Arctic Air Coming East in Stages, Dry Pattern in the West

Large-scale pattern change slowly evolving across North America this week and into next as a result of the major stratospheric warming event that has been ongoing across the northern latitudes.

The first of several shots of Arctic air will be directed into eastern and Atlantic Canada later this week, followed by a second shot later in the weekend and another sometime next week.

At the same time, a persistent ridge of high pressure off the U.S. West Coast will bring a period of dry, tranquil weather to the Pacific Northwest and up through the southern half of B.C. Even, though it will be a dry and relatively mild pattern the ski conditions across western Canada should remain excellent with solid bases.

Details........

1. Expect a round of strong, downsloping, westerly winds across southern Alberta and into Saskatchewan Tuesday as milder air moves in behind the warm front that brought the snow to parts of the region earlier today.

2. A weak storm moving up in the southwesterly flow aloft will bring a period of light to moderate snow from New England into New Brunswick, PEI and northern Nova Scotia Wednesday and Wednesday night.

3. The image below shows the arrival of the first Arctic air mass later this week. Nighttime temperatures Thursday night will get below -20 C. in many areas of southern Quebec into New Brunswick.

As the Arctic front moves in there could be a brief burst of heavier snow later Wednesday night or early Thursday downwind of the lakes and also from the GTA up into the Ottawa region.

Ski areas that were negatively impacted by the brief warm spell should be able to get the snow-making guns running full force Wednesday night, Thursday and Friday, setting up for a good weekend of skiing from Ontario through the Maritimes.

In addition to the cold, there will be a brief period of lake-effect snow in the typical snowbelts downwind of Lake Huron and Georgian Bay Wednesday night into early Thursday.

Gulf-enhanced snow also possible from PEI through NE Nova Scotia and into western Newfoundland Thursday night through Friday as the Arctic air moves over the relatively warmer water.

Also, a series of clipper storms should bring some additional snow from southern Manitoba into the eastern ski country Friday and into the weekend.

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