Montreal’s heat wave may end Wednesday, but thunderstorms will return

The heat wave that has been affecting southern Quebec for several days now could begin to show signs of easing on Wednesday, but the return of cooler weather is expected to be accompanied by thunderstorms.

As of Wednesday morning, southern Quebec was still under a heat warning from Environment and Climate Change Canada (ECCC), as temperatures will remain high early in the day.

The federal agency indicates that maximum temperatures of nearly 30°C are expected Wednesday. Combined with high humidity, this will generate humidex values between 35°C and 38°C.

“It’s already into the high 20s, feeling like the low 30s with the humidex that should rise a little bit more before we get a break due to an incoming cold front, which should bring both showers and thunderstorms to the island as well as some cooler temperatures once that cold front has made its way across,” said Steven Flisfeder, a meteorologist at Environment and Climate Change Canada.

Later, a cooler, less humid air mass will slowly move in from the northwest, which should end the heat wave.

This cold front will initially offer some respite to Ontario, which has also been dealing with intense heat for several days, before making its presence felt in Quebec.

“This cold front makes its way across to date, temperatures should start to moderate back towards near seasonal for the next few days, beginning tomorrow, especially overnight temperatures,” Flisfeder said. “They’ll drop below about 15 degrees Celsius. So much more relief compared to what we’ve been seeing over the past few days. That should be the case for the rest of the week. The weekend may see temperatures bump up towards the 30s one day, either Saturday or Sunday, but that will be a one day blip in the forecast and we return back to near seasonal for the remainder of the seven-day forecast.”

The passage of this cold front could generate rain or thunderstorms in Wednesday afternoon and evening.

“Becoming cloudy this morning with 60 per cent chance of showers late this morning and this afternoon,” ECCC said on Montreal’s forecast for Wednesday. “Risk of thunderstorms this afternoon.”

Starting Thursday, more seasonal maximum temperatures and a drop in humidity are expected, according to ECCC. Nights are also expected to be cooler.

Cloudy and 27°C but feeling more like 34°C with the humidex in Montreal tomorrow. Then clear skies and a low of 13°C at night.

Come Friday, sunshine and a daytime high of 27°C expected.

Saturday is forecasted to be a beautiful one with 31°C and more sunny skies.

Then showers are expected to come in on Sunday, a high of 23°C.

For now, ECCC is forecasting sunshine for Monday and Tuesday next week.

Numerous heat records have been broken in recent days in Quebec and Ontario, as well as in British Columbia, where a heat wave is also underway.

One heat-related death has been reported to the Montreal Regional Public Health Department since the start of the extreme heat.

“So on (August) 10th, a new record of 34.4 degrees Celsius, beating the old record of 32.8, which was set back in 1914,” Flisfeder said. “August 11th, a new record of 35.1 degrees Celsius beating the old record of 35.0 degrees set back in 1944. And finally yesterday, August 12th, a new record of 34.6 degrees Celsius beating the old record of 32.7 set back in 2002.”

The drought accompanying this heat wave is having its own impacts, such as lowered water levels in some rivers and the imposition of watering bans in some municipalities.

The heat persists in the Maritimes

Meanwhile, New Brunswick, Nova Scotia, and Prince Edward Island will continue to record high maximum temperatures on Wednesday.

In these provinces, maximum temperatures will remain above 30 degrees Celsius during the day, with a humidex around 40.

The Maritimes will have to wait until Thursday, or even Thursday night, before the passage of the cold front brings the temperature down somewhat.

In Newfoundland and Labrador, Environment Canada predicts that extreme heat will continue until Thursday, or even Friday in some areas.

—With files from The Canadian Press, first published in French and translated by CityNews