Weather and River Conditions

Weather Radar, Color Satellite Photos, Forecasts, and Current Conditions

AccuWeather, Inc. (http://www.accuwx.com)
CNN Weater (http://www.cnn.com/WEATHER/)
Weather Channel Maps ( http://www.weather.com/weather/maps/)

Watches and Warning (Real Time), Black & White Satellite Photos, Forecasts, and Current Conditions

Interactive Weather Information Network (National Weather Service), with Graphics (updated regularly, with warnings by state) (http://iwin.nws.noaa.gov/iwin/graphicsversion/main.html)
Text Only Version (not fancy, but faster) (http://iwin.nws.noaa.gov/iwin/textversion/main.html)

Hydrological Data

Snow pack data:

Water and Climate Center (http://www.wcc.nrcs.usda.gov/wcc.html

USGS water resources (http://water.usgs.gov/realtime.html)

Other

Sun/Moon rise/set times:

US Naval Observatory (http://aa.usno.navy.mil/AA/data/)