Chilly Valentine’s Day forecast with highs close to -20 C

Thursday will bring a brief period of moderation across southern Alberta before most of the country plunges into frigid temperatures once again.

The forecast high of -9 C in Calgary for Thursday will be one of the warmest temperatures since the start of the month.

According to the public data from Environment and Climate Change Canada, the daytime highs in Calgary between Feb. 1 to Feb 12 have been in the minus double-digits nine times (-10 C to -22 C) and in the minus single-digits three times (-7 C to -9 C).

This is compared to the normal range of daily highs of -2 C at the start of the month to 0 C Feb. 12.

There has been a relatively stagnant weather pattern allowing Arctic air to funnel across Canada and into portions of the continental United States.

The Arctic polar vortex – a strong and tight low pressure system which sits along the northernmost pole of the planet in the upper levels - has strengthened, expanded, and has been riding a low-riding jet stream recently, with the centre often meandering south toward the Great Lakes.

A low pressure system along the Oregon coast will start to track east over the next 24 hours bringing some snow to southern Alberta and opening things up for colder air to return.

From early Friday to midday Sunday, the temperatures in Calgary will likely hover around -20 C and colder.