Sunny Monday Gives Way to Unsettled and Cooler Conditions

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Winnipeg will see a sunny and mild Monday, but cooler weather and unsettled conditions return for the rest of the week.

A weak upper ridge will bring sunny skies and mild temperatures to Winnipeg today. Temperatures will climb to a high near 23°C this afternoon with southerly winds strengthening into the 20 to 30 km/h range. An approaching trough will bring increasing cloud tonight and keep the southerly winds up around 20 km/h. Winnipeg’s temperature will dip to a low near 13°C.

A digging upper-level trough will bring unsettled conditions to the region on Tuesday. With cloudy skies, showers will spread across the region from west to east through the day. More rain will certainly be a concern to waterlogged areas that saw 50 to 100 mm of rain last week; fortunately, this system doesn’t look too strong. Most areas will only see 4 to 8 mm through the day. Winnipeg may find itself on the northern edge of the rain; if so, the city could escape with just a couple mm.

Temperatures will be comparatively cool with a high near 16°C and light winds. Winds will gradually shift west-northwest through the night at 15 to 25 km/h. As they shift, the cooler air moving into the region will help generate lake-effect streamers. This will keep mixed to cloudy skies through the Red River Valley on Tuesday night with a continued chance of drizzle or showers. Temperatures in Winnipeg will dip to a low near 8°C.

More showers will move across southern Mantioba on Tuesday
More showers will move across southern Mantioba on Tuesday

Winnipeg will see mixed skies on Wednesday with northwest winds near 30 km/h. The chance for drizzle or showers will continue off the lakes, but become weaker and more isolated into the afternoon. Temperatures in the city will top out around 14°C. A ridge moving into the region will ease the winds on Wednesday night and send temperatures to a low near +3°C.

Long Range Outlook

Thursday will bring a short break from unsettled conditions as a ridge of high pressure moves through. Things quickly turn around for Friday, though, as another low pressure system moves across the southern Prairies. Another 5 to 15 mm look possible Friday afternoon through Saturday. Cooler weather will return for the end of the weekend with more lake-effect showers possible.

Today’s seasonal daytime high in Winnipeg is 16°C while the seasonal overnight low is 5°C.

Severe Thunderstorm Threat Returns to Southern Manitoba

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Winnipeg will see several rounds of thunderstorms over the next 36 hours, some of which may be severe.

A sharp long-wave trough moving into the region will produce several rounds of thunderstorms over the Red River Valley through the next 36 hours. The initial wave of thunderstorms is pushing through the Red River Valley already. These storms produced a variety of severe weather overnight as they moved through Saskatchewan and southwest Manitoba and will continue to pose a slight chance of producing severe hail or wind gusts.

A large mesoscale convective system developed over SE Saskatchewan into Manitoba on Thursday night and is bringing strong to severe thunderstorms to the Red River Valley this morning.

After those storms move through, Winnipeg should see mixed skies with temperatures increasing to a high near 25°C. Winds will be breezy out of the southeast at 30 gusting 50 km/h.

Another round of thunderstorms will develop later today, likely producing a swath of severe weather extending from the southwest corner of the province right through to Ontario. The storms will begin this afternoon over the southwestern corner of the province and then move through the Red River Valley through the evening. These thunderstorms will be capable of large hail, severe wind gusts, and torrential downpours causing flash flooding.1 It will be a complex and dynamic system this evening, so be sure to stay aware of any watches or warnings issued by ECCC later today.

Another line of strong to severe thunderstorms will move thorugh southern Manitoba later today.
Another line of strong to severe thunderstorms will move thorugh southern Manitoba later today.

Saturday morning will likely bring a brief reprieve before an upper low moves into the region. As it moves in, more showers and thunderstorms are forecast to develop. There will be less energy for the storms to utilize, but they may still produce some hail and rather heavy downpours.2 The unsettled conditions will keep things cool with a high near 20°C expected in Winnipeg. Winds will be light to start the day, but pick up out of the northwest late in the day. Temperatures will drop to a low near 12°C with a northwest wind of 20 to 30 km/h and a continued chance of showers on Saturday night.

Conditions will finally settle for Sunday. Skies will gradually clear out with a northwest wind of 20 to 30 km/h. Winnipeg can expect a high near 19°C. A ridge of high pressure will move in on Sunday night, bringing calm winds and a low near 6°C.

Long Range Outlook

Much of next week looks to bring variable cloudiness and warm to seasonal temperatures. By the end of the week, conditions may turn cloudier with a chance of showers.

Today’s seasonal daytime high in Winnipeg is 17°C while the seasonal overnight low is 5°C.

  1. MLCAPE values near 2000 J/kg combined with 35 knots of deep shear and a perpendicular warm front orientation should support squall-line structures with large hail and strong winds. PWAT values climbing to 50 mm will ensure that the thunderstorms produce heavy rain, and rapid accumulations with flash flooding is possible in any areas that see slower-moving or training thunderstorms. ↩
  2. MLCAPE values near 500 J/kg will combine with bulk shear values of 40 to 50 knots to produce widespread showers with embedded thunderstorms. PWAT values of 35 mm will support moderate to heavy rainfall rates. ↩

Seasonably Warm with Unsettled Conditions Ahead

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Unsettled conditions will usher in cooler, but still mild, temperatures and less humid conditions for Thursday, but more humidity and rain looks likely on Friday.

