Warmer weather will wash across the Red River Valley this weekend as a south-westerly flow brings in mild Pacific air. While the sun won’t be overly present, conditions will be quite pleasant with mild temperatures and light winds. The weekend will finish on an uncertain note as a Colorado Low ejects from the Central Plains with wavering agreement on where it’s heading after that.
500mb winds valid for Sunday morning at 12Z. A complicated set-up will be underway as the polar jet merges with the sub-tropical jet and a shortwave from the northern Prairies merges into a developing Colorado Low.
Skies will be mainly cloudy today as a warm front pushes eastwards towards the Red River Valley. Temperatures will climb up to –7 or –6°C, a welcome break from the cold temperatures we’ve had over the past week. Winds will pick up out of the south-southeast to 30–40km/h this morning with a slight chance of some local blowing snow through the Red River Valley. There will be a very slight chance of a few flakes of snow but there won’t be anything that can be considered significant. Temperatures will drop a few degrees tonight to about –9°C under mainly cloudy skies.
SaturdayA mix of sun & cloud.-4°C
Perhaps the nicest day of the weekend will be Saturday as the clouds begin to break up a little and temperatures climb as high as –4 or –3°C. Winds will remain fairly light through the Red River Valley through the day. Not much to say for Saturday night; skies will likely clear in the evening but fairly quickly cloud over again early in the morning on Sunday.
Sunday is a very complicated weather day. As it stands right now, we may see absolutely no snow or…quite a bit of snow, including the potential for a blizzard through portions of the Red River Valley. Temperatures should remain close to what they look to be right now with highs near –5°C across much of the Red River Valley. Winds will likely remain relatively light, regardless of the overall pattern, as there will be no significant Arctic high building into the region.
As for the complicating factors…
SundayMostly cloudy. Snow/freezing rain uncertain.-5°C
The general synoptic pattern will be as such: a significant Colorado Low will be ejecting into central Nebraska on Saturday night with a sharp trough digging northeastwards into SE South Dakota while, at the same time, a relatively weak low pressure system slides south-eastwards out of northern Saskatchewan towards central Manitoba. By Sunday morning, the Canadian low and it’s associated jet stream will merge with the Colorado Low with the CO low situated in central Nebraska with a sharp trough extending northwards through extreme western Minnesota then arcing through the Red River Valley northwestwards towards The Pas, MB. It’s always a concerning issue when the troughs end up west of the Red River Valley, as it can often mean a northward progression of the weather into our area.
Models have notorious struggles with complicated setups where two distinct atmospheric streams merge. It’s an incredibly dynamic, sensitive process in which even small changes can dramatically effect the evolution of the entire system, so models can often waver wildly on what the outcome will be from small changes in their initial conditions. That being said, using ensemble forecasts, the track of the low, and it’s associated snow, has been creeping northwestwards; two days ago the entirety of the snow was forecast to push only into Central Minnesota; now it’s forecast to clip southeastern Manitoba, including Sprague and portions of the Whiteshell. Model trends can sometimes be more helpful than the actual model output, and combining the ensemble’s northwards trend with the knowledge that this is definitely a situation where the model may not tilt the 500mb trough enough and then, as a result, not bring the low far enough north or west, I can’t say with any certainty what Sunday will bring.
There’s a distinct chance that the snow will remain entirely on the US side of the border and we’ll be relatively unaffected by this system. Should things develop in such a way that the low digs a little more and the trough tilts a little more, it’s also entirely possible that another 5–15cm of snow, or potentially higher, will fall across the Red River Valley. In addition to the uncertainty with all these elements, should the precipitation push further to the NW into Southern Manitoba, there will be a distinct potential for freezing rain as 850mb wet bulb temperatures sit on the positive side of the 0°C mark.
The reality is that for this type of setup, it’s simply too early to tell what’s going to happen. We’ll most certainly be providing updates in the comments below on the development of this Colorado Low. For now, it’s safe to assume that Sunday will be a warmer day with winds in the 20–30km/h range, but the actual weather conditions may end up being quite poor depending on the evolution of this system.