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The Western Star

WEATHER U: Pondering the polar vortex

The polar vortex has been known to become displaced - sinking southward - taking a bitter blast of winter with it.  - WSI graphics
The polar vortex has been known to become displaced - sinking southward - taking a bitter blast of winter with it. - WSI graphics

Remember the polar vortex? In the first two weeks of 2014, much of the continent weathered a cold snap of unprecedented proportions. A weather phenomenon known as the “polar vortex” shattered temperature records on both sides of the border.  

While we’ve not yet had to deal with sustained cold, average temperatures across all of Atlantic Canada have been below normal since early November and people are starting to ask if we should be worried about a repeat of 2014.

Here’s a refresher: the polar vortex is a swath of bitterly cold, dense air, in the middle layer of the Earth’s atmosphere – called the stratosphere. It sits about 32 kilometres above the Earth's surface. The vortex affects daily weather when it drops down into the troposphere, the lowest layer of the atmosphere. When the vortex is stable, winter conditions over Canada, the United States and Europe tend to ordinary. But when the vortex is disrupted, an ordinary winter can suddenly turn severe and memorable for an extended duration.

The unstable polar vortex is back, and it appears ready to deliver a brutal winter to the northeastern corner of the continent, at least for the next several weeks – and maybe longer. However, we should keep in mind that the vortex behaviour can be fickle and predicting the vortex is still a new and inexact science. Stay tuned.

P.S., I got snowshoes for Christmas. Santa must know something.

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