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. ↩
Another spell of above-normal temperatures are on the way to the Red River Valley this weekend with daytime highs possibly reaching above freezing by the beginning of next week. Closer to Christmas, temperatures will return to seasonal values before cooler air slumps southward for the end of December.
Friday
-6°C / -9°C
Cloudy with periods of light snow
Saturday
-4°C / -7°C
Cloudy
Sunday
-2°C / -4°C
Mixed skies with a chance of flurries
Today marks the beginning of the warmup as cloud ahead of an approaching warm front blankets the province almost entirely. Here in the Red River Valley, light snow will likely be fairly widespread thanks to favourable temperature profiles throughout the lower levels of the atmosphere. As is typical in these situations, don’t expect any real accumulation. Temperatures will climb to an above-seasonal –6°C or so with light winds. Temperatures dip down to around –9°C tonight with mainly cloudy skies.
Saturday will be another cloudy day with temperatures climbing to around –4°C under mainly cloudy skies. The main difference will be that light snow won’t be nearly as likely, although a few isolated flurries are possible. Winds remain light and temperatures dip to around –7°C on Saturday night under cloudy skies.
Sunday will start…you guessed it, mainly cloudy once again with temperatures beginning to edge even warmer; the daytime high on Sunday will likely be around –2°C. The cloud may begin to scatter out in the afternoon providing a brief reprieve from the cloudy skies.
Some flurries are once again possible, however any real threat for snow will hold off until the overnight hours where a low pressure system passing to our south will potentially bring a band of snow across the Red River Valley with a couple of cm accumulation.
Snowy(-ish) Return to Winter
Looking ahead to next week, the weather pattern will be dominated by a large low pressure system developing over the eastern half of the United States & Canada. The Red River Valley will be positioned on the back-side of the strengthening low, locking us into northerly winds that will begin pulling Arctic air southwards through the Prairies.
The GFS 850mb temperature forecast valid on Christmas eve shows a trough of cold air plunging southeastwards behind a strongly tilted, major storm system centered over Ontario.
With the cooler air plunging southwards, daytime highs will cool off to the mid-minus teens for the second half of the week. Snowfall is a little uncertain at this point for us, but it doesn’t look like much will be seen here, making for a cool and blustery, but not particularly stormy, Christmas. It is worth noting that this storm system will have dramatic impacts on the eastern half of the country, including Toronto & Montreal, so if you have travel plans for the holidays that involve flying in that direction, be prepared for potential delays.
The weather will remain unexciting as a ridge of high pressure exiting the Prairies gives way to more cloud & flurry activity. Snowfall may become slightly more organized by the end of the week, but no significant events are in the forecast.
Wednesday
-10°C / -18°C
Mainly sunny
Thursday
-9°C / ⇒ -9°C
Increasing cloud; light snow overnight
Friday
-5°C / -9°C
Cloudy with flurries
Today will bring sunny skies and a high near -10°C. Winds will be calm.
Skies will remain clear tonight as temperatures drop to around -16°C. Winds will remain relatively light.
Thursday will start off fairly sunny and become increasingly cloudy through the day. While there’s an ever-so-slight chance of a light flurry through the daytime, the bulk of the activity should hold off until the overnight hours. Temperatures will climb to around -9°C with relatively light winds.
Temperatures will remain fairly steady near -9°C on Thursday night with some flurries looking fairly likely.
Friday will be the warmest day of the week with temperatures climbing to around -5°C. It will also be cloudy with a very good chance of light snow thanks to a weak upper-level trough sliding across the province. Temperatures will dip to around -8°C on Friday night with cloudy skies and a chance of continued flurry activity.
Despite all the snow in the forecast, little of it will accumulate. Friday stands the best chance at seeing something, but even then it would only be a cm or so at most.
Not Much Between Now And Christmas
The weather, in general, is looking quite unremarkable between now and Christmas.
The NAEFS 8-14 day temperature outlook is calling for near-normal conditions over Southern Manitoba.
The temperature outlook continues to be seasonal with no dramatic swings over the next while. Snow-wise, no significant systems look to impact southern Manitoba between here and Christmas. Through the first half of next week it looks like a weak inverted trough may bring a couple of days of light snow or flurry activity to the province, but once again it looks like it would produce little in the way of accumulations.
So in lieu of any interesting weather, get out there and enjoy what is shaping up, for December, to be an exceedingly bearable winter!
