Template:POTD/2009-07-21

Picture of the day

The underside of a weak shelf cloud, a low, horizontal wedge-shaped arcus cloud. Arcus clouds are associated with the leading edge of thunderstorm outflow, or occasionally with a cold front even in the absence of thunderstorms. Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent and wind-torn.Photo credit: Fir0002