Daily Herald, Mark Welsh, Associated Press
Sal Evola of Arlington Heights dons his winter coat and snow shovel and pushes the wet rainy mess away from his driveway and sidewalks around his house as winter decided to show up after all on Saturday, Jan. 3, 2015.

CHICAGO — It'll look like a typical winter when bitterly cold temperatures invade parts of the U.S. this week. The good news is that is won't be accompanied by precipitation that turned much of the southern states into a skating rink and it won't be cold enough to freeze your eyeballs or — maybe worse for parents — close schools.

What is the forecast for the United States?

First, the cold. Chicago will see the tail end of a storm that could leave up to as much as five inches of snow by early Tuesday. After that, Arctic temperatures like those seen in North Dakota and Minnesota on Sunday will rush in — with highs in the single digits.

It'll be a similar story in New York, where rain showers will give way to cold air. By Thursday, "New York City will be lucky if it hits 20" for a high and could see lows near 10 degrees, according to Michael Musher with the National Weather Service's Weather Prediction Center in College Park, Maryland.

The chill will move south, too. Atlanta will see low temperatures down to about 15 degrees Monday and Tuesday — but there won't be any ice to accompany it.

And in the West, a stream of Pacific moisture will drop as much as six inches of rain in the Seattle area — and could mean substantial snowfall in the Cascades. Further south in San Francisco — a part of the country that desperately needs the rain — skies will be sunny.

What's causing the drop in the temperatures?

A dip in the jet stream means cold air from Canada and points north is plummeting into the eastern two-thirds of the United States.

Is it a polar vortex?

The phrase took on a life of its own last year — and was blamed for everything from ice storms to the inability of the New York Giants to score touchdowns. But the National Weather Service is skittish about going anywhere near the words that start with P and end with X.

In this case, the answer is yes and no.

Yes, because, as Musher pointed out, the air is coming from near the north pole. But, no, the low-pressure system isn't going to sink into the United States this year, just the temperatures that precede it.

So, what is this?

Meteorologists have a technical term for what the country is now experiencing: Winter.

What should people do to prepare for the temperatures?

Bundle up. For much of the country, this is the first true taste of winter, so there's a chance people aren't prepared. Dress properly and remember that below-freezing temperatures can cause hypothermia, Musher said.

A bright spot: There doesn't seem to be any huge winter storms poised to strike, meaning travel won't be more difficult than it usually is this time of year.

Is there relief in sight?

Temperatures are expected to be lower than normal for a good chunk of the week, Musher said, but they could rise a bit by the end of the week. But then again, it's only January.