At 5:44 a.m. on Thursday, the National Weather Service issued an updated cold weather advisory valid for Friday between midnight and 10 a.m. for Suffolk County. The weather service says, "Very cold wind chills as low as 6 degrees below expected." "The cold wind chills could result in hypothermia 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.