June 24, 2022 - Clouds of the Day - Altocumulus lenticularis

Lenticularis clouds have a lens or saucer shape. The shape forms in an air mass that has a series of waves flowing in the wind. When watching water flow over rocks in a stream, you will often see a series of waves form downstream of the rocks. The same thing happens in the atmosphere. Flow over mountains frequently forms lenticularis clouds - waves in the air flow made visible as water vapor condenses into a cloud. It can also happen over flat ground when waves are set up in the atmosphere where the air has formed layers. The flowing air can begin oscillating up and down forming waves that move downstream.

The clouds in the photo above have formed the saucer shape that is common with lenticular clouds. The hump in the middle of the clouds is the top of the wave. If there is enough moisture, there may be a series of these waves visible downstream in the flow, spaced equally apart.

If you take a closer look at this photo, you will notice a series of smaller waves embedded within these lenticular clouds. We have the larger lenticular waves with smaller waves superimposed on the larger waves.

Finally, the complete name of these clouds is altocumulus lenticularis stratiformis. Altocumulus refers to the middle level of the atmosphere where these clouds reside, lenticularis comes from the lens shape of the clouds and stratiformis indicates the waves have formed within what is a flat (stratus-type) formation. The principal cloud type is altocumulus.