A strong Arctic ridge has brought the coldest weather so far this winter into the province. Temperatures will be well below seasonal[1] for much of the coming week.
Monday
-21°C / -31°C
Sunny
Tuesday
-23°C / ⇑ -18°C
Mainly sunny
Wednesday
-12°C / -22°C
Mixed to cloudy skies
Today’s post will be a relatively brief one since there simply isn’t much weather to talk about. Today and tomorrow will both be very cold days with highs not even hitting –20°C under mainly sunny skies. Tonight will bring lows dipping below the –30°C mark and winds at 10–15km/h creating wind chill values near or just below –40.[2] Tomorrow night will be quite a bit different, though, as an approaching low pressure system brings increasing cloud and climbing temperatures. By Wednesday morning, skies should be mixed to mainly cloudy with temperatures near –18°C. Through the remainder of Wednesday we should continue to see mixed to cloudy skies with temperatures climbing to around –12 or –11°C. There’s a slight chance for some flurry activity, but in general temperatures look a bit on the cool side for the kind of snow that would be possible. Skies clear on Wednesday night as temperatures drop into the –20 to –25°C range.
New Year, Same Story
Despite the promise of a new year beginning on Thursday, the story will be one we’ve heard before: a return to the deep freeze.
The NAEFS shows a high probabilty of below-normal temperatures next week.
Another shot of bitterly cold Arctic air will begin working its way into the Prairies through the latter half of the week, with daytime highs dropping from the low minus teens into the –20 to –25°C range by the weekend. Overnight lows will follow suit, also dropping through the week and likely dipping below –30°C by the weekend. Little to no snow is expected. The exceptionally cold weather is expected to persist into next week.
Seasonal daytime highs for this time of year in Winnipeg sit near –12°C ↩
–40 is Environment Canada’s threshold for extreme cold warnings, so we may see Southern Manitoba once again blanketed in warnings this afternoon. ↩
As we mentioned on Wednesday, a big cool-down is underway across Southern Manitoba. While we knew earlier that it was going to get cold[1], it’s beginning to become clear that it’s going to get quite a bit colder than that. Just how cold? Winnipeg might see daytime highs in the near future not seen since last January.
Friday
⇓ -13°C / -17°C
Cloudy with sunny breaks; chance of flurries
Saturday
-16°C / -26°C
Mainly cloudy with some flurries
Sunday
-21°C / -28°C
A few clouds
Today will be the coolest day in a little over a week as temperatures will slide towards –13°C by the end of the day. Skies will start out cloudy then gradually become more mixed through the day. With favourable temperature profiles, some patchy non-accumulating light snow is possible. Winds will be out of the northwest at around 15–20km/h. Temperatures will drop to near –17°C tonight.
Daytime highs will drop on Saturday to just –16 or –15°C with mixed skies. Some flurries or light snow is expected as a system slides from Saskatchewan into North Dakota, but amounts aren’t expected to be much more than a skiff at most. Temperatures will drop into the mid-minus 20’s on Saturday night.
Sunday will be a downright cold day a few clouds around. Highs will sit near –20°C through the Red River Valley and winds will be light. Expect lows dipping close to –30°C on Sunday night.
Cold Start to Next Week
The GDPS forecast shows Southern Manitoba embedded in a deep cold trough on Monday afternoon.
Next week will begin with a substantial trough of cold air positioned over Southern Manitoba that will bring daytime highs in the mid-minus 20’s through the first half of the week. There may be a mid-week warm-up, but a return to colder weather would follow quickly behind. No big storms are on the horizon, so in general expect cold, dry weather to persist through the next week.
On Wednesday’s post, we surmised that daytime highs would generally be near –20°C. ↩
After a prolonged period of temperatures some 10 to 20°C above normal, Winnipeg & the Red River Valley is set for a rude awakening after Christmas as Arctic air plunges southwards and brings below normal temperatures to the region.
This graph of the daily average temperature compared to normal illustrates the dramatic warmth Winnipeg has seen in December.
The crash to colder temperatures will be exceptionally jarring considering the abnormal warmth we’ve seen through much of December. Leading up to Christmas, mild weather will persist as an incoming low pressure system helps extend the stay of the warm air that’s been so common the past few weeks. As the system passes on Christmas Eve, though, a major pattern change is set to take place as our fairly weak is absorbed into the rather major East Coast “Santa Bomb” which in itself will induce a shift to the gradual re-establishment of the Polar Vortex over Hudson Bay.[1]
Christmas Eve
Wednesday
-3°C / -6°C
Cloudy with evening flurries
Today will be a pleasantly mild day with highs near –3°C through the Red River Valley and winds developing out of the south to around 20–30km/h. Skies will remain mainly cloudy in advance of the incoming low pressure system with some flurry activity finally pushing into the Red River Valley by late in the afternoon and reaching Winnipeg by evening. Little is expected as far as accumulations go; the main accumulating snowfall will remain north of the Trans-Canada corridor through the Parkland and Interlake regions eastwards into Ontario where around 2–4cm are expected.
Temperatures will drop to around –6°C tonight with winds shifting to the west-northwest at around 20km/h.
Freezing drizzle will once again be possible overnight into Christmas morning as saturated low-levels are left behind the departing low pressure system. Steep low-level lapse rates and only a relatively light wind from the NW may result in another batch of road-slicking freezing drizzle. Due to its nature, freezing drizzle requires a fairly delicate balance of factors to exist, so there will be unavoidable uncertainty until later tonight, but keep in mind that it is a distinct possibility.
