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.
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.
