Author: Brad

Brad lives in Winnipeg with his wife and two children and is the founder of A Weather Moment. He has loved weather from a very young age and has followed that passion through his life so far. He received a B.Sc. in Earth Sciences with Specialization in Atmospheric Sciences and is currently employed in the field of meteorology. You can find the author as WeatherInThePeg on Mastodon.

An Arctic Blast

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This week will feature the coldest weather so far this winter, which is probably about all you need to know.

850mb temperatures on Monday morning

As we come off Monday morning’s very cold low temperatures, daytime highs won’t be able to get very warm, with values in the mid minus twenties expected. When you factor in the wind chill it will feel more like the low minus forties on Monday morning and the mid minus thirties on Monday afternoon. As we move into Monday night temperatures are expected to plummet once again. Models have had significant difficulties figuring out what will happen by Tuesday morning. Models have shown lows as cold as -47C on Tuesday morning (obviously an erroneous value), or as warm as -28C. It seems probable that we’ll end up somewhere between those two extremes, with lows in the mid minus thirties most likely. It shouldn’t be very windy at all on Tuesday morning, so at least we won’t have a big wind chill to contend with as well. It looks like we’ll “warm” up a bit on Tuesday, with daytime highs in the low minus twenties expected.

We shouldn’t see extreme overnight lows again on Wednesday morning since a weak passing weather system will prevent temperatures from bottoming out. However, another arctic front is forecast to pass through Southern Manitoba during the day on Wednesday, setting up more very cold weather for late week.

Unfortunately, there are no indications to suggest that we’ll see a warm-up any time soon. That means we may be stuck with cold to very cold weather for the rest of January.

A Little Snow Before The Coldest Weather This Winter

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Two batches of snow followed by the coolest temperatures of the winter are in store for Southern Manitoba over the next few days.

Clipper Snowfall Totals

Forecast snowfall totals from this clipper system across Southern Manitoba.

An Alberta Clipper will begin it’s march across the Prairies today, rapidly moving from Northern Alberta east-southeast into Northern Minnesota by tonight. This system will drag a warm front eastwards across Southern Manitoba, spreading 1–2cm of light snow across the Red River Valley. The snow will ease off this afternoon to just scattered light flurries as the weak leading impulse moves off into NW Ontario.

Temperatures will warm to around –8°C by this afternoon, with the warmer daytime highs near 0°C locked into the extreme SW portion of the province. A second shot of snow will push into the Red River Valley tonight as the main low centre of the Alberta Clipper moves through the region. Temperatures in the RRV will rise to –4 or –5°C by midnight before starting to drop as the cold front moves through. The bulk of the snow will start near midnight and taper off on Saturday morning with a further 3–5cm of snow accumulation for a total of 4–7cm by the time this whole system moves through.

A few flurries will be around on Saturday as Arctic air begins building into Southern Manitoba yet again. Fairly strong northerly winds gusting up to 60–70km/h will develop early Saturday morning which will result in significant blowing snow in the RRV outside the City of Winnipeg. “Ground blizzard” conditions will be relatively widespread, with particularly poor visibilities as low as 100–200m on west-east running roads, such as the Trans-Canada Highway from Winnipeg to Portage La Prairie. Given the already slick conditions of many roads around the province, be sure to give yourself plenty of extra time if you need to travel on Saturday. The winds will lighten up by mid-afternoon, marking the start of our entry into a major deep freeze. Bitterly cold Arctic air will be pushing southwards behind this clipper system, with temperatures falling to around –25°C by the end of the day. Temperatures will plummet tomorrow night, with overnight lows through the Red River Valley dropping to the –30 to –35°C range. Temperatures will rebound slightly on Sunday as a weak disturbance brings some cloud and a chance of a flurry or two, but even colder air looks to be pushing in on Sunday night.

If the models are to be believed (which I do have some hesitation at the moment), temperatures will drop through the day on Monday to nearly –30°C by the end of the day, with overnight lows dipping to nearly –40°C. I think that the models are getting a little too excited about how cold it will get. The GEM-GLB model’s overnight lows have been 5–6°C too cold over the past week, so it’s more likely that we’ll see lows closer to –35°C than –40°C. At that point, though, it’s colds enough that those numbers don’t even matter. It’s certainly going to be an extremely cold start to next week.

A Cold Second Half to the Week

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Winnipeg will round out the second half of the week with some sun, some cloud, and and very cold temperatures.

Gonna be cold!

