After Manitoba gets brief reprieve this week, ‘you can expect to be cold a lot of the time’: weather expert

It’s hot, then it’s cold, then hot again – or hot for Winnipeg in January, anyway.

But the temperature swing in southern Manitoba this week is more typical than residents might think.

“These big temperature swings are actually pretty normal for Winnipeg in the winter,” said Alex Crawford, an assistant professor of environment and geography at the University of Manitoba.

Although it’s not quite June in January, Winnipeg is expected to reach a high above freezing of 1 C on Wednesday, after reaching a high of just -19 C on Tuesday (–30 with wind chill, according to Environment Canada).

“I think what might feel a little bit different right now is that just with a little push of global warming, the really hot days, the hottest days, are warmer than they used to be,” shared Crawford to host. Marcy Markusa in a Tuesday interview with CBC’s Information radio.

“When you cross the line of whether something is at freezing or not, we really notice.”

Fluctuations occur because of waves in the polar jet stream, the river of fast winds high in the atmosphere, Crawford said. That air moves about 200 kilometers per hour and separates the cold Arctic air north of the city from the warmer air to the south.

“So any time the polar jet stream has a big ridge in it and that ridge comes over Winnipeg, we’re going to get warmer than normal in the winter,” Crawford said.

When there is a trough in the polar jet stream, southern Manitoba is exposed to a pocket of cold northern air and experiences colder temperatures, he said.

“So what’s happened right now, and back in December, is there are these big ridges and troughs, these big waves in the polar jet stream, and they’re leading to these fairly rapid shifts between colder and warmer.”

As for what’s to come, weather experts typically look at what’s happening in the Pacific and Atlantic oceans to gauge what winter temperatures will generally be like for the prairie town, Crawford said, but that’s a challenge this year.

“If you looked at the Pacific Ocean, you’d say we should be a little bit colder than normal this year. But if you look at the Atlantic Ocean, which also affects Winnipeg, you’d say we should be a little bit warmer than normal this year ,” he said.

“This year is a very difficult year to predict for Winnipeg… The best I can say is you can expect to be cold a lot of the time.”