Author: Brad

Brad lives in Winnipeg with his wife and two children and is the founder of A Weather Moment. He has loved weather from a very young age and has followed that passion through his life so far. He received a B.Sc. in Earth Sciences with Specialization in Atmospheric Sciences and is currently employed in the field of meteorology. You can find the author as WeatherInThePeg on Mastodon.

Warm With A Chance of Thunderstorms, Then Turning Drier

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The weather returns to slightly warmer than normal summer fare for Winnipeg to start the week with highs in the upper 20’s and mild lows. It will also be relatively dry, with the only significant chance for rain coming on Monday night as a cold front slowly moves through the Red River Valley.

Today will be a warm and windy day in Winnipeg as breezy southerlies bring summer heat and slightly muggy conditions to the Red River Valley. Skies will become mixed fairly early in the morning as the south-to-southeasterly winds ramp up to 30-40 km/h. These gusty southerly winds will bring mild temperatures into the region, pushing daytime highs just short of 30°C. In addition to the warmth, these winds will maintain the slightly humid conditions in place with dew points remaining in the 16-18°C range. Closer to the cold front — primarily over the southwestern corner of the province but also possibly into the western Red River Valley — moisture will pool and dew points will likely rise into the low 20’s, making for quite a muggy day in those areas.

A potent low pressure system over western Saskatchewan will spread gusty southerly winds across the Red River Valley on Monday afternoon.

By evening, a cold front will be pushing eastwards into the Red River Valley, bringing with it a chance of showers or thunderstorms to much of southern Manitoba.

Going over the MIST ingredients:

  • Moisture: Dew points will climb generally into the mid-teens, but elevated moisture is expected near the cold front as moderate southerly winds enhance moisture pooling ahead of the front. Moisture is also expected to be moderately deep, extending to roughly 850 mb.
  • Instability: Moderate mid-level lapse rates on the order of 7-8°C/km will combine with the low-level moisture to produce MLCAPE values of 1500-2000 J/kg.
  • Shear: Shear will be somewhat lacking with only 25-30 kt of 0-6 km bulk shear; this is fairly low and may be the real limiting factor in any thunderstorm activity that may develop.
  • Trigger: A pronounced cold frontal trough moving eastwards will provide the focus for any convective development.

Overall it seems that there will be enough energy available for severe thunderstorms, but the lack of shear will throw a wrench into the certainty of a large-scale severe weather outbreak.

The highest risk for severe weather in southern Manitoba will be over the southwestern corner where scattered thunderstorms first fire up along the cold front. These storms will have the potential to produce significant hail and strong winds. While an isolated tornado is possible, it won’t be an elevated threat with today’s thunderstorms. As the cold front moves eastwards through the evening and spreads the thunderstorm threat into the Red River Valley, the threat shifts towards favouring strong winds. Temperatures will bottom out overnight around 18-19°C with the winds tapering off.

This simulated RADAR image from the 3km NAM model shows a forecast of thunderstorms for the Red River Valley on Monday evening.

The weather then settles for Tuesday and Wednesday as a broad ridge of high pressure builds into the Prairies. Skies will clear and remain mainly sunny for much of Tuesday and Wednesday as temperatures climb to highs near 27°C both days. It will remain slightly humid with dew points remaining in the mid-teens through the middle of the week. With that humidity remaining in the region, it will keep overnight lows in the mid-teens as well.

Long Range

Gradual upper-level ridging will build into the Prairies late this week and into early next week, bringing continued mild weather and low probabilities of rain. The odd system may slide across southern Manitoba from the northwest, returning temperatures back to seasonal alongside a chance of showers. Overall, though, it appears Winnipeg and the Red River Valley will be entering into a fairly dry pattern.

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.

One More Chance of Severe Thunderstorms, Then Gradually Settling

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A threat of severe thunderstorms will develop across much of Southern Manitoba today as a low pressure system pushes eastwards out of Saskatchewan, however there are several potential hiccups that introduce some uncertainty to where the thunderstorms will actually end up developing. Moving into the weekend, temperatures will cool with highs near to slightly below seasonal and the unsettled weather will slowly improve.

