For current weather conditions see the NOAA National Weather Service Pacific Northwest 7-Day Zone Forcasts Web Site. The site provide provides up the minute weather for a number of lower Columbia River communities including Astoria, Kelso, Kalama, Vancouver and Portland. Tailor your forecast to your paddling destination.
You can also try the National Weather Service Marine Forecast phone: 503-861-2722
This recorded phone line is updated twice daily at 8:00 am and 2:00 pm and provides weather as well as river stage and tide levels for the Columbia River.
Wind and fog are special factors to consider when planning a paddling trip.
Wind: Generally blow from the west or northwest in the summer and are greatest during the afternoon, making mornings the best time to paddle. In the winter southwest winds tend to bring rain, and easterly, down-Gorge winds bring cold air. Topography and differences in temperature and air pressure can also create strong, localized winds.
Fog: Fog can be extremely disorienting. Familiarity with the area or strong compass skills are necessary to navigate in these conditions. Leave room for error. Do not aim for small waypoints, such as a small island or the end of a peninsula. Shoot for large targets, and once you have reached them, proceed along them safely to your next destination. Do not cross shipping channels in the fog.
Finally, remain flexible and and open to schedule changes. Being overly committed to your schedule can encourage rash decisions and more chance taking. Take your time, be safe, and pay attention to weather!