After the flood - heat and smoke settle across southern Quebec

A film of haze and smoke from western Canadian wildfires lies across the Montreal skyline early Tuesday morning. Montreal is reporting some of the poorest air quality on the planet today, with some improvement forecast by Wednesday.

Air Quality Advisory and heat warning are in effect for southern Quebec.

After the flood comes the fire. Montreal has some of the poorest air quality in the world early Tuesday morning, as smoke from western Canadian wildfires drifts into the lower atmosphere over southern Quebec. 

As of 7AM, Trudeau Airport was reporting an unhealthy Air Quality Index (AQI) of 152, which places it 5th in the world among major cities for polluted air. We are also 5th in Canada, just ahead of Ottawa and behind Saskatoon, which has a very unhealthy reading of 239.

Combine that with elevated heat and humidity today. High temperatures will approach 32C (90F), with humidex values near 40C (104F). What does all this mean? Try to limit your outdoor activities, especially during the afternoon hours. This type of weather impacts the very old and young, as well as those with existing repository or other health concerns. The fine particulate matter from the smoke can cause difficulty breathing as well as eye, nose and throat irritations. In the worse cases, the smoke can impact breathing.

The smoke should ease later today in Montreal, but the high heat and humidity will intensify into Wednesday and persist through Thursday before relief comes in the form of a cold front. Wednesday will be the warmest day in this stretch, reaching 34C (94F). Overnight lows will be around 21C (70F).

Thursday's cold front will be accompanied by showers and thunderstorms. as with Sunday, some may be on the strong side, but that will depend on the time of day the front arrives in Montreal. Details to follow as the event draws closer.

Behind the front, much cooler, less humid air will arrive Friday, giving Montreal a much-needed break from the oppressive heat. The high Friday is forecast to be 26C (79F), and more importantly, morning lows will drop into the lower teens.

We are watching the development of what should become Tropical Storm Dexter. The system is expected to cross over the northern portion of Florida over the next day or so, before strengthening in the Gulf of Mexico. The system is expected to be a big rain maker across portions of the southern US and bears watching.

For now, stay cool.