The National Weather Service in Aberdeen has issued a Red Flag Warning for wind and low relative humidity, which is in effect from 11 AM to 8 PM CDT Thursday. The Fire Weather Watch is no longer in effect. * AFFECTED AREA...In South Dakota, Clark, Codington, Hamlin and Deuel. * WINDS...Southwest 10 to 20 mph with gusts up to 30 mph. * RELATIVE HUMIDITY...As low as 21 percent. * IMPACTS...Any fires that ignite will spread rapidly and become difficult to control or suppress.