It was actually a slight misrepresentation to call this "the last few days of the favorable December pattern". The weather pattern has in fact already turned and evidence of this can be found in Whistler-Blackcomb's snowfall report which shows a new 40 inches over the past 7 days. This is a consequence of the very consolidated Pacific Jet Stream, fueled by the La Nina. The same jet which is working rapidly to erode the remnants of the cold which was produced by the early December negative AO.
Does anybody really want any additional details about Sunday's rain event ? If so then I suppose you can read on but if not feel free to skip down, I won't be offended. The rain will arrive later in the day Sunday and some areas could see a period of freezing rain before southerly winds push temperatures regionally above freezing later Sunday evening. Temperatures will climb to about 40 degrees overnight and rainfall totals will range between a half an inch to eight tenths of an inch.
I did mention in the last post the possibility of some terrain induced snow (TIS) on Christmas Eve and Christmas Day and this is still a likely outcome I am happy to say. The culprit is a fairly tight pocket of favorable upper air dynamics which will produce enough instability over the high terrain of Vermont for a few inches of much needed snow by early X-Mas day (I don't think much falls on Christmas Eve however). Later in the week looms another conundrum however as another storm takes the highway to the danger zone (credit - Kenny Loggins). Its too early to for a specific outcome but I am not encouraged at our chances given the lack of available cold air. I am hoping this system late next week simply doesn't come together and avoids us completely.
If there is a sliver of light in all this looking toward New Years Day and beyond its this. Ensembles are indicating a healthy area of jet stream blocking over the Davis Straits even as we continue to hear the roar of a furious Pacific Jet. What I hope this causes is the Jet Stream to split somewhat across the eastern United States. We won't get any real cold air even in this scenario but it would help to keep the storm track farther south which is one way to sneak through this proverbial thorn-brush.
I got one more update prior to Christmas but if this is your last read then a merry Christmas and a happy Winter Solstice to everyone.