* WHAT...Very cold temperatures as low as 40 to 55 below expected. * WHERE...Central Copper Valley, Ernestine, McCarthy, Southern Copper Valley, and Western Copper Valley. * WHEN...From 9 PM this evening to 4 PM AKST Sunday. * IMPACTS...Frostbite and hypothermia are likely if exposed to these temperatures. Very cold temperatures can lead to hypothermia with prolonged exposure. * ADDITIONAL DETAILS...Temperatures will continue to fall each day. Calm winds starting Friday may allow temperatures to drop to 55 to 60 below in some areas Saturday and Sunday.