Warmer air and rain by Monday

The Lake Ontario snow plume stretched over 320km (200 miles) from western NY as far east as southern Quebec on Thursday. The image above from CBC was taken at Bishops University in Lennoxville.

A big warming trend if expected in Montreal and across most of Ontario, Quebec and New England. High pressure will give sunshine today with a cold high near -4C (25F). We start the day on L'Ile Perrot at -8C (18F), one of the coldest mornings this season so far. Clouds will increase on Saturday along with the chance for showers and flurries. This is thanks to a warm front lifting across the St. Lawrence Valley. Depending on how much cold air remains trapped at the surface, a period of freezing rain is even possible overnight Saturday for some portion of our region. By Sunday very warm air will stream into southern Quebec on southerly winds producing highs near 10C (50F). It will seem like summer by Monday with a forecast high of 15C (59F). Along with the warmth will come rain late Sunday and Monday as low pressure lifts north across the central Great Lakes. Colder air will return by later next week with a chance for some snow.

Buffalo Update
The snow will come to an end across western New York today as the lake effect machine is turned off. Totals will be historic once all is counted with amounts generally of 2 to 7 feet in the hardest hit locations south of Buffalo and near Watertown. The death toll is at 12 with numerous other injuries reported. The National Guard continues to help with the clearing effort including trying to remove snow off roofs. Already over 30 structures have had their roofs collapse from the weight of the snowfall. A driving ban remains in effect south of Buffalo as highways remain closed. The NHL game between Buffalo and the Rangers has been postponed. The NFL game this Sunday between the Bills and the Jets has been moved to Ford Field in Detroit. Attention will now turn to a serious flood risk starting Saturday. The warm air and rain forecast will likely melt the snow rapidly resulting in flooding. A flood watch is already in effect for several western New York counties.

One final note, yesterdays plume of snow off Lake Ontario at one point in the morning, stretched over 200 miles from western New York into southern Quebec. Heavy snow fell near Lacolle and over towards Sherbrooke with as much as 10cm (4 inches) in just a couple of hours. This has been one of the most impressive lake effect events I have seen in m years watching the weather.