The hot and humid weather Winnipeg has seen over the past couple days will come to an end today. A low pressure moving across the province will bring mixed skies to the Red River Valley as it gradually pushes the humid air off to the east. The region will have a chance of seeing some showers or thunderstorms, particularly midday into the afternoon, but most of the activity should keep to the west and north of Winnipeg. Temperatures will be a bit cooler today than the last couple, but still above-seasonal with a high near 24°C.

As the day progresses, winds will pick up out of the west into the 20 to 30 km/h range, then shift northwest in the evening as they taper off. Temperatures will head to a low near 13°C. Despite the cooler low, there’s still a chance that Winnipeg may break its record warm minimum temperature for September 18. The city managed to break yesterday’s warm minimum record – 17.8°C set in 1946 – with a minimum of 21.3°C. If temperatures can stay above 15.8°C until 1 AM, then the city will break the previous record set in 1964.

Farily humid conditions will linger through the afternoon before northwest winds move into the region this evening, ushering in a drier air mass.
Farily humid conditions will linger through the afternoon before northwest winds move into the region this evening, ushering in a drier air mass.

Thursday will be a pleasant day across the region as a ridge of high pressure moves through. Expect mainly sunny skies, light winds, and a high near 22°C. The next disturbance on the way will spread cloud into the region on Thursday night as temperatures head to a low near 14°C.

Friday will bring the next significant low pressure system to southern Manitoba. The low is forecast to organize over central North Dakota on Friday, then move across the Red River Valley on Friday night. It will spread showers and thunderstorms into southern Manitoba through the day Friday, that will further organize and strengthen into Friday night. This system will be capable of producing heavy rainfall as it taps into that same humid air that was over Winnipeg on Monday and Tuesday.

It’s still a bit early to be specific in the forecast, but in general it looks like much of southern Manitoba will see showers and thunderstorms with 25 to 50 mm of rain by the end of Saturday. The biggest uncertainties will be when the rain begins—some suggest early Friday, other models keep the rain off until late in the day—and how banded in nature the heavy rain is. Either way, wet weather looks to be back on the way for Friday into Saturday.

Other than the rain, Friday will be seasonably warm with a high near 25°C. A southerly wind of 20 to 30 km/h will draw some humidity back north, making it feel a bit humid out and ensuring that it stays on the warmer side while it rains.

Long Range Outlook

Generally unsettled conditions look to persist through the weekend with the chance for showers continuing Saturday night and mixed to cloudy skies on Sunday with the chance for a few more showers. Temperatures will return to seasonal values this weekend, then continue at seasonal to slightly above-seasonal values through next week.

Today’s seasonal daytime high in Winnipeg is 17°C while the seasonal overnight low is 6°C.

Hot & Humid Weather Returns to Winnipeg

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Summer returns to Winnipeg as hot and humid conditions move in to start the week.

Winnipeg will see hot and humid weather today with plenty of sunshine. The city will see a high near 29°C today with notable humidity developing for the afternoon. Dew point temperatures will rise to 19 to 20°C by the end of the day, making it feel quite muggy out. Winds will be relatively light today out of the southeast at 20 km/h.

Humid conditions will continue tonight, keeping temperatures warm. The city will see a low of just 20°C with a few clouds moving in.

The hot and humid weather continues on Tuesday with a high near 30°C and partly cloudy skies. Winds will be stronger, increasing out of the south to around 30 gusting 50 km/h by the end of the day. Temperatures will head to a low near 20°C again on Tuesday night under mixed skies.

Dew point values will settle near 20°C by the end of the day on Monday, making it feel very humid.
Dew point values will settle near 20°C by the end of the day on Monday, making it feel very humid.

The heat will finally break on Wednesday as a low pressure system moves through the region. As it moves through, it will bring mixed to cloudy skies with a chance of showers or thunderstorms. Winds will shift westerly in the morning and increase to around 30 gusting 50 km/h. The humidity will stay for much of the day with dew points remaining in the upper teens. A cold front will push through on Wednesday evening, bringing northwesterly winds to the region that will push the humidity out. Temperatures will dip to a low near 12°C.

The warm nights ahead won’t just be seasonably mild, they may end up being record breakers. New record warm minimum temperatures may be set for September 17 and 18th. If temperatures stay above 20°C on both days, it will easily beat the current records of 17.8°C (1946) and 15.6°C (1964) respectively.

Long Range Outlook

The second half of the week will continue to be seasonably warm with daytime highs in the mid-twenties. Humidity will return to the region on Friday ahead of a major low pressure system. Showers and thunderstorms will spread across southern Saskatchewan into Manitoba on Friday. Unsettled weather will move through the region on Saturday, followed by calmer conditions and seasonal temperatures on Sunday.

Today’s seasonal daytime high in Winnipeg is 18°C while the seasonal overnight low is 6°C.