Severe storms sweep GTA Wednesday with damaging winds and tornado risk

Two or three rounds of severe thunderstorms are expected to sweep across the GTA on Wednesday, fueled by hot and humid conditions that saw temperatures reach 26°C and a humidex of 35 on Tuesday.

Environment and Climate Change Canada issued a yellow heat warning for parts of southwestern Ontario as the humidex soared into the 40s in some areas. The warning is expected to remain in place Wednesday.

The morning commute will be both foggy and rainy, with fog reducing visibility to less than a kilometre in some areas. An additional 40 to 60 millimetres of rain is expected from possible severe storms. Showers and thunderstorms are expected between 3 p.m. and 5 p.m. initially, with strong wind gusts, hail, and 20 to 40 millimetres of rain falling on already saturated ground.

Towards Wednesday evening, conditions will deteriorate further. Strong damaging winds gusting up to 90 kilometres per hour are possible, with the potential to bring down trees and power lines—power outages are possible throughout a large portion of southern Ontario. There is an elevated tornado risk in some areas as well as the potential for 3 to 5 centimetres of hail.

Early morning storms will come with heavy downpours and strong winds. There will be a break towards the middle of the day, but as evening approaches, storms will move into Toronto through the afternoon and evening commute.

The high humidity will drop on Labour Day weekend as temperatures come back down to seasonal levels and the skies clear out. No inclement weather is expected as kids head back to school on Tuesday, with comfortable temperatures in the low 20s.