* WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...The following counties, in Indiana, Dearborn, Fayette, Franklin, Ohio, Ripley, Switzerland, Union and Wayne, the following counties, in Kentucky, Boone, Bracken, Campbell, Carroll, Gallatin, Grant, Kenton, Lewis, Mason, Owen, Pendleton and Robertson, and the following counties, in Ohio, Adams, Brown, Butler, Champaign, Clark, Clermont, Clinton, Darke, Delaware, Fairfield, Fayette, Franklin, Greene, Hamilton, Highland, Hocking, Licking, Logan, Madison, Miami, Montgomery, Pickaway, Pike, Preble, Ross, Scioto, Shelby, Union and Warren. * WHEN...From late tonight through late Wednesday night. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS... - A warm front will lift north across the Ohio Valley later tonight into Wednesday. Several rounds of showers and thunderstorms will be possible. Widespread rainfall amounts of up to an inch can be expected with local amounts of 2 to 3 inches possible.