Source: Justin Li, CBC News, March 30, 2016
Below-seasonal temperatures could persist beyond 1st week of April, says CBC meteorologist
If you’re in Eastern or Central Canada, don’t put away your winter jacket and toque just yet.
A polar vortex is forecast to hit Ontario later this week before moving through Eastern and Central Canada, injecting below-seasonal temperatures into the region on the heels of a relatively mild 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.”
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.