Environment Canada says Canada Day celebrations may include severe thunderstorms

WEST CARLETON – A renewed risk for severe thunderstorms will fill the skies over Ontario and Quebec during our Canada Day on Saturday.

“Warm, unstable air parked over the region will allow widespread thunderstorms to grow with the heat of the day,” Environment Canada released in a statement today (July 1). “Wind shear could allow the storms to grow strong to severe, especially in eastern Ontario and southern Quebec.”

Keep the radar handy on your phone if you’re under the threat for storms on Saturday (July 1), and make a plan to seek shelter in a hurry if hazardous weather approaches your location. If you can hear thunder, you’re close enough to be struck by lightning.

“Winds wrapping around a low-pressure system will pull a slug of warm, moist air surging into the region,” Environment Canada said. “This pool of unstable air will provide ample fuel for thunderstorms to thrive once they get going in the afternoon and evening hours.”

The combination of unstable air and wind shear will allow thunderstorms to strengthen and organize, some of which will approach severe limits across southern Ontario and a large swath of Quebec.

The strongest storms could produce large hail, strong wind gusts, and heavy rainfall. One or two tornadoes can’t be ruled out, especially in eastern Ontario and southern Quebec.

Thunderstorms will be more widespread than seen yesterday (June 30), and they’ll be slow-movers to boot, which could lead to localized flooding beneath the heftier storms.

Heat and humidity alone will make the day uncomfortably sticky for anyone spending any length of time outdoors. Humidex values will climb into the low- to mid-30s (degrees Celsius) for southern portions of Ontario and Quebec on Saturday afternoon, with a humidex in the upper 30s possible in far southwestern Ontario.