Lenticular clouds - "Flying saucers" over Wales

They look like floating UFOs or macarons in the sky: lenticular clouds are among the most striking cloud formations of all. Lately, they have been visible over Wales.

Meteorologically, they are called altocumulus lenticularis and are typical föhn clouds. These clouds form when moist air flows over mountains or hilly terrain. The air is lifted, cools down, and the excess water vapour condenses. The result is these characteristic clouds.

These fascinating clouds can also be seen occasionally in the Alps and generally over low mountain ranges.