Flurries Mark Descent Into an Arctic Chill

A powerful winter storm brought 20-30cm of snow to much of the Red River Valley yesterday followed by another 4-8cm overnight. This fresh snow combined with powerful northerly winds to produce white-out conditions on area highways. The snowfall accumulations combined with the blowing snow resulted in the closure of many area highways making travel nearly impossible. While conditions will gradually improve, it will be at the cost of the warmth that’s been in place over the region for the past month: the coldest temperatures we’ve seen since February are on the way.

This map from 8:20PM yesterday shows the extensive road closures (red) across Southern Manitoba.
This map from 8:20PM yesterday shows the extensive road closures (red) across Southern Manitoba.
Wednesday
-4°C / -10°C
Flurries with blowing snow

Today will bring flurries to the region as a weak disturbance slides through from the northwest on the backside of the main low pressure system that brought the heavy dump of snow yesterday. The gusty northerly winds will continue with winds out of the north to northwest at 40 gusting 60 km/h. While the snow won’t be nearly as heavy as yesterday, most places can still expect another 2-4 cm of snow.

The one exception to that will be areas in the lee of Lake Manitoba, where a band of lake-effect snow is expected to develop which will move south-southeast off the lake. This will result in a narrow band of snow which could see accumulations potentially reach as high as another 15-20cm, depending on how intense the flurries become.

The 4km NAM model shows a narrow band of enhanced snowfall today in the lee of Lake Manitoba, passing just west and south of Winnipeg.
The 4km NAM model shows a narrow band of enhanced snowfall today in the lee of Lake Manitoba, passing just west and south of Winnipeg.

Snow will taper off this evening, save for lingering snow moving off the lakes. Skies will remain mainly cloudy as temperatures head towards a low near -10°C with winds easing to 30 gusting 50 km/h by Thursday morning.

Thursday
↓ -14°C / -21°C
Cloudy with a chance of flurries

Thursday will continue with mainly cloudy skies and a chance of flurries, but winds will slowly ease to around 20 km/h. Temperatures will remain steady through the morning, but then drop towards the -14°C mark through the afternoon. Skies will begin to clear through the evening, save for a narrow band of cloud coming off each of Lake Manitoba and Lake Winnipeg. There’s a fairly decent chance that Winnipeg will see some flurries from Lake Manitoba on Thursday night as winds shift to more of a WNW direction. Temperatures will drop to a low near -21°C, but may remain a few degrees warmer underneath the lake-effect cloud cover. Wind chill values will be in the -30 to -35 range overnight.

Friday
-17°C / -24°C
Partly cloudy

Much of the cloud cover will break up on Friday with winds dropping off as the Arctic ridge begins moving into the province. While there will be some sun, temperatures will be well below seasonal values with highs near the -17°C mark. Temperatures will dip to a low near -24°C on Friday night.

Long Range

The cold weather will last through the weekend and into the start of next week; Saturday and Sunday will likely see highs in the -15 to -20°C range with the chance of flurries as a disturbance moves through. Even colder air has the potential of building in for the start of next week, potentially pushing daytime highs below -20°C.

NAEFS 8-14 Day Temperature Anomaly Forecast — Valid December 14 to 21, 2016
NAEFS 8-14 Day Temperature Anomaly Forecast — Valid December 14 to 21, 2016
In general for the first half of December, below-normal temperatures are expected as an air mass that had previously been locked over Siberia has shifted across the Arctic and will remain entrenched over the northern sections of North America.

Winnipeg’s seasonal daytime high is currently -8°C while the seasonal overnight low is -18°C.

Major Winter Storm Moving In

Environment Canada has issued a Winter Storm Warning for this system.

A major winter storm is moving in as you read this article. It will bring the first serious snowfall of the year to the Red River Valley, with heavy blowing snow or even blizzard conditions possible in many areas. You may want to reconsider any travel plans early this week!

