* WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...A portion of southeast Nebraska, including the following counties, Gage, Jefferson, Johnson, Lancaster, Nemaha, Otoe, Pawnee, Richardson, Saline and Seward. * WHEN...From 7 PM CDT this evening through Tuesday morning. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Low-water crossings may be flooded. * ADDITIONAL DETAILS... - Several inches of rain have fallen across portions of southeastern Nebraska. Additional rainfall is expected through Tuesday morning, with one to three additional inches expected. - http://www.weather.gov/safety/flood