How to recognize upcoming storm? Look for Altocumulus castellanus
Štěpán Šubík last edited by Simona Polackova
Among all of the Altocumulus cloud species, Altocumulus castellanus has the greatest impact on the weather forecast. So how to recognize it?
Altocumulus castellanus (Ac cas) is a mid-level cloud with its base from 2 km (6,500 ft) up to 6 km (20,000 ft). They are very similar to Stratocumulus castellanus and the main difference is that they look smaller and there is no precipitation connected to them.
But Altocumulus castellanus is a big help in predictions of incoming heavy showers or thunderstorms. Ac cas is created when a mid-level instability appears. If surface-based convection can connect to the mid-level instability, Ac cas can transform into Cumulonimbus clouds.
Have you ever seen this phenomenon? Send us your photos!