It's no secret, snow here in Maine has been sparse so far this season. Snow deficits are impressive. We will make up ground fast this weekend with our first sizable snow event poised to drop several inches.
There certainly isn't any shortage of moisture with the Gulf of Mexico currently getting tapped. The question all along has been could an approaching shortwave tug enough on the storm to drag it and the deep moisture back to the west into New England.
The answer to that appears to be an astounding YES. Shortwaves are small pieces of energy that ride along the jetstream and can influence storm track and intensity. Models have a very difficult time evaluating how strong they are and where to place them especially days in advance. Once they arrive over the North American continent, especially the lower 48, they are sampled much better and storm details become more apparent. The shortwave axis will tilt back to the west acting like a magnet, pulling the storm closer and allowing the moisture in.
Snow should break out by the middle of Saturday, and it will snow lightly through the afternoon. With surface temps still a couple of degrees above freezing, snow accumulation will not be efficient so 2" or less is expected by dark. The bulk of the accumulation will occur tomorrow night with some decent bands of snow setting up at times. The snow will continue through Sunday morning and roads will be slippery and snow covered for holiday shoppers and churchgoers. The snow will be gone by the afternoon and clearing will commence.
It won't be a huge storm, but because it's the first of the season, don't take it lightly. I'd say a general 3-6" across most of Maine and New Hampshire. There will be a couple of exceptions. The jackpot will likely be from around Bangor up into Southern Aroostook County, this is the area with the highest chance to get 6" or slightly more. Conversely, sections of the Mid and Downeast coastlines will be mixing with rain, this will hold amounts down to a 1-3" range.
We are still more than 24 hours from the start so there may still be some wiggles or wobbles. Snow numbers may still be adjusted so check back for updates.