Frigid weather persists - snowfall warning added for Montreal and Ottawa

A very cold sunset across the frozen Lake of Two Mountains on Friday evening. Temperatures will slowly moderate this week, however we can expect significant snow from a strong winter storm moving north from the US. (Valley Weather Photo)

Snowfall Warning in effect for Montreal, southern Quebec and eastern Ontario.

Widespread winter storm and snowfall warnings are in effect across a large portion of eastern North America, including here in southern Quebec and across most of southern Ontario into Atlantic Canada.

It was a frigid day across southern Quebec on Saturday, with temperatures remaining in the minus 20s for most locations. Morning lows were cold, with -25.1C (-13F) here on Ile Perrot, -25C at Trudeau Airport and -26C (-15F) in Ottawa. Other locations in Quebec were as cold as the minus 30s. A northwest breeze pushed windchill values as cold as -37C (-35F) in Montreal.

Arctic high pressure will remain in place for one more night, before a slow moving winter storm approaches the region from the south. Clear skies Saturday night will allow for an overnight low in Montreal of  -22C (-8F). On Sunday, low pressure will develop in the Mississippi Valley and rapidly deepen as it moves to the middle Atlantic coast and north towards Cape Cod. Secondary troughing over the Great Lakes will help transport deep moisture inland across New England and southern Quebec. Montreal will remain on the northern edge of this powerful Nor'easter, with the heaviest snow expected to fall to our south.

Snow is forecast to spread north and east on Sunday, arriving in Montreal late in the day. The snow may be heavy at times into Monday morning. Temperatures will remain very cold, with an high of -16C (4F) on Sunday. The dry, fluffy snow will be blown around easily by northeast winds up to 40km/h. The wind will also provide bitter windchill values in the St. Lawrence Valley into Monday morning. Snow will persist into Monday, tapering off to flurries during the afternoon.

In terms of accumulations, we can expect 15-20cm from the Ottawa Valley towards Montreal. Less snow is forecast northward into the Laurentian, with perhaps 10-15cm. South towards the US border and into New England anywhere from 20-40cm is possible. Travel will be very poor on Sunday night and Monday. The Monday morning commute in Montreal could be greatly affected.

This is the same storm system that is impacting nearly half the United States with heavy snow, freezing rain and strong winds. The storm has resulted in significant travel delays, with over 13,000 flights already cancelled and roads in poor shape. Widespread power outages are anticipated in parts of the southern US, where 15-25mm of freezing rain is forecast.