Prairie Weather (Rural Roots Canada) – An outbreak of cold arctic air sends temperatures plummeting this weekend.
The Polar Vortex!!!
It’s about to get a whole lot colder on the prairies, especially in Saskatchewan and Manitoba, but Alberta won’t be entirely left out. And, this time, it can be properly blamed on, or credited to, the Polar Vortex. It has taken an elongated shape, allowing for something called a cross-polar flow. As the map below shows, cold Siberian air is flowing across the north pole, directly into North America, especially the eastern Canadian prairie and the midwestern US:
The map is showing the flow way up at the top of the atmosphere. All this bitterly cold air could produce wind chills in the -40s from eastern Alberta across to southern Manitoba by Monday morning. Fortunately, this is a dynamic pattern, and the cold outbreak we’ll experience this weekend won’t last long. Unfortunately, it’s not going to bring much in the way of beneficial precipitation.
Thursday
Alberta
The Haida Gwaii Low that’s expected to push snow into the Jasper area Wednesday will quickly cross northern BC, and redevelop Thursday in east central Alberta. It will bring a swath of significant snow (15 to 25 cm) in a line from High Level southeast to Saskatoon, Saskatchewan. A front produced some snow Thursday morning through central Alberta. That has now dissipated, but strong wind can be expected to continue. Southern Alberta (where snow is badly needed) will stay dry, but the wind in southeastern Alberta will pick up late in the day and into the evening. The evening wind could cause blowing snow in those areas where loose snow is on the ground. Further south, it will be dry, windy and warm, with double digit highs possible along the foothills. Elsewhere in the south and south-central regions, highs should reach 0 to 5 degrees. Because of the changing weather pattern, this is the last day of the warm spell.
Saskatchewan
A low tracking across Alberta early in the day, plunks itself over central Saskatchewan in the afternoon. North of the low, expect a relatively narrow band of snow from Meadow Lake southeast, all across the province to Yorkton. The heaviest snow within that swath can be expected north of Saskatoon toward Prince Albert. South of the Low, in southern Saskatchewan, a westerly wind will continue to produce dry weather, with highs again climbing above zero, especially in southwestern Saskatchewan. East of Moose Jaw, highs will likely peak between 0 and -5.
Manitoba
A Low in Saskatchewan will stretch a weak warm front into southern Manitoba, so light snow can be expected in the southwestern part of the province by early afternoon, expanding to the rest of southern Manitoba by evening. We’ll get another warm day out of this, with highs in southern Manitoba ranging from 0 to -5, -5 to -10 in central Manitoba, and up north, highs of -10 are possible.
The animated map below shows the invasion of Arctic air expected from Friday through Sunday. The first frame in the animation shows temperatures expected midday Friday. The last frame shows temperatures expected Sunday in the late afternoon. Note the very cold conditions expected in eastern Alberta and western Saskatchewan this weekend, with temperatures in the -30s on Sunday:
Friday
Alberta
The weather pattern changes, and it gets colder. And snowier. At the surface, an Arctic high develops in the Territories, northwest of Alberta. The wind in Alberta shifts from the warm west to the cold north, and with that change in the weather pattern, there will be snow across most of southern and central Alberta. Light snow will fall through most of the day, peppering Alberta’s agricultural lands with some much needed moisture. As the northerly flow takes over during the day, we can expect a reverse temperature trend for Alberta. In other words, it will be warmer in the morning than in the afternoon, when temperatures will fall to between -5 and -10. In Northern Alberta, highs will be closer to -20.
Saskatchewan
The warm spell is over, and most of Saskatchewan will fail to warm any higher than about -15. Like Alberta, there will be a reverse temperature trend, as it gets colder in the afternoon than in the morning. Morning temperatures will start out near -15, and by the afternoon, it’s closer to -20. Arctic air returns, and along with it, some snow, which will fall in central and southern regions through the day. It will be light snow, so there will be little accumulation on top of the heavier snow that fell Thursday.
Manitoba
Manitoba’s exposure to warmer air this week was all too brief. Friday, cold weather returns, with temperatures remaining below -10. A low passing across the interlake will bring snow to south central Manitoba,, and indications are it will be accompanied by a strong wind. Travel in the region Friday morning is likely to be disrupted by blowing and drifting snow, and a high wind chill. The storm system is moving quite fast, and conditions should improve in the afternoon.
Saturday
Alberta
Arctic high pressure covers the province by Saturday afternoon, and the light snow expected in southern and central Alberta Saturday morning will be quickly pushed off to the south. As the Arctic high moves in, the sky will clear, and there will be afternoon sunshine. Don’t be fooled by the sun. This is an arctic air mass, and it will be cold, especially east of highway 2, where temperatures are likely to hover in the low to mid minus 20s during the day. West of highway 2, temperatures will peak in the minus teens.
Saskatchewan
Mid afternoon temperatures will fall to the mid minus 20s, as the Arctic high moves in. Earlier in the day, there will be scattered snow bands in southern Saskatchewan, but as the high moves in, the snow moves out, and at the end of the day, there will be little new snow on the ground. Cold weather is the big story in Saskatchewan on the weekend….animals ought to be sheltered indoors where possible, and vehicle batteries will need to be kept warm.
Manitoba
Any lingering clouds in southern Manitoba will clear out, as very cold Arctic air circulates into the province around a surface high stretching from southern Alberta all the way to Victoria Island in the arctic archipelago. All day, temperatures will linger in the -20s, with wind chills in the -30s. No significant snowfall is expected, or, for that matter, even possible.
Sunday
Alberta, Saskatchewan, Manitoba
On Sunday, the arctic high is centered over Medicine Hat, clearing out the sky all across western Canada from Vancouver Island to Ontario. All three prairie provinces will be dry, and all three will be cold, especially from southeastern Alberta all the way into northwestern Ontario and beyond. The map below shows afternoon temperatures across the prairies. Southern Alberta won’t be quite as cold as the rest of the prairies, where, even in the afternoon sun, temperatures will be planted in the -20s.
