Those tired of the left-over gloom from the weekend’s weather will be happy to know plenty of sunshine is on the way as a building upper-level ridge brings seasonal temperatures and plenty of sunshine.
The weather for much of this week will be dominated by an upper ridge building across the southern Prairies, bringing pleasant conditions for the end of September with slightly above normal daytime highs. The next few days will bring plenty of sunshine with just a few clouds to partly cloudy skies expected.
Temperatures will gradually climb to around 5-6°C above seasonal by the end of the week; daytime highs near 17°C today in Winnipeg will increase to near 20°C for Thursday and Friday.
The red colours on this map of 850mb temperature anomalies shows the warmer than normal weather expected over Southern Manitoba this week.
Fortunately, it doesn’t appear the wind will pose too much of an issue either. Winds will be calm today, and then increase to around 10-20 km/h out of the south for Thursday and 15-25 km/h out of the south on Friday.
Long Range
The weekend forecast gets a little more complicated, but overall it’s looking like the weather should stay dry until the start of next week.
As the weekend progresses, a long-wave upper trough will dig over the western half of the continent. We should remain relatively unaffected by this with mild weather continuing through the weekend. Late Sunday into Monday, a shortwave will eject northeastwards out of the trough, moving into Southern Manitoba, and will bring some rain to the region. The timing of this is uncertain at the moment, but it looks likely that it won’t move into the province until late Sunday at the earliest.
So until that moves in, the weather should remain quite nice with mild temperatures and relatively light winds.
Winnipeg’s seasonal daytime high is currently 15°C while the seasonal overnight low is 4°C.
After a rainy weekend we’ll have a chance to dry out this week as skies clear. Temperatures will be cool, but generally near seasonal values.
Cool and windy conditions are expected on Monday in southern Manitoba
This Week
Today will see mainly sunny skies as the low pressure system from the weekend moves off to the east. However, it will remain quite windy behind the system with northwesterly winds of 40 km/h gusting to 60 km/h. Temperatures will sit in the mid teens over most of southern Manitoba. There will be a slight risk of frost in low-lying areas tonight as temperatures drop rapidly with the light northwesterly flow.
Tuesday will see slightly improved weather over today as winds calm down and temperatures climb up into the mid teens. Skies will also remain mainly sunny, making for a generally pleasant day.
Wednesday should be one of the warmest days this week. Temperatures are expected to climb up near the 20C mark under light southerly winds and mainly sunny skies.
Long Range
Long range models hint at another strong low pressure system developing to our west later this week. It remains unclear if and when this system may affect us, but it likely won’t be until the weekend at the earliest. The good news is that this system will draw up a warm, southerly flow, perhaps giving us a brief stretch of warm weather before it arrives.
After a relatively benign week, unsettled weather is set to return this weekend as a slow-moving upper trough brings several waves of rainfall through the region.
Today will be the most pleasant of the next few, we see relatively pleasant temperatures for the latter portion of September under mixed to cloudy skies. The cloud is courtesy a large weather disturbance moving into the region driven by a strong upper-level trough1 developing over much of western North America.
Winnipeg will see increasing cloud through the day as easterly winds pick up to around 20 km/h and temperatures climb to around 17°C. As the evening progresses, the entire Red River Valley will see an increasing chance of rain as precipitation lifts northeastwards with the warm front of this system. Precipitation amounts will likely be in the 5-15 mm range with this first wave, although if heavier convective pockets form, localized amounts of 15-25 mm may be possible.
A deep upper-level trough is developing over western North America, and is forecast to extend from the northern tip of Yukon Territory all the way to the southern New Mexico border by Saturday morning.
