Beautiful September Weather Ahead for Winnipeg

With temperatures into the 20s in the coming days, Winnipeg will see some beautiful late-September conditions. But a change late in the week will usher in a period of unsettled conditions.

RDPS 2m Temperature Forecast valid 21Z Tuesday September 26, 2023
Southern Manitoba will see mild temperatures this afternoon as a weak ride of high pressure keeps winds light.

There will be no complaints about the next couple days in Winnipeg as an upper ridge brings sunshine and warmer temperatures back to the region. Highs will climb into the mid-20s today in Winnipeg with light winds as a weak surface ridge lingers over the region. Skies will be sunny through the day and into the night. Temperatures will dip down to around 10 °C tonight.

On Wednesday, temperatures will climb back into the low 20s as a few clouds build into the region along with breezy southerly winds. By mid-afternoon, most of the Red River Valley should see southerlies up into the 30 to 40 km/h range. Those winds will continue overnight in the 20 to 30 km/h range, keeping lows mild in the mid-teens. Along with the wind, skies will likely cloud over as a trough of low pressure moves towards the region.

On Thursday, winds will strengthen to 40 gusting 60 km/h by midday in the Red River Valley. These winds will be strongest just ahead of the warm-sector trough crossing through the Red River Valley. As the day progresses, a mid-level disturbance is forecast to eject northeastwards out of the United States; this could bring showers or non-severe thunderstorms to parts of southwestern Manitoba or the Red River Valley on Thursday afternoon. Temperatures will again climb to around the 20 °C mark.

A weak cold front will push through the region on Thursday night, clearing skies out and allowing the lows to dip back into the single digits.

Long Range Outlook

A series of disturbances will push over southern Manitoba heading towards the weekend thanks to a deepening long-wave trough on the west coast that will continuously eject shortwaves northeastwards. This will likely mean seasonably mild temperatures, mixed to cloudy skies, and chances for areas of showers almost each day.

Current forecasts hold this pattern until early next week, after which cooler air will push back into the region with a return to near-seasonal temperatures.

Today’s seasonal daytime high in Winnipeg is 15 °C while the seasonal overnight low is +4 °C.

Warm With Increasing Humidity This Week in Winnipeg

After the scorching heat last week in the Winnipeg region, it might seem like this week will be cooler with highs of only the upper 20s. That slight cooling will be offset by more humidity in the region, with humidity levels possibly reaching downright muggy levels by Friday.

GDPS 2m Dew Point Temperature Forecast valid 00Z June 3, 2023
A extended southerly flow will bring a more humid air mass from the Gulf of Mexico northwards to southern Manitoba by the week’s end.

It will be another unsettled day in the Winnipeg area thanks to a shortwave lifting across the region from the Dakotas. As it moves into the warm and relatively humid air mass in our region, scattered showers and thunderstorms will once again develop. These will persist through the afternoon and into the evening before tapering off.  The city will see a high in the mid-20s give way to an overnight low in the mid-teens.

Heading into mid-week, an upper ridge will begin to build over Central Canada. It will bring warmer temperatures to the region while also supporting a deep southerly flow from the Gulf of Mexico northwards through the American Plains. Daytime highs will rise into the upper 20s, but at the same time, an increasingly muggy air mass will build northwards. Dew point temperatures will increase from around the mid-teens to close to 20 °C by Friday. This will make for very muggy conditions to end the week that will make the highs in the upper 20s feel more like the mid-30s.

Along with the heat and humidity will come some unsettled conditions as well. Isolated to scattered [thunder]showers may be possible as the week progresses.

Long Range Outlook

Very warm conditions will return for the weekend with daytime highs likely climbing into the low 30s. If the humidity remains high, then it would almost certainly result in another heat warning for Winnipeg and the Red River Valley. Again, though, it won’t be completely stable and some showers or thunderstorms will be possible through the weekend.

More settled conditions will return next week as the humidity begins to leave the region. With a drier air mass, highs will hover in the upper 20s with overnight lows in the mid-teens through the first half of next week.

Today’s seasonal daytime high in Winnipeg is 22 °C while the seasonal overnight low is 8 °C.

