It’s no secret that spring can be a tumultuous time for the Canadian climate, and as an unusually mild winter with El Niño gives way to summer, there are bound to be some temperature swings that seem out of the ordinary.
However, from Ontario to the Atlantic, this week is about to get a little erratic.
Forecasts show that as a mix of weather systems move east from the Prairies in the coming days, Ontarians can expect to range from temperatures as low as below zero to well into the 20s.
Meanwhile, parts of Newfoundland and Labrador could experience freezing rain and snow this week, as the leading edge of the system brings storms across Atlantic Canada.
As of Wednesday, Environment Canada has issued freezing rain. alerts along the east coast from Great Harbor Deep, Newfoundland, north to Cape Porcupine, Labrador. Further north, in the Postville and Makkovik area, a snow advisory is in effect.
As for Ontario, Toronto and the Niagara and Windsor-Essex-Chatham-Kent regions are under frost advisories overnight Wednesday into Thursday morning, warning residents to protect their frost-sensitive plants and trees. For the weekend, temperatures are expected to rise sharply, with Windsor and Toronto at 24 and 22 degrees, respectively, on Sunday.
“It’s a bit of a complicated pattern; there’s a lot going on,” Jennifer Smith of the Canadian Weather Service said in an interview with CTVNews.ca on Wednesday. “[As is] “It’s typical of the climate, all these things are related.”
Smith said the peculiar combination of conditions may be related to a low pressure system that has been churning over Hudson Bay for weeks, pushing colder temperatures south and east into Ontario and Quebec.
At the edge of that cold zone is a jet stream that is expected to bring storms that will dump significant rainfall on Newfoundland and Labrador. As colder air moves east over the weekend, warmer air from the Prairies is expected to spread across southern Ontario.
But as varied as the conditions may seem, Smith points out that they shouldn’t be taken as especially strange for the season.
“This is business as usual,” he said. “It’s a very changeable time of year… we’re seeing active weather, followed by cold and warm periods, alternately… spring is quite active, like that.”
El Niño weakens
This spring follows an unusually warm winter, in which the erratic weather phenomenon known as El Niño caused regular cold weather patterns to fade, if not completely alter.
In fact, the 2023-24 season marked One of the most pronounced El Niño impacts on record.according to the World Meteorological Organization [WMO].
But as the months go by, experts say the El Niño period, which can often last up to 12 months, has passed its peak.
“It is now gradually weakening, but will continue to impact the global climate in the coming months,” reads a March update from the WMO. “Above-normal temperatures are forecast for almost all land areas between March and May.”
The organization notes that El Niño has a 60 percent chance of persisting until May, but that between April and June, there is a four in five chance that the global climate cycle will move to more neutral conditions. The WMO predicts a possible shift later this year towards La Niña, an opposite phenomenon that causes colder temperatures in much of the world.
Smith says that when it comes to these types of patterns, it can be difficult to make concrete predictions.
“It’s hard to say how that will affect Canada going forward during the spring season,” he said. “There are many things we still don’t know.”
With files from Megan DeLaire