Seasonal temperatures in store for Thunder Bay as summer begins

Seasonal temperatures are in the forecast for Thunder Bay as summer officially begins, Environment Canada says.

"For the most part, we are looking at seasonal temperatures, which means daytime highs around 20, 22 degrees [Celsius] or so," said Gerald Cheng, a warning preparedness meteorologist with the national weather agency. "We're very close to that."

Cheng says there would likely be some showers over the weekend, followed by a brief spike in temperatures on Tuesday. However, he says a heat wave is not expected, as temperatures are expected to return quickly to normal.

"What we see in the pattern is very seasonal in general…. I don't see anything out of the norm," he said.

"But in the summertime, we we do expect thunderstorm activity, so that's something that we have to prepare for."

Recent precipitation in Thunder Bay and the surrounding region has helped to keep forest fire activity to a minimum — as of Friday afternoon, there were no active fires reported in the northwest, said Alison Bezubiak, a fire information officer with Ontario's Aviation, Forest Fire and Emergency Services.

"Each fire season is really variable based on the weather trends that developed throughout the season," she said. "Through the spring, we received really regular and widespread precipitation, as well as cooler temperatures, and that helped to keep the fire load to a minimum up to this point."

So far this fire season — which began April 1 — 39 wildland fires have been confirmed in the northwest. They've burned about 52 hectares of land.

During the same period in 2023, 182 fires had been reported, which burned more than 85,000 hectares of land, Bezubiak said.

"At the moment, we're observing a mostly low-to-moderate wildland fire hazard across the northwest region," she said. "Most of the region did receive significant rainfall earlier this week, but it was accompanied by widespread lightning, which can be the source of holdover fires."

Holdover fires, Bezubiak explained, "are fires that occur when lightning strikes a tree or other forest fuels and ignites a fire under the forest floor."

"Once weather dries up, winds increase [and] temperatures rebound, holdover lightning fires can appear up to about a week later," she said. "Instances of lightning fires do tend to increase as we head into the summer months. Given that we're starting to see a slight drying trend right now, we are carefully monitoring for new starts from lightning."

However, forest fire activity is very hard to predict, Bezubiak said.

"It's very much a weather-driven phenomenon. Weather plays a significant role in determining the frequency and the severe severity of wildland fires," she said.

"Because of how the weather has played out, and will continue to play out, that will determine fire season as we go forward."