Southern Ontario: Thunderstorm Outlook for Tuesday, June 8, 2021

Forecast Discussion

Two rounds of thunderstorms are expected to affect Southern Ontario on Tuesday starting with a cluster of storms developing around the London area during the early morning hours and tracking through the GTA during the mid to late morning. These storms will be non-severe but they could be moving quite slowly and like with the storms we saw on Monday, flooding could be an issue with localized rainfall amounts exceeding 50mm. The second round will occur during the afternoon and evening hours with pop-up storms developing around the Golden Horshoe into Southwestern Ontario along with another zone in Northeastern Ontario including Sudbury, North Bay and Algonquin Park. Any storms that develop will again pose a flooding threat along with some small to moderate size hail. The environment is much stronger up towards Northeastern Ontario which is why we’ve included an isolated severe risk for this area due to stronger wind gusts and sizable hail. Storms will quickly fade out after sunset and the daylight heating that was fueling them disappears.