This is going to be another big year for the Pacfic NW with the La Nina. The La Nina will not be as strong this season but that doesn’t affect the Pacific NW really as the storm track will spend a lot of time running right through it. The season has already started out on a snowy note and that will continue today as another storm is moving in today. That will drop more snow on top of 6 inches in the past 24 hours for Mt. Baker and an almost 6 ft. base already.
The storm pushing in today is a fairly cold one so snow levels will drop down as low as 2000 ft. over the Cascades. Below is the map of the total precip by Friday. We should see snow accumulations of 20-32 inches on Mt. Baker, 7-14 inches at the Summit at Snoqualmie, and 12-18 on Mt. Hood. Further East into the Bitterroot Range and place like Sun Valley we should pick up around 3-6 inches of snow. With the cold nature of this storm the highs will only be in the 20’s at the lower elevations and the teen in the higher elevations making for some light powdery snow.
There is another storm approaching the coast for Saturday. This storm will draw a lot of mild air up ahead of it raising snow levels above 6000 ft. That will mean rain for most locations except for the highest peaks above 6000 ft. Saturday night the cold front will push through and drop snow levels below 5000 ft. for Sunday with heavy snow continuing. Above 5000 ft. we could see another 2 feet over the weekend bringing the storm totals up to 3-4+ feet for Mt. Baker up top. The precip with this storm will mainly be confined to Western Washington and Northern Oregon, and not much further to the East.
Here is the 5 day forecast for Mt. Baker. This is the forecast every ski area is dreaming of coming to them soon.
As we go into next week the ridge in the West is really going to amplify Northward and try hard to push the storm track all the way up into Canada. There is another semi-cold storm moving in on Tuesday night and right now it looks like it may be able to push just far enough South to affect the Northern tip of the Cascades. This would be a light snow producer with several inches possible for Mt. Baker. There is a similar storm possible again on Friday. Below is the total precip map out through next Friday. There is enough liquid there for 4-5 feet on Mt. Baker.
Right now the PNA (Pacific North American) teleconnection pattern is going positive which favors the building of a ridge along the West Coast. A La Nina favors a negative PNA so this positive PNA shouldn’t last that long. Looking out two weeks it looks like the ridge is going to really build Northward all the way up into the Gulf of Alaska forming a block and keeping the storms up into Alaska and Canada. Some models show the ridge a little further West which would drive some of that Arctic air from Alaska down the West Coast. That would also bring the chance of light snow. Other models keep the ridge a little closer keeping the cold air to the East.
One thing that is possible when there is high pressure blocking in the gulf of Alaska is that sub-tropical jetstream can come underneath into the West Coast. In La Nina with the colder water along the equator there really isn’t a sub-tropical jet to do that. The wild card can be the MJO (Madden Julian Oscillation) that can create psuedo El Nino conditions for about a week when it moves through the Pacific and is strong enough. Right now it is strengthening in the Indian Ocean as it circles the globe. We will have to watch it as it moves towards the Western Pacific over the next 2 weeks. Stay tuned….BA