A cold weather advisory was released by the National Weather Service on Thursday at 12:05 p.m. valid from 7 p.m. until Friday 11 a.m. for St. Lawrence and Franklin counties. The weather service comments, "Very cold wind chills as low as 20 to 30 degrees below expected." Understanding cold weather alertsCold weather advisory: Be Aware. A cold weather advisory is issued when seasonably cold air temperatures or wind chill values, but not extremely cold values, are expected or occurring. An extreme cold warning is issued when dangerously cold air temperatures or wind chill values are expected or occurring.