I just took this screenshot of my weather radar (Yahoo Widgets) and there is this strange S pattern, even more strange is i live right under part of the "rain" band and theres absolutely no rain clouds, just sun!
Same happenend accross whole west europe when a dutch military jet made a test with some anti-radar-device that ejects little aluminium-paper stripes. When a waether radar detects them it interprets them as heavy rain
What you are looking at is a image from the Doppler radar site itself; sometimes if the atmospheric conditions are right, the very sensitive radar will pick up any sort of moisture in the radars nearby vicinity and display it as precipitation.