I was hearing a lot of noise a few weeks ago that eastern North America was lined up for a torch in December. To be perfectly fair, climate models were indicating a warm month and there are those that put a lot of credence in the European model weekly forecasts and those were spitting out some very mild temperatures as well. The exceptionally warm November we are experiencing certainly doesn't seem encouraging either and a more persistence based forecast would argue that things that are happening will continue to happen. I am actually a fan of giving some weight to persistence based predictions but I don't put much stake in the climate models or the European weekly forecasts so it does not surprise me that we appear headed toward a rather interesting and very stormy few weeks and a period that is NOT expected to stay exceptionally mild. One thing for sure, it does not bear a resemblance to a typical La Nina winter weather pattern. There's split flow, phasing storms and cool weather in the south. Although La Nina doesn't make those occurrences impossible, they are infrequent.
Unfortunately Vermont does not appear to be in the best position to hit this La Nina knuckle ball but it will be exciting nonetheless and we should be in a much better place 2 weeks from now throughout the state. November will end mild but only because we end up on the mild side of a powerful and fully phased winter storm - a southern streamer that will take in a polar pacific impulse and explode over the northern Appalachian Mountains Monday. The explosive intensification results in the bowling ball - looking upper air environment and in this case it means the mild air and rain comes our way with the cold and snow impacting the Ohio Valley and Great Lakes. There is no escaping this and it might as well happen now with little to no snow on the ground. Rain will arrive late on Monday and continue through the evening before tapering to the more intermittent stuff by Tuesday. Your smart phone might be telling you rain on Tuesday but most of the day will actually be rain-free with temperatures hovering around 50. All this happens while the snow piles up over portions of the eastern Great Lakes. There isn't really any arctic air with this storm but it will get colder by Wednesday and we should see mixed precipitation become snow. Again, just intermittent stuff but by Thursday morning, the high country is likely to be white.
The pattern won't stop delivering after the Monday/Tuesday event. There are strong indications of a 2nd storm next weekend (December 5-6) and although we would certainly like to see more cold air support, there are indications of a bit more help from a storm track that is likely to set up farther east. Storm impact remains 8-9 days out which means inherent uncertainty and it would be unwise to expect a powdery bonanza without the help of much arctic air. This one is worth watching however so stay tuned.
There are a lot of neutralizing teleconnection indices that are allowing the pattern to become the stormy madness. The Pacific is a little strengthier than I would like but not terrible. AO/NAO will remain relatively neutral while the PNA turns varying degrees of favorable depending on what model you believe. Though arctic cold is not expected to be a part of the equation during the first 6 or so days of December, we should see some enter the weather picture as we approach the time frame of December 10th. If we keep a bit of this storminess alive, and there are indications that we will, we could reach the middle of the month in decent shape.
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