If you live in or east of Manitoba, don't put away your winter jacket and toque just yet.
A polar vortex is forecast to hit parts of Canada this week, bringing below-seasonal temperatures to a number of provinces on the heels of a relatively mild winter.
"At least initially, that push of cold air will influence Manitoba," says Geoff Coulson, a meteorologist with Environment Canada.
Coulson says the chilly system will move eastwards during the first week of April, travelling through Ontario, Quebec, and ultimately into Atlantic Canada.
In Toronto, Coulson forecasts Monday's high temperature to be 0 C, well below the normal seasonal high temperature of 8 C. In Montreal, Coulson forecasts a high of -4 C on Sunday, compared to a regular seasonal high of 7 C.
"So these are quite significant departures from normal," says Coulson.
Coulson expects colder-than-normal conditions to move into Winnipeg starting early Friday, reaching Ontario and Quebec between Sunday and Monday, and moving to the Maritimes by Monday and Tuesday.
Chilly blast after a warm winter
"For many Canadians, this winter was defined by an El Nino weather pattern, which brought warmer-than-normal weather," says CBC meteorologist Jay Scotland.
Due to a polar vortex, Scotland says, the temperatures in the first few days of April in Central and Eastern Canada will be "winter-like."
MULTIMEDIA What is a polar vortex?
Scotland says temperatures could drop to a few degrees below freezing this weekend, as much as 10 degrees lower than the seasonal average.
The colder-than-normal temperatures could persist beyond the first week of April, he says, and there may be a chance of snow.
Scotland advises folks who may have already done a bit of gardening to cover up their plants in the coming days, and he suggests drivers hold off on changing their winter tires, noting the possibility of snow creating "messy, winter-like road conditions."
Arctic air moving south
A polar vortex is a large circulation or cyclone of cold air usually from the Arctic or North Pole that makes its way farther south when a jet stream — or "ribbons of fast-moving air" that divide northerly cold air from southerly warm air — fluctuates, says Scotland.
"Imagine jet streams as a skipping rope," he says. "If you give it a wiggle, you will see a ridge or a trough, which work down the rope with a wave."
Scotland says those troughs "open the door" for the cold Arctic air to make its way south, which in turn causes the mercury to dip.