Much of the U.S. East braced for a renewed round of harsh, soggy weather Saturday, with snowstorms predicted in the Northeast and heavy winds bringing the threat of tornadoes to the Mississippi Valley.

Snow and arctic temperatures swept much of the Midwest and Upper Plains, covering roads in eastern Nebraska, northern Iowa and much of Wisconsin. Winter weather advisories were issued for parts of those states and Michigan, with up to 10.6 centimeters of snow predicted throughout Iowa, southern Wisconsin and most of Michigan by Sunday evening.

Meteorologists said the U.S. was about to get its 10th and coldest polar vortex stretching event this season, with the northern Rockies and northern Plains first in line. Weather forces in the Arctic are combining to push the chilly air that usually stays near the North Pole into the U.