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Arctic blast over central U.S. set to worsen, expand

The bitter cold has its origins in Siberia, as air flows across the North Pole and down into North America

Forecast minimum temperatures on Thursday morning. (Pivotal Weather)
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(This story was updated on Tuesday)

Subzero temperatures engulfed the majority of 10 states Tuesday morning, part of a bitter Arctic blast swallowing much the north-central United States. Temperatures some 20 to 40 degrees below average are set to dominate for more than a week, tied to the same polar vortex-induced weather pattern bringing stormy weather to the Northeast.

After Sunday’s slush fest, another winter storm threatens D.C. by Wednesday night

While the temperatures themselves may not break all-time records, the duration of this cold snap is unusual. Frigid conditions look to linger into at least mid-February, with temperatures dropping below zero in places such as Minneapolis, Chicago and Des Moines.

The cold could team up with gusty winds to bring dangerously cold wind chills down to 50 below.

Bone-chilling air first surged south late last week, bringing temperatures as low as minus-16 to Minneapolis. The Twin Cities didn’t make it above zero Sunday, and Minneapolis’s high was only a minus-3.

The city bottomed out at minus-9 again Monday morning, and minus-9 early Tuesday. A comparatively balmy high of 7 degrees was forecast Tuesday afternoon.

Farther north, temperatures fell to as low as minus-36 at International Falls, Minn. on Monday morning. Wind chills tumbled below minus-50. The airport there hasn’t been above zero since 6 p.m. Friday; they were still sitting at minus-16 degrees at 11 a.m. Monday morning. Their next shot of reaching temperatures above zero isn’t until Sunday or Monday.

That would be a sum of ten or eleven days below zero, the longest such since streak there since at least 1971.

In many places, the cold is more remarkable for its longevity than intensity. Omaha, Neb. will nab a stretch of at least nine consecutive days below 15 degrees, one of the top five longest streaks on record. It would also be the longest cold streak of that magnitude since the 1980s.

In South Dakota, Aberdeen Regional Airport hit minus-20 degrees Monday morning, while Mound City, about 80 miles west-northwest of Aberdeen, dropped to minus-24. Mound City has a population of 71. Aberdeen had dropped to minus-13 early Tuesday.

If current forecasts verify, it’s likely that Aberdeen could record a string of ten or more consecutive days with lows below minus-10 — the first streak that long since the 1990s.

What a ‘wrecked’ polar vortex means for winter-starved Americans

The extreme cold even tripped up weather satellites, which ordinarily only see temperatures that frigid when signals bounce off high-altitude clouds. Early Monday, however, those minus-20 degree readings were coming from the surface.

Farther north in Canada, widespread minus-40s were observed. The cold tundra landscape in recent nights has been illuminated by spectacular displays of the aurora borealis.

The leading edge of cold air surged southwest Sunday, bringing a 22-degree temperature drop in Denver in 18 minutes. The eastern flank of the Arctic air mass brought blizzard conditions to the Corn Belt last Thursday, sparking a 40-car pileup in Iowa.

By early Tuesday, cold air had bled south from Montana and Wyoming to the Front Range and north central Kansas. Most of the Corn Belt was in the crosshairs of the Arctic’s icy breath as well, with the rim of the cold pushing up against the Great Lakes.

Chicago was expecting a high around 14 on Tuesday, about 20 degrees below average for this time of year. After dropping to minus-7 early Sunday, the Windy City is forecast to remain above zero until the upcoming weekend, when temperatures may once again plummet.

Kansas City reported snow and single-digit temperatures Monday and early Tuesday, but the extreme cold wasn’t set to arrive until late week. Lows below zero are expected beginning Thursday night, with temperatures forecast to be as frigid as minus-11 on Saturday night. Subzero lows are now only a quarter as common in Kansas City as they were in the 1970s.

Assuming the current forecast holds, it will be the longest string of subzero lows there in at least 11 years.

“Frigid temperatures are expected to continue for as long as our models go,” wrote the National Weather Service in Kansas City. “This weekend temperatures could be reaching near record cold... proper preparation and apparel is a must for anyone venturing outside over the next several days.”

In Des Moines, highs only made it into the single digits on Monday; the city could drop to minus-15 late week. Minneapolis could get even colder, vying for a minus-18 on Saturday night.

Billings, Mont., could set a record Thursday morning; the record minimum for the date is minus-15, and the forecast calls for a morning low of minus-18. Friday morning could tie a record low at minus-22.

In Nebraska, the extreme cold and presence of moisture near ground level has led to light pillars being spotted, the result of hexagonally shaped ice crystals in the air. It usually only happens when temperatures are exceptionally frigid.

At the southern periphery of the chill, icy roads near Oklahoma City resulted in a multi-vehicle accident involving at least 15 cars Monday morning.

The cold will make some progress east into Michigan by Wednesday, and should become more firmly established in Chicago late in the week.

Thereafter, there are signs that a reinforcing shot of very cold air may accompany a dome of Arctic high pressure sliding south out of Alberta and Saskatchewan and into the central Lower 48. Confidence is growing that freezing temperatures could slide all the way down to the Gulf Coast.

Behind the Arctic blast that’s plunging into the U.S.

In central Texas, the potent “Blue Norther” front could drop temperatures from the upper 60s to the teens in hours. If the air mass proves as dramatic as modeled, it’s not out of the question that parts of the Upper Midwest could fall to minus-30, with lows in Chicago approaching minus-20. Subzero readings would be possible as far south as the Oklahoma-Texas border. Houston might even dip into the 20s.

The pattern is tied to a disruption of the polar vortex, which has allowed lobes of cold to spill south to the mid-latitudes in North America and Europe. Signs point to below-average temperatures being here to stay for much of the Central United States through at least mid-February.

Initially, models had hinted at a chance that the East Coast could get into some of the wintry feel present beneath the shot of Arctic air, but now that’s appearing less likely or at least delayed.

The overarching weather pattern, which features cold west of the Appalachians and a jet stream slicing to the east, favors repeated bouts of storminess and wintry weather for the Mid-Atlantic and Northeast.