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Tornado warning briefly issued in southwestern Ontario amid severe storm

Tuesday, July 27th 2021, 11:20 pm - A severe thunderstorm pushed into southwestern Ontario Tuesday evening, prompting a brief tornado warning for Sarnia-Petrolia-Western Lambton County that has since expired.

A tornado warning was briefly issued by Environment Canada for parts of southwestern Ontario Tuesday evening as a severe thunderstorm crossed into the province from Michigan. It has since been dropped, however. The storm threat will subside in the overnight hours. By Wednesday, conditions will improve, as the passage of a cold front will allow for the removal of the heat and humidity. The next thunderstorm chance will come on Thursday, ahead of a potent cold front. For more, read below.


By Wednesday, the muggy and sticky conditions will clear out, as temperatures actually dip a couple of degrees below seasonal. The last week of July would typically see a seasonal high of about 27°C in Toronto for example, but daytime highs on Wednesday will sit closer to 25°C.

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The rain and thunderstorm chances return ahead of a potent cold front on Thursday, with a brisk northwest wind knocking temperatures even cooler for the start of the August long weekend on Friday. Temperatures will only reach the lower 20s for southern areas, and remain in the teens across cottage country and north of the St. Lawrence.

"A pleasant start to the weekend, though temperatures will be on the cool side of seasonal, but we will see some sunshine," says Dr. Doug Gillham, a meteorologist at The Weather Network. "However, another cold front will approach and then cross the region with a period of rain and thunderstorms Saturday night and/or Sunday."

Gusty winds and a hint of autumn will be left behind the cold front on Sunday. Temperatures will likely remain in the teens across cottage country for the holiday on Monday, and for most of Quebec as well.

The comfortable, and cooler than seasonal pattern will continue through early August, so we do not expect any prolonged periods of hot weather over the next couple of weeks.

Stay with The Weather Network for the latest forecast across Ontario.

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