may change and we may even have to introduce a severe risk zone if the storm risk becomes stronger. We’ll have more details with our final forecast on Monday evening.