Snowstorm likely for much of Southern Ontario by midweek News

Environment Canada Meteorologist Jeff Coulson says temperatures are expected to be seasonable in southern Ontario this week and we could even see a snowstorm by midweek.

“We're tracking a storm system out of Colorado late Wednesday that could affect southern Ontario by Thursday afternoon,” Coulson said in an interview Monday morning.

“Right now it looks like for areas around the GTA, it's going to be mostly a snow event, but it could mix with or change to rain as it moves down toward the Niagara Peninsula and the north shore of Lake Erie.”

He said initial snow totals with this system could be around 5 to 10 centimeters for the GTA.

“There's not a lot of snow, but given that we haven't seen a lot of snow this winter and the snow is likely to fall during the Thursday evening rush hour, we may be looking at some slowdowns,” he said. .

Weather models are mostly showing a snow event for the GTA, with temperatures near zero, but he said that's not the case in the south.

“As you go down towards Grimsby, St Catharines, Welland, you'll see more chances of it mixing or even changing to rain. It looks like it's mostly a snow event for the Golden Horseshoe itself, with the exception of areas on the Niagara Peninsula.

As you get a little further north, the amount of snow is likely to increase, he said.

“Toward the north of the city (Toronto), the King City area, Lake Simcoe, Barrie, the amounts could be a little higher, they could see 10 to 15 centimeters from this system.”

As for this week's return to seasonal winter temperatures, he explained, “we're seeing some changes in the upper-level wind patterns that drive our weather systems and bring in the air masses.”

“So we've seen a southwesterly flow for most of February, but it looks like it's going to shift more to the west or northwest next week.”

Normal temperatures for this time of year for the GTA, he said, are -1 C for a high and -8 C for a low, adding: “It looks like we'll be around those values ​​by the end of the job. week and the coming weekend.”

For example, today's forecast for Pearson Airport in Mississauga is 3 degrees today, -2 degrees overnight, followed by a high of 2 degrees on Tuesday — all well above seasonal normals. But during the night from Tuesday to Wednesday, the low of -9 degrees will reach the seasonal norm.

The rest of the forecast from Wednesday is zero or slightly lower.

That could threaten an unusual stretch of mild weather since Jan. 23, when high temperatures have consistently hovered above freezing and sometimes in the double digits in many southern Ontario communities. We are not even close to the normal minimum.

The stretch is not only “very unusual” for its length, Coulson said, but for two other reasons.

The first, he says, is the timing of mild spells that occur “usually during the coldest part of winter, which is late January to early February.”

And the second reason, he repeated, “is just the amount of sunlight. Traditionally, when you see sunshine in January and February, it's usually associated with a cold arctic air mass: it's cold dry air, not much moisture, not a lot of clouds.

“But we've been able to combine above-normal temperatures and a fair amount of sunshine over the last week.”

And despite the snowstorm in the forecast, he said there's still plenty of sunshine in the forecast.

“We'll probably see some (sunshine) this (Monday) afternoon. The satellite is showing that the clouds have thinned out a bit, and yes, the sun will come out today, and again on Wednesday, right now, maybe even through the weekend.

“So it looks like the sun will be closer and closer in the coming days.”