* WHAT. Flooding caused by excessive rainfall is possible. * WHERE. A portion of northeast Oklahoma, including the following counties, Craig, Nowata, Osage, Ottawa, Pawnee and Washington OK. * WHEN. From 9 PM CDT this evening through Wednesday morning. * IMPACTS. Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS. - Showers and thunderstorms are expected to develop this evening along a frontal boundary slowly moving into the region. Potential exists for training of storms along and near the OK/KS border through the overnight hours over already saturated areas. Rainfall of 1 to 3 inches will be common, with locally higher amounts of 4 to 5 inches possible. - http://www.weather.gov/safety/flood