Early Week Heat Brings Chance of Thunderstorms

A low pressure system crossing the province will bring hot and unsettled conditions to southern Manitoba today. The heat will be short-lived, though, as a cold front ushers seasonal temperatures back into the region for Wednesday.

RDPS 2m Temperature Forecast valid 21Z Tuesday August 2, 2022
A low pressure system moving into Manitoba today will bring hot, humid conditions to the region.

In the wake of a warm front that moved through overnight, temperatures will soar into the upper 20s and low 30s across southern Manitoba today. Alongside the heat, humidity levels will also climb through the day, reaching fairly muggy levels by the evening.

Thunderstorm activity will be the most notable, and challenging, weather of the day. There will be several features moving through the region that that may support thunderstorms today. The first will be an area of showers and thunderstorms — the remnants of overnight convection — that will continue eastwards through the Interlake. This activity will weaken as the morning progresses. While most of it should stay north of the Red River Valley, the southern edge might clip along the Trans-Canada Highway corridor. The second feature will be the warm front itself, which may have some ongoing thunderstorms along it this morning. Any activity along it should shift eastwards into the Whiteshell and then weaken.

Once all the morning activity pushes out, the Red River Valley will see more sun as things heat up. Later in the day, a risk of severe thunderstorms will develop as several features begin pushing across southern Manitoba. Both the low centre, warm-sector trough, and cold front could support thunderstorm development later today. The heat and humidity will combine with favourable winds aloft to pose a notable risk of severe weather.

ECCC Prairie Thunderstorm Outlook valid 1:00PM to 1:00AM CDT
ECCC’s Thunderstorm Outlook issued on Monday afternoon shows a notable severe weather threat for southern Manitoba on Tuesday.

The combination of energy (from the humidity and instability) and shear (from how winds change with height) is highly favourable for severe thunderstorm activity across southern Manitoba today. The biggest uncertainty with storms in the afternoon/evening will be whether or not they actually develop. A layer of warm air aloft will keep storms down until late in the day. It seems likely that the forcing will be strong enough by evening for isolated to scattered thunderstorm development. The activity will likely begin in the southwest and push into the Red River Valley. These thunderstorms would be capable of producing damaging wind gusts, damaging hail, and torrential rain. In addition, an isolated tornado or two may be possible with these thunderstorms as well.

The last unknown related to thunderstorm development will be exactly how warm temperatures end up. Satellite imagery yesterday evening showed a fair amount of high-level smoke moving eastwards from fires over southern British Columbia. If that smoke inhibits temperatures even a couple degrees, that could be enough to thwart thunderstorm development. All those things being taken into account, the weather later today is a bit of an unknown. It will be important to stay up to date on any watches or warnings issued by ECCC later today.

The thunderstorm threat will diminish in the evening as temperatures fall to a low in the mid-teens. Winnipeg will see pleasant conditions on Wednesday with clearing skies, breezy northwest winds, and a high in the low 20s. On Thursday, breezy southerlies will push a warm front northwards and send highs back into the upper 20s. Thursday night might be very warm with southerlies continuing and lows warmer than 20 °C possible.

Long Range Outlook

Friday could bring some morning showers or thunderstorms to the Red River Valley, followed by mixed skies and a high in the upper 20s again. It might also get humid on Friday as well.  A cold front will sweep through by Friday evening, ushering cooler temperatures back into the region for the weekend. Highs will likely sit in the low 20s with lows in the low to mid-teens on Saturday and Sunday. A few showers might be possible on Sunday as well.

Next week is looking like it will start off with near-seasonal temperatures and plenty of sunshine.

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

Seasonably Cool and Showery Weather Ahead

A northwesterly flow will bring seasonably cool and showery weather to southern Manitoba this week.

RDPS 300mb Wind and Height Forecast valid 18Z Wednesday July 27, 2022
An upper low will slump across Manitoba over the coming days, bringing cooler temperatures and unsettled conditions.

An upper low slumping from northern Manitoba towards Lake of the Woods will usher a northwest flow into Manitoba and bring seasonably cool temperatures to the region. Today will start off with showers ending early, followed by mixed skies with more showers likely later in the morning and into the afternoon. A few thunderstorms may even develop in the afternoon, but no organized severe weather threat will exist with them. Temperatures will climb into the low to mid-20s this afternoon with a northwest wind increasing to 30 gusting 50 km/h.

The showers will taper off in the evening with the loss of daytime heating. Partly cloudy skies will linger overnight with a low in the mid-teens.

