Severe weather threat returns to the eastern Prairies and northwestern Ontario
Another night of strong winds, heavy rain and potential floods to rock the Prairies and northwestern Ontario
A stormy weekend continues into Monday after severe thunderstorms lined parts of the Prairies, while tornado warnings went active for southern Manitoba.
Storms brought heavy rain and strong winds on Sunday, with 50-75 mm of rain recorded over bands of eastern Saskatchewan, and 35-55 mm over western Manitoba. Similar conditions are expected to continue into Monday, along with a flood risk, mainly in eastern Saskatchewan.
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Stay alert for rapidly changing conditions in your area. Localized flooding is possible. Never attempt to drive across a flooded roadway. It’s impossible to tell how deep the water is until it’s too late.
It'll be important to remain weather-aware, and stay up-to-date on all of the latest watches and warnings as conditions change.
Stormy start to the new work week Monday
The severe weather is lingering thanks to an Omega blocking pattern, causing the active pattern to be a slow mover. An upper-level high pressure system is being flanked by a low pressure system centred on either side.
This is causing the low pressure system around the Prairies to be blocked from moving eastward, slowly dragging the stormy weather up and around the ridge created along the jet stream.
Severe weather pushes from Manitoba into Ontario
From the afternoon into the evening, thunderstorms are expected across the waterfront as the low system lifts over the border with the U.S., possibly bringing another round of severe storms, as well.
The main risk is expected to be strong winds that could build up to 80 km/h, while the airmass associated with the storms is quite moisture-laden, creating heavy downpours.
While the risk of flooding remains for eastern Saskatchewan, the heaviest of the rainfall is expected to shift eastward into Manitoba, with heavy rain in northwestern Ontario as well by the late afternoon.
By the evening, storms south of the border and rains in northwestern Ontario may move into Manitoba as they get less intense, but still bring down heavy rainfalls.
Southern Manitoba into northwestern Ontario will be the most active weather spot across Canada, while the rest of the country, and the majority of the population, can expect to see dry weather for the next week.
And alongside strong winds and rainfalls, large hail is expected to be a threa. Nickel-sized or greater, should be expected in isolated areas.
On top of all that, there is a chance of a rotating storm forming between eastern Manitoba and northwestern Ontario during the late afternoon into the evening. With thunderstorms forecast to have the potential to form, all the way from Thunder Bay to Cranbrook.
The areas with the greatest potential for supercells to form are Dryden, Sioux Lookout and Red Lake, while in the evening the risk will move north towards Sandy Lake, Ont.
The northward movement of the rainfalls is expected to keep the Interlake region and southern Manitoba rainy at all times, thanks to the northward pull of the low pressure system. Tuesday will bring more scattered storms for these regions as a trough behind the system slumps southward.
But the thunderstorm risk will continue, as stronger storms are brought into northwestern Ontario with the passage of the low-pressure system.