Increasing heat, humidity and thunderstorms for Montreal

A warm and humid airmass will invade southern Quebec through the end of the week. Humidex values will soar into the middle and upper 30s. Some heavy showers and isolated thunderstorms are possible, with 25-50mm of rain falling for some locations. (Valley Weather Photo)

Severe Thunderstorm Watch in effect for Southern Quebec including metro Montreal for Wednesday.

A few strong thunderstorms are possible late Wednesday and again on Friday across Southern Quebec.

A summery airmass will move into southern Quebec through Sunday, with increasing heat and humidity as well as showers and thunderstorms. A warm front will lift across the region on Wednesday, accompanied by showers. Late today, increasing humidity will lead to scattered thunderstorms, some may have heavy rain and gusty winds. High temperatures will remain in the middle 20s Wednesday in Montreal, rising into the upper 20s to near 30C through Saturday. Overnight lows will remain on the warm and muggy side, near 21C (70F).

Cooler air arrives by late Sunday along with more widespread showers and thunderstorms. Highs will drop into the low 20s. Much cooler air will move into southern Quebec early next week, and is showing signs of remaining in place through the end of the month. Highs will be in the low 20s, with morning lows in the low teens.

A rotating shelf cloud southeast of Winnipeg near the community of Ste Anne, Manitoba, likely produced a tornado on Tuesday afternoon. It was part of a significant severe weather outbreak across Saskatchewan and Manitoba including torrential rain and large hail. (CBC)

Severe Weather in Manitoba & Saskatchewan

A significant severe weather outbreak occurred on Tuesday afternoon and evening across southeastern Saskatchewan, Southern Manitoba and adjacent North Dakota. In Saskatchewan, a tornadoes were reported at North Portal, Alemeda and Oxbow, with significant damage occuring. Heavy rain and tennis ball size hail was also observed. 

Storms were more widespread in Manitoba, with tornadoes observed near Ste Anne and Otterburne. Funnel clouds occurred across the Red River Valley. Hail the size of tennis balls fell in numerous locations. Torrential rain fell with the storm cells, causing widespread flash flooding across the southern portions of the province, including Winnipeg. Over 250mm fell in Stonewall, with 117mm at The Forks in Winnipeg. Winds gusted to 94km/h in the city as well. A peak non-tornado wind gust of 130km/h was recorded at Dand and Deloraine. Wind and hail damage as well as flash flooding occurred and is still being assessed on Wednesday.

Widespread tornado watches were in effect from Saskatchewan into northwest Ontario on Tuesday. The severe weather, though less intense, will shift into southern and eastern Ontario on Wednesday.