We are in for another active start to the week in the Prairies and parts of Northwestern Ontario, with heavy rain and strong thunderstorms threatening several areas. The heavy rains led to Tornado Watches in Ontario on Monday morning.

Gusty winds, widespread heavy rain, large hail and unseasonal warmth will accompany the storm as it heads into Canada. It will feel remarkably similar to what we experienced in the Prairies last week, with two consecutive days of unsettled weather and the threat of severe thunderstorms.

Visit our complete Fall 2024 guide for a detailed look at the fall forecast, planning tips, and more!

CURRENT TORNADO WARNINGS (Ontario):

10:06 a.m. EDT – A tornado warning is in effect in northwestern Ontario due to the threat of severe storms for Monday afternoon/evening. A tornado regard means that conditions are favorable for the development of tornadoes.

Conditions are favorable for the development of severe thunderstorms that may spawn tornadoes. Strong winds, large hailstones and heavy rain are also possible.

The original article with the full forecast for the Prairies and Northwestern Ontario continues below.

Strong risk of storms Monday to Tuesday:

In parts of the southern prairie, there is a risk of severe weather during the day on Monday, which will continue overnight and into Tuesday morning.

Thunderstorms will initially develop over North Dakota during the day on Monday. These storms will move north along a warm front throughout the afternoon and evening, eventually reaching southern Manitoba and northwestern Ontario. This danger also applies to the city of Winnipeg, where there is a risk of torrential rain, strong winds and large hail up to the size of golf balls.

As the warm front from North Dakota moves into northwestern Ontario during the afternoon, there is a chance of one or two tornadoes.

As the storm surge continues throughout the night, there is a possibility of localized flooding.

WARNING: There is a risk of heavy hail and flooding in the Prairies

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Risk of locally heavy rainfall until mid-week:

Further west, we need to monitor the bulk of the low pressure system as it meanders across Saskatchewan and Alberta.

As the storm moves toward Canada, it will bring heavy rain for several days, with the heaviest rainfall expected in areas of eastern Alberta and western Saskatchewan.

There will be more scattered precipitation on Tuesday, but more organized rain bands will move in from Montana on Wednesday, peaking Wednesday afternoon and evening. By Thursday afternoon, the low pressure system will weaken and gradually move eastward.

Some communities near the provincial border could see up to 100 mm of rain through Thursday as this storm moves through the region.

Gusty northwest winds will also blow in Alberta and western Saskatchewan during the storm. People can expect gusts of up to 80 km/h in parts of Alberta, and gusts of up to 70 km/h are possible in Saskatchewan.

Large temperature range arises

On the east side of the storm, summer temperatures will result in temperatures up to 9°C above the seasonal average on Monday and Tuesday, particularly in Manitoba, including Winnipeg and Dauphin.

Meanwhile, cooler air moving in on the western side of the system will keep temperatures well below seasonal throughout southern Alberta, with Calgary and Lethbridge unlikely to reach temperatures above 15 degrees on Wednesday.

SEE: Canada’s 2024 fall forecast: Fewer storms and warm weather ahead

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