A split temperature pattern across the U.S. is in the offing this week, with the western half of the country seeing below-average temperatures while warmer air remains in the East, according to the FOX Forecast Center.
A dip in the jet stream over the West that will allow cold air to settle across the region, while in the East, the jet stream pushes north and allows a warmer air mass to build into the region.
A cold air mass originating from the Arctic is being transported south thanks to a strong area of high pressure over Canada.
As the cold air surges south, temperatures across the West will run about 10-30 degrees below average, and some locations in the higher elevations may see temperatures even drop into the single digits.
Heading into Tuesday, about 68 million Americans in the west will be dealing with the cooler-than-average temperatures. As the week continues, however, that number will grow.
By Thursday, more than 100 million Americans from the West Coast through the Plains and into the Upper Midwest will be below average for this time of year.
Some cities across the West could also break records as temperatures could dip into the 40s across parts of California, while cities like Eureka, Nevada, could drop into the teens.
Elsewhere across the West, high temperatures will continue to fall as the week continues.
Denver, for example, will see a high temperature of around 48 degrees on Tuesday. By Wednesday, the high temperature is only expected to make it into the low 20s.
Across the eastern half of the country, the FOX Forecast Center says an unseasonably warm air mass originating from the Gulf of Mexico will surge north thanks to a storm system spinning across the southern U.S.
As that warmer air slides off to the east, it will cause temperatures to rise well above average for this time of year.
Across the South, temperatures will likely rise into the 70s, while Florida could see record-high temperatures in the 90s later in the week.
In the mid-Atlantic, some areas could see temperatures climb into the upper 60s and low 70s.