A reminder that you can read more about Norlun Troughs in last night's post, and you can always find more weather including a video technical discussion on my Weather Analysis Page.

Norlun troughs are the epitome of nowcasting - especially when multiple convergence zones are expected to focus snowfall.  As of 10:30 PM Thursday night, the first trough had set up in extreme southwest Connecticut, and with the strong upper level storm approaching from the west and ready to interact with this trough, it seems apparent that the first round of locally heavy snow will focus on Western Connecticut, along and west of Interstate 91 Friday morning.  Another mesolow (small scale storm) is evident on radar imagery south of Penobscot Bay, Maine, and this is likely to focus another band of snow Friday somewhere along the Maine coast - perhaps just northeast of Casco Bay.  For many New Englanders, snow bursts will hopscotch across the region Friday and Friday night, but Northern New England including the Maine coast may deal with snow bursts through Saturday.  Finally, Vermont Ski areas may make out very well from this weekend, as winds blow from just about every favored direction, and some spots may quietly pick up a cumulative foot of snow by the end of Sunday.  The reason I say best estimates may fall short of expectations?  There will be a lot of local variability.  Some of us will see less, some more, than expected - there is no question in my mind about this...it is the nature of the Norlun Trough, and an accepted reality of even a perfectionist forecaster.