A strong low pressure system will bring heavy snow and strong winds to southern Manitoba early this week
A strong low pressure system will bring heavy snow and strong winds to southern Manitoba early this week

Today

Monday
0°C / -2°C
Snow beginning

A strong low pressure system will move off the Rocky Mountains and into North Dakota today. It will spread moderate to heavy snowfall into parts of western Manitoba this morning, before snow spreads over the rest of southern Manitoba later in the day. Snowfall will fall for the entire day in most of western Manitoba, with total accumulations of 10-15 cm expected in most areas. Further east, the Red River Valley will see lesser amounts today, with 2-5 cm in the Winnipeg area and more like 5-10 cm near the International border. Local amounts of 15 cm may occur along the International border in south-central Manitoba. Winds will be gusty from the east at 20-30 km/h, producing some blowing and drifting snow.

Tuesday

Tuesday
-2°C / -4°C
Blizzard Developing with Heavy Snow

Conditions will really begin to deteriorate early Tuesday as winds shift to the northwest. Snow will continue to fall as well, with an additional 10-20 cm possible in the Red River Valley on Tuesday. Snow will taper off in southwestern Manitoba, but another 2-5 cm will be possible. The northwesterly winds that develop will be strong at 40 km/h gusting to 60 km/h, with higher values of 50 km/h gusting to 70 km/h in some treeless areas. This will likely result in blizzard conditions over large parts of southern Manitoba, especially south and west of Winnipeg. Those areas that don’t quite meet blizzard criteria will certainly see heavy blowing and drifting snow, with travel becoming difficult or impossible in some areas. Road closures are likely, especially the Trans-Canada Highway west of Winnipeg and Highway 75 south of Winnipeg. Conditions will not improve significantly until early Wednesday.

Expect storm-total snowfall accumulations by Wednesday morning.
Expect storm-total snowfall accumulations by Wednesday morning.

Wednesday

Wednesday
-12°C / -20°C
Snow and blizzard ending

Snow should finally taper off on Wednesday morning in all of southern Manitoba, but not until most areas have received significant accumulations of snow. Southwestern Manitoba can expect 15-25 cm, while Winnipeg can expect 10-20 cm. Areas along the International border in south-central Manitoba can expect to receive 20-30 cm. Locally higher amounts may occur where heavier bands of snow persist for a longer period of time. Large snow drifts will be a problem on Wednesday, even once the snow ends. Some rural roads may be impassable due to heavy drifting. Blowing snow will persist on Wednesday, but winds will slowly decrease throughout the day. Temperatures will have dropped noticeably on Wednesday as this system begins to pull down a cold arctic air mass.

Long Range

Conditions will finally calm down on Thursday as winds taper off. However, in the wake of this strong low we’ll see a blast of arctic air, with temperatures likely dropping into the minus twenties on Thursday and Friday. This frigid pattern is expected to persist for awhile, so make sure to get out those winter clothes!

Cool With Occasional Snow, Then Temperatures Plunge

The coming days will see a fair amount of cloud and several chances for snow, but temperatures will continue to be slightly above seasonal values. A big change is on tap for next week when a massive blast of Arctic air will plow through much of Canada and the United States, sending temperatures plummeting off a cliff. Time to dig out all the winter clothes.

More of the same. This weekend’s weather will bring little difference from the past several days as low cloud continues to linger through the region. The high temperature today will sit near -2°C with a light winds. Winnipeg & the Red River Valley may see some light isolated snow showers, but no accumulations are expected and for the most part it should just be a mainly cloudy day.

Temperatures will drop to a low near -5°C tonight with a few breaks in the cloud showing up overnight. Winds will pick up out of the south to about 15 km/h by Saturday morning.

Saturday may bring some sunshine through the morning hours, but skies will cloud back up through the afternoon ahead of the next low pressure system moving through. Temperatures should climb to a high near 0°C with continued south winds at 15-20 km/h. Heading into the evening, an area of light snow will spread eastwards into the province as a low pressure system moves into the Interlake from southeastern Saskatchewan. Temperatures will dip to a low near -2°C.

An area of snow will push across Southern Manitoba Saturday night into Sunday morning.
An area of snow will push across Southern Manitoba Saturday night into Sunday morning.

