A frontal system will move across southwest Washington and northwest Oregon this evening. Precipitation is expected to begin around midday along the coast and then spread inland. The heaviest precipitation can be expected from late afternoon through about midnight Wednesday. Snow levels late this afternoon over southwest Washington and far northwest Oregon will be around 500 feet. Snow levels for the central coast are expected to be closer to 1000 feet. There is a chance for some accumulation below 500 feet this evening in the Lower Columbia of Cowlitz County in southwest Washington and 500 to 1000 feet in the central and south Willamette Valley and in coastal areas. Major roadways should not be be impacted, but there is the possibility of slushy spots on bridges, overpasses and higher-elevation road surfaces. For the most up-to-date forecast visit www.weather.gov/portland and for current road conditions dial 5-1-1.