Sunday, January 20, 2013

Very cold upcoming week will hopefully conclude with some significant snow

Temperatures are falling across Vermont and in the coming days, the mountain, the state and the entire region will be in the deep freeze. It is as impressive of an outbreak of cold as the region has seen in the last half a decade, perhaps even dating back to 2004 which was the last January outbreak of cold that challenged records across New England. The stronger outbreaks of cold in New England and particularly in Vermont occur when cold is delivered straight out of Canada as opposed to the Great Lakes region directly to the west. This initial blast of chill Sunday night into Monday has been modified somewhat by the open waters of the Great Lakes. A clipper system, the last of a 3-part series will ultimately bring unmodified arctic air of a very intense variety. We are of course most interested in the clipper for its snow. It will have a very limited amount of moisture as it tracks through the Great Lakes on MLK day but it will get juiced a bit by the warmer Atlantic Ocean. Precipitation will be in the form of snow obviously but most of it will be across coastal New England while a very fluffy 1-3 inches falls across the high terrain of central and northern Vermont. The snow from this system will fall Monday night into Tuesday. Temperatures will be in the 0-10 degree range through Tuesday but will plummet further Tuesday night, perhaps all the way to -20 by Wednesday morning. It may then be all the way until Thursday afternoon before temperatures get above zero again.

The elephant in the room, as it is most of the time, involves snow. The sooner we get a big snow the sooner the Single Chair begins spinning and the main mountain opens. As of January 20th, new snow has been quite sparse this month and the need is great in the wake of last weekends thaw. Our big chance, what I hope will be the first of many, comes Friday. This is a system that will come out of the Rockies early Thursday and proceed quickly through the Great Lakes. It will move quickly and will thus have a limited time to gather both moisture and any serious strength along the Atlantic coast. Nonetheless, the system has the ingredients to produce snow, mainly as a result of what should be a broad overrunning surface. Everything with this system will hinge on the track. The polar jet will need to ease its grip just enough to allow this system to track toward Cape Cod. It's not asking a lot and two of the three major computer simulations are currently suggesting a healthy dose of snow on Friday following the two day period of extreme cold. The American GFS model has at times suggested this system remaining to the region's south, keeping the mountain dry and cold.

Still looking at a very fluid situation for the last 6 days of the month. Friday's potential storm is followed by another push of arctic cold, though not quite as strong as what we expect Wednesday and Thursday of this week. Ensembles are keying in on a warm-up and a potential brief thaw around the 29th or 30th of the month only to be quickly followed by another period of colder weather by the beginning of February. Through all this, we should continue to see at least some support from NAO and AO and we have to hope that the blocking can help mitigate the effects of any mild push of air. It is not an unreasonable expectation. Milder pushes can appear dangerous but can also prove to be a mechanism for new snow.

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