The National Weather Service in Billings has issued a Red Flag Warning...which is in effect from noon Saturday to midnight MDT Saturday night. The Fire Weather Watch is no longer in effect. * IMPACTS: Low humidities, hot temperatures, and increasing thunderstorm activity will create erratic fire behavior and new fire starts. * AFFECTED AREA: In North Central WY Fire Zones...274...284. In South Central MT Fire Zones...123...124...125...126...127 128...129. In Southeast MT Fire Zones...130...131...132. In Southeast MT and Northwest SD Fire Zone...133. * COUNTIES AFFECTED: In Central MT...Golden Valley...Musselshell...Wheatland. In North Central WY...Big Horn...Johnson...Sheridan...Washakie. In Northwest SD...Harding. In South Central MT...Big Horn...Carbon...Park...Stillwater Sweet Grass...Yellowstone. In Southeast MT...Carter...Custer...Fallon...Powder River Rosebud...Treasure. In Southwest MT...Gallatin. * WIND: Southwest 10 to 15 mph with gusts up to 25 mph. * THUNDERSTORMS: Widely scattered afternoon and evening thunderstorms will produce gusty and erratic winds, and spotty rainfall. * HUMIDITY: As low as 11 percent. * TEMPERATURES: Up to 108.