Time lapse of the rare, UNDULATUS ASPERATUS (agitated or turbulent) wave clouds that rolled over Lincoln NE on July 7, 2014. Asperatus clouds are starting to get considered as a whole new cloud category. These clouds are formed when there is rising air currents that create wide-spread cloud cover with wind shear that blows across the rising air. This causes gravity waves where air moves up and down as buoyancy and gravity fight it out, causing long rippling waves that carry the clouds up and down.
