Parts of Ontario could see first signs of snow this weekend

Ontario could see its first snowflakes of the season this weekend thanks to an incoming fall storm that could also bring a steep drop in temperatures and heavy winds.

According to The Weather Network's latest forecast, the storm could bring lake-effect snowflakes to parts of southern Ontario, and by Friday night, precipitation could shift to a rain-snow mix in the snowbelts and parts of Algonquin.

Although rain is expected to ease up across the province throughout Friday, local amounts could reach anywhere between 20 and 30 mm in parts of eastern Ontario. After the storm, strong northerly winds will cause temperatures to drop rapidly overnight, with some areas falling below freezing.

Toronto is expected to see a low of 2 C on Friday night into Saturday, but it will feel much colder at -3 C with the heavy winds.

"The sharp contrast between the incoming cold air and the relatively warm Great Lakes will fuel lake-effect rain downwind of Lake Huron and Georgian Bay," The Weather Network writes in its latest forecast, noting that some areas might see precipitation mix with snow overnight as temperatures continue to fall.

Still, the snow is expected to fall in areas with higher elevations, with other communities likely to see a rain-snow mix instead.

While parts of Ontario could get a brief taste of winter this weekend, the province's weather over the coming months could be influenced by a major climate pattern developing in the Pacific Ocean, referred to as El Niño.

The natural climate phenomenon is characterized by unusually warm ocean surface temperatures in the central and eastern equatorial Pacific, and usually occurs every two to seven years.

The pattern has the ability to alter global atmospheric circulation and can shift temperature and precipitation patterns around the world, including here in Ontario. In Toronto, the average date for the first snowfall of at least 0.2 cm in the city is Nov. 11, but during strong El Niño events, that date has shifted up to Nov. 3.

While the climate phenomenon does often bring an earlier taste of winter, the cooler pattern that tends to develop throughout the fall usually breaks down by the time winter rolls around.

December temperatures during strong El Niño years have averaged 2.6 C warmer than usual in Toronto.