A series of Pacific storms that will be loaded with moisture will sweep into British Columbia over the next week, and the result will be heavy rainfall and potential flooding along the coast and rounds of heavy snowfall in the mountains.
By the middle of next week, portions of western Vancouver Island may end up with 200 to 300 mm of rain from all these storms.
Some ski resorts in the Coastal Mountains of southwestern BC may end up with close to 3-4 feet (a meter or more) of new snowfall by the middle of next week. There will also be significant snow in the BC Rockies (1-2 feet through the period) and over the higher elevations of interior Vancouver Island.
Most of the Arctic air will be kept out of North America through the first week of January due in part to that strong Pacific jet delivering all that moisture into BC.
There are some indications of an upcoming stratospheric warming event over the far northern latitudes later this month. Typically, these can eventually translate into a surge of Arctic air coming southward through a portion of North America in about two to three weeks after the warming event. Based on this early information, we may see a significant pattern change starting around the second week of January. Computer models are usually slow to catch on to these changes from these stratospheric warming events.