Altostratus (As)


Source: http://www.meteo-world.com/dossiers/dossier2_1.php

Level: 6,500 ft. to 23,000 ft.

Composition: Water and Ice

Typical Conditions: Stable but moist atmosphere. Usually seen ahead of an approaching storm system that contains a wide area of non-convective precipitation.

Appearance: Uniform light gray sheet, often covering the entire sky. If the sun or moon is visible at all through the clouds, it is usually dim and lacks the halo seen under cirrostratus.