On Wednesday, the upper low will drag a trough southwards over the Red River Valley, bringing more showers to the region. Temperatures will be even cooler with a high only around 20 °C. The region will see breezy northerly winds again through the day. The showers will taper off in the evening, but some cloud will continue to linger into the night. Temperatures will dip down into the low teens overnight.

The whole disturbance will begin to move off from the region on Thursday. Winnipeg should see mixed clouds with just a small chance of any more rain showers. Temperatures will climb back into the low 20s with light northerly winds. Skies should finally clear out by Thursday evening as a ridge of high pressure builds into the region. Temperatures will head to an overnight low in the low teens again on Thursday night.

Long Range Outlook

The heat returns for the weekend with highs climbing back to seasonal or seasonably warm values. There should be plenty of sunshine and little chance of rain. Overnight lows will also warm substantially, climbing back into the upper teens.

If the next few days of cooler, showery weather isn’t your cup of tea, don’t worry! The summer heat is right around the corner.

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

Showery Friday Night Leads to Seasonal Summer Weekend

A low pressure system moving through tonight will bring [thunder]showers to southern Manitoba, but leave behind pleasant summer conditions for the weekend.

Today will start off with beautiful conditions as temperatures climb into the upper 20s under mainly sunny skies. As the low approaches later in the day, cloud cover will start to build into the Red River Valley, particularly later today into the evening. The low will pass by to the south tonight, spreading showers across southern Manitoba. There may be enough instability to produce a few thundershowers, but no severe weather threat is expected. Temperatures will head to a low in the mid-teens with showers likely continuing into Saturday morning. By the time it all tapers off on Saturday, it’s likely that Winnipeg will receive at least 10 mm of rain with amounts high as 20–30 mm if some heavier showers end up developing as well.

The one exception to all this will be southwestern Manitoba, where strong to severe thunderstorms are possible later this afternoon into the evening. Be sure to stay aware of any watches or warnings issued by ECCC later today.

The cloud cover will begin to break up as the showers taper off on Saturday afternoon. Temperatures should still manage to climb into the low to mid-20s with a bit of a northerly breeze. A few clouds will linger through the region Saturday night with a low in the 10–15 °C range.

Sunday will bring mainly sunny skies to the region with a high in the low to mid-20s.

Long Range Outlook

Monday will start next week with pleasant conditions and seasonal temperatures. After that, though, the overall pattern looks to turn more unsettled. Beginning Monday night into Tuesday, the region will see mixed to cloudy skies with several chances for showers or thunderstorms that will last into later in the week before settling down again. The work week should end with pleasant conditions as sunnier skies and highs in the upper 20s return.

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

Hot Summer Weather Ahead

The heat will slowly build over Southern Manitoba in the coming days as the region heads towards a very hot weekend.

GDPS 500 mb Height Forecast (with Anomaly) valid 12Z Wednesday July 13, 2022
The forecast 500 mb heights with the climatological anomaly overlaid shows a strong upper ridge building across Manitoba on Tuesday.

This week will see an upper ridge building into and strengthening over the Prairies. As it does, conditions will stabilize as temperatures slowly climb.

Southern Manitoba will see a sunny start to the day give way to mixed skies. Temperatures will climb into the upper 20s across the region with a bit of a northerly breeze. Some lingering instability will result in a few scattered showers that will move through the Red River Valley in the afternoon with the risk of a thundershower. Skies will clear in the evening as temperatures head to a low in the mid-teens.

Wednesday will be a beautiful day across the region with sunshine, light winds out of the south and a high in the upper 20s. Temperatures will fall to a low in the upper teens on Wednesday night.

On Thursday, an upper disturbance lifting northeastwards across the Prairies will bring some cloud to the region along with increasing heat and humidity. Temperatures should climb to the 30 °C mark with breezy southerly winds developing. The humidity will gradually climb through the day, likely beginning to feel a bit muggy by the end of the day. Showers and thunderstorms are likely across the region in the evening, and with the heat and humidity present there could be a risk of severe weather.

Long Range Outlook

The upper ridge will rebound and strengthen heading into the weekend, bringing increasing sun and even warmer weather. Daytime highs will climb into the low to mid-30s for the weekend under sunny skies. The humidity will likely be moderate to high which will help keep overnight lows mild near 20 °C.

The heat will continue into Monday before the upper ridge begins to break down, bringing slightly cooler weather and the chance of rain back to the region.

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