Though it's a glancing blow and a weakened airmass, the first real chunk of arctic air is making a charge at Vermont. It's an important airmass and one that that is impacting northern New England only and will ensure a colder storm late Wednesday into Thursday while we get our snow. Snow showers capable of producing a small accumulation can be expected across the high country Tuesday but our eyes are fixed to the approaching storm and its potential snowfall.
First I want to provide the friendly reminder that I forecast weather where we ski while other very talented weather prognosticators are providing the intel where most of us live. There is a big difference when discussing weather and especially snowfall amounts. Both Mad River Glen and Sugarbush average twice as much as snow as the valley floor in an average winter and almost 3 times as much as the Champlain Valley. The forecasts found in this blog are both foolish and useless in many of the places we call home even though occasionally I will make mention of these specific distinctions. Regarding our upcoming storm, everyone in northern Vermont will see accumulating snowfall but the high country is certainly the spot where the most will fall. Snow will begin within an hour or two of 3 pm Wednesday and our storm total is highly contingent on our ability to front-end thump. Not many places in the world can front-end thump quite like New England and this refers to overrunning type snow that falls when antecedent cold is enveloped by moisture. This said, I've honestly disappointed that our higher resolution short term models are not front-end thumping harder. I mean after all, this is our specialty. Sure, data is indicating a nice 5-8 inches Wednesday evening, but I was hoping to see indications that deep moisture will get pile driven northward into northern Vermont and produce 2-3 inch an hour snowfall rates for a time and a quick foot of snow. The American model continues to show signs of this, but as we get closer to the storm, it is wise to begin weighting the higher resolution data a little more and medium range model data a little less. So, in an effort to be informative I am providing the strict interpretation of the last round of model data while also pointing out that it continues to look like a favorable setup for heavier snowfall, so long as we get the robust development of a new area of low pressure which will begin to establish itself over eastern Pennsylvania Wednesday evening and move toward eastern Maine Thursday. A several hour long dry slot and a brief change to sleet continues to be possible very early Thursday though the layer of warmth over MRG is very minimal (within 1-2 degrees of freezing if that) and the high country is quite capable of enduring that layer without a changeover at all. Back end snow on Thursday afternoon is then expected to provide a fluffier finish to the storm though with the storm rapidly exiting to the unblocked northeast, our window for this is small. Factoring in all of these different variables yields a 8-14 inch forecast for this storm as of Tuesday afternoon with 6-8 falling prior to the ski day Thursday and 2 to as much 6 inches falling beginning late morning Thursday and Thursday evening. Expect to see a break in the precipitation around daybreak Thursday with any precipitation falling as some light sleet or possibly freezing drizzle though I don't think this lasts long enough to be a major issue.
We are once again grazed with arctic air on Friday in the wake of our storm with temperatures generally in the teens atop our fresh snowcover on Friday though the blustery conditions that will be with us Thursday night should abate. The first Alberta Clipper since I don't know when is then expected to spread clouds and some very light snow into the region on Saturday. This system is simply too far north to provide snowfall of any significance but its passage can bring just enough moisture for an inch or two of accumulation.
The pattern just has a classic cold La Nina look to it with arctic air dominating much of southern Canada along with portions of the high plains and west but struggling to make in-roads over the mid-atlantic and southeastern United States. Weather systems will progress along the area of this clashing temperature regime and the first of these systems could bring some moisture, falling as snow, to the region on Sunday. An accumulation is certainly possible here on the order of a few inches but a large snowfall is unlikely as any such storm appears both disorganized and fast moving. Arctic air will fight to establish a presence over Vermont during the last two days of January before another potentially more organized storm brings more potential for winter weather. A likely outcome here is snow but one should never underestimate the power of the dark side of La Nina which in this case would be a warm intrusion of air stemming from a storm that decides to track as an inland runner or lake cutter, whatever your favorite terminology might be.
The period between February 2-5 are setup for some of the coldest weather in this very mild winter season so far. Expect to see some sub-zero readings in this time frame and hopefully we get a system embedded within those days to provide us with some additional snowfall. After about February 6th the southeast ridge appears stronger and more capable of throwing an inland runner at us later in the first full week of February. Some arctic air is indicated to remain present across southern Canada which will be a much needed ally if such an evolution takes place.
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