Definition: A middle-level cloud located between 6500 and 20,00 feet, altocumulus clouds are either banded or rounded in formation. Sometimes, they look like balls of cotton stuck into the blue background of the sky, while other times they look like rows. Often, these clouds have shadows or dark areas and can sometimes signal bad weather is approaching. They are made of water whereas high-level clouds are made of ice.
What do altocumulus clouds show about approaching weather? Altocumulus clouds that appear on a clear humid morning can indicate a thunderstorm will approach later in the day. The reason is altocumulus clouds often precede cold fronts.
Pronunciation: (al-toe-CUE-mew-lus)
Also Known As: "Ac" - the common abbreviation for altocumulus clouds.
