Did you know that you can tell a lot about the weather by just looking at and observing the clouds? In this article, I hope to introduce you to the general classifications of clouds and briefly discuss what type of weather pattern they foretell. Let’s start with classifications. There are four main clouds groups
- High Clouds
- Middle Clouds
- Low Clouds
- Clouds with vertical development
Each one of these cloud groups obviously have different heights in the atmosphere, however they do vary depending on where on earth the clouds are. Let’s start with the high clouds and discuss their significance. High clouds are usually found between 16,000 and 40,000 feet in the atmosphere.
Cirrus Clouds are the most common type of high cloud. They are thin and wispy and are blown by high winds into long streamers called mares’ tails. They usually move across the sky from west to east, indicating the prevailing winds at their height in the atmosphere. They generally indicate fair weather.
Cirrocumulus clouds are small, rounded, white puffs that may occur individually or in long rows. When in rows, the cloud has a rippling appearance that distinguishes it from the silky cirrus and the sheetlike cirrostratus. They only cover a small portion of the sky. These clouds strongly resemble the scales of a fish so the expression “mackerel sky” comes from this type of cloud.
Cirrostratus clouds usually cover the entire sky and are so thin that usually the sun and moon can shine through them. The ice crystals in the cloud is able to bend the light to form a halo around the sun or moon. These clouds usually indicate an approaching storm. They can be used to predict rain or snow within 12 to 24 hours, especially if they are followed by middle-type clouds.
Middle clouds have cloud bases between 6500 to 23,000 feet. These clouds are composed of water droplets and when the temperatures get low enough, ice crystals.
Altocumulus clouds appear as gray, puffy, masses, sometimes rolled out in parallel waves or bands. Usually one cloud appears darker than the other, which helps separate it from the higher cirrocumulus. When these clouds look like little castles, it indicates rising air at the cloud level. When these storms appear on a warm, humid summer morning, it often means thunderstorms by late afternoon.
Altostratus clouds are gray and blue-gray clouds that often cover the whole sky. In thinner sections of the cloud, the sun or moon can appear as a round disk as if shining through ground glass. The sun sometimes is called a “watery sun” when shining in this fashion. These clouds usually form ahead of storms having widespread and relatively continuous precipitation. If the precipitation reaches the ground, it is then called a nimbostratus cloud.
Low clouds have their bases lying below 6500 feet and are almost always composed of water droplets and in cold weather can contain ice crystals and snow.
Nimbostatus clouds are dark, gray, “wet” looking clouds associated with more or less continuous falling precipitation, usually light to moderate. This precipitation is not the heavy, showery variety unless well -developed cumulus clouds are embedded within the nimbostratus.
Stratocumulus clouds are low lumpy clouds that appear in rows, in patches, or as rounded masses with blue sky visible between the individual cloud elements. We often call these clouds “broken”. Sometimes the sun shines through the cloud breaks, causing crepuscular rays. Although precipitation rarely falls from these clouds, precipitation in the form of showers may occur in winter if the cloud develops vertically.
Stratus clouds are uniform grayish clouds that often cover the entire sky. It resembles a fog that does not reach the ground. Actually, when thick fog lifts, the result is a cloud deck of low stratus and is usually accompanied by a light mist or drizzle.
Clouds with vertical development may have their bases as low as 3300 feet and grow at tall as 60,000 feet. Familiar to everyone is the puffy cumulus cloud, which takes on a variety of shapes, although the most popular may be the cotton ball shaped. Cumulus clouds are usually detached from one another and indicate fair weather, usually. There are several types of cumulus clouds, however.
A cumulonimbus cloud is the official name of a thunderstorm cloud.
Now when you look up at the sky, you will have a general sense of what to expect weather-wise just by observing the clouds.