Weather Forecasts, Facts and News for Winnipeg & Southern Manitoba
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.
It’s safe to say that alongside all the smoke from forest fires raging across the Northern Prairies, summer has arrived. With daytime highs in the mid- to high–20’s for the coming 5 days and overnight lows similarly warm at nearly 5°C above normal, the cool weather of just under two weeks ago[1] is long gone!
Hot and increasingly humid weather is in store for the second half of the week, however temperatures will likely fall short of what their potential is given the haze and smoke that will advect over the southern half of the province from the fires to our northwest in Saskatchewan & Alberta.
Today will be a mild day with highs in the mid–20’s or so and some haze moving in. There’s a marginal chance of some isolated thundershower activity, but the haze & smoke aloft will likely keep things just cool enough that any convective activity is halted or severely limited.
The humidity will remain mild today with dew point values around 15–17°C. Expect temperatures to dip to around 16°C tonight.
Thursday and Friday will both be warm days with more noticeable humidity present. Dew point values are expected to climb into the upper teens, making it start to feel a bit swampy out there. There may be a bit of a reprieve from the smoke on Thursday, with just a bit of haze around, but it looks like more noticeable smoke will return for Friday. Both days will see highs in the mid- to upper–20’s, but with a bit of a footnote[2] that the high could be a degree or two higher or lower depending on exactly how much smoke manages to advect into the region for Friday.
Wet Weekend Ahead?
Weather models are beginning to come into agreement of a fairly significant storm system impacting the Prairies over the weekend.
The GDPS is forecasting a wide swath of rainfall across the Southern Prairies on Saturday night.
It’s still early to say, but it looks like there’s the potential for elevated convection on Saturday night, perhaps bringing some night-time thunderstorm activity to Winnipeg, and Sunday looks like it may bring a few showers to the region with a bit of remnant instability. We’ll keep tabs on this system as we head towards the weekend and have an update in Friday morning’s blog post!
Overnight lows dipped to just 4.6°C on the morning of June 18th! ↩
True summer warmth is on the way for Winnipeg with temperatures soaring into the upper 20’s and overnight lows in the mid- to upper-teens. However, alongside the warmer weather, multiple threats for severe thunderstorms will return to the region.
Friday
Friday
29°C / 17°C
Partly cloudy, chance of a thunderstorm
Today will be a very warm day with temperatures climbing into the upper 20’s and light winds. Skies will start off sunny, and then we’ll see some afternoon cloudiness develop over the valley alongside some scattered thunderstorms. There’s little organizational feature, so it will be rather hit and miss as to whether you see a thunderstorm where you are or not.
Further north and west, there will be a slight risk of severe thunderstorms. MUCAPE (a measure of instability) values of 1000–1500 J/kg coupled with 25 kt of bulk shear will be substantial enough to support the organization of severe thunderstorms. A mid-level disturbance will slump to the southeast into Parkland Manitoba and the Interlake by early- to mid-afternoon and provide a focus and trigger for thunderstorm initiation.
A slight risk of severe thunderstorms exists today over southwest Manitoba into the Interlake region.
Severe thunderstorms are not expected widespread, but isolated severe cells are possible. Over the western sections of the slight risk area, large hail and heavy rain will be the primary threats. Those threats also exist further east in the slight risk area – mainly along the Red River Valley escarpment into the Interlake – there will also be a slight chance for funnel clouds or weak landspout tornadoes due to the additional “spin” provided by a shortwave moving through.
Temperatures will remain quite warm overnight with lows dipping to just around 16 or 17°C.
Saturday
Saturday
27°C / 14°C
Mixed skies; risk of a severe thunderstorm
Saturday will see a severe thunderstorm threat return to Winnipeg as more humidity pushes northwards ahead of a significant shortwave and associated trough line approaching from Saskatchewan. Dew point values are expected to climb into the upper teens producing MLCAPE values over 2000 J/kg. Strongly veering wind profiles coupled with over 40 kt of bulk shear will result in a moderate severe thunderstorm threat. While some models show surefire convection, there may be issues with a capping inversion depending on exactly how warm it’s able to get.
