On Thursday at 2:17 p.m. EST the National Weather Service issued a cold weather advisory valid for Friday between midnight EST and 10 a.m. EST for Shiawassee, Genesee, Lapeer, St. Clair, Livingston, Oakland and Macomb counties. The weather service says, "Very cold wind chills as low as 15 degrees below zero expected." "The cold wind chills as low as 15 below zero could result in hypothermia or frostbite if precautions are not taken," says the weather service. 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.