* WHAT...Flash flooding caused by excessive rainfall from thunderstorms is possible. The risk of flash flooding includes recent burn scars such as the Robertson Draw and East Side Fires south of Red Lodge, and the Elk Fire along the eastern slopes of the Bighorn Mountains. * WHERE...Portions of Montana, including the following areas, Absaroka/Beartooth Mountains, Beartooth Foothills, Bighorn Canyon, Golden Valley, Livingston Area, Melville Foothills, Musselshell, Northeastern Yellowstone, Northern Big Horn, Northern Carbon, Northern Stillwater, Northern Sweet Grass, Paradise Valley, Pryor/Northern Bighorn Mountains, Red Lodge Foothills, Southeastern Carbon, Southern Big Horn and Southwestern Yellowstone and north central Wyoming, including the following areas, Northeast Bighorn Mountains and Sheridan Foothills. * WHEN...Through late tonight. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - Expect slow-moving thunderstorms capable of producing very high rainfall rates. - http://www.weather.gov/safety/flood