* WHAT...Urban area and small stream flooding caused by excessive rainfall is expected. * WHERE...Multnomah County in northwestern Oregon... Washington County in northwestern Oregon... Southern Clark County in southwestern Washington... * WHEN...Until 200 PM PST. * IMPACTS...Minor flooding in low-lying and poor drainage areas. Overflowing poor drainage areas. Ponding of water in urban or other areas is occurring or is imminent. * ADDITIONAL DETAILS... - At 1041 AM PST, Doppler radar and automated rain gauges indicated heavy rain. This will cause urban and small stream flooding. Overflowing poor drainage areas will cause minor flooding in the advisory area. Up to 0.5 inches of rain have fallen in the last 12 hours and up to 0.25-0.35 inch in the last hour. - Additional rainfall amounts up to 1 inch are expected over the area. This additional rain will result in minor flooding. - Some locations that will experience flooding include... Hillsboro, Battle Ground, Washougal, Portland Downtown, Vancouver Downtown, Portland, Vancouver, Gresham, Beaverton, Tigard, Tualatin, Forest Grove, Camas, Troutdale, Banks, Maywood Park and Rivergrove. - http://www.weather.gov/safety/flood