(CNN) The week before Christmas is kicking off with a busy forecast.

Millions will either wake up to snow and ice or heavy rain and severe thunderstorms Monday as a storm system moves east.

Wintry weather from the Great Plains to the Northeast

As snow, freezing rain and mixed precipitation blanketed the Midwest and Ohio Valley Sunday, "a wide swath of snow" is expected Monday to hit areas in the central Plains eastward through the Midwest, the lower Great Lakes, central Appalachians and into the northern Mid-Atlantic States, according to the National Weather Service's short range forecast

A couple of areas of low pressure will be tracking across the Eastern US Monday and Tuesday, bringing wintry precipitation to much of the Ohio Valley, eastern Great Lakes, central Appalachians, northern mid Atlantic and most of New England. pic.twitter.com/lX3XSkZtVH — NWS Eastern Region (@NWSEastern) December 16, 2019

Winter weather advisories cover areas just west of Washington D.C., Baltimore, Philadelphia and west of New York City and Boston. In these regions, a mix of sleet, snow and eventually rain is forecast.

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