Christmas Day
Thursday
⇒ -5°C / -12°C
Mainly cloudy with scattered flurries
Christmas Day will be a mixed bag in Winnipeg. Temperatures will remain above-seasonal, but the push of cold air will already have begun. As a result, temperatures will likely remain steady near –5°C as any potential daytime heating is offset by the cooler air moving in. Freezing drizzle is possible through the morning hours, while flurries are more likely through the afternoon.[2] Skies will remain mainly cloudy, although a brief glimpse of sunshine is possible.
Temperatures will head down to the –12°C mark or so overnight with a continued chance for flurries and gradually diminishing cloud.
Boxing Day
Friday
⇓ -16°C / -24°C
Mixed skies with a chance of flurries
Boxing day will be when the real surge of Arctic air begins pushing in. Expect mixed skies with a chance of flurries through much of the day. Temperatures will drop through the day to around –16°C by evening. Skies should clear out overnight as the Arctic ridge begins moving in and temperatures drop to around –24°C. This will be the coldest overnight low we’ve had since November 30th into December 1st when the temperature dipped to –27.1°C. Given that the normal overnight low for this time of year is –22°C, that’s not too bad.
Cold Pattern Persists
The cold weather will be here to stay for a while as a persistent northwesterly flow develops over the province thanks to gradually establishing polar vortex over Hudson Bay.
The NAEFS 8–14 day temperature outlook is foreacsting a good chance of below-normal temperatures for Southern Manitoba.
In the end, it means a relatively dry pattern with daytime highs generally in the –15 to –20°C range.[3] This pattern looks to continue at least until late next week, so dig out those real winter clothes again and get the block heater ready, winter’s on its way back.
$.bigfoot()
The persistent vortex over Hudson Bay – for all intents and purposes a “polar vortex” – is a regular occurance over Hudson Bay in the winter months and is the most common cause for prolonged cold weather in Southern Mantioba. ↩
If things end up just a tad cooler, the freezing drizzle risk could be just a chance of flurries; if things end up a tad warmer, the freezing drizzle risk could persist through much of the day. ↩
The coldest temperatures so far this season will be settling in for a short stay in Southern Manitoba before a powerful series of clippers move across the Prairies at the end of the week, bringing what may become one of the most potent winter storms seen so far this winter.
Wednesday
-18°C / -30°C
Mainly sunny
Thursday
-17°C / ⇑ -14°C
Increasing cloudiness
Friday
-10°C / -13°C
Chance of flurries
The deep freeze settles over Manitoba today as a potent high pressure system moves in from Northern Saskatchewan, bringing with it a fresh shot of Arctic air. Temperatures will warm to around -18°C from the mid-minus-twenties present this morning under mainly sunny skies. Tonight will bring the coldest temperatures of the season to Winnipeg and the Red River Valley with overnight lows dropping dangerously close – or even just below – the -30°C mark. Tonight’s record low for Winnipeg is -36.1°C set in 1891, so some solace can be had knowing it’s been colder.[1]
Tomorrow will see the cold air exit the region as a major system making landfall in British Columbia begins pushing warmer air eastwards across the Prairies. Temperatures will be on their way up, up, up with a daytime high near -17°C followed by a rising temperature trend overnight that brings temperatures up to around -14°C by Friday morning. While Thursday will start off clear, cloud will start spreading into the Red River Valley sometime midday or into the afternoon, with things becoming completely cloudy sometime in the evening.
Some light snow is possible on Thursday night along a mid-level trough in the region. While more consistent snow is likely over southwestern portions of the province, here in the Red River Valley little is expected in the way of accumulations. We’ll keep an eye on it, but it looks like amounts will remain less than 2cm in any activity that develops.
Friday Brings Winter Storm to Portions of Manitoba
Friday will likely be a bit of a mess of a day…somewhere. A potent low pressure system will track eastwards near the international border, spreading an area of snow ahead of it and another area of snow to its north. It’s really too early to make too many accurate predictions other than a whole host of weather being possible on Saturday. Some areas of the Red River Valley will likely see some snow while a more organized snow event occurs (once again) through Parkland Manitoba eastwards through the Interlake and into the Berens River Region. There’s simply too much uncertainty with the track and strength of the low at the moment to create a snowfall forecast; it looks like a possible snowfall warning event will occur through the Interlake[2] while lesser amounts track along and south of the Trans-Canada corridor. We’ll be making a snowfall forecast graphic a little closer to the event when we can have more confidence in the amounts.
Just one of many model solutions, the GDPS shows lighter precipitation amounts (just 2-5cm of snow, generally) in Southern Manitoba from Friday morning to Saturday morning.
On Friday evening, temperatures will continue to rise with southerly winds into the mid-minus single digits, but then the low will pass and the winds shift around to northwesterly at 30-40km/h. Ample low-level moisture coupled with an incoming – and very dry – 50kt jet at 700mb may result in some freezing drizzle or snow grains overnight. The northwesterly winds will bring in substantially colder air with temperatures dropping to around -12 or -13°C after the evening rising trend.
Colder Air Returns for the Weekend
Saturday will bring clearing skies as another ridge of high pressure moves into the province. Temperatures will only recover slightly from Friday’s overnight low thanks to a fairly breezy northwesterly wind before dropping into the mid-minus 20’s on Saturday night under clear skies. Sunday looks sunny with a high in the low minus teens and calmer winds.
