Southern Manitoba will see its third clipper-like system of the week, with a very fast moving low-pressure system descending out of Saskatchewan Thursday night.
“It’s been active week as we transition out of this long stretch of well above average temperatures to what is looking likely to be at least seven to ten days of very cold conditions for this time of year,” said CMOS Accredited Weathercaster Chris Sumner. “The best way to describe how this Alberta clipper will move through the region would be ‘blast’, because it is moving at a very good clip, and will pack a strong punch for a relatively short period of time starting late tonight.”
Snowfall began in southwestern Manitoba Thursday afternoon, and will progress eastward throughout the remainder of the day, with the expectation that by late afternoon or early this evening flakes will be falling in much of the region.
“We’re not expecting a lot of snow, more than likely similar figures to Tuesday’s clipper, which brought up to 5cms in most locations,” he added. “We could see slightly higher amounts, but not significantly more. The real story over the next twenty-four hours will be the wind, and how severe of a blowing snow event we may see.”
Ahead of the system’s arrival, southerly gusts up to 60 km/h will be possible, shifting northwesterly as the low’s cold front passes through.
“On the backside of this low we’ll see winds subside for a bit, and then late tonight and overnight into Friday, they will pick up quickly, gusting up to 70 km/h,” noted Sumner. “The strongest gusts are projected to be within the Red River Valley.”
It’s a pretty easy equation, strong winds plus light fluffy snow will mean blowing snow for a period of time late tonight into Friday morning.
“The potential is there for significantly reduced visibility, especially in the open areas of the Red River Valley,” said Sumner. “That area south of Winnipeg with Brunkild, Winkler, Vita and Steinbach forming the for corners is where I would suggest the highest potential is for brief periods of visibility of only a few hundred meters or less.”
Environment Canada issues Blowing Snow Advisories when when blowing snow, caused by winds of at least 30 km/h, is expected to reduce visibility to 800 metres or less for at least 3 hours.
“Whether we’ll see any of those issued tonight will be dependent on just how long those very strong winds are projected to last,” he said.
Friday will mark the beginning of a dramatic downward plunge in temperatures, as arctic high pressure builds behind the aforementioned low, allowing a lobe of the Polar Vortex to sneak southward and settle in for an extended period of time over Western Canada.
“We’re talking seven to ten days of temperatures well below average,” stressed Sumner. “At this point, it’s looking like through the end of January and the first weekend of February is the timeline for the really cold conditions. Some of the long range forecast models are suggesting we could see a little moderation to warmer temperatures after February 4th or 5th, but it could be short lived before another round of chilly weather.”
Average daytime highs for this time of year are -11, with overnight lows of -20. From Saturday through early February, highs are expected to range between -19 to -23, with overnight lows nearing or dipping below -30.