|GFS model forecast for Sunday evening|
The southern Manitoba situation tomorrow morning and afternoon is complicated. What is certain is that we will be in the ''warm sector'' of the system for most of the day. Temperatures are expected to rise slightly above zero in southwestern Manitoba in the afternoon. Here in the RRV and southeastern Manitoba, highs between -2°C and 0°C are expected in general, and these highs will likely be reached late afternoon or early evening. Winds will be brisk out of the south or southeast. Light precipitation is expected on and off through the morning and afternoon throughout southern Manitoba, however timing and location of this is too uncertain to point out. It is important to note however that freezing rain and ice pellets are a possibility thanks to some above zero air above the surface. Although amounts are expected to remain light, it could certainly be enough to make travel quite slick in some areas. The best chance for this light freezing drizzle or rain will be in southwestern Manitoba and along the US Border. This threat will diminish later in the afternoon in southwestern Manitoba and here in eastern areas in the evening as colder air moves in. The heaviest precipitation tomorrow in the day will be along and north of the warm front, in other words generally in the Interlake, central, western and eastern Manitoba. Precipitation in those areas will remain as snow.
The centre of the low pressure system is expected to move over southern Manitoba in the evening. Thus, light to even calm winds are expected in that timeframe (would be brief however). The cold front will quickly sweep across the area however, and at this point it is expected to reach Winnipeg by mid or late evening. Winds will strengthen dramatically behind this front, and snow will begin falling either as the front passes or a little before it passes (likely a couple hours before). Snow will continue through most of the night, and winds will continue to strengthen.
This is where the most problematic part of the system begins. Winds are expected to be out of the northwest or north at about 40 to 50 km/h with gusts to 60 km/h in the RRV on Monday morning. This will create serious blowing snow in open areas, especially if we get a lot of new snow.
At this point, it looks like snowfall will wind down in the morning, with just a few flurries in the afternoon here and there. Total amounts are expected to be in the 5-10 cm range in Winnipeg, but higher amounts are definitely possible. Heaviest snow totals with this system right now are expected in central and eastern Manitoba and then into northwestern Ontario.
Temperatures will remain steady or fall slightly throughout the day on Monday. We will likely be waking up to temperatures around -10°C in Winnipeg on Monday morning, and then temperatures will likely remain steady in the mid minus teens through the day. Lows in the minus twenties are expected Tuesday morning.
This is how I see this system right now. With the great uncertainty in the models, I wouldn't be surprised if things end up a little different. That's why I'll be updating later today, and of course through the day on Sunday.