Widespread Arctic Blast Coming This Weekend

January 5,2016
January's reputation for frigid temperatures will be on full display by this weekend in the nation's midsection as a widespread blast of arctic air begins to take hold of the region. The air mass responsible for the incoming plunging temperatures will originate from above the Arctic Circle near the North Pole, as the animation below illustrates.
The northern tier of the Midwest is likely to see subzero temperatures, while wind chills may dip as low as 30 degrees below zero. Colder-than-average temperatures will also take over the rest of the Midwest and into parts of the South.

This animation shows the arctic air (purple shadings) moving from near the North Pole late Monday, Jan. 4 south through Canada and into the Lower 48 by Sunday, Jan. 10.

Prior to the arrival of this surge of cold air, above-average temperatures will take hold of many states from the Mississippi River Valley to the East Coast by late week. This will bring milder conditions to the Northeast, where many cities saw their coldest morning so far this season Tuesday.
(MORE: Record December Warmth)
Below we have a look at the forecast for the chilly temperatures set to arrive this weekend, followed by a recap of the early week chill in the East.

Widespread Arctic Invasion Starts This Weekend

By middle to late week, bitterly cold air is forecast to build south across parts of northern and western Canada. That cold air mass will then head into the Lower 48 this weekend as a large southward dip in the jet stream develops in the central states.
(MORE: January-March Temperature Outlook)
As is typical with invasions of arctic air in winter, the air mass will be accompanied by a strong area of surface high pressure plunging south to the east of the Rockies. The pressure gradient between the high and lower pressure in the East will contribute to gusty winds, resulting in low wind chill values as well.
Here's a general timing of when the cold air will arrive by day:

• Saturday: Highs 15 to 25 degrees below average will engulf Montana, the Dakotas, western Nebraska and northeast Colorado. Temperatures 10 to 15 degrees below average will be found southward through the Plains into the Texas Panhandle. 
• Sunday: Highs 10 to 25 degrees below average will grip much of the Plains and Midwest, from Montana, Wyoming and Colorado to Illinois and Wisconsin.
• Monday: Below average temperatures continue throughout the Plains and Midwest.

The map below shows the forecast high temperatures Saturday through Monday when this wave of arctic air will spread southward through the Midwest and Plains. Keep in mind that this forecast is subject to change, so check back for updates. There also remains uncertainty with how long this mid-January blast of cold air may last.

Forecast Highs Saturday-Monday

For cities in the Upper Midwest and northern Plains, including Minneapolis and Fargo, North Dakota, highs may not get out of the single digits or teens. Parts of the Great Lakes and central Plains, including Chicago and Omaha, Nebraska, may only see highs rise into the teens or low 20s.
(FORECAST: Bismarck, North Dakota | Chicago | Minneapolis)
As for low temperatures, single digits and teens below zero are likely in the northern Plains and Upper Midwest. Lows in the single digits above zero are expected from the central Plains to the southern Great Lakes.

Forecast Morning Low Temperatures

Temperatures will feel even colder when factoring in the winds. The "feels like" temperature, or wind chill, will drop into the 20s or even 30s below zero by Sunday across the Dakotas and Upper Midwest.

Forecast Wind Chills

Early Week Cold Recap (January 4-5)

On Tuesday, temperatures ranged from to 10 to 15 degrees or more below average from Georgia to portions of New York and New England. While not record breaking, for locations like Atlanta, Georgia and Richmond, Virginia, it was the coldest day since Feb. 24-25, 2015. At New York City, Philadelphia and Washington D.C., it was the coldest day since March 6, 2015.
Temperatures plunged as low as 27 degrees below zero Tuesday morning in Clayton Lake, Maine, and 22 degrees below zero at Saranac Lake in the Adirondacks of upstate New York. Subzero lows were also noted across much of New Hampshire and Vermont as well as the Catskills of New York and the nearby Poconos in northeast Pennsylvania. Several locations in southwestern New York and northwestern Pennsylvania also fell below zero.

Observed low temperatures at selected locations in the Northeast on Tuesday, Jan. 5,2016. For both New York City and Boston, the readings were the lowest since Feb. 24,2015, when New York hit 4 degrees and Boston bottomed out at 2.

Boston dipped into the single digits and wind chills as cold as zero extended as far south as Washington, D.C., Tuesday morning.
Despite that, there were no reports of record lows at any of the major long-term weather observation sites in the Northeast Tuesday.