Time-lapse form-changing lenticular clouds

These lens-shaped orographic wave clouds form when the air is stable and winds blow across hills and mountains from the same or similar direction at different heights through the troposphere.

What are lenticular clouds?
These strange, unnatural looking clouds sometimes form downwind of hills or mountains. They are quite unusual in the British Isles but do occasionally occur. They look a lot like the traditional shape of flying saucers in science fiction, and real lenticular clouds are believed to be one of the most common explanations for UFO sightings across the world.

How do we categorize lenticular clouds?
There are three main types of lenticular clouds: altocumulus standing lenticular (ACSL), stratocumulus standing lenticular (SCSL), and cirrocumulus standing lenticular (CCSL), varying in altitude above the ground.