Fog, rime ice dominate stagnant Prairie weather pattern

Saskatchewan is caught in a rinse-and-repeat weather pattern.

Day after day there has been cloud cover, fog and rime ice on trees.

For some, it's a beautiful winter paradise. For other, the days are gloomy and drab.

Here's what's causing this pattern.

The upper atmosphere is controlled by the jet stream, a narrow band of fast-moving air that is wrapped around Earth. It generally separates warm air to the south from colder air to the north.

Usually, the jet stream bevels and bends as it makes its way around the world, but it has been unusually straight this past while. This straightness — also known as zonal flow — prevents warm air from being pulled north and arctic air from being dragged south.

With the overall flow of the atmosphere nearly stalling as a result, temperatures have stayed relatively consistent day after day.

The jet stream has also placed itself south of Canada, which has allowed consecutive storm systems to ride it and slam into states like California and Nevada.

The surface of the atmosphere has also been eerily quiet. This time of year low pressure systems usually pass by, bringing snow and wind. But with a lack of those systems, there's been nothing to "mix up" the atmosphere.

This stationary pattern has allowed a temperature inversion to form.

"Generally, when you go up through the atmosphere from the surface … the temperature cools," said Terri Lang, a meteorologist with Environment and Climate Change Canada. 

"In the case of an inversion, the temperature actually warms up [as you go higher]."

The inversion creates a sort of cap on the atmosphere near the surface, trapping everything inside.

"All the moisture, be it from open lakes or open rivers — we've [also] got sources of heat and moisture from industries and cars — that all gets trapped under the inversion," Lang said.