A strengthening Colorado Low will bring a long-duration, widespread snowstorm to portions of British Columbia, Alberta, and Saskatchewan before lingering into Manitoba and Northern Ontario.
A weak low is expected to bring a snowstorm to the mountains of British Columbia and Alberta on Friday lasting through to Sunday. Strengthening into the weekend, on Saturday, a strong low is expected to form near the Wyoming/Colorado border before moving east towards Northwestern Ontario before phasing out and reorganizing into a low which will bring widespread rain to portions of Northeastern and Southern Ontario.
WESTERN PRAIRIES & SOUTHERN BRITISH COLUMBIA SNOWFALL TOTALS
Accumulations from the snowstorm will vary greatly throughout Southern Alberta/Saskatchewan with the heaviest accumulations throughout the mountains. Current guidance suggests snowfall totals will be highest between 30 and 60cm, locally higher towards 70cm+, in the extreme southwestern portion of Alberta throughout Waterton Lakes National Park towards Pincher Creek, where the extent of red is shaded in the forecast map. Isolated totals near 100cm may be possible. Along the United States border extending into the mountains, highlighted in pink, snowfall totals between 15 and 30cm are likely with pockets of snow towards 40cm possible throughout the mountains. The highest snowfall totals are due to the position of the low creating an ‘up-sloping’ event where the snow is driven up and into the mountains and foothills allowing for significant accumulations. Snowfall ratios in this region will likely peak around 10:1 (10 inches of snow for 1 inch of water).
Down the mountains into the foothills and into the Central-Northern Rocky Mountains, Purcell Mountains, and Northern Selkirks Mountains, snowfall totals will be limited to 10-20cm with local totals towards 20-30cm. This includes Banff and Cranbrook, as well as, this region is highlighted in purple on the forecast map. In Extreme Southern Alberta, outside of the foothills will likely see between 10-20cm of snow. This includes the City of Lethbridge extending towards the southeast, also seen in purple on the forecast map. The snowfall totals may significantly drop off outside of the mountains and foothill regions as temperatures on Saturday through to Monday across the lower Prairie regions will be within 2 degrees of 0, meaning, snow may change over to rain at the lower elevations. This would significantly limit accumulations. The temperature change would be most prevalent in Extreme Southeastern Alberta into Southern Saskatchewan. Snowfall totals in this region are expected to be between 5-15cm are likely, which can be seen in purple on the forecast map, and circled. If temperatures trend cooler for this region, 10-20cm wouldn’t be out of the question for Southern Alberta and Southwestern Saskatchewan, extending as far in to include Shaunavon. Snowfall ratios will peak around the 3:1 and 5:1 range.
A general 5-15cm, locally up to 25cm, can be extended throughout the Rocky Mountains from the Lake Lousie region northwest into British Columbia extending towards Fort Nelson, as well as the Southern Selkirks Mountains and portions of the Monashees and Cascade Mountains. This would include Jasper and Grande Cache. This is highlighted in dark blue on the map. Across Southern Alberta and Southwestern Saskatchewan, a widespread 5-10cm, locally 15-20cm can be expected, also highlighted in dark blue. This includes Calgary, Medicine Hat, Swift Current, Rockglen, and Penticton. Elsewhere in light blue, flurries are likely. Snowfall totals around 5cm with local totals to 10-15cm are likely around Kelowna and Vernon. Snowfall totals will range under 5cm with local pockets sticking up to 10cm for portions of Saskatchewan and Central Alberta. Generally, the snow will melt-on-contact for a majority of the event for these highlighted regions, including Red Deer, Regina, and Saskatoon.
Environment Canada has issued widespread special weather statements across Southern, Western and Central Alberta, as well as, portions of British Columbia. Winter storm watches have been issued ahead of the snowstorm for Pincher Creek, Waterton Lakes National Park, Canmore, Okotoks, Cardston, and Fort Macleod regions.
Weather alerts can be monitored on Environment Canada’s website: https://weather.gc.ca/warnings/index_e.html
MANITOBA & ONTARIO SNOWFALL TOTALS
As the snowstorm producing low-pressure system crosses east, bringing the precipitation with it, light to moderate showers are likely across Southern Manitoba, and most of Northern Ontario. Alongside these showers, a band of flurries to light snow will cross portions of Central/Northern Manitoba into Far Northern Ontario. Snowfall totals less than or near 5cm are likely due to the snow mainly being melt-on-contact. A few pockets across Southwestern Manitoba and into Far Northern Ontario may see local totals towards 10cm. The highest confidence for locally higher totals is circled in red.
BLOWING SNOW & STRONG WINDS
As the snow falls across the Southern Prairies, increasing wind speeds will bring the threat for hazardous traveling conditions in fast accumulating snow and falling snow. Current guidance suggests wind speeds will range from 30-50km/h across Southern Alberta and Southern Saskatchewan later in the day on Saturday extending through to Sunday morning. During the afternoon and evening on Sunday, winds will likely increase to 40-70km/h before 40-60km/h wind gusts settle in across Saskatchewan, Manitoba, and Ontario as the system weakens and phases out beginning mid-day Monday.
Blizzard conditions are possible.
Blowing snow and falling snow may make travel hazardous on Highway 1, 2, 3, and 4 across Southern Alberta and on Highway 1, 13, 18, 21, and 37 in Southern Saskatchewan.