Above: High Resolution NAM forecast for 9 PM Friday night. (Click to enlarge).
With cold air established at the surface and milder air moving in above 1000 feet, scattered, light mixed precipitation will develop during Friday. The precipitation will tend to become a bit more substantial and transition to mostly freezing rain and rain Friday night, leading to icy conditions in many places. Snow accumulation will be minimal before the changeover south of MA - a dusting to an inch or so (highest amounts in the northern CT hills), with higher snow amounts (perhaps up to 4"-5") across parts of northwestern MA. Periods of freezing rain may linger in some of the valleys into early Saturday morning. Current guidance (subject to change) is showing a quarter of an inch of freezing rain in the Hartford area. Any lingering freezing rain changes to plain rain or showers Saturday, with temperatures trying to get into the 40's. Sunday looks dry & seasonable (30's-low 40's). The Christmas Eve/Christmas Day forecast is still somewhat uncertain, however there is a pretty good chance for snow showers Sunday night into Christmas morning due to a mid-level shortwave swinging over the area. Whether or not the precipitation is enhanced by a coastal, surface low is still debatable.