Thursday, December 17, 2009

Winter to Start on the WHITE Foot.........

Great weather and nice early season snow pack is the word this weekend. Highs will be in the 40's and a nice thick base thanks to the onslaught of storms last week. First day of winter (Monday the 21st) to start on the right foot with more snow.

Ridge in place over CA is keeping another strong storm to our North into the Pacific NW. Next storm will be off the Pacific NW coast by Sunday. As the ridge kicks East, this storm will bring a cold front through Tahoe Monday night. With just the cold front we are looking at a storm similar to the storm at the end of November that dropped a quick 6 inches of fluffy snow with cold air behind it. Models this evening are hinting at the idea of a piece of the storm splitting off and forming a low over Central CA. This would increase the snowfall into Tuesday and give us a bit more. Let's hope the wet trend continues. Either way it looks like some snow to freshen up the base for Christmas week.

After the storm moves through the ridge will try and build in over Pacific NW and British Columbia. Step 2 would be for the jetstream to break through under the ridge Christmas weekend. Models have shown this, and shown the ridge a little too far South keeping the Southern jetstream from forming. Could use a little help from the MJO like last week. It emerged in phase 4 and was forecast to strengthen going East in the Pacific towards phase 7 which would have strengthened the Southern jetstream. It has since weakened and is now forecast to briefly strengthen in phase 7 in the next few days before looping back around. This may be enough to bring a strong storm in Christmas weekend.

Not sure that the models are catching onto the influence from El Nino. SOI tanked down to around -30 the last few days which would create ideal conditions for strengthening in the short term. NWS is predicting above average precip over the next two weeks in CA. See the map below. Stay tuned for the details of the Monday storm......BA

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