Dangerous heat, high humidity this weekend in Montreal: Environment Canada

Intense heat and humidity will envelop Montreal and its surrounding areas this weekend, with humidex values expected to reach as high as 45, according to an Environment Canada heat warning issued Saturday morning.

The warning is in effect for the following areas:

• Châteauguay-La Prairie
• Laval
• Longueuil-Varennes
• Island of Montreal

The government agency is recommending people check on those who are vulnerable, such as the elderly, people with chronic illnesses and those who live alone or who have limited autonomy.

During periods of high heat and humidity, Montreal public health officials recommend residents spend up to three hours a day in air-conditioned places, drink water on a regular basis and never leave children alone in cars.

In a heat dome

The scorching weather conditions are created by a so-called heat dome brought on by high temperatures travelling up from south of the border and across the Great Lakes into Canada.

Global News chief meteorologist Anthony Farnell says temperatures will feel “all the more tropical” because of a large amount of rain dumped around the Great Lakes as well as the southern and central U.S.

WATCH: Much of the U.S., like Canada, is caught in the grip of a punishing heat wave

1:09 Much of the U.S., like Canada, is caught in the grip of a punishing heatwave

“A heat dome can form in the summer under particularly strong areas of high pressure,” explained Farnell.

Farnell says the heat will subside on Sunday when a cold front will force the heat dome back down south.

Showers are in the forecast for many areas, including Ottawa, Toronto, Montreal and Kingston.

Heat warnings are issued when very high temperature or humidity conditions are expected to pose an elevated risk of heat-related illnesses, such as heatstroke or heat exhaustion.

—With files from Global’s Kalina Laframboise and Kerri Breen