Clouds of the Day - Thursday, November 12, 2020

/

Altocumulus are middle level clouds with an altitude between 6,500 feet and 20,000 feet. This common form of altocumulus is shown below with pillow-like cloud cells formed in a broad sheet. Since it is a broad layer of cloud with small cells vertical development it is a stratiform version of altocumulus. The cloud elements are arranged in disorganized lines, indicating undulations (waves) are in the flow moving through the layer. The clouds are enhanced at the crest of a wave. The lighter areas around the cells are caused by sinking air motion around the edges of the cells and at the troughs of the waves. Only time lapse photography would show the waves.

Alto means “high” so altocumulus means high cumulus. Cumulus are found in the lower layer of atmosphere, below 6,500 feet, so high cumulus indicates the clouds are in the middle level. The middle level is between the low layer and the high cloud (cirrus) layer. Altocumulus stratiformis indicates the cloud is a layer cloud. Altocumulus indicates there are cumulus formations present within the layer.

Altocumulus stratiformis undulatus

Altocumulus stratiformis undulatus

Altocumulus stratiformis

Altocumulus stratiformis

Altocumulus stratiformis with organized undulations visible bottom center to bottom right. The undulations appear as darker bands across the lower part of the photo and give stratiformis the second name (species) in the cloud name.

Altocumulus stratiformis with organized undulations visible bottom center to bottom right. The undulations appear as darker bands across the lower part of the photo and give stratiformis the second name (species) in the cloud name.

Altocumulus stratiformis undulatus.

Altocumulus stratiformis undulatus.

Stratocumulus. This low type cloud is a layer of cumulus clouds with the stratus (layer) characterisitics. Therefore the name is stratocumulus.

Stratocumulus. This low type cloud is a layer of cumulus clouds with the stratus (layer) characterisitics. Therefore the name is stratocumulus.

This turbulent sky was filled with cumulus in unorganized ragged patterns. In this photo the cumulus were not part of a consistant layer. They were mostly individual cells.

This turbulent sky was filled with cumulus in unorganized ragged patterns. In this photo the cumulus were not part of a consistant layer. They were mostly individual cells.