Alaska is witnessing its coldest air in nearly two years, and some of the biting chill is forecast to plunge into the western United States in about a week’s time.

The temperature tanked to minus 31 degrees in Fairbanks on Tuesday morning, ending a 624-day stretch in which it was warmer than that – the second longest on record. Tuesday afternoon, the mercury only recovered to minus 21, ending a record 658-day stretch with highs above minus 10.

As the cold continues to build over Alaska and western Canada over the next week, some of it will begin to bleed south.

Computer models are unanimous in bringing a significant blast of cold air to the western United States in six to eight days. On Wednesday afternoon next week, temperatures are forecast to be 20 to 30 degrees colder than normal in much of the Rockies and western Plains.

Some of this cold air is likely to shift toward the eastern half of the country in eight to 10 days, but models suggest it will lose some of its intensity.