Winter storm watch for Connecticut

What's the difference between a winter storm watch, an advisory and a warning? And can they mean different things for ...
The National Weather Service has proactively issued winter storm watches for Westchester, Rockland and Putnam counties ...
The National Weather Service issued a winter storm watch at 3:52 a.m. on Friday valid from Saturday 1 p.m. until Sunday 5 a.m ...
On Friday at 3:16 a.m. an updated winter storm watch was issued by the National Weather Service valid from Saturday 7 p.m.