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.

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.

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.

After a very pleasant Friday that will see temperatures soaring into the upper 20’s under sunny skies, the weather will turn more unsettled as a complex of low pressure systems move across Manitoba. It won’t be a rainy weekend, but multiple chances for showers or thunderstorms will exist.

Warm but Windy Friday

Today will be a fairly pleasant day across the Red River Valley save for one aspect: the wind. Temperatures will climb into the upper 20’s, topping out at around 28°C with comfortable humidity as dew points settle around 15°C or so. The wind, however, will strengthen out of the south through the day as a low pressure system begins working its way into western Manitoba.

The winds will ease up this evening under mainly clear skies. It will be quite a mild night with the temperature dropping to only around 17°C. Some cloud cover will roll into the Red River Valley overnight as a cold front approaches.

Severe Thunderstorm Threat Returns Saturday

Tomorrow will bring a threat of severe thunderstorms to the Red River Valley. A slow-moving cold front will push across the region and is expected to trigger thunderstorms through the afternoon. Where exactly sees thunderstorm activity will depend on exactly how quickly the front manages to push eastwards, which is a bit of an uncertainty at this point.

Most convective parameters look pretty good; CAPE values are expected to climb to around 1500 J/kg as we head to a high near 28°C with a dew point around 17–18°C. This slightly humid air will make it feel more like 33–34°C before the cold front passes through. Ample bulk shear with a 50+ kt jet at 500mb looks favourable, however some synoptic subsidence may occur due to unfavourable jet positioning.

All in all, there exists a risk for severe thunderstorms along the cold front with main threats of strong winds and large hail. Other modes of severe weather are possible – such as tornadoes or flash flooding – in any severe thunderstorm, however are not expected to be primary threats on Saturday’s storms.

Otherwise, it will be a fairly pleasant day with a mix of sun and clouds and winds out of the south at around 30km/h becoming light as the day progresses. We’ll see some scattered cloud overnight on the way to a low in the mid-teens.

Showers Possible Sunday

Sunday will be a calmer day than Saturday, however the chance for some showers or even a rogue thundershower exists across much of Southern Manitoba as another disturbance ripples over the region. In general, it looks like Sunday will bring mixed to cloudy skies with a decent chance of some scattered shower activity. Temperatures will be cooler with highs of only around 23°C or so in the Red River Valley[1] thanks to the cloud cover and slightly cooler air mass. Skies should begin to break up through the Red River Valley on Sunday evening as temperatures dip to 13 or 14°C again.