Today is…complex. A huge number of variables are at play, all of which can impact the outcome of today with even small changes, and it’s important to state up front that this is being written on Thursday evening and that how thunderstorms develop overnight will have the potential to make a large impact on Friday’s weather.

With that out of the way: there’s a potential for significant thunderstorm activity later today across much of southern Manitoba. But first, this morning. To start the day, there may be some isolated to scattered thunderstorm activity across southern Manitoba that developed overnight. Any activity still going should weaken and diminish through the first half of the morning. Once that’s out of the way, Winnipeg & the RRV should see mixed skies with temperatures climbing up to a high near 27°C and east to southeasterly winds at 15-25 km/h.

Just one guess at what may happen today: perhaps a line of strong thunderstorms already near the Manitoba border in the early afternoon?

Severe thunderstorms are very likely in eastern Saskatchewan this afternoon, triggering along a warm front that is slowly sliding eastwards. These thunderstorms will push eastwards into southern Manitoba in the early evening, and then continue into the overnight hours. Near the Saskatchewan border, these thunderstorms will have a good chance of producing all manner of severe weather associated with thunderstorms: torrential rain, large hail, damaging winds, and/or a tornado. If they haven’t by the time they move into Manitoba, these thunderstorms will then quickly develop into a line of thunderstorms pushing eastwards and transition towards a primary threat of large hail and strong winds. There is the potential for this line of thunderstorms to develop bow echoes which are segments of the line that accelerate eastwards more quickly than the rest of the line as strong straight-line winds punch through them. It’s important to note that bow echoes can produce damage on par with weak tornadoes, so they can pose a danger to property.

Environment Canada’s thunderstorm outlook for today from yesterday afternoon sums up the severe weather potential well for Manitoba this evening.

The biggest question is what the extent of this line will be and exactly where it ends up. Some models suggest that the line will move through Parkland Manitoba & the Interlake with a gap through the Trans-Canada corridor and then a second set of storms further south, while others plow the line straight down the Trans-Canada Highway and through Winnipeg and the Red River Valley. The simple reality is that with highly dynamic setups like this, the best we can do is be aware of the hazard potential — primarily large hail and strong winds in the Red River Valley — and then monitor things as they develop and see where that hazard will end up being realized. We’ll be keeping an eye on things and sharing updates on social media, so be sure to give us a follow on Facebook or Twitter if you’d like to stay up to date!

Saturday will be dominated by a cold upper-level low moving through the region. This will keep temperatures a bit cooler than seasonal as breezy northwesterly winds move into the region. There will be a fairly good chance of some showers or thunderstorms in Winnipeg and the Red River Valley by late-morning and through the afternoon. No organized severe weather threat will exist, but some marginally severe hail1 may be possible. Additionally, with the cold upper low moving through, funnel clouds will be possible, although that looks more likely to the north and northeast of Winnipeg. Everything will settle down on Saturday night with clearing skies as temperatures dip to a low near 13°C.

A cold low over Manitoba on Saturday – seen by the dark green colouring around Winnipeg – will trigger showers and thunderstorms.

And finally, a quiet and calm Sunday is in store for Winnipeg with clear skies and a near-seasonal high around 25°C. Expect temperatures to drop into the mid-teens on Sunday night.

Long Range

Next week looks quieter with the only weather system of note moving through on Monday night, potentially bringing some scattered showers or thunderstorms to the region. Otherwise we expect near-seasonal temperatures for the remainder of the week with a fair amount of sunshine.

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.

  1. Environment & Climate Change Canada defines severe hail as hail with diameter of 20 mm or more. ↩

Warm with Risks of Thunderstorms

Brad 3 Comments

The second half of the work week will bring warm weather to Winnipeg with several chances for showers or thunderstorms.

