Severe thunderstorm watch for much of southern Quebec

Hazy yellow skies cover parts of Quebec amid a severe thunderstorm watch

Much of southern Quebec remains under a severe thunderstorm watch issued earlier Tuesday morning by Environment Canada.

The weather agency says a severe thunderstorm watch is in place from the Ontario border right to Gaspe, including the Montreal area.

• Hourly and 7-day forecast on our CTVNewsMontreal.ca weather hub

“This afternoon and evening, conditions will be favourable for the development of severe thunderstorms capable of producing strong wind gusts, large hail and heavy rain. There is also a risk of a tornado,” it said in a weather alert for the region.

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It is warning people to stay off the water because “nautical activities may be hazardous due to sudden, severe wind gusts over bodies of water.”

Before the storm, expect high temperatures in the Montreal area, with a high of 33 degrees Celsius and a Humidex of 42. The UV index is 9 or very high.

Thunderstorms are expected to end near midnight.

Smoke from forest fires turns the Quebec sky yellow

Parts of Quebec were covered by a thick blanket of smoke Tuesday, turning the sky yellow, due to forest fires in northwestern Ontario and Quebec.

As of 7:45 p.m., Montreal is currently ranked 27^th in the world for air pollution, according to IQAir, which tracks air quality data from major cities globally.

Satellite data from the Weather Forecast Research Team at the University of British Columbia shows plumes of smoke from the fires in Ontario are being pushed eastward across the country by the winds.

Smoke from the fires is settling over a large portion of Ontario and Quebec.

The PM2.5 (airborne particle measurement) concentration is currently 58, or 2.6 times the World Health Organization annual guideline value.

Because this phenomenon occurs at high altitudes, it doesn’t affect air quality at ground level, said Environment Canada meteorologist Simon Legault

Sensitive groups should still avoid outdoor exercise and close their windows.

Environment Canada meteorologist Jean-Philippe Bégin said the yellowish haze over Quebec is expected to be short-lived, as the weather forecast for Tuesday should clear the smoke from the sky.

Orange watches in southern Quebec

“Orange watches” have been issued for about 20 areas in the southern part of the province, where “infrastructure, homes, and the natural environment could be severely damaged or destroyed.”

Strong winds, large hail, and heavy rain are also possible.

The risk of tornadoes is even higher for the Mauricie, Eastern Townships, Montérégie, and Lanaudière.

Tornado “orange watches” were in effect Tuesday morning for the following areas: Bécancour-Villeroy, Berthierville-Saint-Gabriel, Cookshire, Drummondville, Lac-aux-Sables, Lac-Mégantic, Lotbinière, Louiseville, Mascouche, Matawin-Mauricie National Park, Nicolet, Portneuf, Rawdon-Joliette, Richmond, Saint-Donat-Mont-Tremblant Park, Saint-Hyacinthe-Acton Vale, Saint-Michel-des-Saints, Sainte-Anne-de-la-Pérade, Shawinigan, Sorel-Yamaska, Thetford Mines, Trois-Rivières, Verchères-Beloeil, Victoriaville, and Weedon.

“Yellow watches” are in effect for virtually all regions of the province where “orange watches” are not currently active, including Montreal.

Weather alert system: How it works

The weather alert system used on the federal agency’s digital platforms employs three colours: yellow, orange, and red. Each one represents a level of risk.

Yellow alerts—the most common type—indicate hazardous weather conditions that may cause damage, but whose impacts are generally moderate, localized, and/or short-lived.

An orange alert is issued when severe weather is expected. It also warns of potential damage or health effects, but with consequences that could be major, widespread, and/or last for several days.

In the case of a red alert, weather conditions are expected to be extremely hazardous and potentially life-threatening. They can result in significant, long-lasting impacts.

With files from The Canadian Press and Noovo Info