Winnipeg Set For A Mild Weekend, But A Big Cool Down Looms on Horizon

The mild weather Winnipeg has seen lately will last for a few more days, but a low pressure system that tracks across the northern United States on Sunday night will usher in a major pattern change which will allow Arctic air to spill southwards across the Prairies, bringing significantly colder temperatures to southern Manitoba.

Warm, unremarkable weather is on tap for Winnipeg today and tomorrow as a slack flow remains over the region with just a few very weak upper-level disturbances moving through. A weak upper-level disturbance moving into the region will bring increasing cloudiness today as temperatures head to a high near +1°C. No precipitation is expected and winds will remain light. Temperatures will dip down to a low near -7°C tonight with the clouds clearing out by Saturday morning.

Winnipeg will see partly cloudy skies on Saturday with temperatures rebounding to a high near 0°C with light southerly winds. Temperatures will then dip to a low near -6°C on Saturday night with increasing cloudiness.

Everything begins to change on Sunday as a low pressure system develops across the northern Plains of the United States. There’s still a fair amount of uncertainty associated with this low; some models want to keep it relatively progressive and move it through South Dakota, while others develop a more potent Colorado Low that lifts northeastwards towards Thunder Bay. Either way, it should bring mainly cloudy skies to the region on Sunday with a chance for snow moving in on Sunday night. Given the significant uncertainty with this system, an update on what to expect will be posted sometime Saturday evening or Sunday morning.

Long Range Outlook

Without question, the biggest aspect of the long-range forecast is the dramatic cool-down that will occur next week.

By Tuesday morning a much cooler air mass is forecast to be in place over the province

As Sunday’s low pushes eastwards, a large upper-level ridge will build over British Columbia, remaining anchored over the Rockies. A large upper-level trough will develop over eastern North America, bolstered by the incoming low pressure system from the Northern Plains.

This pattern will result in a steady northwesterly flow over the Prairies, setting up an Arctic pipeline that will usher much colder air southwards into the Prairies. It appears that by mid-week, daytime highs in Winnipeg may fall into the mid-minus teens. Another way: by the middle of next week, Winnipeg’s daytime highs may fall to what the seasonal overnight lows are for this time of year.

So, enjoy the mild weather while it lasts, by this time next week it will be a whole lot colder than it is now!

Winnipeg’s seasonal daytime high is currently -7°C while the seasonal overnight low is -16°C.

Warmer, Cloudier Weather Ahead

Winnipeg will see mixed to cloudy skies over the coming days as near-seasonal temperatures return to the region. The milder weather will continue until the end of the week, brought to an end by a low pressure system moving through that will usher Arctic air back into the southern Prairies.

Today will bring more cloud to Winnipeg as warmer temperatures move into the region. Highs will climb to around the freezing mark today as south-southeasterly winds pick up to 20 km/h. A few sunny breaks may show up later in the day, however southeasterly winds tend to keep the low cloud stuck in the Valley until a westerly component can develop, so we may see the cloud stick around all day. Winnipeg should see variable cloudiness overnight with winds continuing out of the south near 20 km/h. Temperatures will dip to a low near -3°C.

On Tuesday, a low pressure system will cross through the province, bringing with it variable cloudiness and winds that gradually diminish while shifting more westerly. No rain or snow is expected for Winnipeg and temperatures will climb to a high near +1°C. More cloud will move into the Red River Valley on Tuesday night as winds shift northwesterly behind a cold front and winds pick up to around 30 km/h. Temperatures will dip down to a low near -7°C.

RDPS Forecast 850mb Temperatures valid 12Z Tuesday November 14 to 00Z Wednesday November 15, 2017
The forecast 850mb temperatures show the cooler air pushing southwards behind the cold front as the day progresses

Wednesday will bring cooler temperatures to Winnipeg alongside cloudy skies. Highs will climb back to just around -5°C as northerly winds gradually taper off through the day. There will be a slight chance of flurries, but it looks like there’s no significant chance of accumulating snow. Winds will continue to taper off on Wednesday night as a ridge of high pressure moves into the province, sending temperatures down to lows around -9 or -10°C.

Long Range Outlook

Temperatures will climb back towards seasonal values for Thursday and Friday as another low pressure system begins working it’s way into the western Prairies. Thursday night into Friday looks to bring the chance of some snow as the low passes, then much cooler weather will move back into the province once again, sending highs back down to the -8 to -10°C range with overnight lows dipping back into the mid-minus teens.

Winnipeg’s seasonal daytime high is currently -1°C while the seasonal overnight low is -9°C.

Sunny Skies, Cooler Temperatures, Build Into The Red River Valley

After several days of cloudier conditions, Winnipeg and the Red River Valley will see the sun return for the second half of the week.

