Updated 7:24 AM EST, Tue January 21, 2014



Polar blast hits much of the country




Kerplunk!

That's the sound of the temperature dropping early this week as a batch of cold air moves from the Tennessee Valley and lower Midwest over to the East Coast.

There will be 3 to 9 inches of new snow to go along with that from the Virginias to Massachusetts, the National Weather Service said. Much of it is expected to fall in the daylight hours Tuesday.

Add to that areas that are frigid already, and about half to the nation -- the eastern half -- will shiver through temperatures 10 to 25 degrees below average.

The vast area is expected to stay in the icebox until the weekend. That can mean lows in the teens in Memphis, Tennessee, and in the single digits from Louisville, Kentucky, to Boston.


A second frigid weather system is moving down from Canada and will plunge low temperatures into the double-digit minus degrees all along the border. Whipping winds will knock the wind chill down to 20 to 40 below zero from the Upper Plains states to northern Missouri.

A small but intense snowstorm is dumping up to 10 inches of snow in metropolitan Chicago as moisture over Lake Michigan mixes with frigid air.

Transportation woes:

Though it covers only a small area, Chicago's storm appears to be enough to make air traffic at least more annoying. O'Hare International had canceled about 5% of flights in and out of the airport before dawn Tuesday, according flightaware.com.

But much more frightful nightmares appear to be taking hold in the Northeast. From New York City to Washington, major airports had canceled a quarter to a third of scheduled flights by early Tuesday.

At Philadelphia International Airport, Southwest Airlines plans to suspend operations at 3 p.m., CNN affiliate WPVI reported.

The flakes should be falling at full tilt about then, the weather service said.

The federal government is telling D.C. employees to dispense with the drive to work and is closing its offices. Only emergency employees are required to appear on the job, the Office of Personnel Management said.

Even Boston's Logan International Airport had reduced air traffic by at least 20% early Tuesday, according to flightaware.com.

The cancellations at snow-doused airports may cause ripple effects throughout the nation's air traffic system.

About 1,900 flights had been canceled nationwide as of early Tuesday, flightaware reported.