Winter weather travel advisories are in effect for southern Ontario, as a band of lake-effect snow off Lake Ontario impacts the region through Friday. The snow picked up late Thursday night and will be enough to slow commute times to end off this week ahead of the holidays.
A widespread 2-5+ cm is possible through Friday, with some higher amounts likely for the western Greater Toronto Area (GTA) due to some lake enhancement.
“Motorists should expect hazardous winter driving conditions and adjust travel plans accordingly,” says Environment and Climate Change Canada (ECCC) in the travel advisory. “There may be a significant impact on rush hour traffic in urban areas.”
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Immediately following this wintry system arrives a noticeable temperature drop into the negative digits. This frigid air will bring the coldest air of the year to several parts of the GTA.
Through Friday: Pack your patience for a slower Friday drive
A clipper system from the Prairies moving across the southern Great Lakes will result in an all-snow event across southern Ontario through Friday.
Early Friday AM Ontario snow timing
A widespread 2-5 cm of snow is expected, but parts of the GTA could see some higher totals with help from Lake Ontario.
The system is tracking south of Ontario, forcing an easterly wind off Lake Ontario. This setup could bring a stronger band of snowfall to places like Burlington, and to the west end of the GTA, where locally 5-10 cm may fall.
Baron – ON snow totals – Dec20
This blast of snow will affect Friday travel along major routes including the QEW, Don Valley Parkway (DVP), and the Gardiner Expressway, so make sure you brace for slower commute times.
“Slow down driving in slippery conditions. Watch for taillights ahead and maintain a safe following distance,” says ECCC. “If visibility is reduced while driving, turn on your lights and maintain a safe following distance.”
Snow squall watches for locally heavy snow near Lake Huron
Lake-effect snow squalls are expected to develop over Lake Huron later Friday night, potentially bringing locally heavy snowfall with accumulations between 10-20+ cm.
Blowing snow and near zero visibility are possible at times in areas that see heavy snow, and travel along Highway 402 will likely be impacted.
Drivers are urged to consider postponing non-essential travel until conditions improve. The squalls are expected to taper to light flurries by Saturday afternoon.
Coldest weather of the year this weekend
This weekend will bring our coldest weather of the season thus far as Arctic air is forced eastward. Saturday and Sunday wind chills will be in the negative teens in the GTA, and down to the -20s in cottage country.
Ontario Saturday wind chills
Next week however, will feature quite a warming trend.
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Rain or snow for Christmas?
We are closely watching a relatively weak system and warm front, which is expected to impact the region during Christmas Eve and possibly into Christmas Day. This will not be a major storm, but the timing relative to Christmas makes this a more interesting story.
This could bring us a coating, perhaps a few centimetres, of wet snow, but there is also a significant risk for a changeover to rain as temperatures rise above freezing, especially for more southern areas.
Mild temperatures will dominate the final week of December with the potential for a couple of low-pressure systems that will bring rain, or possibly a messy mix of precipitation. However, winter is not over. A colder pattern is expected to develop during the first week of January and dominate through the middle of the month.
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Be sure to check back for all the latest on conditions across Ontario.