From Ambient Weather:
The Weather Exchange is a free PC desktop application that accesses live community weather from the world's largest free personal weather station network. The Weather Exchange also provides up to the minute forecasts, radar, warnings, and detailed weather maps, keeping you instantly informed of any changes in the weather. The Weather Exchange displays a tremendous array of real-time and animated regional and national weather maps. Colored coded temperature, wind chill, humidity, dew point, UV, wind, jet stream, radar, visibility, satellite, fronts, snow, and air-quality maps turn even the casual weather observer into a meteorologist.
The Weather Exchange sounds personal alarms you set based on wind speed, wind chill, temperature, humidity, barometric pressure, rainfall, dew point, and heat index, each customized for your favorite station or network of stations. The Weather Exchange hides away, and can display the temperature and weather advisory/alarm level on your taskbar.