Snow squalls to batter region as Environment Canada introduces new colour-coded weather warning system

Snow squalls will batter southern Ontario on Thursday into Friday as Environment Canada unveiled a new colour-coded warning system. Julie Atchison explains.

With the unveiling of a new colour-coded weather warning system and snow squalls off Lake Huron battering southern Ontario, it’s been a busy weather week.

Here’s what people in the London, Ont. region should know.

What does Canada’s new colour-coded weather warning system mean?

On Wednesday Environment and Climate Change Canada introduced a new colour-coded tiered weather warning system.

“This is what we’re looking at now for our weather warnings: Formerly watches, yellow now indicates impacts are moderate,” CTV News London Meteorologist Julie Atchison said. “As we go up to orange that was our snow squall warning. Rarely will you see a red impact.”

Atchison adds orange is less common but will have a “major and widespread impact” in the area.

“When we take a look at our watches and warnings, now we have alerts,” she said.

Snow squalls to batter southern Ontario

Looking to regional forecasts, a yellow alert issued for London and eastern Middlesex County means there is the potential for snow squalls to develop. Atchison says snow squalls could set up over London, with the potential for between two to four centimetres of snowfall and blowing snow Thursday evening into Friday morning.

“The potential for another five centimeters but that snow squall has to drop a bit further south,” she explained.

“If you are traveling from London east northeast you will encounter some whiteout conditions and some very rough roads,” Atchison warned. “If you don’t have to travel tonight it is best to stay home especially if you are heading north of London.”

Going northward, Atchison says snow squalls are “hammering” parts of Huron and Perth counties and therefore find themselves in an orange alert as the impacts are “major and widespread.”

Towards southern Grey and Bruce County, Atchison says the region is seeing high amounts of snowfall accumulation heading into the afternoon and “whiteouts are an issue.”

Atchison says towards Kitchener-Waterloo and Mount Forest snowfall accumulations could approach 30 centimeters with the potential for 40 centimeters right off Lake Huron.

“Now just north of London we’re seeing heavy accumulation again potential for about 20 to 30 plus centimeters of snowfall. So that just shows you how localized they are,” she said. “You can go from clear dry conditions and right into a wall of blowing snow and whiteouts.”

Road closures will occur heading into Thursday night as streamers off Lake Huron will make their way as far as Toronto.

As snow batters the region cold air continues the flood the region.

Many communities will be affected by the snow heading into the weekend, while temperatures will hover around the freezing mark. Winds will shift to the northwest with sustained winds of 40 km/h and gusts of 50 km/h

“The main risk for snow squalls in London will be tonight and heading into Friday morning,” Atchison said.

Here’s a look at London’s long range forecast

Thursday night: Flurries with risk of snow squalls. Local blowing snow. Local amount 5 to 10 cm. Wind west 40 km/h gusting to 60 km/h. Low - 3C.

Friday: Flurries with risk of snow squalls. Local blowing snow. Local amount 5 cm. Wind northwest 40 km/h gusting to 60 km/h. High zero. Wind chill - 11 in the morning. UV index 1 or low.

Saturday: Cloudy with 30 per cent chance of flurries. High 1C.

Sunday: Cloudy with 60 per cent chance of flurries or rain showers. High 3C.

Monday: Cloudy. High – 2C.

Tuesday: Cloudy. High – 1C.

Wednesday: A mix of sun and cloud. High – 1C.