Altostratus Opacus

Altostratus types of clouds are layered type of clouds and possess a uniform and flat sort of a texture in the mid level altitudes. Generally, altostratus clouds are either thick or thin layered and often allow sunshine to pass through them. However, if they are near the earth's surface, they are thick enough as to hide the sun or the moon. An example of these clouds is the altostratus opacus.

What are altostratus opacus clouds?

These are a type of altostratus clouds that form very near the earth’s surface and are blue-grayish in color. As a result of this, they completely hide the sun or the moon from the normal view. These types of clouds normally form just before the occurrence of a storm. When altostratus clouds form, continuous precipitation does occur over a large area as they are widespread. When the rain or the snow finally hits the ground, they then change to become nimbostratus clouds. Altostratus clouds are grayish in color, an indication that significant rainfall or snowstorm is just about to occur.

What height are altostratus opacus clouds found?

Like any other altostratus clouds, altostratus opacus clouds are middle level clouds which are formed from the condensation of large amount of lifted air masses. And like any other altostratus clouds, they are formed between 2000 to 7000 meters above the ground level. They are normally comprised of tiny droplets of water and ice crystals, especially when they form particular high above the ground.

How are altostratus opacus clouds formed?

Altostratus opacus clouds form when there is enough moisture in the air and significant rising air that is in motion. The rising motion is a result of un-even heating of the earth’s surface causing surrounding air to get warm. As this warm air rises, it meets with cold air in the skies, condenses to form tiny ice crystals and water droplets, which in reality are the clouds. The formed clouds are then classified and named according to how high they are, texture, appearance and color.

What do altostratus opacus clouds look like?

Altostratus opacus clouds are darker in appearance than other versions of altostratus clouds and in most cases completely blocks the sunlight and the moonlight. These types of clouds may actually move lower and near the earth’s surface, mostly becoming denser until it completely obscures the moon or the sun.  After they have reached this stage of their development, they are classified as nimbostratus types of clouds.

How common are these clouds?

Altostratus opacus clouds are mostly common in such areas as the oceans or generally areas that are close to masses of water. Areas such as England and the Pacific Northwest which normally experience foggy condition see a lot of low-lying altostratus opacus clouds.
These types of clouds are not the best weather forecasting tools that other clouds like cirrus are, so they can not accurately be used to foretell the day’s weather.

Characteristics of altostratus clouds

• These clouds form in layers and quite near the earth’s surface.
• They are dark in appearance, therefore completely blocks the sun or the moon when they form.
• They are found all over the world, especially around the coast and the mountains.
• They are mid level clouds which typical altitudes is 2000 to 7000 meters above the ground level.

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