Clouds of the Day - Friday, August 25, 2023 - Stratocumulus at Sunset

Stratocumulus

Stratocumulus is a low cloud type that has both stratus and cumulus characteristics. It is stratus because the cloud is a layer formation. Any vertical development is less that the horizontal extent of the layer. It is cumulus because of the rolls and puffy nature of individual portions within the layer. Rather than picking one over the other the name stratocumulus fits its shape and extent the best.

While this example is in a patch, stratocumulus often cover much of the sky when colder air spreads across the area. This often happens when a large storm system is exiting the area. The cool air in the lower levels is unstable and moisture from the passing storm has moistened the ground and the lower layers of the atmosphere. The stratocumulus layer forms under the base of a stable layer of air aloft which limits the top of the cloud layer. The air is weakly unstable up to the cloud layer which supports the formation of the clouds.