The exceptional temperatures of around 30°C for the south-west of the province, announced from Thursday to Saturday, could plunge this sector into a potential record heat wave of the last 130 years.

Due to an atmospheric blockage and a high pressure ridge, all of Quebec is expected to experience a significant increase in mercury in the coming days.

Thursday, in Montreal, the maximum temperature should reach 29 ° C. The last heat record recorded on May 12 in the Montreal region dates back to 1893, when the mercury was 28.9 ° C, explained Environment Canada meteorologist André Cantin. “It’s still exceptional,” he added.

Friday and Saturday, the maximum expected is 30 ° C, or 10 degrees above the normal maximum of 19 ° C in the metropolis in mid-May. It is therefore appropriate to speak of the start of a heat wave, which occurs each time three consecutive days occur, with a minimum of 30°C.

According to meteorologist Gilles Brien, it only happens every three years that a day reaches 30°C in Montreal during the month of May. In his opinion, the fact that the hot weather sets in as early as May is an impact of global warming.

The disturbance is explained by two low pressure systems, one near the Canadian prairies struggling with cloudy conditions and the other located farther towards the Atlantic, said the two meteorologists. “These two systems move very little or not at all,” said Mr. Cantin.

Quebec, which is under a ridge of high pressure, is wedged between the two stagnant systems. In addition, the prevailing southerly winds bring mild and very warm air from the American Midwest.

Eastern Quebec will be cooler, because the presence of the river will generate temperatures of 15 to 20°C, which remains above normal in these sectors.

Dry and tolerable

According to Mr. Brien, an episode of drought is gradually setting in in Quebec. An open fire ban is in effect across the province. “This measure prohibits anyone staying in or near the forest from making open fires,” said the Ministry of Forests, Wildlife and Parks (MFFP) on its website.

The low humidity means that Environment Canada is not issuing an oppressive heat warning for the population for the next few days. “Since it’s very dry, it will still be tolerable,” said Mr. Cantin.

In addition, the nights will be relatively cool, with forecasts of 15 to 18 degrees in Montreal. “It is at night that heat waves take their toll,” said Mr. Brien.

This blockage should end on Sunday and the heat wave should be replaced, the following days, by possibilities of showers and thunderstorms.