3z SREFs has a mean snowfall of 6.45" over HYA from tomorrow evening through Monday evening.  Some members are over 20" of snow and half are about 12"+, so there is a lot of spread in the means, and plus while the 00z EURO didn't show much precipitation over Cape and Islands, the model did up the ante with the upper level low and the surface low strengthening.  Also, the HRRR 6z run shows a lot of lightning developing with the surface low as it reaches the coastline, this could impact the surface low track by pushing it more towards the coastline as it ramps up within the upper-level trough.