MILWAUKEE, Wisconsin -  A heat wave is prompting some schools in northern Wisconsin to cancel classes.

Public schools in Green Bay are canceling classes Friday. The Appleton school district is calling off elementary and middle school classes on Friday.

WLUK-TV reports the Neenah school district also canceled classes for Thursday.

The National Weather Service reports hot, humid weather is expected Thursday through Saturday. Friday will be the hottest day.

A heat advisory is in effect from noon Thursday to 11 p.m. Friday across southern Wisconsin. Hot and humid conditions are expected, with the heat index rising to 110 degrees (43 degrees Celsius) Friday afternoon.

The Salvation Army is opening cooling centers in Milwaukee and Greenfield.