The Snowy Descent

Take heart and treasure the mild weather we have this morning; the Arctic cold front is on it’s way and through a series of low pressure systems we’ll see a snowy couple days drag us back into the icy grip of winter.

Friday
3°C ⇘ -12°C / -25°C
Light snow beginning midday. 2-4cm. Clearing & windy in the afternoon.

Saturday
-17°C / -24°C
Increasing cloud in the afternoon; snow overnight.

Sunday
-19°C / -30°C
Risk of a blizzard. Snow ending midday. Windy.

Mild Weather Forced Out

Our daytime high will not happen this afternoon. In fact, it will be roughly around where we are at the time of this being posted; an expected high temperature of -3°C sits only a couple degrees above where we are at right now and then we’ll see temperatures start going the wrong way behind a cold front set to push through midday.

We may see a few flurries this morning but the more organized precipitation will hold off until midday when a cold front begins working it’s way southwards. Complicating things will be an upper level shortwave that is rippling down in a northwest flow will ride along the frontal boundary and provide additional lift, helping make snow a little more widespread than it would be otherwise. Due to that, most areas across Southern Manitoba will see some snow through midday as everything passes through. Significant amounts are not expected as mid-level moisture will be somewhat lacking and limit the amount of snow that can be produced. In general, around 2-3cm will be seen in many areas. There’s a slight chance we’ll see a little more in the southwest Red River Valley – near Morden, Winkler, Altona & Gretna – thanks to a closer proximity to the upper-level shortwave and a little more mid-level moisture. Even there, though, I don’t expect to see more than 4 or 5cm.

The snow will taper off this afternoon and stronger northerly winds will develop to around 30 gusting 50km/h. Some local blowing snow might develop through the afternoon, but it shouldn’t be a widespread issue. Temperatures will begin tanking as the northerly wind ushers in cooler Arctic air, but fortunately the big cool-off will hold off a couple more days. Temperatures should drop through the afternoon to somewhere between -10 to -15°C by evening and then onwards to an overnight low close to -26°C or so under clear skies and diminishing winds.

A Cool, Calm Day

GDPS 850mb temperature forecast for Saturday showing a strong baroclinic zone through the Prairies.
GDPS 850mb temperature forecast for Saturday showing a strong baroclinic zone through the Prairies.

Saturday will bring fairly benign weather and act as our calm before the storm. A cold, sunny start to the day will go on to see a high around -17°C under increasing cloudiness as a compact but powerful system zips towards the province along a strong baroclinic zone. A few flurries are possible anywhere there’s cloud, but the organized snow will push into Western Manitoba midday and work it’s way towards the Red River Valley by evening. Around 5cm will fall over Western Manitoba while just 2-4cm are expected here in the valley with the potential for some higher amounts along the western escarpment thanks to an upslope flow that will develop overnight.

Winds will remain fairly light throughout the day and night. Flurries will persist until Sunday morning and we’ll drop to an overnight low of around -24°C.

Miserable Weather for Sunday

The NAM (among others) is forecastinga strong pressure gradient over Southern Manitoba on Sunday.
The NAM (among others) is forecasting a strong pressure gradient over Southern Manitoba on Sunday.

The big story behind the departing low pressure system on Sunday will be the absolutely massive Arctic ridge racing into the Prairies behind it. A very strong pressure gradient is set to develop over Southern Manitoba which will produce strong winds. At this point, it looks like winds will steadily increase early Sunday morning to 40 gusting 60km/h in most places. Through the southern Red River Valley winds will likely climb into the 50-60km/h range thanks to the funnelling effect of the terrain.

Anyone with highway travel plans for Sunday should keep updated on the weather conditions and be prepared for potentially hazardous weather conditions with near-zero visibility on highways.

These strong winds, combined with instability in the low-levels thanks to more cold air pushing southwards and the fresh snow of the past couple days will very likely produce widespread blowing snow. It does look like a blizzard may be possible, although things may end up being a little too marginal. For a blizzard on the Prairies, Environment Canada requires:

  1. Winds of at least 40km/h or greater.
  2. Visibilities of 1/4SM (400m) or less in blowing snow or blowing snow with falling snow.
  3. Both (1) and (2) lasting for 4 hours or more.

The best chance for blizzard conditions will be south of Winnipeg in the Red River Valley and southwards into North Dakota. A strong pressure gradient coupled with ample fresh snow and the funnelling effect of the valley will likely make it quite easy to go down to near-zero visibility. For most other regions, a blowing snow warning seems very possible[1]. Either way, highway travel will likely be poor-to-closed on Sunday. We’ll keep an eye on this as it develops and provide updates a little later this weekend on how things look to be shaping up for Sunday.

Other than the winds, we’ll see skies clear out through the day and our temperature remain steady from Saturday’s low or dropping slightly. The winds will taper off in the late afternoon and we’ll head to a low near -30°C.

Blizzard Update

Right now it looks like this may be the most significant ground blizzard of the winter so far.

Everything seems to be fairly lined up for a significant blizzard event to develop overnight tonight. Winds will begin to pick up through SW Manitoba late overnight and slowly spread eastwards towards the Red River Valley by midday. At this point, it seems like widespread winds of 40-50km/h are possible, although it is possible the winds strengthen as high as 50-60km/h in some areas. Gusts to 70-80km/h are quite likely throughout much of Southern Manitoba.

Widespread blowing snow is expected on Sunday. Maximum blizzard potential exists through SW Manitoba, the western Red River Valley and southwards into North Dakota.
Widespread blowing snow is expected on Sunday. Maximum blizzard potential exists through SW Manitoba, the western Red River Valley and southwards into North Dakota.

These strong winds will work in tandem with fairly deep low-level instability and a surprising amount of moisture to make very favourable conditions for blowing snow. The strong winds will persist for at least 6-9 hours in most places, making a long-term blowing snow or blizzard event quite likely. If you have any plans to travel on highways in Southwest Manitoba or the Red River Valley on Sunday, it is best to give yourself ample time & make alternate arrangements; white-out conditions are very likely and some highways may be closed. Right now it looks like this may be the most significant ground blizzard of the winter so far.

This blizzard event will extend all the way southwards into North Dakota where there is absolutely no question that a significant ground blizzard will be underway. Just to repeat, conditions will get worse as one travels south. Winds will begin to ease and let conditions improve from north to south through the evening hours.

All in all it will be a lousy day for highway travel. Don’t do it if you don’t have to and stay safe.


  1. Like a blizzard warning, but only requires 1/2SM visibility (800m) and 3 hour duration.  ↩
Brad

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 Twitter.