Send in the Clouds! (2)
Thanks once again to NASA's Astronomy Picture of the Day for this amazing Photograph.
Explanation: What type of cloud is that? This retreating cumulonimbus cloud, more commonly called a thundercloud, is somewhat unusual as it contains the unusual bumpiness of a mammatus cloud on the near end, while simultaneously producing falling rain on the far end.
(Credit: Amazing Sky Photography: Alan Dyer)