Sunday morning will see the snow gradually tapering off with total amounts close to 2 cm. After that Winnipeg will be left with mostly cloudy skies and the continued chance for some isolated light snow showers. Temperatures will remain steady near -2°C before falling to a low near -6°C on Sunday night under partly cloudy skies.

Long Range

Monday will bring the potential for another snow storm to the region as a low lifts northwards through eastern North Dakota into northern Minnesota. Best guesses at this point are for another 5-10 cm of snow over the Red River Valley and 10-20 cm over southeastern Manitoba. Slight changes in track could result in significant changes to forecast snowfall amounts, though, so we’ll have to keep an eye on it as this system develops through the weekend.

Behind that system, the big story will be the temperature crash over North America:

The GDPS is forecasting a substantial outbreak of Arctic air next week.
The GDPS is forecasting a substantial outbreak of Arctic air next week.

Temperatures over a large area are forecast to be 10-20°C below normal as a cold air mass crosses over the pole from Siberia into North America. Here in Manitoba, it appears like we’ll avoid the worst of it with temperatures dipping to seasonal to slightly below seasonal values, but to the west and south winter will be arriving in full force. After a November that saw every single day with above normal temperatures, it will likely be quite a shock to the system!

Winnipeg’s seasonal daytime high is currently -7°C while the seasonal overnight low is -16°C.

Colorado Low Looms

Our first significant Colorado Low in some time will bring a variety of precipitation types to southern Manitoba today. Rain, snow, freezing rain, and ice pellets will be possible.

A variety of precipitation types will be possible in southern Manitoba today. The map shows areas of rain (green), snow (blue), freezing rain (purple), and ice pellets (red).
A variety of precipitation types will be possible in southern Manitoba today. The map shows areas of rain (green), snow (blue), freezing rain (purple), and ice pellets (red).

Today

Monday
2°C / 1°C
Mixed precipitation early, then rain

A powerful Colorado Low will bring a mixed-bag of precipitation to southern Manitoba today. Precipitation will likely start out as freezing rain or ice pellets in portions of the Red River Valley and south-eastern Manitoba this morning, before changing to rain later in the morning. Rainfall amounts of 5-10 mm are expected in most areas, with higher amounts possible near the International border. There may be a bit of snow at times, but little accumulation is expected – and any that were to accumulate will be melted by rain later in the day. However, the story will be different in western Manitoba, where snow will be the dominant precipitation mode for the day. Accumulations of 5-10 cm are likely in most areas by tonight. Winds will be gusty out of the north-east at 30 km/h gusting to 50 km/h, bringing some blowing and drifting to open parts of western Manitoba.

Tuesday

Tuesday
1°C / -1°C
Periods of snow

This Colorado Low will take its time exiting our region, affecting us once again on Tuesday. Unfortunately (for some), rain will change to snow on Tuesday in the Red River Valley and south-eastern Manitoba. Accumulations of 4-8 cm are likely in addition to possibly a couple millimetres of rain or mixed precipitation early in the day. Western Manitoba can expect another 5-10 cm on Tuesday, bringing totals up to 10-20 cm. The model graphic shown below, which considers a wide-range of possible solution, shows a very high probability (>80%) of over 10 mm of total precipitation in most of southern Manitoba. Winds will remain gusty out of the north on Tuesday at 30 km/h gusting to 50 km/h.

Most of southern Manitoba stands a very high chance of receiving over 10 mm of precipitation with this system (NAEFS graphic).
Most of southern Manitoba stands a very high chance of receiving over 10 mm of precipitation with this system (NAEFS graphic).

Wednesday

Wednesday
-1°C / -4°C
Mainly cloudy with flurries

The Colorado Low will continue to linger on Wednesday, but snowfall rates will decrease. Flurries are expected throughout the day, but accumulations should be small. Winds will remain breezy from the north at 20-30 km/h.

Long Range

It appears that we’ll see generally seasonal to slightly-above seasonal temperatures as we move into early December. However, longer-range models do hint at a very cold arctic air mass being pulling down from the north about one week into the month. This will have to be monitored, as it would be our first significant bought of below-normal temperatures in quite awhile.