High winds and snow began to hit southern Ontario Monday afternoon, and are expected to peak overnight and continue into Tuesday's morning commute.
Two low-pressure systems that "collided over the U.S. Eastern Seaboard" on Monday night were blamed for the return to snowy weather across southern Ontario, according to the Weather Network.
In Toronto, 10 to 15 centimetres of snow was forecast to fall by Tuesday night. Although the city received some snowfall from early Monday afternoon into the early evening, the heaviest accumulation is expected overnight and into Tuesday morning.
"Northeast winds gusting to 50 km/h are also expected this evening into Tuesday resulting in localized blowing snow," says Environment Canada in its special weather statement for Toronto.
Travel conditions Monday into Tuesday night may be "hazardous," the agency adds.
At least 48 flights were cancelled and another 60 delayed at Toronto's Pearson airport Monday afternoon and evening as winds gusted up to about 40 km/h.
Elsewhere in the Golden Horseshoe, Hamilton, Halton and Niagara remain under a winter storm warning from Environment Canada.
"While total snowfall amounts of 15 to 25 centimetres are expected, some areas in the Hamilton to Niagara corridor could see locally higher amounts of 30 centimetres," the agency says.
Special weather statements have also been issued for the Kitchener-Waterloo and Windsor regions, which could get 10 to 15 centimetres of snow by Tuesday night.
There are no special weather advisories for Ottawa, but temperatures are expected to feel like close to –30 with the wind chill.
In the U.S., the National Weather Service has issued winter storm warnings for New York and Pennsylvania, with New Jersey remaining under a blizzard watch.