The weather service describes, "Dangerously cold wind chills as low as 3 above degrees possible." Understanding cold weather alertsExtreme cold watch: Be Prepared. An extreme cold watch is issued when dangerously cold air temperatures or wind chill values are possible. An extreme cold warning is issued when dangerously cold air temperatures or wind chill values are expected or occurring. A cold weather advisory is issued when seasonably cold air temperatures or wind chill values, but not extremely cold values, are expected or occurring.