Monday, December 6, 2010

More Base.........

Northstar was right on track with the forecast with 4 inches at the base and 10 inches on top. I went out for first tracks this morning. It was shin deep powder on top and then around 6 inches of cake by the time you got to the lift. Good snow to improve and build the base.

We have a very complex weather pattern shaping up that circles the globe. Lots of variables and the slightest change could have big impacts on us. The one thing that is for sure is that it is a mild pattern for the next 10 days. When there is precip the snow levels will be above 7000 ft. and when there is not precip the temps will be in the 40's to near 50 at the lake.

There is a large low spinning in the Northeast Pacific. It will bring precip into the area Wed-Fri. The mountain tops will pick up several inches of snow but the bottom half of most resorts and the lake will have rain. A ridge will build in by next weekend with mild temps and sun.

There is a blocking high pressure to the Southwest of Alaska all week and a ridge over or just off the coast of Southern CA. That will keep the heaviest precip North of us. The whole pattern is jammed up due to the NAO being negative in the North Atlantic and holding the cold in the East. It is trending positive, but the forecast is split whether it continues to go positive weakening the block or goes back negative. It was expected that the East would have the cold in December and then that will reverse for the winter in January. A block in the Pacific a little East of where it is this week can bring us a strong enough jetstream to crush the ridge over CA.

The GFS model has been fairly consistent with this happening the middle of next week. If it happens the low in the pacific will push a little more South and East and bring the jetstream into Northern CA with a series of storms for us. They could have quite a bit of precip and lowering snow levels. If the NAO trends negative again a week from now it could mean we ridge up again the week before Christmas.

There are 2 things that could help to keep the NAO from going negative. The Arctic Oscillation is forecast to drop through the floor which means a large displacement of the Arctic Cold into the country and that usually comes west eventually bringing cold and snow like that big storm series in November. The other thing is that the MJO is strengthening in the Maritime Continent region and heading West. When it hits the Western Pacific in about a week that usually juices the jetstream and brings it into CA about a week later. The PNA is also forecast to stay negative which helps prevent ridging near CA. You can follow the progress of the MJO on the Side bar. You can follow the NAO, PNA, & AO on the "Forecasting Tools" page under "Teleconnections".

Basically all this means that there is a strong jetstream in the Pacific and we are right on the edge of it. A slight shift East of all the blocks around the globe or a break down of them and we could get pounded. All of this should become null in January as the true La Nina signal takes over as we are on the edge of a strong La Nina. The cold over the East should shift West and the blocking high pressure in the Pacific will move to the Gulf of Alaska directing the jetstream underneath into the Pacific Northwest and Northern CA. Stay tuned.....BA

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