Seasonal Warmth Returns to Winnipeg

Winnipeg will see temperatures climb back towards seasonal values after this week’s late-season cold snap.

A low pressure system crossing the northern Prairies will usher warmer conditions back to southern Manitoba. Under sunny skies, southerly winds will increase to 40 gusting 60 km/h this afternoon. Temperatures will climb into the upper teens; Winnipeg should see a high near 19 °C. Tonight, an approaching trough will keep winds around 30 km/h as it spreads clouds into the region. Temperatures will dip to a low near 9 °C in Winnipeg.

On Saturday, Winnipeg will see cloudier skies as the trough moves into the Red River Valley. It will bring a chance of showers to the region, but it will weaken through the day as its main energy source pulls away to the south. Winds will stay out of the south again in the 30–40 km/h range. The winds will finally ease on Saturday night to 15–25 km/h with a low near 10 °C.

RDPS 2m Temperature Forecast valid 21Z Sunday May 30, 2021
Warmer weather will return to Winnipeg this weekend.

On Sunday, a weak cold front will sweep through the region. It won’t bring more than partly cloudy skies with breezy northwest winds for the afternoon. The high in Winnipeg will be around 22 °C. Skies will stay clear on Sunday night with a low near 7 °C.

Long Range Outlook

Next week looks mainly dry across the Red River Valley with highs in the mid-20s. Overnight lows should see a boost and stay in the low to mid-teens through the week.

Today’s seasonal daytime high in Winnipeg is 22 °C while the seasonal overnight low is 8 °C.

Showers and Thunderstorms Move Into Southern Manitoba Wednesday Evening

A low pressure system over the American Plains will bring widespread showers and thunderstorms to southern Manitoba tonight.

More unsettled weather is on tap for southern Manitoba tonight as a warm front lifts northwards through the Northern Plains. Under increasing or mostly cloudy skies today, the Red River Valley will see temperatures climb to a high near 18°C. Winds will persist out of the northeast near 15-20 km/h.

The main event will begin this evening and persist through the night. As the warm front approaches the province this afternoon, showers will blossom over the Red River Valley and southeastern Manitoba. As the night progresses, the activity will organize along a southwest-northeast line parallel to the warm front, gradually shifting eastwards. Most areas in the Red River Valley will likely see showers and/or thunderstorms through the night. Given the convective nature of the rain, accumulations may be highly variable, but most1 areas should see 10-20 mm with the potential for over 40 mm in areas where thunderstorms linger for longer. Some gusty winds are possible in thunderstorms but will otherwise remain in the 10-20 km/h range. Temperatures will dip to a low near 14°C this evening then slowly rise to around 16°C on Thursday morning.

Forecast models have generally good agreement with the convective activity tonight, but amounts will likely be more variable than represented here.
Forecast models have generally good agreement with the convective activity tonight, but amounts will likely be more variable than represented here.

As this system departs on Thursday, it will leave behind abundant cloud cover with winds shifting out of the northwest at 15 to 25 km/h. Winnipeg may see a bit of light rain or drizzle in the morning, but things should dry out for the afternoon. Temperatures will be near-seasonal with a high near 19°C in Winnipeg. There’s a slight chance of some more showers or thunderstorms on Thursday afternoon and evening, but it will likely to remain in southeastern Manitoba and the southern Red River Valley. Skies will remain mostly cloudy on Thursday night with a low near 9°C.

Friday will bring a bit of sunshine as skies become mixed in the afternoon. Temperatures will be a tad warmer with a high near 21°C. Wind will remain light, making for a pleasant afternoon. Temperatures will dip to a low near 9°C on Friday night with mixed skies.

Long Range Outlook

Looking ahead to the weekend, another low pressure system is forecast to develop over the northern Plains. This system will will spread more cloud cover into to the region alongside a couple more chances for showers or thunderstorms.

Winnipeg’s seasonal daytime high is currently 19°C while the seasonal overnight low is 6°C.

  1. Again, given the variable nature of the precipitation, some areas may see nothing while nearby areas receive heavy rainfall.