Severe storms possible in GTA Wednesday, fueled by ongoing heat

As temperatures rise throughout Tuesday and Wednesday, the risk of thunderstorms also climbs in the Greater Toronto Area (GTA). Tuesday began foggy and saw temperatures steadily increase, peaking at 26°C with a humidex of 35. Showers, thunderstorms, strong wind gusts, and hail are anticipated between 3 p.m. and 5 p.m., along with an additional 20-40 millimeters of rain on already soaked ground.

Environment and Climate Change Canada has issued a yellow heat warning for some parts of southwestern Ontario as the humidex climbs into the 40s in certain regions. This warning is expected to remain in effect on Wednesday.

A low pressure system moving across the Plains and into the U.S. Midwest is also expected to produce severe weather on Wednesday, adding to unsettled conditions. The GTA is forecasted to experience two or three rounds of storms throughout the day, driven by hot and humid conditions. The morning commute will be both foggy and rainy, reducing visibility to less than a kilometer in some areas. Another 40-60 millimeters of rain may fall due to potential severe storms.

Towards the evening of Wednesday, strong damaging winds gusting up to 90 kilometers per hour are possible. Such winds have the potential to topple trees and power lines, leading to possible power outages across a large portion of southern Ontario. There is an elevated risk of tornadoes in some areas, as well as the potential for 3-5 centimeters of hail.

Early morning storms will bring heavy downpours and strong winds as they move through. A brief respite is expected midday, but as the day progresses, storms will move into Toronto through the afternoon and evening commute.

The high humidity will decline over the Labour Day weekend as temperatures return to seasonal averages and clear skies prevail. No significant weather disruptions are anticipated as children return to school on Tuesday, with comfortable temperatures in the low 20s.