A slight risk of severe thunderstorms exists on Saturday through the Red River Valley, Interlake and eastwards to the Ontario border.
An updated convective outlook graphic is available in the comments below.
Given the uncertainty, a slight risk for severe thunderstorms exists on Saturday through the Interlake into the Red River Valley. As the issues with the capping inversion become clearer, the threat may be upgraded to a moderate risk.
The primary threat with storms on Saturday would be damaging hail, strong winds and torrential downpours. Shear profiles are supportive of supercells, and while it’s not considered a significant likelihood, it’s important to remember that supercell thunderstorms can produce tornadoes.
Regarding non-thunderstorm weather on Saturday, temperatures will climb into the upper 20’s which will feel more like the low- to mid–30’s with the increased humidity. The winds will be out of the south at around 20km/h. Skies should clear on Saturday night as temperatures drop to the mid-teens.
Sunday
Sunday
28°C / 15°C
Mainly sunny
Sunday will finally see both warm temperatures and quiet weather. Temperatures will climb back into the upper 20’s with winds out of the north at around 15–25km/h. With those northerly winds, the humidity will be quite a bit more comfortable than on Saturday.
Some thunderstorm activity will occur in Manitoba on Sunday, but it will most likely be constrained east of Lake Winnipeg & down into the northern Whiteshell. The thunderstorm activity does not look like it has an organized severe threat.
Expect temperatures to dip back to the mid-teens on Sunday night.
Winnipeg is set to see summer-like heat slowly build into the region over the coming week, however the unsettled weather brought about by the zonal flow that’s been in place over the past several days will continue doing its thing for another few days yet before more stable conditions build into Manitoba.
Today will be a similar day to yesterday with daytime highs in the low 20’s through the Red River Valley and fairly light winds. Dew point values are expected to climb to around 16 or 17°C today, which when combined with a bit of daytime heating will provide some fuel for scattered thunderstorm mid-day through the afternoon. Applying the MIST principles:
Moisture: As mentioned, dew point values are expected to rise to around 16 or 17°C thanks to some pooling along a weak trough through the region coupled with an easterly to southeasterly flow tapping into higher dew points to the southeast.
Instability: Moderate mid-level instability will be in place thanks to a shortwave moving through the region. CAPE values, driven largely by the favourable thermodynamics in place, will be in the 1000–1500 J/kg range.
Shear: Bulk shear of 25–35 kt will be marginally supportive of organized thunderstorms. Directional profiles will be somewhat anomalous, with easterly low-level winds backing to the northwest/west thanks to the approach of an inverted trough. End result is that, particularly through western Manitoba, storm motion will likely be quite slow, making rainfall accumulations a potential hazard with today’s storms.
Trigger: This may be the weakest aspect of today’s storms. A very weak frontal trough will be in place, alongside a weak upper-level shortwave and impinging inverted trough. Lack of any strong focus will likely be biggest inhibitor to widespread storm organization and will diminish the severe storm potential for the day.
With those factors taken into account, we’ll likely see scattered thunderstorms across much of Southern Manitoba today, however the threat for severe thunderstorms will be quite low with just an isolated marginal severe storm risk. The exception to the rule will be in the southwest portion of the province closer to the inverted trough. Shear profiles have strongly backed surface winds with a backing profile, making slow-moving storms more likely there. With adequate bulk shear to support & ventilate the storms, heavy rainfall is a heightened risk in that area due to slower storm motion.
A slight risk of severe thunderstorms exists over SE Saskatchewan & SW Manitoba, extending eastwards along the international border.
That said, we’ll see mixed skies today alongside our chance for thunderstorms. Expect the storms to taper off this evening as we head to a low near 13°C.
Thursday will be off to an unsettled start as another disturbance rolls through the region and brings a chance for showers or thunderstorms through the morning hours. After that, we should see some clearing skies as the temperature heads on its way to a high in the mid–20’s. Expect clear skies Thursday night with a low near 14 or 15°C.
Friday looks gorgeous with sunny skies and a high near 27°C. Mainly clear skies should prevail Friday night with a low 12°C.
