* WHAT...Flooding caused by excessive rainfall continues to be possible. * WHERE...Northwest Oregon and southwest Washington including the following counties. In Oregon: Benton, Clackamas, Clatsop, Columbia, Hood River, Lane, Linn, Lincoln, Marion, Multnomah, Polk, Tillamook, Washington, and Yamhill. In Washington: Clark, Cowlitz, Pacific, Skamania, and Wahkiakum. * WHEN...Through Saturday afternoon. * 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. Storm drains and ditches may become clogged with debris. Area creeks and streams are running high and could flood with more heavy rain. Landslides and debris flows are possible during this flood event. People, structures, and roads located below steep slopes, in canyons, and near the mouths of canyons may be at serious risk from rapidly moving landslides. * ADDITIONAL DETAILS... - An atmospheric river is forecast to bring periods of heavy rain to northwestern Oregon and southwestern Washington today. This system occurs at a time when area rivers continue to run high and soils remain saturated following heavy rain earlier in the month. During initial heavy rainfall today, the urban and small stream flooding threat will be most urgent, although the details of precise timing and location of the highest risk remains uncertain at this time. As runoff works its way downstream, the river flooding threat will increase tonight into Friday, with numerous area rivers now forecast to reach at least Minor flood stage. Slower reacting rivers may stay in flood stage into Saturday afternoon. - http://www.weather.gov/safety/flood