A winter storm watch is in effect for Lewis County from 8 p.m. tonight through Sunday afternoon.
The National Weather Service is warning of accumulations of 6 inches or more of heavy, wet snow, with visibilities as low as a half mile at times.
The heavy nature of the snow means may cause downed tree branches and limbs, which may lead to isolated power outages, the service warns.
In St. Lawrence County, forecasters are calling for snow and sleet accumulations of 3 to 5 inches, along with a trace of ice. The wintry mix is expected to taper off into scattered rain by Sunday afternoon, the service predicts.
In Jefferson County, the service is calling for a mix of rain and snow into Sunday, with between 2 and 4 inches of accumulation expected.
The full advisory can be viewed at http://wdt.me/HQL7uY.