A Look Ahead to the Weekend
The weekend is looking like a bit of a mixed bag. The warmth will continue to build into the Prairies, particularly in the Western Prairies as the upper ridge begins building in. Here, Saturday looks potentially wet with the possibility of a low pressure system riding down the upper ridge through Southern Manitoba which would bring another batch of rain to the region. Sunday looks nice by all accounts with a fair amount of sun and highs climbing into the upper 20’s!
Showers and thunderstorms will once again make their return to Winnipeg & the Red River Valley for the next few days…with a catch. Despite the unsettled weather, it might end up actually being fairly pleasant this weekend for the most part!
Today will be a bit of a mixed bag with some cloudy periods and a high near 21°C. Winds will pick out out of the south to around 30km/h or so through the day.
The first of two systems that will be affecting Winnipeg & the Red River Valley today will be a convective complex lifting northeastwards out of North Dakota. It will spread cloud and a chance through southeastern Manitoba, with just a slight chance of some midday showers in Winnipeg.
The second system that will bring a risk of showers or thunderstorms to Winnipeg is a trough of low pressure that will move into our region tonight from Saskatchewan. There still exists quite a bit of uncertainty as to whether or not any precipitation will push into the Red River Valley tonight; in general, confidence is much higher over eastern Saskatchewan and southwestern Manitoba, where a significant threat for severe thunderstorms exists today.
A moderate risk of severe thunderstorms exists over SE Saskatchewan & extreme SW Manitoba today.
The most likely outcome at this point is that much of the convection heading towards the Red River Valley will either taper off or dive south into North Dakota where a severe convective event called a bow echo seems probable. There is a slight chance that we’ll see some thunderstorm activity in the Red River Valley overnight, but it doesn’t appear that it would be severe.
Saturday looks like a fairly pleasant day with mixed skies about and a high near 22 or 23°C. There will be a chance for showers late in the day into the evening hours, but in general the activity isn’t expected to be very widespread over the Red River Valley. The temperature looks to drop into the low teens on Saturday night.
The threat for thunderstorms returns to the Red River Valley on Sunday afternoon as another disturbance moves through the region. Temperatures will once again top out in the low 20’s with overnight lows dropping into the low teens.
Father’s Day Forecast Update
Father’s Day
25°C / 15°C
Mainly sunny
Weather will be generally pleasant for Southern Manitoba this Father’s Day with generally sunny skies and high temperatures in the mid-20’s with fairly light winds. This is excellent news for the Manitoba Marathon; today will be a far nicer day to run than last year’s less than pleasant weather. The only exception will be in areas along a line from Swan River east-southeastwards across the Interlake towards Berens River where some pop-up showers and thunderstorms are possible this afternoon.
An more organized thunderstorm threat will develop through the day, however, beginning early-to-mid-afternoon in Saskatchewan and then progressing eastwards through southwest Manitoba this evening and through the Red River Valley overnight. Thunderstorms are expected to develop in the Regina area southwards towards the American border; these storms will be developing in an area with marginal energetics, however very favourable shear profiles will likely result in scattered thunderstorms with isolated supercell thunderstorms. As they track eastwards, a southerly low-level jet will intensify, supporting upscale growth of the convective complex as it heads into the evening.
A slight risk of severe thunderstorms exists over SE Saskatchewan today and will spread into Southern Manitoba this evening & overnight.
I expect that early in the evening, the thunderstorms will have developed into a line of showers and thunderstorms heading eastwards into Southern Manitoba. In general, the severe threat in Manitoba is expected to be minimal, except for areas near the U.S. border. There is a chance that as the storms push eastwards, supported by a 50-60kt westerly jet at 500mb and running just north of a warm front in North Dakota, that the storms develop bowing segments. Bowing segments are when the thunderstorms produce strong winds that, quite literally, push part of the storm forward, making a ) shape on RADAR imagery.
Primarily for that reason, I’ve carried a slight risk for the overnight period along the US border into the Red River Valley; I’m generally expecting the worst weather to dive into North Dakota fairly early, but there’s a slight chance some of the winds end up remaining on the Manitoba side. For the remainder of the general area through southwest Manitoba into the Red River Valley, non-severe nocturnal thunderstorms are possible through the evening/overnight period.
