Weekend snow squall risk in Ontario, watching a major storm next week
Winter is finally on the move across Canada after record-setting warmth to start the season. A one-two punch of impactful systems will arrive in Ontario and Quebec over the next couple of days.
The issues start with a sneaky snow squall threat this weekend around the Greater Toronto Area (GTA) that could make for dangerous driving amid slippery roads and reduced visibility.
MUST SEE: Record-breaking: El Niño stole winter from Ontario in December
Looking ahead to next week, forecasters are watching a formidable Texas low brewing south of the border that could spill widespread foul conditions across both Ontario and Quebec through mid-week.
Here's what we are watching in the days to come.
Snow squalls threaten GTA, area highways this weekend
A strong storm passing through the U.S. will bring just enough moisture and a favourable wind direction for lake-effect snow to develop over Lake Ontario this weekend.
Lake-effect snow occurs in very narrow bands of intense snowfall often surrounded by perfectly calm weather in nearby communities. Rapid changes in road conditions are common over very short distances.
This lake-effect snow risk will focus on the GTA and surrounding regions late Saturday into Sunday. A very narrow band of locally heavy snowfall is forecast to develop, but there is some uncertainty as to where the squall will lock in. The shores of Lake Ontario from Burlington to Oshawa, including Toronto, are all at risk.
While most areas will see no snowfall, others could wind up recording 2-5+ cm by Sunday. Travel routes including the Gardiner, DVP, 404, 400, 410, 427, and 401 all stand at risk for slowdowns early Sunday. If you’re travelling east of the city, 5-10 cm is possible for areas from Oshawa to Cobourg along the 401.
RELATED: Why snow squalls are one of the hardest events to forecast
There’s still room for change in the forecast due to the small-scale weather ingredients that generate lake-effect snow. A slight shift in wind direction or temperatures a degree or two colder can significantly alter where the snow falls.
Be sure to check back on Saturday and Sunday as we monitor your community’s snowfall chances.
Major Texas low is a storm to watch for next Tuesday
A sprawling Texas low will bring significant snow to millions across North America by next week.
This will be the first major system of 2024 for both Ontario and Quebec. While it is still far too early to give specifics on storm impacts, Tuesday and Wednesday will be the days to watch.
EXPLAINER: How Texas lows influence Canadian weather
It’s a classic wintry setup across the U.S. that’ll have significant implications for Canadian weather. Some areas will see significant snows and winter travel woes, but ice and rain may be a factor elsewhere.
A cold Arctic air mass will collide with warm, humid air flowing north out of the Gulf of Mexico. This infusion of moisture will lead to heavy snow on the colder northern side of the storm and prolific rains and possible severe thunderstorms on the system’s warmer southern end.
The track of the storm is key to where these precipitation types occur. Small changes will have large implications for this system’s ultimate impacts.
SEE ALSO: Winter to finally show up in January as El Niño bested by polar vortex
Currently, the storm’s projected track aims right for the Great Lakes, likely delivering a widespread swath of high winds and significant snows in its wake. The U.S. National Weather Service paints an incredibly large portion of the United States under a risk for high wind gusts of 80+ km/h during this storm—an extent spanning more than 2,000 km, nearly half the width of the U.S.
These same threats will not stop at the border, either. The Texas low is likely to strengthen prior to impacting Ontario late on Tuesday.
Parts of Ontario and Quebec can expect a swath of heavy snowfall through Wednesday, with some rain mixing in for those south of the low pressure centre.
The storm track will make all the difference, so be sure to continue to check back this weekend as we nail down your first major storm of 2024.
