First Call For Season's First Winter Storm Tuesday Night into Early Wednesday
Heaviest Accumulations Likely North & West
Synoptic Overview
Eastern Mass Weather forecast a busy month of December in what promised to be an active start to the 2025-2026 winter season across the southern New England forecast area, and it now appears that Tuesday evening will mark the start of the onset of what will likely be a parade of winter storms. However, before this pattern becomes established, a strongly positive NAO will conspire with energy over the western CONUS to raise eastern heights on the east coast enough to allow one more milder rain event to track across northern New England on Sunday night.
This system will head through the Canadien maritimes and into the North Atlantic, where it will help to elevate heights in the NAO domain as the system number two begins to eject out int the Tenessee valley by Tuesday morning.
Heights over the east will subtly descend as the energy shifts east, and the riding builds in the vicinity of Greenland. This will displace the PV slightly further to the south and suppress the storm track just enough to provide the forecast areas with it's first winter storm of the season for early Tuesday evening into early Wednesday morning, before this system also pulls away into the Maritimes.
Anticipated Storm Evolution
Snowfall will overspread the area from southwest to northeast late Tuesday afternoon into the early evening hours, likely around the time of the PM commute, which is important to keep in mind. Precipitation is likely to be rain from the outset over perhaps the immediate south coast, cape and islands.
The snowfall should grow heavier before mixing with and changing to sleet and rain across all but the northwest third of Rhode Island, and the immediate Boston area inside of route 128 by around midnight early Wednesday AM. Some mixing with sleet is likely up to at least the Mass pike and possibly the route 2 corridor after midnight, before colder air works back in by dawn, as the system begins to pull away.
Precipitation should come to an end as snow showers virtually everywhere on Wednesday morning. Delays and even some cancellations, especially north and west of Boston, are likely.
Final call will likely be issued either Monday night or Tuesday morning.
FIRST CALL: