Get ready for "Polar Vortex, The Sequel"

Prepare yourself for an invasion from the north. A blast of polar air is about to send temperatures plunging in the heart of America.

It's the return of the polar vortex that brought misery a year ago. A mass of whirling cold air will dip southward this weekend, sending the mercury plunging.

As the cold air moves south and east, it has the potential to affect as many as 243 million people with wind chills in the single digits in some places and snow.

It's all triggered by a Super Typhoon named Nuri.

Images from the European Space Station show that Nuri is a growing meteorological bomb blanketing the Bering Sea.

The 50-foot waves and 100 mile-an-hour winds will make conditions similar to those we had two years ago, and could make Nuri the biggest storm of the year.

But it would be wrong to think that it will affect only Alaska's far-flung Aleutian Islands or those famous fishermen who work in the North Pacific. WBBM's meteorologist Megan Glaros in Chicago explains.

"The remnants of Super Typhoon Nuri will create a big buckle in the jet stream," Glaros says. "And in several days time, it's going to mean a big dip in the jet which will connect us with a big mass of Arctic air -- taking temperatures east of the Rockies down to 10 to 30 degrees below average."

Say "a big mass of arctic air" to anyone who lives in the Midwest and it conjures painful memories of the dreaded polar vortex that hit the region last winter.

In Chicago, an average temperature of 18 degrees was accompanied by 80 inches of snow and 32 fatalities.

Ice was also a major threat across the region, as CBS News saw first-hand in February.

"I'm standing on the shoreline of the Kankakee River and all of this ice in front of me has come up over the bank -- and threatens to keep coming."

Chicago is already storing salt like a squirrel stores nuts. Charles Williams of the Streets and Sanitation Department says the city will face the winter with 400,000 tons on hand.

"We're going to have 115,000 tons more on the ground this season than last," Williams says.

The cold weather is expected to last for several days over much of the country before the polar vortex goes back to where it belongs -- in Canada.

  • Dean Reynolds

    Dean Reynolds is a CBS News National Correspondent based in Chicago.