Mild temperatures, above seasonal for this time of year, will be in place over Southern Manitoba, but the potential warmth will be limited over much of the Red River Valley and areas east thanks to an extensive area of low cloud that has moved into Manitoba and North Dakota within the outflow from a ridge of high pressure situated over Michigan.
Today will be 7-8°C above seasonal for this time of year[1] with temperatures climbing to the -2 to -1°C mark by late this afternoon under cloudy skies. It will be moderately windy too with sustained wind speeds in the 30-40km/h range with gusts up to around 50km/h, making it feel like a much cooler day than it actually will be.
The warming temperatures are thanks to a large upper-level ridge moving into the region which will develop an increasingly southwesterly flow across the Prairies and shift the jet stream further north. These two things together are helping push mild Pacific air into the southern Prairies. Unfortunately for Winnipeg, a ridge of high pressure anchored over Michigan will result in a persistent flow of colder air near the surface which, coupled with the cloud cover, will result in temperatures much lower than will be seen further west where a combination of more sun, terrain and some slightly more favourable wind directions will push temperatures towards record high territory.
Temperatures will barely drop tonight, perhaps just a degree or two, with winds tapering off to around 20km/h. The cloud cover will possible break up a little bit, but will likely remain cloudier than not.
Thursday will likely be another mostly cloudy day as the stratus continues to limit our daytime highs. We should see the temperature climb up to around 0°C with the southerly winds near 20km/h diminishing to light through the day. Thursday night will bring some scattering of the clouds, although mixed skies persisting until morning is the most likely situation at this point. Indications right now show that there may be a slight risk for freezing drizzle on Thursday night. Expect a low near -2°C.
Friday will be the nicest day of the three with a little sunshine looking a bit more likely than today or tomorrow. Temperatures will likely climb up to around 0 or +1°C, however if we end up with substantial amounts of sunshine, +2 or +3°C may even be possible.
Much Warmer over Western Manitoba
For areas in Western Manitoba, especially those on the northern side of the Turtle Mountains or those in the Dauphin area near the Riding Mountains, temperatures will be quite a bit warmer over the coming days. A combination of several factors, including:
- Further proximity from the ridge over Michigan will minimize the amount of cold air being reinforced near the surface in a return flow.
- Winds have a more southerly to slightly southwesterly component which will help tap the warmer air.
- Terrain is not a valley that likes to keep cold air caught in it.
- Downslope mixing on the northern side of larger terrain features will help couple the surface and warm air aloft.
This all means that for several days, beginning today, daytime highs will generally climb into the +2 to 5°C range for areas in the more generally open area to warmer values of +5 to +8 in regions downwind (north of) major terrain features such as the Riding Mountains or Turtle Mountains.
Warmth Spreads into the Red River Valley on the Weekend
The even warmer weather will spread into the Red River Valley for the weekend, however, as winds shift into a more southwesterly flow, helping push out the cold air and get some of that more substantial warmth into the region. Saturday looks to bring highs in the low-to-mid single digits with cooler air filtering in on Sunday, dropping highs back to the cooler side of 0°C alongside a chance for some light snow.
- The seasonal daytime high for Winnipeg this time of year is around -9°C. ↩
