Snow squalls and frigid weather for the week ahead

Snow squalls in southern Quebec and especially along the 401 corridor in Ontario, will make for dangerous and highly changeable road conditions Monday and Tuesday. Strong winds and frigid cold return this week, with the chance for more snow. Even colder air arrives by next weekend, with lows in the -20s.

Snow Squall Watch - Cornwall to Montreal. Afternoon and evening snow squalls are possible for Montreal and southern Quebec.

Snow Squall Warning - west of Cornwall to Port Hope - Lake effect snow squalls today, with dangerous travel expected along Highway 401.

Cold from Montreal all the way to Florida and west across the Great lakes will be the big story this week. Several arctic boundaries will introduce progressively colder air this week, along with scattered snow showers and snow squalls. Some of the squalls, especially close to the Great lakes, will be very intense, with blizzard conditions, heavy snow, zero visibility and dangerous windchills.

For Montreal, we can expect light snow today ahead of the main front, as low pressure travels well north of the city. Temperatures will be around -5C (23F). Monday afternoon and evening, the front arrives, accompanied by strong southwest winds up to 70km/h and occasional flurries, with the risk of squalls. Generally less than 5cm is expected, but some locations toward the Ontario border may see as much as 10cm. Strong winds will cause blowing snow and reduced visibility.

Very cold temperatures flood in behind the front, along with strong winds into Tuesday. Lows will drop to -15C (5F) and struggle to -12C (10F) on Tuesday. Windchill values will be in the minus 20s Even colder air arrives by the end of the week, but will will cover that in future posts.

For Ontario, dangerous snow squall are forecast to develop off Lake Ontario an impact the region along the 401 corridor from Cornwall to Port Hope. In this zone 10 to 20cm is possible, with very poor travel conditions. Visibility in 70-90km/h winds will drop to near-zero at times. Travel along the 401 from Montreal is not advised today.

Snow fell as far south as northern Florida over the weekend. Even colder air will spread south over the upcoming week. (Photo: Florida Weather Center)

The squalls are expected to be so intense, that Environment Canada has issued a rare Blizzard Warning for Prince Edward County at the northeast corner of Lake Ontario. Strong winds up to 90km/h, will be accompanied by heavy snow, with 20-40cm possible. Those same conditions will be possible along Interstate 81 south towards Watertown and also east of Lake Huron.

Over the weekend, freezing temperatures and snow occurred as far south as the Florida panhandle. More frigid weather and snow is likely this week and into next weekend, from New England to Florida.