A low pressure system crossing the Prairies will bring another wave of unseasonably mild air into Southern Manitoba and help temperatures climb above 0°C for the second time this week. Heading into the latter half of the weekend, unsettled weather will develop over Southern Manitoba bringing flurries as cooler air begins gradually slumping southwards out of the Arctic and across the Prairies.
Today will be a much nicer day for Winnipeg than it appeared like it would be earlier this week, all thanks to a more northern track for today’s low pressure system crossing the province. As a result of this trajectory, Winnipeg will still see the warmth we expected before, but much less of the precipitation, which will now mainly fall through Central Manitoba and the Interlake before heading off into Ontario.
For the city, today will start off with a chance of…well, just about anything—snow, freezing rain, or showers—as a warm front pushes through and brings our temperatures above zero. As the warm front pushes off to the east relatively early in the day, we’ll be left with skies on the cloudier side and temperatures in the +1-2°C range. Windswe will start out of the south at around 30-40km/h before shifting to westerly behind the warm front at similar speeds. The chance for showers will redevelop mid-day and through the afternoon as a little bit of cooling aloft moves across the region. Expect temperatures to drop to around -2°C tonight with a few clear breaks developing.
Saturday will bring more warm weather cloudier skies once again, although a few sunny breaks are certainly possible and the southwestern Red River Valley may actually end up seeing a fair amount of sunshine. Temperatures will climb to around +1°C with lighter winds than Friday.
A cold front will begin slumping southwards through the region on Saturday night. This will bring cooler temperatures and send our overnight low down to around -11 or -12°C under cloudy skies. Alongside the cooling will be a chance of some light flurry activity.
Sunday will be a cooler day with a high in the near -6°C or so. Under mainly cloudy skies, Winnipeg will see a slight chance for flurries throughout the day thanks to favourable temperatures throughout the lower atmosphere. This cooler weather will mark the leading edge of a return to seasonal and below-seasonal temperatures for a short while.
Long Range: Colder, But For How Long?
Looking forward into next week, it looks like cooler weather will return to the Prairies as the conditions that have supplied the warmer weather to the region over the past week collapse southwards and allow cooler Arctic air to slump southwards.
The GEPS[1] is showing a transition into slightly below normal conditions next week. This image shows the maximum temperature expected in each 6-hour time period from Monday through Saturday. Ensemble forecast systems produce numerous forecasts, and then statistical analysis can be done on the output to (in theory) produce more accurate forecasts, especially in the long range. In the image above, the easiest way to understand it is that the value along the line is a fairly reasonable "most likely" temperature, while the red shading on either line represents the certainty; if there’s little shading extending from the line that means there is high confidence in the values; if there’s a lot of shading extending above and below the line, it means that there’s more uncertainty associated with the forecast at that time.
The GEPS shows fairly reasonable confidence that daytime highs will be dropping into the -15 to -20°C range early next week, a fair amount below the seasonal highs of -11°C for this time of year. With daytime highs in that range, it’s likely overnight lows will dip into the mid-minus 20’s. Heading toward the end of the week, though, there begins to be a lot more uncertainty on the weather pattern, so we’ll just have to wait and see for when the warm-up returns!
- Global Ensemble Prediction System ↩
