Severe weather is expected to bring subzero temperatures the northern Plains as soon as Thursday, then reach the Mississippi Valley, the Northeast and the Ohio Valley by Sunday.

A potentially historic, massive winter storm will slam more than half of the United States today, moving east as it brings heavy snow, widespread ice accumulation and dangerous cold.

"This will be a large and potentially historic storm, with major impacts over a very large area (more than 2 dozen states)," said AccuWeather meteorologist Bob Larson in an email to USA TODAY.