Before the system on Sunday and Monday, we will have to contend with plummeting temperatures tonight. Lows will easily reach the mid minus twenties in Winnipeg with the potential for lows in the low minus twenties (between -25 and -28°C). Luckily winds will be light and really wont begin to increase until Sunday morning. The day Sunday will actually start quite bright and that will be the case for much of southern-central and southeastern Manitoba with clouds gradually increasing through the morning. Skies will become cloudy by afternoon with a chance of scattered flurries ahead of the main stuff later in the day. Winds will be brisk out of the south or southeast at 30 km/h and gusting up to 50 km/h throughout the afternoon before diminishing in the evening. This will likely cause some drifting snow on highways after the bit of snowfall that fell yesterday.
Now I have to talk about a winter storm for Sunday night and Monday. This particular storm will be thanks to a Montana Low moving through North Dakota Sunday night spreading snow northwards into Manitoba along with an inverted trough. These inverted trough scenarios unfortunately are known to bring southern Manitoba some really heavy snowfalls.
Temperatures will only reach near -10°C late afternoon Sunday and will remain steady around that mark throughout the evening and most of overnight Monday. Snow is expected to begin in Winnipeg near supper on Sunday (between 4 and 7 pm) and remain steady throughout the evening and overnight hours before calming Monday morning. Winds will be relatively light during the overnight hours, however they will increase dramatically as we enter the colder and windier side of the system early morning Monday (right now it looks like that will be sometime between 4 and 9 am; this will be clearer tomorrow). They will increase to 40 gusting to 60 km/h out of the north or northwest and remain around that speed throughout Monday morning and afternoon before weakening Monday evening. This will create lots of blowing and drifting snow on highways creating poor visibility and hazardous road conditions. Travel is not recommended on Monday as a result. Inside the city, drifting snow will be an issue. These winds are expected to be strongest in the Red River Valley.
Temperatures will also plummet beginning early morning Morning, likely falling into the mid minus teens and stabilizing through the rest of the day.
As for snowfall totals, surprisingly weather models are in a fairly close agreement at this point with a general 5-15 cm of snowfall across southern Manitoba. However, I do feel that some areas will see even higher amounts under some heavier bands but it's too early to know the exact location of these. Heaviest hit areas could see up to 25 cm. Right now, I think 10-20 cm is a good bet for Winnipeg.
I will have a new post tomorrow with my forecasted snowfall totals for a few select cities across southern Manitoba.