Tuesday, November 29, 2016

Mild weather in the near term but colder air and snow in the forecast picture for the longer term

Mild weather and a couple of upcoming rain events have put the more than proverbial damper on the excitement we had about a week ago. That said, the wet near term forecast will be followed by a more wintry outlook and all but ensures that December 2016 will make a welcome detour from the route taken by December 2015.

The pattern gripping the United States as a whole is not especially mild or arctic but rather stormy. One storm spinning it's way through the northern plains will eliminate a large chunk of last week's snow by early Thursday as it tracks up through Lake Superior and into eastern Canada. Modified Pacific air will envelop the region later Thursday and allow for the return of some snow showers and flurries to the mountains but accumulations will be minimal. The upcoming weekend will certainly see it's share of sub-freezing temperatures but the absence of arctic air will also allow readings to climb above the freezing mark for a few hours during each of the afternoons. None of this is particularly atypical for December.

The 2nd potentially wet weather event is not etched in stone. This system will intensify in the southern plains over the weekend and advance northeastward. There isn't much in the way of available cold air to work with and there is a growing consensus that the storm will track toward the eastern Great Lakes and thus the thinking is for an ice->rain situation. A lot can happen in 6 days however and the possibility for more snow or even base-building sleet entering this forecast period remains. I am not particularly optimistic but if the system can transfer it's energy from the Great Lakes to the coast, it could lead to a much different outcome early next week so don't completely tune this one out.

The arctic door swings open as we advance through the next week period. Much of the cold will focus it's attention on the western half of the country while New England remains on the milder side of average through roughly December 8th. Some of the longer range ensembles then show that the long wave pattern will get reinvigorated as the cold advances toward us allowing for the possibility for snow to accompany the colder weather during the weekend of December 9th to the 11th.

There has been some hype-casters floating around the internet predicting all sorts of extremes for the middle to back half of December and plenty of snow. There will be a lot more of this in the coming years as we become more fully emerged in the bait and click world of information. Weather is certainly not an exception  when it comes to the inherent public appetite for sensationalism so hypecasters will always get attention. The data however does not point at all toward an extremely cold middle to back half of December. Cold weather will, as mentioned, dominate the weekend of Dec 9-11 along with some snow and the chilly temperatures should linger through part of the work-week that follows. Ensembles though continue to suggest a stormy rather than cold dominated outlook and this is supported mainly by the negative PNA which will keep the west more unsettled and snowy for the ski areas out that way. Out our way, I am hoping for more snow but additional pushes of mild air are going to present a challenge as they often do in December. I can say though with great confidence that the month won't disintegrate into the tropical-mudfest that 2015 turned into.

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