* WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...Portions of southwest and western Texas, including the following areas, in southwest Texas, Central Brewster, Chinati Mountains, Chisos Basin, Davis Mountains, Davis Mountains Foothills, Lower Brewster County, Marfa Plateau, Pecos, Presidio Valley and Terrell. In western Texas, Andrews, Borden, Crane, Dawson, Ector, Gaines, Glasscock, Howard, Loving, Martin, Midland, Mitchell, Reagan, Reeves County Plains, Scurry, Upton, Ward and Winkler. * WHEN...From 7 PM CDT this evening through Friday morning. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. Low-water crossings may be flooded. * ADDITIONAL DETAILS... - Moisture from Hurricane Simon will stream over West Texas the next several days. Periods of heavy rain are expected from this system that will likely cause flash flooding, especially in urban areas and low water crossings where drainage is poor. - http://www.weather.gov/safety/flood