WEATHER

What to expect during the final day of the polar vortex in Wisconsin

Appleton Post-Crescent

Rejoice, Wisconsin, you've almost made it through the polar vortex.

The wind chill warning in effect for the state since Tuesday ended noon Thursday — and a less-severe wind chill advisory replaced it — as the polar vortex prepared to move east and the frigid air warmed slightly.

But heading outdoors Thursday was still not advised, according to the National Weather Service, as wind chills in the morning hit as low as minus 49 in Marshfield and minus 47 in Appleton.

Temperatures rose a little midday Thursday to single-digits below zero in northeast and central Wisconsin, with wind chills in the minus 20s. Meteorologists expected temperatures in Oshkosh to reach 10 degrees above zero by noon Friday and 34 by the same time Saturday.

The Weather Service continued to remind people to bundle up and bring a safety kit for driving as frostbite could still occur on exposed skin within 10 minutes.

According to the Associated Press, the cold the past few days was the result of a split in the polar vortex, a cold air mass that normally stays farther north in the Arctic. The split allowed the air to move much farther south than usual and affect the Midwest.

Oshkosh, Wisconsin Rapids and Marshfield broke a 1951 record for the lowest high temperature on Jan. 30 ever, hitting minus 11 and minus 15 degrees, according to the Weather Service.

And Thursday morning's extreme cold hit even colder historic markers across northeast Wisconsin. Oshkosh tied its 1918 record for lowest Jan. 31 temperature at minus 26, and that same temperature tied Green Bay's 1899 record.

Appleton bested its 1996 record of minus 22 by 4 degrees, and Marshfield tied its 1996 record of minus 30.

Road conditions also continued to improve throughout Wisconsin during the final day of the deep freeze. According to 511wi.gov, nearly all major northeast, central and southern Wisconsin highways, including Interstate 43, Interstate 41 and Interstate 39 currently have good winter driving conditions.

The site listed portions of U.S. highways north of Green Bay, Antigo and Merrill as having slippery conditions.

A large portion of Wisconsin schools and state offices remain closed Thursday due to the cold weather. The United States Postal Service announced Thursday that it would resume mail services Friday across the state after two days without delivery due to the frigid temperatures.

“As we resume delivery, we ask our customers to continue clearing sidewalks, paths and approaches to the mailboxes for the continued safety of our letter carriers,” said Acting Lakeland District Manager Derron Bray.