What's left of this east coast storm and tracking heavy snow potential in the west for early next week

Wednesday, November 27, 2013, 6:24 PM -

System snow has moved out of the Niagara region and Golden Horseshoe of Ontario, but lake effect has settled in in its place. Canada’s busiest airport, Toronto’s Pearson International, picked up its first official accumulation of snow with this system. Accumulations ranged from 5-15 cm across Niagara region and 2-10 cm across the Greater Toronto Area. Though there wasn’t a lot of accumulation, many of the major on- and off-ramps on major GTA highways were slick and east of Toronto, accidents were plentiful on the highways.

Lake effect snow has now developed off of Lake Huron and Georgian Bay with the dominate band being off of Lake Huron. Bulletins for snow squalls have been issued by Environment Canada warning of snowfall rates of 15 cm per hour in the heaviest lake effect bands. Should the dominant band off of Lake Huron remain stationary, some areas could see 20+ cm. It is important to keep in mind that bands of lake effect snow tend to meander slightly so snowfall totals could be limited if the band moves around slightly. On the other hand, if it remains stationary, a lot of snow in a short period of time isn’t out of the question. Once more, areas between and including London and Strathroy are in the crosshairs of the lake effect snow machine. Squalls are expected to intensify Wednesday evening and overnight with flurries expected to continue until Friday morning.

The Weather Network's radar image at 7:00am EST Wednesday morning with heavy snow coming off of Lake Huron and Georgian Bay.

NAM forecast weather model's solution (06Z run) for lake effect snow amounts in southern Ontario (in inches).

As of Wednesday morning,the big snowfall amounts, though, are in eastern Ontario and parts of Quebec. As of this morning, Ottawa’s airport has reported almost 25 cm of snow with the heaviest snow in that region now tapering off. Montreal’s Trudeau airport reported 12 cm of snow before changing over to a cold rain at 1°C this morning. South shore areas of Montreal saw only about 5°C with an early change to rain that kept the snow melting. Unfortunately, this didn’t happen in time for the morning commute which was a headache for anyone travelling in and around Montreal. Areas just north of Montreal are reporting 20-25 cm with snow still falling as of Wednesday morning. Freezing rain has been reported along the St. Lawrence River in Quebec where Freezing Rain Warnings were in effect for 2-5 mm. East of the aforementioned areas have been in Rainfall Warnings with 50-90 mm of rain on tap. Precipitation is expected to come to an end for southern Quebec by Thursday morning.

The Weather Network's radar image at 3:30am EST Wednesday morning of heavy snow (in blue), rain (in green-yellow-red) and freezing rain/mixed precipitation (in pink).

The Maritimes and Newfoundland have been getting in on the storm as well but are getting the heavy rain rather than the heavy snow. All Atlantic Provinces are expected to be hit with very strong winds and Labrador could see very high snowfall amounts from the storm. The Maritimes (especially Nova Scotia and southern New Brunswick) are en route to receive 40-80 mm of rain with 80+ mm possible along the Fundy shores. Southwestern Newfoundland from Ramea to Channel-Port aux Basques are forecast to receive 60-100 mm of rain. At least 20-30 cm of snow is possible for the majority of Labrador.

Wind will be a big story across all four Atlantic Provinces Wednesday evening and overnight into Thursday. Gusts 90-100 km/h are possible over Newfoundland, Prince Edward Island, New Brunswick and mainland Nova Scotia with gusts to 140 km/h over Cape Breton and gusts to 170 km/h for Channel-Port aux Basques area. Atlantic Canadians are likely to experience power outages over the course of Wednesday night and Thursday morning due to the high winds so if you can, make sure you prepare with flashlights and/or candles and charge up your phones.

GEM forecast model's solution (00Z) for wind speeds (in knots) overnight Wednesday into Thursday morning.

November is coming to a close and winter is certainly fighting its way into the backyards of Canadians if it hasn’t done so already. Looks like another blast of winter is in the cards across the west for the beginning of next week as a low pressure system is forecast to slip down from the Arctic bringing the cold and snow. The first week of December looks to be cold for many Canadians from British Columbia to northern Ontario.

NAEFS model's solution for probability of above- (reds), normal- (purples) or below-normal (blues) temperatures.

We will continue to monitor the potential heavy snow for western Canada early next week so check back for updates. Precipitation is expected to come to an end in Atlantic Canada by Friday morning with the winds dying down throughout Friday.