Winnipeg will see a slight chance of a thunderstorm today as a weak disturbance rolls through the region. While this morning will bring some sunshine, conditions will cloud up midday with a chance of showers or thunderstorms throughout the afternoon. It will be relatively mild despite the cloudier afternoon conditions, though, with daytime highs reaching around 25°C. Winds will pick up out of the south this morning to around 30 gusting 50 km/h. Expect skies to clear out this evening as winds taper off and temperatures head to a low near 15°C.

Thursday will bring mainly sunny skies and warm temperatures as daytime highs climb to 29 or 30°C. Winds will be fairly light, making for a wonderful summer day. A disturbance moving through on Thursday evening will spread cloud into southern Manitoba and bring a chance of showers or thunderstorms overnight into early Friday morning. Temperatures will dip to a low near 17°C.

Despite the chances for rain today through Friday afternoon, some models manage to keep it outside Winnipeg.

Friday will be another warm day with highs around 29°C. An incoming low pressure system will begin spreading cloud into the region midday. By late-afternoon, skies should cloud up completely and yet another chance for showers or thunderstorms move into the region for Friday evening and overnight. Temperatures will dip to a low near 18°C.

Despite several chances for rain, overall there are no strong signals that it will affect a widespread area. As we show in the image above, some forecast models produce essentially no rainfall for Winnipeg. The one thing that can be said with some confidence? Areas closer to the international border have a higher chance of seeing something.

Long Range

The weather this weekend will largely be shaped by a low-moving low pressure system that will track across the province from northwest to southeast. Saturday will bring a chance of showers with risk of a thunderstorm to Winnipeg, which will then looks to transition into a chance of showers overnight into Sunday. High temperatures will likely be slightly below normal with highs in the lower 20’s, but overnight lows will be near-seasonal at around 13 or 14°C.

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.

Generally Mixed Weather Ahead

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Winnipeg will see a little bit of everything over the next few days as warm and humid conditions are replaced by a northwest wind that ushers in slightly cooler and much drier air. Winnipeg will also see several chances for thunderstorms this week.

This morning will start off cloudy with the chance of a thunderstorm for Winnipeg & much of the Red River Valley as elevated convection that developed overnight moves through the region. Behind the morning convection, temperatures will climb to a high near 28 or 29°C with winds of 15-25 km/h out of the northwest. It’ll get rather humid this morning with dew points climbing up to around the 18°C mark before drier air works in from the northwest for the afternoon. Skies will break up somewhat for the afternoon and then clear out in the late afternoon or evening. Temperatures will head to a low near 14°C under clear skies tonight.

Slightly cooler weather will be in place over Southern Manitoba on Tuesday

A ridge of high pressure will move across the province on Tuesday, bringing slightly cooler temperatures and mainly sunny skies for Winnipeg. A disturbance moving through North Dakota may spread cloud cover across the southern Red River Valley, but there’s still a bit of uncertainty about that. Temperatures will be just a touch below-seasonal for the latter half of June with a high near 25°C, but winds will be light, so it’ll feel like a pretty nice summer day. Temperatures will dip to a low near 13°C on Tuesday night under clear skies.

Wednesday will bring the next chance for thunderstorms to the province as a warm front moves in. It’s expected that elevated convection will from ahead of the warm front on Tuesday night in Saskatchewan, and then spread across southwest Manitoba overnight and into the Red River Valley on Wednesday morning.

The general consensus is that thunderstorm activity that develops on Tuesday night will move across the Red River Valley on Wednesday.

In these situations, there’s almost always a significant amount of uncertainty, so we’ll definitely be keeping an eye on how things develop. The end result will be a “cloudy with sunny breaks” kind of day with a high near 25°C once again. Winds will be fairly light. Skies will clear by evening & temperatures will be on the way to a low near 15°C.

Long Range

The remainder of the week looks continue the pattern. Temperatures will edge up a few degrees for Thursday and Friday, but it appears that things will turn increasingly unsettled Thursday night into Friday morning, and Friday night into Saturday.

Extended forecasts hint that we may see a stretch of warm, dry weather beginning Sunday, but that’s been advertised more than once this summer and vanished like dust in the wind, so we’ll hold off on promising that.

So…pleasant overall, but still no sign of that big hot, dry summer stretch.

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.