Southern Ontario: Thunderstorm Outlook for Wednesday, July 7, 2021

Forecast Discussion

An area of heavy rainfall with embedded non-severe thunderstorms is expected to track into parts of Southwestern Ontario and Central Ontario from Michigan overnight into Wednesday morning. Any thunderstorm will be quite weak, but widespread rainfall totals between 15-30mm and even up to 50mm for those that see thunderstorm activity is possible. So isolated flooding could be an issue especially since we’ve seen lots of rain over the past few weeks.

Later in the day, there could be some storms that develop through Extreme Southwestern Ontario. The environment is favourable for a few of these storms to reach severe levels with strong wind gusts and large hail possible. It doesn’t look like the tornado risk is particularly strong so we haven’t included it on the map, but keep in mind that it never is out of the question when we’re dealing with severe storms. Storms will weaken and move out of the region by midnight with potentially some non-severe thunderstorms and rain continuing overnight into Thursday.