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Undulatus clouds – definition
Clouds in patches, sheets or layers, showing undulations. These undulations may be observed in fairly uniform cloud layers or in clouds composed of elements, separate or merged. Sometimes a double system of undulations is in evidence. This term applies mainly to Cirrocumulus, Cirrostratus, Altocumulus, Altostratus, Stratocumulus and Stratus.
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Opacus clouds – definition
An extensive cloud patch, sheet or layer, the greater part of which is sufficiently opaque to mask completely the Sun or Moon. This term applies to Altocumulus, Altostratus, Stratocumulus and Stratus. In Altocumulus, often, the base is even and its apparent subdivision into merged elements results from the irregularity of its upper surface, sometimes the…
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Stratiformis clouds – definition
Stratiformis clouds is a cloud Species which spread out in an extensive horizontal sheet or layer of separate or merged elements. They are seen in Altocumulus, the most frequently occurring species, Stratocumulus and, occasionally, Cirrocumulus clouds.
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Cirrostratus – definition
Cirrostratus are transparent, whitish cloud veil of fibrous (hair-like) or smooth appearance, totally or partly covering the sky, often producing halo phenomena.
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Cumulus mediocris – definition
Cumulus mediocris are clouds of moderate vertical extent, with small protuberances and sproutings at their tops. Cumulus mediocris generally produce no precipitation.