Ready or not: First burst of snow comes to southern Ontario
Get ready for a significant drop in temperatures as cold air moves into southern Ontario, leading to lake-effect snow along Georgian Bay and Lake Huron--with accumulations of 5-10 cm for some areas
While other provinces have had a snowy taste of the winter to come, temperatures in Ontario have stayed well above seasonal thanks to a block of high pressure off the United States' East Coast.
But that is about to change. A deep, upper-level trough is forecast to dig across much of Eastern Canada and the U.S. by the end of the week, dragging cold, northern air southward.
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That means some areas are in line to see some of their first snowfall of the season. While accumulations may not be high, the first snowfall can catch many drivers off guard, especially for those who haven't put their winter tires on.
Potential for first flakes by Friday
This is expected to be the coldest burst of air of the season so far for southern Ontario, with temperatures forecast to fall Thursday into Friday.
Daytime highs across the region on Friday are forecast to stay in the single digits, and wind chills should make it feel even colder.
Toronto's best chance to see the thermometer dip to freezing will be Thursday night.
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A low-pressure system from Illinois brought showers to southern Ontario on Wednesday. As it continues to retreat through Thursday, cold air will be pulled south, fuelling lake-effect flurries south of the Great Lakes on Friday morning.
Most will see less than 3 cm, but near 5 cm is possible for Sarnia-Lambton counties and near Collingwood.
There are uncertain totals with frequent transitions over to rain during the day, leading to snow melting.
Some brief flurries may make it into the Greater Toronto Area (GTA) with Toronto possibly seeing its first flurries and first freezing-mark temperature of the season on the same day.
Areas to watch will be Sarnia and the snowbelt communities for the first accumulation of the season. However, Sarnia and surrounding cities will see a rain-snow mix from Thursday night through Saturday morning, reducing snow totals.
Lambton County could see 5-10 cm of snowfall through Saturday, although the rain-snow mix will cause some of the accumulation to quickly melt.
The snowbelt off Georgian Bay's southern shore is also in store for some snowfall, with the heaviest-hit areas forecast to see 5-10 cm, as well.
Stay with The Weather Network for more information and updates on your forecast across Ontario.