Tag: Thunderstorms

Seasonal Temperatures With Unsettled Conditions

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Winnipeg will see seasonal temperatures in the mid-20s this week, but several passing disturbances will bring chances of showers or thunderstorms to the region.

RDPS 24-hour Precipitation Accumulation Forecast valid 12Z Wednesday August 23, 2023
Most of the organized shower activity on Tuesday will spread across the central Prairies, but a few showers are also possible further south in southern Manitoba.

Today will be another cooler day in Winnipeg as easterly winds undercut moisture streaming over the province in the upper-level flow. The city will see easterly winds around the 20 km/h mark much of the day. Skies will likely be cloudy through the day, but a few sunny breaks are possible in the Red River Valley and southeast corner of the province. North of the city in the Interlake, showers are likely through much of the day, while further south the best chances will be early in the morning, then again in the late afternoon. A few thundershowers may be embedded within these showers.

The showers will taper off this evening as the winds diminish and temperatures head to a low in the mid-teens. Skies will stay mainly cloudy overnight as the next disturbance approaches the region.

On Wednesday will be another cloudy day in Winnipeg. Showers and/or thunderstorms will likely push into the southwest corner of the province early in the day, then gradually spread eastwards through the day. By mid-afternoon, the chance of showers or thunderstorms will begin to increase in the Red River Valley. This activity will slump southeastwards through the evening and exit the province overnight. Temperatures will head down to a low in the upper teens on Wednesday night.

On Thursday, a bit of sun will return to the region, but cloud will push back in later in the day as another disturbance pushes towards the region from Alberta. More showers or thunderstorms will develop near the Saskatchewan/Manitoba border late in the day and then gradually spread eastwards through the evening. This will bring a chance of thunderstorms or showers to Winnipeg overnight, with a slight chance of showers lingering into Friday morning. The city will see the overnight low dip down into the mid-teens.

Regarding daytime highs, much of the week will bring near-seasonal highs in the low to mid-20s.

Long Range Outlook

Heading into the weekend, an upper ridge will begin to re-establish itself over the Prairies, bringing more settled conditions. Sunnier weather looks likely for the weekend with daytime highs climbing towards the upper 20s.

Today’s seasonal daytime high in Winnipeg is 24 °C while the seasonal overnight low is 11 °C.

Cool, Showery Weekend Ahead

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An upper low crossing the Prairies this weekend will keep temperatures cool in southern Manitoba with some showers or thunderstorms likely in the days ahead.

RDPS 12-hour Precipitation Accumulation valid 00Z Saturday August 12, 2023
Rainfall will be scattered throughout southern Manitoba today as showers and thunderstorms develop over the region.

A weak low pressure system will move across southern Manitoba today, the lingering feature from the system that brought 5 to 10 mm of rain to Winnipeg yesterday evening. As this low trundles into the Red River Valley this afternoon, it will support the development of scattered showers and thunderstorms. Severe weather is unlikely; energy will be limited with only 500 to 1000 J/kg of MLCAPE and bulk shear is also low at only around 15 to 20 knots. A marginally severe thunderstorm with large hail can’t be ruled out, but much of the area will mainly see the chance of showers and shorter-lived pulse thunderstorms.

Much of the activity will taper off in the evening, but a few showers may linger into the night, supported by both a shortwave sliding across the region and a weak trough extending from southern Manitoba northwestwards into central Saskatchewan.

On Saturday, the region will continue to see mixed skies with a slight chance of showers. Much less activity is expected than on Friday; there will be few, if any, features to support and organize showers. A bit of lingering instability may be left behind, but for the most part, mixed skies with just a slight chance of an isolated shower or two is most likely.

On Sunday, another low pressure system is poised to dive southeastwards through the province, bringing a good chance of rain to many parts of southern Manitoba. Some uncertainty remains on the track, but in general areas south of a line that runs roughly from Dauphin to the Whiteshell are likely to see accumulating rain at some point from early Sunday morning through the end of the day.

Temperatures over the next three days will be steady in the 20 to 25 °C while winds will generally be on the lighter side. Winds both today and tomorrow will mainly be westerly, while the passing low will shift the winds more northerly on Sunday.

Long-Range Outlook

It’s looking like unsettled conditions will continue into next week. Monday should bring a reprieve from any wet weather, but the chance of rain will return several times through the rest of the week. Winnipeg’s daytime highs and lows will sit at near-seasonal values through next week.

Today’s seasonal daytime high in Winnipeg is 26 °C while the seasonal overnight low is 12 °C.

Heat Builds in for the Weekend

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An upper ridge building into the eastern Prairies will bring hot conditions to southern Manitoba this weekend.

RDPS 2m Temperature Forecast valid 21Z Sunday July 2, 2023RDPS 2m Dew Point Temperature Forecast valid 21Z Sunday July 2, 2023
Sunday will bring the warmest weather of the next few days as hot temperatures and high humidity build into the region.

Seasonably warm conditions will build into southern Manitoba over the next few days with daytime highs climbing towards the 30 °C mark. In Winnipeg, today will bring mainly sunny skies that give way to some cloud in the afternoon while a ridge of high pressure brings sunny skies for Saturday.

