January's Cold Reality Sets in Next Week

Brian Donegan
Published: December 28,2016
As January arrives, a pattern change will bring a reality check by ushering in much colder temperatures for a large swath of the United States.
(MAPS: 10-day Forecast High/Low Temperatures)
A southward diversion of the polar jet stream will allow arctic air to flow southward out of Canada into much of the Lower 48 states by later next week.

European model forecast jet stream (white lines) and surface temperatures (color contours) for Thursday, Jan. 5, 2017, based on the 00 UTC, Dec. 28, 2016, model forecast.

The chill looks to arrive just after the New Year's holiday weekend in the northern Plains and northern Rockies before expanding its reach south and east through the week.
(MORE: New Year's Holiday Weekend Outlook)
High temperatures Monday will be 15 to 30 degrees below average in the northern Rockies and 10 to 25 degrees below average in parts of the northern Plains. This translates to highs mainly in the teens and single digits in those regions.

Forecast Highs Compared to Average Monday

The arctic air will spread a little farther south and east each day next week.
By late next week, the well below-average temperatures should cover much of the Lower 48 states, with the exception of parts of Florida.
Highs in the 20s are possible as far south as the Texas panhandle, which is at least 15 degrees below average for the first week of January.
(MORE: When Is the Coldest Time of the Year?)

European Model's Forecast 850-Millibar Temperatures Next Friday

The worst of the cold, however, appears likely to remain locked into the northern Plains and Rockies, with highs up to 30 degrees below average possible later next week. Some places won't even reach zero degrees Thursday or Friday, especially across parts of Montana, North Dakota and Minnesota.
(FORECAST: Missoula, Montana | Fargo, North Dakota | International Falls, Minnesota)

Forecast Highs Compared to Average Next Friday

Since high temperatures will be so cold, you can bet on low temperatures being even more frigid.
Morning lows could reach the teens and 20s below zero in the coldest locations of the northern Plains and Rockies next week. These readings are 20 to 40 degrees colder than average for this time of year.
Wind chills will reach dangerously cold levels, placing you at risk for frostbite or hypothermia if you are outdoors and not properly bundled up.
(MORE: What Does Wind Chill Really Mean?)

Rockies, Plains Forecast Next Week

This cold reality check won't reach the East until the end of next week or next weekend, and the air mass will likely modify by that point and not be quite as bitter as it will be over the rest of the country.
For more details on what the rest of January may bring, check out our January outlook.

MORE: Coldest Places on Earth