Saturday morning will start with overcast skies with the chance of drizzle throughout much of the Red River Valley. Winds will be out of the southeast at 20-30 km/h with relatively warm temperatures—a high near 22°C is expected–but the main weather story will be a cold front pushing from the southwest to the northeast through the afternoon and evening. As it lifts northeastwards, a large band of rain is expected to develop along it and give another 5-15 mm in about a 3-6 hour window. Here in the Red River Valley I expect it to move through early Saturday night, but with complex systems like these, its possible that timing could change by 4-6 hours either way. We’ll keep an eye on it as things develop.
A cold front will push across Southern Manitoba on Saturday as a large low pressure system lifts to the northeast.
The cloud will likely break up a bit on Saturday night as winds taper off a bit and temperatures head to a low near 12°C.
We won’t be free from the clutches of this system on Sunday either. There’s a chance we have a nice start to the day with some sunshine, but things will quickly cloud up as a fair amount of wrap-around cloud and showers move in from the north behind this low pressure system. For areas that see rain, amounts should be fairly light with accumulations more in the 2-5 mm range, but will be accompanied by brisk northwesterly winds and a high near 17°C. The scattered showers will likely hang round through the overnight period as temperatures head down to a low near 10°C.
Summary
It won’t rain non-stop all weekend. It appears that the rain will come through 3 waves: first on Friday evening/night, then on Saturday afternoon/evening, and then on Sunday sometime midday to the evening and persisting until Monday morning. Rainfall totals will vary, but guidance suggests the heaviest rainfall will occur in Saskatchewan, clipping through Parkland Manitoba with over 50 mm possible.
Here in the Red River Valley, there may end up being a strong discrepancy of rainfall accumulation based on location, but in general totals of 10-30 mm seem possible at this point.
It’s worth noting that relatively minor variations in track of this particular system could result in significant shifts in how much rain we’ll see, so updates will be provided if needed as the weekend rolls on.
Long Range
After we escape the clutches of this system on Monday morning, conditions look fairly good through the remainder of the week. At this point, it appears Winnipeg will see near-seasonal highs in the mid- to upper-teens and overnight lows dipping just below 10°C through much of the week. Not a lot of cloud is expected, and winds look to to be fairly light. So a bit of a crummy weekend, but we’ll be making up for it with a stretch of pleasant fall weather!
An upper-level trough is a feature in the upper atmosphere that is evident via a large dip southwards in the jet stream. ↩
Cloudier conditions will be on tap for Winnipeg & the Red River Valley through the remainder of the work week, however with little precipitation expected and seasonal to slightly above seasonal temperatures, conditions will be fairly pleasant.
Skies will be mixed to cloudy across Winnipeg & the Red River Valley today as a complex disturbance in the United States spreads cloud across much of the Southern Prairies. A chance of showers exists along the American border, but further north the chance drops off quite quickly. Winds will be fairly light as temperatures climb to a high near 18°C. Heading through tonight, skies will be partly cloudy to mixed as temperatures drop to a low near 7°C.
With the jet stream riding across the southern Prairies, southern Manitoba will see cloudier conditions with a chance for some shower activity near the American border.
Thursday will likely start with partly cloudy skies, but see more cloud cover move in through midday. Temperatures top out near 18°C with fairly light winds. Expect cloudy conditions on Thursday night as temperatures dip to around 8°C.
Friday is a bit of a wildcard at this point, but it appears that morning cloud will give way to some afternoon sun before more cloud cover moves into the region on Friday night. Temperatures will top out near 19°C with winds out of the east at 20-30 km/h.
Friday night will bring cloudy skies with a good chance of rain as a more organized area of rain moves from southern Saskatchewan and southwestern Manitoba into the Red River Valley.
Long Range
The weekend is looking quite unsettled and wet with rain likely both Saturday and Sunday as a slow moving upper-low moves towards the region. At this point, it looks like there may be a significant convective element to this system, meaning that rainfall amounts could be highly variable across the region. Daytime highs will continue to sit near 17°C through the weekend with overnight lows in the low teens.
Winnipeg’s seasonal daytime high is currently 17°C while the seasonal overnight low is 5°C.
