Potent Clipper

Blowing snow along Vermont State Highway 2 in the Lake Champlain Islands on Saturday. ValleyWX Pic

9pm UPDATE: Just a brief update this evening. Snow is still falling here in southern Quebec with between 5-10cm on the ground. Temperatures are still chilly in Montreal having dropped from -3C around 4pm to -7C at 8pm. This is likely because of the northeast wind in the St. Lawrence Valley. West of us it has warmed above freezing across eastern Ontario with Ottawa at 1C and light rain. Radar is showing snow across southern Quebec and into extreme eastern Ontario. The snow should mix with light rain in Montreal overnight as temperatures rise to 0C.

Most Alberta Clippers this year have been moisture starved and on the weak side, however we have a potent one tonight crossing northern Ontario moving southeast towards Montreal by Monday morning. This storm, fueled by cold arctic air to the north and a strengthening flow of moist air from the south, is producing a swath of heavy snow along and north of its track across Ontario and Quebec. Between 10-20cm of fresh snow is expected from Montreal north and east of the city with lesser amounts from Montreal south and very little snow in northern New York and Vermont. Steady snow is falling in Montreal at 5pm with low visibilities and snow covered roads. Heavy Snow Warnings are in effect for the regions north of Montreal including the Laurentians and Quebec City. The snow tonight will be accompanied by rising temperatures, so there is a risk of a messy mix of rain and snow in Montreal. On Monday temperatures will begin to drop late in the day with gusty northwest winds and snow squalls possible. There could be blowing and drifting snow again especially off island to the south and west of the city. It will be very cold Monday night and Tuesday before a major warming trend Wednesday.

I was in Vermont on the weekend and despite the gusty winds and blowing snow, very little new snow was falling. The same is occurring with this system as most of the snow remains north of the international border.

On Saturday in southern Quebec, around 5cm of new snow fell early, driven around by strong south winds. I was driving along the south shore early Saturday morning on the new section of Highway 30. The blowing snow made roads slippery and visibilities low. As I headed south on Highway 15 towards Champlain, New York, the snow tapered off until the roads were completely dry at the border with no snow falling at all.