Winter storm warnings and winter weather advisories are in effect across 23 states as a major storm system threatens to bring heavy snow, creating hazardous travel conditions and the risk of widespread power outages.

Wisconsin’s Tony Evers and Arizona’s Katie Hobbs, plus three open seats with no incumbents in Michigan, Georgia and Virginia, are categorized as tossups. Just one race with a sitting Republican governor – Lombardo in Nevada – is rated a tossup.