Warmer Westerly Flow keeps Unsettled Skies into the Weekend

Canadian Rockies Daily Snow

Heads up, there may be fresher snow! Read the latest Canadian Rockies Daily Snow

By Bob Ambrose, Forecaster Posted 1 year ago February 2, 2023

Summary

A short-lived ridge of high-pressure builds in for Thurs and Fri warming things up considerably. A westerly, or zonal flow aloft blows in a weak system on Fri night that looks to drop light accumulations for the resorts Banff north to Jasper through Saturday. Cloudy Sunday with isolated flurries and trace amounts with slightly higher accumulations possible on Monday, mainly north of Banff.

Short Term Forecast

Below: Looking westward into the BC Rockies from the top of Standish chair at Sunshine shows dark skies semi-clearing as high-pressure builds across the Rockies.

Thursday: Reported 24-hour fresh snow totals on Thursday morning: 5cm Sunshine, 6cm Lake Louse, and 5cm Marmot Basin. Webcams Thursday morning indicated flurries still falling at Marmot, with clouds starting to clear at Sunshine and Louise. Transient high-pressure builds across the Rockies on Thursday bringing a mix of sun and cloud to most resort locations, with isolated flurries at Marmot Basin. Gusty W/SW winds in the moderate category (stronger w/gusts to 60 kph at Castle) will keep the warming trend going with alpine highs at 2200m ranging from -4C at Castle, to -8C at Louise.

Friday: As a westerly flow has developed over Western Canada, Pacific moisture will be transported over the Divide as a leeside low in northern Alberta aides in the process. This system will also have a warm component to it with freeze levels rising as high at 1300 to 1600m across the range. Look for a mix of sun and cloud to start Friday across the Rockies with increasing cloud (mainly the mountains Banff north to Jasper) by the afternoon hours. Trace accumulations are possible Sunshine north to Marmot Basin. Strong W/SW winds are likely Friday on wind exposed passes and ridgetops. Continued mild with alpine high temps (2200m) of -3C to -7C.

Saturday: Flurries continue overnight on Friday under a moist westerly flow with trace accumulations up to 5cm on west facing slopes at Sunshine, Louise, and Marmot Basin by Saturday morning. Trace accumulations are slightly possible to the south at Castle Mountain. Look for isolated flurries to continue at the SkiBig3 resorts north to Marmot Basin during the day on Saturday as bits of moisture embedded in the westerly flow move through. Trace accumulations up to 3cm are likely. For Nakiska, and the resorts of the South Rockies (Castle Mountain, Powderkeg) mainly a sun and cloud mix with a stray morning snow flurry. Moderate west winds continue across the ridgetops and exposed passes, except in the strong category at Castle Mountain. Continued mild, with alpine highs reaching -2C at Castle, Powderkeg, and Nakiska, with -3C to -5C at the SkiBig3 resorts and Marmot Basin.

Sunday: A zonal flow of mild Pacific moisture will continue to sputter out into light flurries on Sunday as moisture gets wrung out along the Divide. Sunday looks to be mainly cloudy with isolated flurries north to south along the Alberta Rockies. Best chances of accumulating snow in the trace to 3cm range will be (once again) at Sunshine, Louise, and Marmot. Temps will stay slightly above seasonal norms under this zonal flow on Sunday. Moderate W/SW west winds up top.

Monday: A deepening trough of low-pressure will help transport a Pacific shortwave through mainly the north half of the region on Monday. Chances of accumulating snowfall have increased in day-to-day model runs recently, especially for the mountains/resorts along the Divide from Banff north to Jasper. Still a bit to figure out on amounts but it does look promising. Expect gusty west winds to continue along with mild alpine temps.

Below: High resolution Canadian model for snowfall from Friday morning 2/3 through Saturday morning 2/4 shows light accumulations to 5cm along the Divide, mainly north of Banff.

Extended Forecast

For the period Tuesday 2/7 through Thursday 2/9, a deeper and more organized Pacific low-pressure system looks to bring chances of significant snowfall (up to 20cm) for the Tuesday night through Thursday morning time frame. This is followed by a building ridge on Thursday PM into Saturday 2/11. Temps look to stay just above seasonal averages through the extended period.

Below: The GEM (Canadian) model for the period Friday 2/3 through Friday 2/10 depicts an active westerly flow over Western Canada quite clearly. The only problem is that the majority of these systems lose most of their moisture in BC. Still, areas to the north of Banff will continue to see light accumulations with the best chance for deeper accumulations on next Wednesday 2/8.