We've actually gotten through the worst of the warmth though it remains quite mild relative to average. The first in a series of three precipitation producing systems arrive Sunday morning and will bring rain and some areas of freezing rain to Vermont. This should all begin during the pre-dawn hours of the day. For the first time in what feels like forever, the snow/rain line with this system is actually within driving distance, setting itself not far from Montreal Sunday.
A refreshing looking side shot of arctic chill will then dry the region out Sunday night and send temperatures back toward 20 degrees by Monday morning and keeping readings in the 20's during the day. The high pressure center responsible for the cold will try and anchor itself in the Canadian Maritimes as a stronger system advances toward the region straight out of Texas. There is lots of moisture with this storm though it's a fairy garden variety event. The track is not ideal with the primary low passing through the central Great Lakes while a new coastal low tries to reinvigorate the storm off the New England coast. It's all adds up to a rather familiar New England winter storm story but we will take it. Snow should begin across the region sometime after midnight Tuesday and a few hours of moderate snow during the early morning should allow a few inches to cover the northern half of Vermont. Across the high country, we should see snow change to sleet and freezing rain during the midday hours and continue through the rest of the day. We saw a few models advertise an all snow event on Christmas Eve and Christmas Day but the consensus of data has converged back toward this snow/sleet/ice scenario. A good foundation laying event but nothing epic.
A few relatively mild days will follow in the wake of Tuesday's system. Clouds should keep temperatures on the mountain in the 30's but below 3,000 feet should be mostly above freezing both Wednesday and Thursday. Lingering upper level energy in the midwest is going to try and take more subtropical moisture and churn up another storm. There has yet to be any real consensus regarding any of this except the lack of cold air. Whatever falls Thursday, rain, drizzle or just a shower or two will be the liquid form. I don't think whatever falls will be enough to eradicate the early week foundation.
Winter gradually establishes itself across the region New Years Day and this should begin an extended period of sub freezing temperatures. It's also a period where any precipitation that falls should be in the form of snow. Though there are no indications of big east coast storms, there are clipper systems that dot the weather map on all of the extended models. Furthermore, I am not a believer that the southern branch goes completely dormant. This is a giant El Nino year and both Gulf of Mexico and Atlantic Ocean moisture should be able to stay involved in the weather pattern somehow though the models aren't showing that as of the time of this update.
I can't advertise the coldest of weather patterns in January but enough to make it wintry. The American Ensemble members are suggesting a more aggressive turn by the AO index into negative territory while the European and Canadian Ensembles show a more modest move to just slightly negative. The MJO which continues to be worth watching this winter, will continue to move toward phases that teleconnect to much colder weather in eastern North America, ultimately landing right in the middle of phase 7 in early January. If nothing else, this should control the evil empire and keep the Pacific away from its menacing December self. Meanwhile, the dominant player should be a large ridge in western North America which will keep the PNA positive and keep temperatures mostly south of the freezing mark.