Parade of storms over - coldest air of the season moves in

Strong southwest winds last Sunday pushed intense snow squalls along the St. Lawrence Valley as far as Ile Perrot and parts of extreme southwestern Quebec. An arctic front added to the squalls as it moved southeast across the region. The result was heavy snow, blowing snow and difficult travel conditions for a few hours during the afternoon. (Valley Weather)

After four low pressure systems in the last 10 days, the parade of storms is over for southern Quebec, at least for the next few days. Tuesday's system moved along the eastern seaboard leaving Montreal on the extreme northwest edge. We managed 4 to 5cm of fluffy snow, enough to make travel slick during the evening commute. 

The big story for the next few days will be the cold. A modified arctic airmass will deliver the coldest air of the season so far to southern Quebec. This morning's low of -14C (7F) was the coldest so far this winter for Montreal, a clear indication of just how mild the 2023-2024 winter has been. The next few days will feature party cloudy skies, perhaps a stray snowflake or two, with lows of -15C (5F) to -18C (0F) and daytime highs of -7C (19F) to -13C (9F). Southwest winds of 30-50km/h in the Montreal region on Tuesday, are producing local blowing snow, along with windchill values around -20C (-4F). To date Montreal's Trudeau Airport has received 110.2cm of snow, nearly half of that over the last 10 days. 

Heavy snow squalls pound Watertown, New York on Wednesday afternoon, January 17. In excess of 50cm was expected, with storm totals approaching 100cm. (webcamtaxi.com)

For the balance of this week, the heavy snow will be confined to the Great Lakes region, with lake effect snow hammering both Buffalo and Watertown, New York, as well as communities along Georgian Bay in Ontario. Some locations are expecting close to 100cm (40 inches) of snow. This is on top of the 50-100cm that feel last weekend. Lake effect snow occurs in narrow bands downwind of the lakes. It develops as cold winds blow across the relatively warm waters, creating convective cells which organize into bands of heavy snow. The snow has been accompanied by strong winds and even thunder and lightning. Last Sunday, some of the squalls moved along Highway 401 as far as extreme southwestern Quebec.

A NOAA satellite image showing the arctic air streaming across the ice free Great Lakes producing heavy lake effect snow in Buffalo and Watertown, NY. The coldest air this winter, along with just a few clouds and flurries were expected for the balance of the week in Montreal.

Much of the country is being chilled by arctic air moving into the central portion of the continent. Over the last week, Edmonton International Airport set a record with 5 consecutive days in the minus 40s, including last Friday mornings low of -45.9C (-50.6F).

The good news is a significant warming trend in on the horizon, with much of the country going above normal once again by the last week of January.