Severe Thunderstorm Threat Returns to Southern Manitoba

Winnipeg will see several rounds of thunderstorms over the next 36 hours, some of which may be severe.

A sharp long-wave trough moving into the region will produce several rounds of thunderstorms over the Red River Valley through the next 36 hours. The initial wave of thunderstorms is pushing through the Red River Valley already. These storms produced a variety of severe weather overnight as they moved through Saskatchewan and southwest Manitoba and will continue to pose a slight chance of producing severe hail or wind gusts.

A large mesoscale convective system developed over SE Saskatchewan into Manitoba on Thursday night and is bringing strong to severe thunderstorms to the Red River Valley this morning.

After those storms move through, Winnipeg should see mixed skies with temperatures increasing to a high near 25°C. Winds will be breezy out of the southeast at 30 gusting 50 km/h.

Another round of thunderstorms will develop later today, likely producing a swath of severe weather extending from the southwest corner of the province right through to Ontario. The storms will begin this afternoon over the southwestern corner of the province and then move through the Red River Valley through the evening. These thunderstorms will be capable of large hail, severe wind gusts, and torrential downpours causing flash flooding.1 It will be a complex and dynamic system this evening, so be sure to stay aware of any watches or warnings issued by ECCC later today.

Another line of strong to severe thunderstorms will move thorugh southern Manitoba later today.
Another line of strong to severe thunderstorms will move thorugh southern Manitoba later today.

Saturday morning will likely bring a brief reprieve before an upper low moves into the region. As it moves in, more showers and thunderstorms are forecast to develop. There will be less energy for the storms to utilize, but they may still produce some hail and rather heavy downpours.2 The unsettled conditions will keep things cool with a high near 20°C expected in Winnipeg. Winds will be light to start the day, but pick up out of the northwest late in the day. Temperatures will drop to a low near 12°C with a northwest wind of 20 to 30 km/h and a continued chance of showers on Saturday night.

Conditions will finally settle for Sunday. Skies will gradually clear out with a northwest wind of 20 to 30 km/h. Winnipeg can expect a high near 19°C. A ridge of high pressure will move in on Sunday night, bringing calm winds and a low near 6°C.

Long Range Outlook

Much of next week looks to bring variable cloudiness and warm to seasonal temperatures. By the end of the week, conditions may turn cloudier with a chance of showers.

Today’s seasonal daytime high in Winnipeg is 17°C while the seasonal overnight low is 5°C.

  1. MLCAPE values near 2000 J/kg combined with 35 knots of deep shear and a perpendicular warm front orientation should support squall-line structures with large hail and strong winds. PWAT values climbing to 50 mm will ensure that the thunderstorms produce heavy rain, and rapid accumulations with flash flooding is possible in any areas that see slower-moving or training thunderstorms.
  2. MLCAPE values near 500 J/kg will combine with bulk shear values of 40 to 50 knots to produce widespread showers with embedded thunderstorms. PWAT values of 35 mm will support moderate to heavy rainfall rates.
Brad

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 Twitter.