Saturday, January 3, 2015

Another layer of concrete solidifies the base prior to a wintry week

Nice swath of moderate to heavy precipitation of many varieties has impacted much of New York state Saturday. This stuff will all move into Vermont as snow Saturday evening and all of the latest and greatest information available suggests a nice little thumping in a window between 6 pm and midnight Sunday. There is no way of avoiding a dramatic rise in temperatures that is expected above 5,000 feet after midnight. This should change precipitation to a sleet and freezing rain mixture. The question then becomes whether or not the warmth can mix its way to the surface by early Sunday allowing precipitation to be all rain. My guess is that a few hours of rain does occur with temps reaching the high 30's Sunday. This after 4-8 inches of snow and sleet Saturday night. After it turns dramatically colder by Monday morning, the frozen conglomeration on the ground will just be another foundation layer.

After a mostly dry and chilly Monday, clouds will advance back into the state Tuesday and moisture from the approaching clipper system will begin falling as snow during the afternoon. Still some mixed indications from the model on where the best plume of limited moisture sets up Tuesday but my guess is that it is south of MRG. The storm will eventually gather some strength but in all likelihood this will occur a few hours too late. What we should see is a nice combination of Lake Champlain induced and terrain induced snow showers Tuesday night into Wednesday. The contributions of both the clipper system and the lake/terrain induced snows should amount to another 4-8 inches. This snow will be much fluffier than the concrete underneath. It will turn brutally cold late Wednesday with temperatures falling to sub -10 Thursday morning. Temperatures will moderate a little by Friday afternoon (perhaps back into the teens) before another clipper provides another refreshing dose of light snow prior to the weekend of the 10th and 11th.

In the prior post we discussed the expected "softening" of the pattern which is expected to occur after Jan 10. There is little doubt that this will happen but I've become more confident of a productive softening. We lose the support of the Arctic Oscillation and the North Atlantic Oscillation and much of the high latitude blocking is expected to vanish. Still, there remains support to keep the mean ridge in the Jet Stream over western North America, keeping the door open for some excitement and reducing the risk of a thaw. The pattern is in fact a setup very typical in an El Nino winter. If the southern branch of the jet stream can produce a system or two, we will be off to the races for the middle of Jan.

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