January thaw comes to an end in Ontario as winter resumes with snow

After a brief January thaw in southern Ontario late week, including an incredibly warm Friday when temperatures soared to typical late-April or early-May values, winter makes its triumphant return this weekend.

Temperatures will plunge back below the freezing mark, heralding the return of below-seasonal temperatures and opportunities for snow.

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As well, a new system will bring widespread snow to the region on Saturday afternoon and evening. Widespread amounts of 5-10 cm are expected, with a chance of slightly higher totals in some of the snowbelt communities.

That won't be it for the snow, either, for the snowbelt communities as the lake-effect machine will kick in upon the system departure for Sunday.

Brief pause ends with weekend system

Unseasonably warm air spread over southern Ontario to end the week. Friday’s highs made it up to 16.0°C in Sarnia and 15.2°C at Pearson International Airport.

At leas six stations soared to above 15°C, including:

• Sarnia: 16.0°C

• Hamilton: 15.6°C (warmest January day since Jan. 8, 2008 - 16.7°C)

• Port Weller: 15.6°C

• Vineland: 15.6°C

• Toronto: 15.2°C (warmest January day since Jan. 8, 2008 - 15.5°C)

As well, powerful wind gusts topping 90 km/h ripped across portions of Ontario. The highest gusts include:

• Hamilton: 96 km/h

• Toronto: 96 km/h

• Windsor: 93 km/h

• Peterborough: 93 km/h

• Trenton: 89 km/h

• Ottawa: 85 km/h

We’re leaving that midwinter comfort behind this weekend as a new system collides with colder air moving back into the region. Temperatures will plunge back below the freezing mark, heralding the return of below-seasonal temperatures and opportunities for snow.

Widespread snowfall will develop late Saturday afternoon into the evening as a system pushes into the Great Lakes, spreading across all of the shorelines through the day. Expect the heaviest snowfall by the evening hours.

Wet snow is expected north of Highway 407 and regions to the north and east of the major highway stretch. A sharp gradient will develop across Toronto, with rain to the south and snow to the north.

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Snowfall becomes heaviest by the evening, but well northwest of downtown Toronto and when most of the GTA is just dealing with rain.

Snowfall impacts Ottawa Saturday evening and overnight, with about 10 cm forecast to fall.

A burst of lake-effect snow will build into portions of southern Ontario on Sunday in the main system’s wake.

All told, we’re looking at widespread snowfall totals of 5-10 cm from the Lake Huron shores through eastern Ontario. Slightly higher amounts are possible for parts of the snowbelt communities. Totals will quickly reduce to zero near the shores of Lake Ontario thanks to the cutoff between rain and snow.

Stay with The Weather Network for all the latest on conditions across Ontario.

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