Temperatures both days will climb into the upper 20s. Humidity levels will be comfortable in the mid- teens both days. For those heading out to enjoy Canada Day ???????? on Saturday, it will be a beautiful day to spend time outdoors!

On Sunday, the heat will really arrive as temperatures climb into the low 30s with increasing humidity. By the late afternoon, dew point values could reach as high as 20 °C, which would make it feel more like the upper 30s.

On Sunday afternoon, a warm-sector trough — typically an area of lower pressure near the middle of a large area of warmer air — will begin pushing across southern Manitoba. This feature will be an area of concern for severe thunderstorm development later on Sunday.

The thunderstorm potential will be significant on Sunday thanks to ample heat and humidity at the surface and relatively cool temperatures aloft. MLCAPE values could exceed 2,000 J/kg in an environment with 20 to 30 knots of 0–6 km bulk shear. Veering wind profiles would support supercell structures, but moderate westerly forcing along the line would likely support upscale growth into the evening hours. Capping will be marginal — 700 mb temperatures are forecast to be around 9 °C — so there is uncertainty with where the southern end of the line would develop. Wind profiles aren’t overly backed at the surface, so this setup wouldn’t likely produce a widespread tornado threat. If a thunderstorm was able to tap into all the available energy, though, an isolated tornado threat could develop. More likely, these thunderstorms would be capable of severe hail and torrential rainfall.

The details of this could change between now and Sunday, but at this point it looks like Sunday will be the hottest day of the next few and bring an organized severe weather risk to the region for late in the day.

Long Range Outlook

A weak cold front will push through Sunday night easing the humidity across the region.

Through the start of next week, temperatures should sit closer to seasonal values with variable cloudiness as cooler air moves in under a slow-moving upper trough that moves into the region. Some showers could be possible, but right now it looks like the start of the week will be mostly dry for Winnipeg.

Today’s seasonal daytime high in Winnipeg is 25 °C while the seasonal overnight low is 13 °C.

Unsettled Weather Shifts Towards Sunnier and Warmer Conditions For The Weekend

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Thunderstorms will be possible for another couple days across southern Manitoba. By the end of the week, an upper ridge moving across the Prairies will bring calmer, warmer weather to the region.

NSSL-WRF Simulated Reflectivity Forecast valid 22Z Tuesday June 27, 2023
Scattered thunderstorm activity is expected to develop across southern Manitoba and North Dakota this afternoon.

The weather over the next few days will be driven by a disturbance slumping southeastwards across the Prairies into southern Manitoba. As it dips southwards, its cool air aloft will encounter a warmer air mass with more moisture in it. These two features combined will result in a couple days of unsettled conditions over southern Manitoba.

Today will start out with a chance of showers or thunderstorms in the general Winnipeg area; while it’s a bit uncertain as of writing, lingering instability combined with the northward push of a warm front could be enough to trigger some morning convection. If it develops, it should push eastwards out of the area through the morning hours.

Once any morning convection clears out, it won’t take too long for things to get cooking. With mixed skies, most areas will see temperatures climb into the upper 20s fairly quickly. By early afternoon, scattered convection will likely begin to develop across southern Manitoba. With moderate instability and limited wind shear — around 1,000–1,500 J/kg of MLCAPE and 15–25 knots of bulk shear — there will be a risk of severe thunderstorms but it’s not looking like a widespread severe weather day. The most likely area for severe weather will be northwest of Winnipeg, especially in Parkland Manitoba and along the escarpment areas, but there is a small risk of an isolated severe thunderstorm in areas further southeast like Winnipeg.

The biggest unknown with the afternoon convection will be (a) if/where morning thunderstorms develop and (b) what the strength of the cold pool they may leave behind would be. That cold pool could work both ways, limiting thunderstorm development over it, but also acting as a focus along its boundaries to help trigger thunderstorm development.

Much of the activity will diminish tonight with temperatures heading down to a low in the mid-teens. There’s a small chance of an isolated shower or thunderstorm by early Wednesday morning.

On Wednesday, the upper low will dip through southern Manitoba, bringing similar instability, slightly better shear, and less inhibition of thunderstorm development. Scattered thunderstorm activity will develop across the region on Wednesday with mixed to cloudier skies. There will again be a risk of isolated severe thunderstorms.

By Thursday, the upper low will beginning to exit the province. Behind it, an upper ridge will be building eastwards across the Prairies. Skies will likely be mixed and there’s a chance a few showers might linger into the day, but things should really begin to clear out by the afternoon. Temperatures will be a bit cooler in the wake of the upper low with highs in the low to mid-20s. Skies will clear out on Thursday night with temperatures heading to a low in the mid-teens.

Long Range Outlook

The upper ridge will continue to build into the province for the end of the week, bringing sunny skies and warm weather. Temperatures will climb into the upper 20s for Friday, Saturday, and Sunday with relatively light winds shifting from northerly to westerly through the days.

Early indications are that a disturbance will begin working its way into the province later Sunday, bringing a chance of thunderstorms on Sunday night into Monday.

Today’s seasonal daytime high in Winnipeg is 25 °C while the seasonal overnight low is 12 °C.