Sharp north-south temperature contrast in Ontario

Digital WritersThe Weather Network
Digital Writers

This will be a Friday you'll want to enjoy as temperatures soar into the 20s across southern Ontario, likely for the final time of the year.

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Though parts of the north have stayed cool this Friday, with lingering snow, it couldn't be a more different story in the south, with daytime highs looking to top 20°C for what could be the last time this year. But a descending cold front is set to trigger potentially severe thunderstorms across much of the south in the late afternoon and evening, leaving behind chilly temperatures for the weekend. A closer look, below.


WEATHER HIGHLIGHTS

  • Periods of light snow continue Friday for the north, showers in the south for the evening

  • Chance of thunderstorms for much of the south, potentially severe in the southwest

  • Daytime highs above 20°C for most of the south, feeling like the mid-20s with the humidity on Friday

  • Sharp cooldown with potent cold front later Friday, chilly but clear weekend


FRIDAY: HUMIDEX VS. WIND CHILL

Summer's somewhat seasonally displaced last gasp was upon southern Ontario Friday afternoon. Temperatures crept above the 20°C mark, feeling like the mid-20s for some, and if you have a chance to step outside, you should take it.

"While we can't rule out a 20-degree day during November, most likely this will be the final time that we reach 20°C during 2020," says Weather Network meteorologist Dr. Doug Gillham.

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The dividing line between the warm and cold air is a sharp one, as areas further north -- take Wawa for example -- will be battling freezing temperatures and a wind chill of -3 on Friday, with bouts of snow and a raw northerly wind -- with some lingering light snow lasting into Friday evening.

After some morning fog, southern Ontario's skies cleared by the late morning and early afternoon, but looming beyond is a descending cold front arriving later in the day. Thanks to the warmth and humidity, it might even bring a strong thunderstorm as well Friday evening.

"A strong to severe storm is possible with strong winds and torrential downpours," Gillham warns.

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Based on computer models, a brief tornado along the front can't be ruled out, especially with low level wind shear forecast to be favourable for the potential.

Be sure to keep an eye on the watches and warnings in your area as these storms begin to bubble up.

LONG RANGE: WIDESPREAD CHILLY WEATHER RETURNS

That cold front will usher in some markedly colder temperatures for the weekend. Daytime highs will be mostly in the single-digits, below seasonal, and the chill will dominate through the end of next week and into the first days of November as well.

"However, much milder weather to our west is expected to slowly spread into our region later in the week and we are watching the potential for a stretch of above seasonal temperatures heading into the second week of November," adds Gillham. "Of course, seasonal temperatures by that time are cooler so it is unlikely that we will see 20°C again."

Stay tuned to The Weather Network for the latest forecast details.