The low pressure system that brought a few showers to Winnipeg over the past couple days — although more notably a major winter storm to the southwestern Prairies — is finally making its way out of the region. The upper-level support will finish moving out of the province this morning with mostly cloudy skies giving way to afternoon clearing. Temperatures will climb to a high near 13°C this afternoon with winds picking up out of the southwest to around 30 km/h.

Temperatures will be quite cool tonight as a shot of Arctic air moves through the region. Under clear skies and diminishing winds, overnight lows will dip down to around the +1°C mark in Winnipeg, however that’s for most of the urban areas. At the edges of the city, as well as into the Red River Valley, overnight lows may dip down to the 0 to -2°C range. There will be a risk of frost throughout the region, including Winnipeg.

RDPS Forecast 2m Temperature valid 12Z Thursday October 5, 2017
The Red River Valley will see a risk of frost early Thursday morning as temperatures dip near or below the freezing mark.

Thursday will bring mainly sunny skies to Winnipeg with light winds as a ridge of high pressure slumps through the southern Prairies. Temperatures will be near seasonal with highs climbing to around 13°C again in Winnipeg and overnight lows dipping back down to around the +3°C mark.

Friday will also bring sunny skies to the region with a light southerly wind developing in response to a low pressure system building into the far northern Prairies. Daytime highs will climb up to around 16°C as slightly warmer air pushes northwards, and overnight lows will follow suit dropping to only around 6°C.

Long Range

Conditions look fairly dry for the next while, although a more significant pattern change will move in for early next week. Temperatures look to climb into the upper teens on Saturday with breezy southerly winds, with a cold front then passing through on Saturday evening. At this point, the passage of the front looks dry, and will be followed by a second cold front moving through the region on Sunday night.

GDPS Forecast 500mb Height Anomaly valid 12Z Monday October 9, 2017
A large upper-level trough (shown in blues and purples) will develop over the Prairies early next week, bringing below-seasonal temperatures to the Prairies.

That will leave the Prairies underneath a large upper-trough for Thanksgiving Monday. Temperatures will be below normal with highs just in the upper single digits under cloudy skies with a breezy northwesterly wind and a chance of showers. The road to recovery will be slow, with temperatures gradually rebounding towards seasonal through the remainder of the week.

The Sun Makes A Return

After a streak of cloudy and wet weather which brought the most significant multi-day rainfall totals of 2017 to Winnipeg, the sun is finally set to return. Winnipeg will enjoy several relatively sunny days ahead with temperatures rebounding back towards seasonal values.

After seeing 65.1 mm of rain in the past 10 days, Winnipeg is poised to enjoy a few days to finish drying out1 as fairly benign weather returns to the region. Today will be quite a pleasant day; skies will start off sunny this morning and become more mixed in the afternoon with temperatures climbing to an above-seasonal high near 18°C. Winds will be light until a weak cold front passes through this afternoon, after which they’ll switch to the northwest at around 20-30 km/h for a few hours before diminishing near sunset. Skies will remain partly cloudy to mixed overnight with temperatures dipping to a low near 7°C.

RDPS 2m Temperature Forecast valid 21Z Wednesday September 27, 2017
Temperatures will climb into the upper teens this afternoon across southern Manitoba

Thursday’s main driver for the weather will be a large ridge of high pressure building southwards out of the Arctic. As it pushes towards the southern Manitoba, it will keep winds out of the north at 20-30 km/h with slightly cooler temperatures in place as highs climb to a seasonal 16°C. Skies will remain partly cloudy much of the day. Thursday night will be a cool one as the high pressure centre moves across Southern Manitoba. Temperatures will dip to a low near 2°C with patchy frost an outside chance, but it looks relatively likely (for now) that extensive fog development may occur through the night, which would likely keep lows above the freezing mark. That said, it’ll certainly be cool, so if you have temperature-sensitive plans, probably best to take care of them before Thursday night.

GDPS 2m Temperature Forecast valid 12Z Friday September 29, 2017
The GDPS suggests a patchy freeze will be possible on Friday morning

Friday will bring mainly sunny skies to Winnipeg & the Red River Valley, outside of any fog that may be in the region in the morning. As the high pressure system moves off to the southeast, it will bring southerly winds at around 10-20 km/h as temperatures climb to a high near 16°C again. Temperatures will dip to a low near 8°C on Friday night with winds increasing out of the south to 20-30 km/h.

Long Range

Warmer, but windy, weather will move into the Red River Valley on Saturday with daytime highs climbing towards the 20°C mark as an upper ridge pushes into the eastern Prairies. Conditions begin turning on Sunday as another significant low pressure system moves towards the region. During the day on Sunday will likely be mild, although cloudy, with breezy southeasterly winds. At some point, there will be a more organized chance for rain; likely on Sunday night into Monday morning, but it could easily shift by 12 hours between now and then.

The work week will start off with seasonal temperatures and some lingering unsettled weather until things clear up mid-week again.

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

  1. And perhaps letting the grass grow long enough to need to be cut again…