Lots of mid-level altocumulus castellanus clouds in the sky

And this is how it looks from the ground with a lot of mid-level altocumulus castellanus clouds in the sky. This cloud is named for the turret-like protuberances that grow from its main deck, resembling the battlements of a medieval castle. While not a spectacular formation, it is significant in that it indicates instability in the middle layers of the atmosphere and may therefore point to thunderstorm development later in the day. However, this is highly unlikely to happen over the Maltese Islands.

Castellanus generally occurs when a layer of colder air slides across an area of altocumulus cloud. This creates instability, and localized bubbles of air start to rise from the cloud deck. Condensation within these pockets of air creates the castellanus effect. of mid-level altocumulus castellanus clouds in the sky.