Trying to make sense of a wintry forecast

Depending on when you read this, we are about to start or have just started what we hope to be our first extended stretch of below freezing temperatures. We should see our first flurries Wednesday evening and night  but snowfall will be minimal by the looks of things, may take a few days before amounting to anything significant. Snowfall will mostly be confined to the Great Lakes Thursday in the traditional snowbelt areas. That said, we expect a band or two of snow to make it over the Adirondacks and get slight boost from the warm waters of Lake Champlain. This should be enough to whiten the mountains around the Mad River Valley but the best snow Thursday appears to be from Stowe northward to Jay where I would expect a few inches.

Snow prospects for the weekend did not move in the direction that I would have preferred. Moisture and energy associated with a nearly stalled front off the Atlantic coast will linger too close to the coastline though not close enough. I referred to this the other day as "baroclinicity" and it often becomes the focal point for moisture and storms. Unfortunately, when energy is consolidated just off the Atlantic coast as is the case this weekend, the weather will remain quiet across interior New England and devoid of snowfall. We are in fact between two systems Saturday with the energy offshore representing one area of storminess and clipper across the Great Lakes concentrating snowfall well west of Vermont. Decaying moisture from this clipper system will finally reach Vermont later on Sunday or Sunday night bringing what I would expect to be our first light accumulation to the region but the bigger possibilities are laying in wait and may at that point be consuming most of our attention by the end of the weekend.

The storm situation in question involve the Tuesday-Wednesday time frame or December 12th and 13th. The pattern will relax somewhat in the wake of the passage of the late weekend clipper but as this is happening, the jet stream will be gearing up for another, even bigger amplification. We don't have any southern branch jet energy to work with but a series of shortwaves will accompany this next incoming surge of cold weather. Can any of these shortwaves be the match that lights the fuse ? Models, all of them, have been erratic and inconsistent in answering this question. The European model had a classic Gulf of Maine bomber on the run released Tuesday afternoon but it was not shown Wednesday morning. The American model seems to be back and forth on this question every 6 hours. The lack of consistency in the operational model runs simply reveals the uncertainty regarding this storm at this juncture. The ensembles, as of early Wednesday, continue to suggest strong hints of a significant snow for all of interior New England. My interpretation ? It's a coin flip - 50 percent.

Even if we end up on the wrong end of this "50 percent", we should be on the receiving end of at least some lighter snowfall. We should get some of this as early as Monday the 11th thanks to a weak area of overrunning moisture  and then some additional snow Tuesday from the clipper. Modestly cold air follows for Wednesday and Thursday of next week and then we have the possibility of more snow on Friday December 15th and into the weekend.

The longer range looks about the same as it did several days ago. Though the PNA appears as if it wants to relax as we approach the Winter Solstice the AO will remain decidedly negative and there are no glaring indications of jet tightening in the Pacific though this situation will bear watching in the days to come.