lenticular clouds over Yorkshire, England. Lenticular clouds (Altocumulus lenticularis) are stationary lens-shaped clouds that form in the troposphere, normally in perpendicular alignment to the wind direction.
CUMULONIMBUS INCUS at Mykonos, Greece - photo by Sfortis, via Wikipedia; a cumulonimbus cloud which has formed the characteristic flat, anvil-top shape. They can form into supercells resulting in severe storm phenomena such as tornadoes.
Rare disc-shaped clouds caught on camera by motorist
70 Lightning Strikes in One Shot Photograph by CHRIS KOTSIOPOULOS Photographer's Description: Fire in the sky! This is an image sequence containing 70 lightning shots, taken at Ikaria island during a severe thunderstorm.
A huge tornado funnel cloud touches down in Orchard, Iowa, at p. on June The Globe Gazette and Mitchell County Press News reported that Lori Mehmen of Orchard took the photo from outside her front door.