A Wind Chill Advisory is in effect for the following counties, Lyon, Sioux, Plymouth, Cherokee, Woodbury, Ida, Adair, Cass, Madison, Audubon, Crawford, Dallas, Guthrie, Mahaska, Marion, Polk, Warren, Adams, Appanoose, Clarke, Davis, Decatur, Lucas, Monroe, Ringgold, Taylor, Union, Wapello, Wayne, Jefferson, Henry, Des Moines, Van Buren and Lee. This will be in effect at least through Friday morning. A Wind Chill Warning is in effect for the following counties, Osceola, Dickinson, OBrien, Clay, Buena Vista, Black Hawk, Boone, Bremer, Butler, Calhoun, Carroll, Cerro Gordo, Emmet, Franklin, Greene, Grundy, Hamilton, Hancock, Hardin, Humboldt, Jasper, Kossuth, Marshall, Palo Alto, Pocahontas, Poweshiek, Sac, Story, Tama, Webster, Winnebago, Worth, Wright, Mitchell, Howard, Winneshiek, Allamakee, Floyd, Chickasaw, Fayette, Clayton, Benton, Buchanan, Cedar, Delaware, Dubuque, Iowa, Johnson, Jones, Keokuk, Linn, Washington, Jackson, Clinton, Muscatine, Scott and Louisa. This will be in effect through at least Friday morning. Dangerous wind chills of -25° to as low as -45° will be common across the state through Friday. With actual readings between -10° and -20° in the morning, only a slight breeze of less than 10 mph will drop wind chills to these dangerous levels. Frost bite can occur in less than 10-15 minutes in these conditions. Bundle up if you need to go out in this weather.