A potent Pacific storm will track inland across Washington state Thursday morning then rapidly weaken. This storm will produce a period of heavy snow (15-30 cm) over the Coastal Range in BC through Thursday morning before shifting into the Rockies during the afternoon and Thursday night. I expect a general 10-20 cm for the BC Rockies.
Despite a favorable surface low track, there will be a splitting of energy, which means there will be a mid-level storm tracking farther north across the northern half of Alberta, which greatly reduces the chance of accumulating snow from Edmonton on south as there will be too much of a westerly gradient aloft. For much of central and southern Alberta snowfall will be less than 5 cm with the exception of the high elevations close to the Divide.
Cold and snow showers return to the East
Strong cold front will sweep through southern Quebec early Thursday then continue east into the Maritimes later in the day.
Cold air crossing the Great Lakes will lead to rain showers downwind of Huron and Georgian Bay during the afternoon and early evening.
Once again, the warmth of the Great Lakes and the fact that this air mass will not be as cold as the last one will mean that the bulk of the precipitation in areas downwind and close to the lakes will be liquid. However, once you get at least 50 km away from the lakes and gain some elevation it will be in the form of wet snow Thursday night into Friday.
Major cold early next week and possibly some snow
An Arctic front will drop south through the Prairies on Sunday then continue southeast and reach southeastern Canada by Tuesday next week.
Temperatures behind this front will be well below normal. Strong energy aloft will dive toward the Ohio Valley Tuesday and Wednesday and depending on the speed of this energy we may see a surface storm developing over the eastern U.S. With fresh, cold air coming in, there could be a swath of accumulating snow northwest of the surface storm over the interior northeastern U.S. and possibly into extreme southern Ontario Wednesday/Thursday as the storm eventually strengthens off the U.S. Northeast coast and turns into a major storm for parts of Atlantic Canada by Thursday.
Not all of the models are on board with this idea though, as some are much more progressive and just have the cold air overwhelming southeastern Canada and the Northeast U.S. and suppressing any storm development farther to the south and keeping it weak.
We should have a better idea on the evolution of all this by Friday/Saturday. We are still in the wait and see period with this. I will certainly keep you posted.
The overall pattern does look unusually cold for the western third of Canada as we get into the middle of the month which would be good news for the western ski areas.
Widespread above-normal temperatures will likely dominate into the first half of December.
My thoughts on the snow through Tuesday in the East and West.
Other than a blast into western Canada next week, most of the Arctic air will remain north of the Arctic Circle into December with just brief intrusions while mild, Pacific air takes hold from west to east.
Still happy with my old snow map.
Accumulating snow this weekend for parts of southern, central and eastern Ontario.
Wild storm in the West through Tuesday. A little snow in the east for the weekend?