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Halloween freeze: Frigid blast of Arctic air to bring record cold temperatures to much of the U.S. next week

Chicago could drop below freezing while Denver plummets into the teens.

A frigid blast of wintry air will descend over much of the Lower 48 states next week, bringing the potential for record low temperatures from the Midwest to the Rockies. The stage is set for a bone-chilling Halloween for a large swath of the continental United States, thanks to an air mass whose leading edge is already plowing through the lower Mississippi Valley.

There is a chance that next week, the country could play host to the most unusually cold air mass anywhere on the planet.

One of two cold fronts heralding the impending chill raced across the southern Plains on Thursday, flipping rain to snow in the Texas and Oklahoma panhandles and focusing a slug of heavy rainfall up and down the Mississippi Valley.

This animation shows a model projection of air temperatures during the next week as a sharp cold front rolls across the United States. (WeatherBell.com)

Amarillo, Tex., recorded its high temperature just after midnight Thursday, falling from 51 degrees to 32 by 11 a.m. Thundersnow was reported at noon, with heavy snowfall accompanying the rumbles and flashes at 2 p.m. The city picked up 5.5 inches of snow, its heaviest October snowfall on record.

The snow bands pivoted east, sneaking into northwest Oklahoma and dumping pancake-like snowflakes on the town of Woodward:

A nearby town picked up 13 inches, setting Oklahoma’s state snowfall record for October.

A second, more powerful cold front will begin the trek east across the nation on Saturday, passing through the Plains and Ozark Plateau before sagging south through the lower Mississippi Valley Monday and Tuesday. By Halloween, it will wind up in the vicinity of the Appalachians, with some models giving it a final push all the way to the Atlantic.

While it is uncertain how things will ultimately unfold for the Eastern Seaboard, including in Washington, it is a safe bet that the stubborn chunk of cold will dominate a big portion of the country. The coldest air will be focused across the Rockies and Central United States, including parts of the Midwest.

Temperatures will fall like a rock behind this second strong cold front. Denver will go from a high of about 70 degrees on Saturday to the upper 20s on Monday. This front will also bring the city’s fourth snow event of the month, with the National Weather Service forecasting the possibility of greater than 6 inches of snow from the Front Range foothills into the Interstate 25 Urban Corridor. Higher elevation areas could see a foot of snow from this event.

Kansas City could stay below 40 degrees on Tuesday and Wednesday. So will Chicago on Wednesday, close to 20 degrees below the average high temperature for the end of October, which is 58.

Bismarck, N.D., could top out only around 25 degrees on Tuesday. Its average high temperature at this time of year is near 50.

The coldest period for those in the Midwest and Ohio Valleys looks to come toward the middle of next week. Temperatures along the central Gulf Coast may even dip into the 40s. New Orleans, for example, is predicted to bottom out around 44 degrees next Thursday and Friday nights.

The Climate Prediction Center has included a very high chance of below average temperatures virtually everywhere across the contiguous United States, save for the Atlantic and Pacific coasts (if you want unusually mild weather, head to Florida).

The Climate Prediction Center is forecasting that the next 6 to 10 days will be cooler than average nearly everywhere except for the immediate West Coast and Eastern Seaboard. (CPC/NOAA)

Of note is the anomalous warmth in Alaska, which is related to the cold over the central United States. The “ridge” of high pressure that is shunting the jet stream north over Alaska helps foster a downstream dip, allowing a plunge of cold air to spill southward. On Monday, the jet stream is forecast to look like this:

That is only part of the reason Alaska is warm, though. The high-pressure ridge keeping Alaska on the warmer side will start to break down next week. The Alaskan warmth is largely the result of warmer ocean waters and a lack of sea ice, which would normally keep regions near the Chukchi and Beaufort seas much cooler.

During events like this, many who reject mainstream climate science findings take to social media to share blue-dominated maps of the United States, claiming the domination of cold “debunks” the voluminous evidence pointing to human-driven climate change. However, the planet will still be unusually warm next week, with the cold anomaly across the United States standing out for its intensity.

Rather than looking at single day or weekly temperature departures from average, scientists studying climate change examine far longer climate trends to discern what is shifting the global climate. Studies of such long-term global warming show that it is occurring as a result of human emissions of greenhouse gases and will continue to worsen unless emissions are sharply curtailed.

According to a 2017 federal climate science report, global annually averaged surface air temperature has increased by about 1.8°F (1.0°C) over the past 115 years, and we are now living in the warmest climate in the history of modern civilization.

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