This morning's model runs are even colder with the storm this weekend. Everyone is complaining about the storm being warm but this is not warm for a storm with these dynamcs. A storm pulling moisture from all the way back by Hawaii should be much warmer. We are lucky that the polar jet will be merging with the subtropical jet providing colder air. We also have upward verticle motion that will help with the cooling of the air. The thicknesses I normally look at for snow levels has the snow level below lake level the entire storm. With the warmer subtropical air being drawn in there may be a warm layer that causes the snow levels to come up just above lake level during the day on Saturday at the height of the storm, but I'm pretty confident as of right now that only affects the Village. Then the snow levels come back down below lake level through Sunday. So the mountain is in for lots of heavy snow.
The snow could start as early as tomorrow morning and then become heavy tomorrow night. Snow levels start well below lake level so several inches should accumulate even in the Village by Saturday morning. The heavy snow, with 2+ inches an hour rates, should continue all the way through Sunday until the cold front comes through and ends the heavy snow. The liquid amounts have not changed so snowfall on the mountain from the base lodge up should be in the 3-5 foot range by Sunday night. In the Village and up it will be in the 1.5-3 foot range with slightly lower amounts due to the possibility of rain mixing in on Saturday. Plenty of heavy snow on Sunday after the snow levels come back down. The snow showers should linger into Monday with the moist flow off the Pacific continuing.
The models are still struggling a little with the Tuesday storm on snow levels. This morning the snow levels looked lower for the Tuesday-Wednesday storm as well, but the latest run of the GFS digs the storm so deep off the coast that it loses the polar jet and pumps up milder air. This will make a big diffence between a lot of snow at lake level or rain on Tuesday, but a cold front on Wednesday brings heavy snow back below lake level similar to Sunday. The two storms look almost identical with identical snowfall amounts. Just double the weekend amounts by Thursday so that is 6-8+ feet by Thursday on top. Northstar has over 140 inches already this season for total snowfall, and another 100 inches would put us at over 60% of the total average annual snowfall. Winter doesn't even start till Tuesday so that is crazy.
The low in the Northeast Pacific directing the storms into Central CA this week will shift back Northwest as the blocking high at around 170w moves back near the Aleutian Islands. This is the same pattern we had last week with milder and drier conditions expected the end of next week into Christmas weekend. There is a strong storm that could push the jetstream back into Northern CA by the day after Christmas on that Sunday for a return of snow. The pattern then looks to continue to repeat itself as the blocking high pressure moves back to a position around 170w in the Pacific. That would bring a return of the strong jetstream to Northern CA by the end of the month with more storms and snow. I don't see any reasons looking at the long-term teleconnection forecasts why this pattern should change. If anything it may just get colder with the Arctic Oscillation going negative and the displaced Arctic Air looking for someplace to go. Once the blocking high over Greenland weakens towards the end of the month the colder troughs should have an easier time coming into the West Coast instead of the East. BA