You might want one of these for the next little while…

On the backside of yesterday’s system that brought a quick 2–3cm of snow to Winnipeg, a deep pool of bitterly cold Arctic air is infiltrating southwards into the Red River Valley. With sunny skies and a breezy north wind, temperatures will plunge back below the –20°C mark today, bottoming out early this afternoon around –23 or –24°C. Winds will (mercifully) ease off around lunch time, which will minimize wind chill. Temperatures will drop further tonight, with overnight lows dropping below –30°C entirely possible through the Red River Valley, although Winnipeg will likely bottom out at “only” –28 or –29°C.

850mb Temps Thursday Morning

850mb temperatures for Thursday morning from the GFS model. A sharp boundary will slice across the Prairies with pleasant, mild air over the southwestern half and bitterly cold Arctic air over the northeastern half.

Thursday will bring another cold day with plenty of sunshine. The daytime high will struggle to reach –22°C with a light wind out of the south that will increase to around 20km/h by the end of the day. This will keep things feeling closer to around –27 or –28 for much of the day. Proving that the weather can be merciful at times, clouds will begin to roll in Thursday night ahead of the next push of warm air from Alberta. The timing of the cloud cover will strongly impact what the overnight low will be; the sooner the clouds move in, the warmer the overnight low is. At this point, it looks like the temperature will bottom out around –25°C.

Why do clouds impact overnight lows? Clouds can make a big difference for two reasons. First, they act like a big blanket; as the ground radiates heat upwards and cools off, instead of escaping off into the upper atmosphere, it is trapped closer to the surface. This dramatically slows the rate the temperature will cool off. Secondly, clouds radiate heat, generated through internal processes and absorption of the energy the surface is releasing, towards the ground. This also helps to slow down how quickly the temperature drops, or in some cases, even warm it up a little.

On Friday we’ll be under the influence of the next impulse coming across the Prairie. While we won’t get to see the warm air with this system, it’s proximity to us will at least warm us up to around –13 or –12°C. There will likely be periods of light snow across most of the Red River Valley with 2–3cm accumulations likely by the end of the day.

Light snow will persist through the night into Saturday morning. Saturday will bring with it gusty northwesterly winds as things clear out and that bitterly cold Arctic air re-establishes itself over the region. Up to another 2–3cm are possible on Saturday before things clear out. Sunday looks to be sunny and very cold, with daytime highs near –24°C.

Alberta Clipper to Bring More Snow This Week

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An Alberta Clipper will bring more snow to Southern Manitoba this week. The system will also bring moderating temperatures, followed by another arctic blast.

Map of Tuesday's Alberta Clipper System - NAM Model

Before the Clipper arrives on Tuesday, we’ll see cold weather again on Monday. High temperatures on Monday will be in the high minus teens with light winds. A southerly flow will begin to develop over Manitoba on Monday night ahead of the next low pressure system. The south wind will become quite strong during the day on Tuesday, with wind speeds of 30-40km/h gusting to 50-60km/h in most areas (except in the Red River Valley where speeds may be a bit higher than that). These strong south winds will bring in much warmer air, with highs on Tuesday likely to be in the low to mid minus single digits in most areas. The Alberta Clipper is expected to begin spreading snow into Southern Manitoba on Tuesday afternoon. Areas in western Manitoba can generally expect 2-4cm of snow, with lower amounts the further south you go. In eastern Manitoba the highest amounts are expected, with total accumulation of 4 to 8cm expected (with higher amounts the further north you go). In the Red River Valley generally 2-5cm is expected, with Winnipeg and Selkirk having the best chance at higher end amounts. As the clipper moves past on Tuesday night, north-westerly winds will develop. These winds will be fairly strong, with readings of 40km/h gusting to 60km/h expected. This will generate blowing and drifting snow in open areas on Tuesday night. Blizzard conditions are not expected, but poor road conditions are still probable.

Models are suggesting that we may see another weaker Alberta Clipper pass by on Wednesday. At this point it’s too early to say exactly how much snow it will produce, but it has the potential to produce amounts similar to those experienced on Tuesday.

Beyond Wednesday it’s hard to tell what will happen next. It appears that Southern Manitoba will be right near the boundary between very cold arctic air to the north and somewhat milder air to the south. If this boundary ends up a bit further south than expected we’ll be firmly placed in that arctic air mass, but if the boundary is further north than expected we may get into the milder air. More weak Alberta Clipper systems are forecast to ride along this arctic boundary, so our position near it suggests we may see more light snowfall events later this week.