Dangerously cold air originating from the Arctic regions will bring subzero temperatures to portions of the Plains and Rockies this week.
By Thursday morning, temperatures across portions of Montana, Wyoming and the Dakotas will dip to between 10 and 20 degrees below zero.
Temperatures will get progressively colder as late week approaches.
High temperatures on Thursday and Friday will not get above zero in some spots and overnight low temperatures will be 20 to 30 below zero. A few locales can get colder than 30 below zero.
To put this cold wave into perspective, temperatures will average 20 to 40 degrees below the seasonal average for early December for the middle and latter part of the week.
When taking other factors into consideration, it will feel even colder.
"With the wind factored in, it will feel more like 40 degrees below zero," AccuWeather.com Expert Senior Meteorologist Elliot Abrams said.
"That kind of cold is extremely dangerous," Abrams went on to add.
Prolonged exposure to these temperatures can cause frostbite, hypothermia and even death. Children and the elderly are especially vulnerable to extreme cold.
If traveling in these extreme conditions, you should keep your gas tank at least half-full to prevent the fuel line from freezing up. In addition, you should have an emergency kit that includes a cell phone, charger, jumper cables, warm clothing, food and water.
Pets should be brought indoors as the extreme cold can have adverse effects if they are left outside for a long period of time.
Cattle, especially young calves, should be brought to sheltered areas and given plenty of water.