The National Weather Service has issued an Excessive Heat Warning that goes into effect today as of 1:00 p.m. for the listening area. The warning will be in effect through Friday night at 7:00 p.m. Both the Senior Center in Marshalltown and the Salvation Army Citadel will serve as formal shelters while the Marshalltown Mall and the Marshalltown Public Library also invite people in if they wish to seek refuge during this time from the excessive heat. Peak heat indexes are forecast at 109 degrees Wednesday and 110 degrees on Thursday. If you are in the Grinnell area the Grinnell Regional Medical Center Cafe is also offering shelter during the three-day time span.