The National Weather Service issued a winter storm watch for all of Massachusetts on Thursday afternoon ahead of a system that could bring at least a half foot of snow to the region this weekend.

BOSTON - Now that Thursday's snow is over, there's an excellent chance of plowable snow falling this weekend in Boston and most of Massachusetts. It could be the biggest snow storm of the season so far.

A winter weather advisory is in effect in Massachusetts today as several inches of snow is expected to fall across the state, according to the National Weather Service's Boston office. Snow is already beginning in western Massachusetts as of 8 a.m. Thursday, and it will pick up in the eastern part of the state later this morning.