Saturday, December 24, 2016

Potential storm precedes New Years holiday weekend after a very brief post Christmas thaw

Vermont enjoyed a bit of wet snow on Christmas Eve and the mountain is skiing a lot better than one might think. Perhaps it's the soft bigotry of low expectations coming off of last year's misery but wet snow is a great way to get through this adverse weather pattern. Speaking generally, I don't want this point to get lost on me or anyone. Last year when the prognosticated weather pattern appeared less than idea, the end result was typically 50-degree blowtorch or rain. This recent stretch of dicey weather has certainly not been a powder fest, but we have managed our way through it with only 1-period of rain and a handful of above-freezing days.

The worst of the post-Christmas thaw will actually come over a small stretch of the upcoming Monday (Dec 26) and Tuesday (Dec 27 period. In classic New England fashion, Monday will see temperatures start the day near 5 degrees but readings will warm to 35 by the end of the day and continue to rise up towards 40 during the overnight hours as a decaying occluded storm system brings its moisture into the region. This storm will peak out Christmas Day in the plains bringing blizzard-like conditions to portions of the Dakotas and the southern central provinces of Canada, particularly Manitoba. The storm will track well into eastern Canada and were it not for the occlusion (post-maturation), the storm might likely bring excessive 50-degree warmth to Vermont early Tuesday. Instead, we can expect temperatures as high as about 40, about a quarter of an inch of rain and some wind. The base of the mountain will take a small hit but we could do a lot worse given the weather pattern. Tuesday will be a mild day, but temperatures will eventually fall back toward freezing by late in the day with flurries.

The best part of the forecast involves the overnight Wednesday into Thursday period (Dec 28-29). This was suppose to be the 2nd part of our potential Christmas Thaw but no more. I am pretty confident that the this next potential storm system will have just enough cold air and just enough moisture to provide a good bit of intrigue.  Models are still battling it out over key details but they are on board with the general theory that temperatures will stay sub-freezing during the event and that most if not all precipitation stays snow. The disagreement involves potential sub-tropical moisture that may or may not play an important role in the eventual personality of this system. One model, our beloved European, is suggesting a healthy infusion of sub-tropical moisture and this ultimately allows the system to blow up along the New England coastline allowing for a big accumulation of snow of 6 or more inches to Vermont, New Hampshire and parts of Maine on the 29th. Other models suggest a more garden variety event of a few inches. All indications have some garden variety chill persisting New Years Eve and New Years Day with some snow showers possible on the latter. What a big improvement in the forecast over the last 4-5 days or so.

The weather pattern isn't screaming thaw during our first full week of January but we can't quite get rid of this persistently negative PNA jet configuration. This is essentially a pattern where the jet trough is favored across western North America while a jet ridge persists across the east. That said, the jet stream is expected to loosen somewhat in the Pacific and the Arctic Oscillation is expected to attain a more negative index. In the end, I think it will mean more cold on the playing though the possibility will remain for a mixed precipitation or rainy type system. Given what has taken place however, it would be ill-advised to sell ones soul to the devil. If we can manage to get snow during this pre-New Years stretch we can certainly score out of a slightly less unfavorable pattern after New Years. Have faith and Merry Christmas ! Hope everyone stays safe !

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