-- The final days of 2014 will feature the arrival of an arctic air mass that is expected to send temperatures plummeting across much of the country during the first half of the upcoming week.
The colder air will begin to move into the northern Rockies and Plains on Sunday and Monday, and then continue to push south and east towards the middle of next week. The colder air will even make its as far south as the Mexico border by New Year's Eve.
The majority of the month of December, including Christmas, featured temperatures that were running above normal. This also helped yield the lowest Christmas Day snow cover across the contiguous United States since 2011.
In contrast, the summits of Mauna Lao and Mauna Kea in Hawaii did experience a white Christmas, with several inches of snow on the ground and strong winds that prompted blizzard warnings for only the second time since 1986.
The coldest temperatures will be experienced on Tuesday when high temperatures will remain in the single digits from Billings, Montana, to Denver, Colorado, and eastward to Minneapolis. Some of the coldest locations may even see high temperatures remaining below zero.
The northern Rockies and Plains is where the core of the upcoming arctic blast will end up. Across this region, high temperatures will be running 20 to as much as 40 degrees below normal. As this arctic air pushes east on Tuesday and Wednesday, it will moderate significantly. Major cities in the east will see colder temperatures, however it will end up near or just slightly below normal for this time of year.
Midnight temperatures will be at or below freezing for most of the country as the new year begins. The ABC News Weather Team is currently forecasting temperatures in the mid 20s for New York City at midnight and in the upper teens in Chicago.
It will be ever colder in Denver; around midnight, temperatures will only be in the single digits.
Blustery conditions across the northern tier of the country will likely send wind chills below zero from Denver to Minneapolis after sunset on New Year's Eve.