We continue with the review of the different types of clouds cataloged by the World Meteorological Organization (WMO). On this occasion we begin to analyze the middle clouds and we will begin by describing the characteristics, genesis and other curiosities of the altocumulus.
This type of cloud is described as a bank, thin layer or layer of white or gray clouds, or both white and gray, that have shadows composed of tiles, rounded masses, rollers, etc., which are sometimes partially fibrous or diffuse and that may or may not be united; most of the small elements regularly distributed, they have an apparent width between 1º and 5º.
They are usually made up of water droplets. When the temperature is very low, ice crystals form. Its genesis would be as follows, when a large air mass, pushed by a frontal system, ascends to the middle levels (4-6Km.) And subsequently condenses. In turn, these clouds are formed by unstable air masses, which gives them their cumuliform appearance. They are usually part of the cold fronts and the warm fronts. In the latter case they are mixed in a single layer with Altostratus, occupying extensions of thousands of square kilometers.
As for whether they give us clues about the weather to come, it is known that isolated ones indicate good weather. On the other hand, if they appear in increase or mixed with Altostratus they indicate the proximity of a front or a storm. In these cases they can give off precipitation. They should not be confused with Cirrocumulus, the Altocumulus are larger, nor with the Stratocumulus, since the Altocumulus are smaller.
To photograph these clouds the ideal is backlight, as in the main photo, they show a formidable appearance. In the early hours of the morning or late in the afternoon its details are better appreciated. With a “Wide Angle” lens they are captured in all their greatness. At sunset, they briefly turn red.
Altocumulos can occur in 4 varieties (Stratiformis, Lenticularis, Castellanus and Floccus) and 7 species (Translucidus, Perlucidus, Opacus, Duplicatus, Undulatus, Radiatus, Lacunosus).
Source: AEMET