Columbia River - Knapp Landing Rainfall ForecastUnited StatesWAClark CountyColumbia River - Knapp LandingToday 19 Apr20%Sun 20 Apr45%Mon 21 Apr10%Tue 22 AprNo RainWed 23 AprNo RainThu 24 Apr20%Fri 25 Apr35%Columbia River - Knapp Landing rainfall forecast issued today at 6:08 am. Next forecast at approx. 8:08 pm.1-Day3-Day5-Day Graph Plots Open in Graphs Rainfall Probability Forecast NOAA Rain Today Real-Time Portland RadarNational SatelliteNational SynopticGet WillyWeather+ to remove ads