* WHAT...Flash flooding caused by excessive rainfall is possible with thunderstorms this afternoon and evening. * WHERE...Portions of central, north central, and southwest Montana. * WHEN...Until midnight MDT tonight. * IMPACTS...Excessive runoff may result in flooding of creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas and near burn scars. * ADDITIONAL DETAILS... - Heavy rainfall produced by thunderstorms may lead to flash flooding. Rainfall rates in excessive of 1 inch per hour are possible under heavier thunderstorms. - Some locations that may experience flooding include... The Horse Gulch burn scar, Great Falls, Bozeman, Helena, Lewistown, Townsend, Fort Benton, White Sulphur Springs, Cascade, Big Sandy, Stanford, Lincoln, Belgrade, East Helena, Three Forks, Manhattan, Belt, Geraldine, Denton, Hobson and the Horse Gulch burn scar. - http://www.weather.gov/safety/flood