AccuWeather.com
Offers current local conditions, 5-day, 10-day, 15-day and extended weather forecasts plus weather maps, doppler radar, and historical weather information.
Portland Climatology
Studies the snowfall, precipitation, and temperature in Portland from 1950 to the present.
The Weather Channel - Portland
Local current weather and ten day forecasts provided.
Weather Underground: Portland
Local radar, satellite, present, extended, and marine forecasts, historical conditions, and current temperature.