AccuWeather’s 2019 Canada autumn forecast

By Brian Lada, AccuWeather meteorologist and staff writer

Warmth will be stubborn to retreat from Canada this autumn, delaying the first wave of cold air for some of the country’s most populated areas.

The persistence of the warmer weather could have implications for the latter part of the wildfire season across British Columbia and the Canadian Rockies. 

Active end to western Canada’s wildfire season

Canada’s wildfire season got off to a quick start this year with massive blazes erupting across western Canada in late May.

But as of late, wildfires have not been as active across the region.

However, the changing of the seasons will spell a change in the wildfire outlook.

“The fire season is far from done,” AccuWeather Canadian Weather Expert Brett Anderson said. “We believe there may be a second surge in fire activity during the month of September from British Columbia to Saskatchewan.”

The region around Yukon and northern British Columbia may escape the worst of the fire danger due to the anticipated wet pattern heading into the new season.

“The main storm track this fall will be directed into northern British Columbia, but this will also feed mild, Pacific air into much of the West as well,” Anderson said.

“The snow season in the Rockies is also expected to get off to a slower start later this fall.”

In this July 5, 2015 photo, flames rise from a wildfire near La Ronge, Saskatchewan. (Corey Hardcastle/Ministry of the Environment/Government of Saskatchewan via AP)

Large wildfires that do ignite could potentially have far-reaching effects across North America.

As the fires burn, their smoke rises through the atmosphere.

The jet stream may occasionally carry this smoke eastward across North America, delivering smoky, hazy skies to areas thousands of miles away.

Smoke from wildfires lingering over the Canadian Rockies and Prairies on May 31, 2019. (Image/NASA Worldview)

These far-reaching blankets of smoke across the atmosphere can lead to more colorful sunrises and sunsets.

Dry start to autumn for the Prairies

Similar to the west, the Canadian Prairies are forecast to start autumn under the influence of a largely warm and rain-free weather pattern.

“The drier and warmer conditions may aid in the fall harvest across the Prairies during September,” Anderson said.

While the dryness may benefit some farmers, it could also lead to some concerns.

There are pockets of moderate drought in the Prairies, according to the Canadian Drought Monitor. Below-normal precipitation throughout the fall could cause these pockets to expand and the drought to worsen.

However, a mid-season flip in the weather pattern will usher in big changes to the Prairies.

“During the month of October, there may be an early season surge of unseasonably cold air directed into the eastern Prairies and northwest Ontario,” Anderson said.

The intrusions of chilly Arctic air may bring about the first freeze of the season from eastern Saskatchewan through Manitoba slightly earlier than normal.

Summer warmth to linger from southern Ontario to Labrador

Shorts and short-sleeve shirts will continue to be the garb of choice for many across eastern Canada early this autumn as summer warmth and humidity linger across the region.

“Fall will get off to a late start around the Great Lakes and into Quebec as the main storm track allows for surges of late-summer season warmth and humidity,” Anderson said.

This includes Toronto, Ottawa, Montreal, Quebec and even Halifax.

“This pattern may delay the annual first freeze by a week or two from southern Ontario to southern Quebec and the Maritimes, which would extend the growing season,” Anderson added.

The first chill of the season is predicted to arrive during October as Arctic air starts to penetrate farther south.

“Any surges of cold air coming down across the warmer Great Lakes during October may lead to an outbreak of thunderstorms and waterspouts,” Anderson said.

RELATED LINKS: 
Brett Anderson's Canadian weather blog 
10 things you need to know before visiting Atlantic Canada 
Canada weather center

While October will bring waves of chilly air to Ontario and Quebec, Atlantic Canada will remain warmer than normal.

“Tropical activity in the Atlantic is expected to steadily pick up through September and may linger well into October or even November,” Anderson said.

There is a near-average threat for a landfalling tropical cyclone in Atlantic Canada this season.

On average, there is one landfalling hurricane in Atlantic Canada every three years.

These systems will pull in warmer air from the tropics, as well as bring the potential for damaging winds and flooding rain.