Thursday, February 4, 2010

January Re-cap/Weekend Snow....

The month of January started off dry with almost no snow the first two weeks of the month. Second half of the month featured 10 straight days of snow as well as a few more storms. Even with the storms the second half of the month we ended January in the Tahoe basin at only 92% of average precip. Good news is that the snowpack ended at around 115% of average. Temps for the month ended up slightly above average at .7 degrees thanks to lots of cloudy nights which prevents radiational cooling and kept the nights warmer than average.

Low pressure in the Gulf of Alaska is going to spin two storms into the area over the weekend. First storm comes in Friday and the second storm Friday night into Saturday. Current thinking is still that the total snowfall is up to a foot in the Village, with 18 inches above 7000 ft. Most of the energy with the storms will dive to our South. GFS has had a couple model runs showing a split in the second storm which if it pans out could reduce snowfall amounts. What will be interesting is if it snows a foot in Truckee and in Atlantic City the same day. Not sure if I've ever seen that happen. The area from D.C. to Philadephia is way above average for snowfall already with amounts of 200-300% above average, with several more snow storms on the way for them.

Another storm is going to be off the coast by Tuesday. The storm is going to split with a piece going North into Washington and the other piece diving South down the CA coast. The question with this storm is how far inland the storm comes. A slight shift to the East or West will make the difference in no snow or a decent amount of snow.

The stormy pattern would love to continue with low pressures setting up in the Gulf of Alaska, one after the next, sending storms into the West coast. The problem won't be a positive PNA putting a ridge off the West coast, and it won't be a negative NAO put a block in the pattern off the Atlantic coast. It will be the AO (arctic oscillation) going deeply negative for a week sending arctic air pouring into the entire country. This will hold a small ridge in place over CA keeping storms away for about 5 days until the cold air moderates and the pattern can get going again. As soon as that happens it looks like game on starting sometime over President's weekend. The AO will head back positive and with no blocking in the pattern we should see a train of storms begin to enter the West Coast.

The pattern the second half of the month will be one in which a big storm could finally form. Not a bunch of moderate storms in a week like we keep having, but hopefully one that can drop several feet in one day. Stay tuned.........BA

"We don't know a millionth of one percent about anything." Thomas A. Edison

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