Emergency shelters for the homeless are open in central Pennsylvania. The National Weather Service expects high temperatures to remain below 32 degrees Friday, a rare occurrence this early in winter.

The brutal cold will continue with temperatures Monday night as much as 20 degrees below normal, forecasters say.

“The average minimum temperature in Phoenix is around 45 degrees in December, so it’s usually too warm to see snow,” said Erinanne Saffell, Arizona’s state climatologist. “But rarely, a really cold weather system might loft a few snowflakes here or there in the metro area.”