EXPLAINER: Arctic blast sweeps US, bomb cyclone possible

NEW YORK (AP) — An arctic blast is bringing extreme cold, heavy snow and intense wind across much of the U.S. this week — just in time for the holidays.

The weather system, which may build into a “bomb cyclone,” is expected to move east in the week leading up to Christmas, disrupting travel and causing hazardous winter conditions. Where is this winter weather coming from, and what's in store for the coming days?

WHAT’S HAPPENING?

A front of cold air is moving down from the Arctic, sending temperatures plunging.

Much of the U.S. will see below-average temperatures through the middle and end of the week, said Bob Oravec, lead forecaster for the National Weather Service in College Park, Maryland.

Temperatures may drop by more than 20 degrees Fahrenheit (11 degrees Celsius) in just a few hours, the National Weather Service predicts.

And with winds also expected to pick up, wind chill temperatures could drop to dangerous lows far below zero — enough to cause frostbite within minutes. In parts of the Plains, the wind chill could dip as low as minus 70 degrees Fahrenheit (minus 57 Celsius).

On top of the frigid cold, the weather system is expected to send a snowstorm through the Midwest near the end of the week.

Those in the Plains, the Upper Midwest and the Great Lakes should expect blizzard conditions as heavy winds whip up the snow, according to the National Weather Service.

WHO WILL BE AFFECTED?

Pretty much everyone east of the Rockies — around two-thirds of the country — will see extreme weather in the coming days, said Ryan Maue, a private meteorologist in the Atlanta area.

Though much of the West Coast will be shielded from the cold, the Arctic front is expected to pass east and south all the way through Florida.

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