Discover the facts of clouds

Cloud is a visible mass of water droplets or frozen ice crystals suspended in the atmosphere above the surface of the earth. Clouds give us a clue about what is going on in our atmosphere and how the weather might change in the hours or even days to come. Each type of cloud forms in a different way, and each brings its own kind of weather. 

Cool Condensation 

Clouds are water. As you probably know, we can find water in three forms: liquid, solid and gas. Water as a gas is called water vapor. Clouds form when water vapor turns back into liquid water droplets. That is called condensation. It happens in one of two ways: when the air  cools enough, or when enough water vapor is added to the air. You’ve seen the first process happen on a summer day as drops of water gather on the outside of a glass of ice tea. That’s because the cold glass cools the air near it, causing the water vapor in the air to condense into liquid. Unlike the drops on the side of your glass though, the droplets of water in a cloud are so small that it takes about one million of them to form a single raindrop.  Most clouds form this way, but the cooling comes not from ice in a glass, but as the air rises and cools high in the sky. Each tiny cloud droplet is light enough to float in the air, just as a little cloud floats out from your breath on a cold day.

Too Clean for Clouds? 

Our air has to be just a little bit dirty for clouds to form. That’s because water vapor needs a surface on which to condense. Fortunately, even the cleanest air has some microscopic particles of dust, smoke or salt for water droplets to cling to, so the air is rarely too clean for clouds to form. 

Common Cloud Types 

1.Stratus Clouds(Low Clouds)

It's Latin for "covering" or "blanket."  Stratus clouds look like a flat blanket in the sky.

Stratus clouds are layered and cover most of the sky. They are much wider than they are tall.   If you see them in broken or puffy layers, they are stratocumulus clouds.  If you see them in thin high layers that turn the sky solid white, they're cirrostratus clouds. The tiny prisms of ice in a cirrostratus layer can bend the sun's light. As a result, often you can see a halo or veil of rainbow colors around the sun.  When stratus clouds are very thick, they become dark nimbostratus clouds, which can produce rain, drizzle or snow.  

Stratus clouds are uniform grayish clouds that often cover the entire sky. They resemble fog that does not reach the ground. Usually no precipitation falls from stratus clouds, but sometimes they may drizzle. When a thick fog "lifts," the resulting clouds are low stratus.

Nimbostratus clouds form a dark gray, "wet" looking cloudy layer associated with continuously falling rain or snow. They often produce precipitation that is usually light to moderate.

2. "Alto" Clouds(Middle Clouds)

Clouds with the prefix "alto" are middle level clouds that have bases between 2000 and 7000 m (6500 to 23,000 ft.).

Altocumulus clouds are middle level clouds that are made of water droplets and appear as gray, puffy masses, sometimes rolled out in parallel waves or bands. The appearance of these clouds on a warm, humid summer morning often means thunderstorms may occur by late afternoon.

Altostratus clouds are gray or blue-gray middle level clouds composed of ice crystals and water droplets. These clouds usually cover the entire sky. In the thinner areas of the cloud, the sun may be dimly visible as a round disk. Altostratus clouds often form ahead of storms that will produce continuous precipitation.

3. Cirrus Clouds(High Clouds)

It's Latin for "curl."  Cirrus clouds look like curls of white hair.

Cirrus clouds are high and thin and made entirely of ice crystals. Forming above 20,000 feet in the atmosphere, they often look like wisps of white hair. Cirrus clouds, which are a sign of warm moist air rising up over cold air, are sometimes an early signal that thickening clouds could bring light rain or snow within one or two days.

Cirrus clouds are thin, wispy clouds blown by high winds into long streamers. They are considered "high clouds" forming above 6000 m (20,000 ft). Cirrus clouds usually move across the sky from west to east. They generally mean fair to pleasant weather.

Cirrostratus clouds are thin, sheetlike high clouds that often cover the entire sky. They are so thin that the sun and moon can be seen through them.

Cirrocumulus clouds appear as small, rounded white puffs. The small ripples in the cirrocumulus sometimes resemble the scales of a fish. A sky with cirrocumulus clouds is sometimes referred to as a "mackerel sky."

4. Cumulus Clouds

In Latin, this means "heap."  Cumulus clouds look like a heap of cotton balls or whipped cream.

Cumulus clouds are low individual billowy globs that are low, have flat bases and look a little like cauliflower. They are at least as tall as they are wide and form on sunny days from pockets of rising air.  Their constantly changing outlines are fun to watch because they can take the shapes of almost anything, including animals and faces.  Cumulus clouds usually signal fair weather. If they build into the middle or high part of the atmosphere they get the name cumulonimbus. A cumulonimbus cloud is tall, deep and dark and can bring lightning, heavy rain and even severe weather such as hail, damaging winds or tornadoes. It is a sign of rapidly rising and sinking air currents.

Cumulus clouds are puffy clouds that sometimes look like pieces of floating cotton. The base of each cloud is often flat and may be only 1000 m (330 ft) above the ground. The top of the cloud has rounded towers. When the top of the cumulus resembles the head of a cauliflower, it is called cumulus congestus or towering cumulus. These clouds grow upward, and they can develop into a giant cumulonimbus, which is a thunderstorm cloud.

Cumulonimbus clouds are thunderstorm clouds that form if cumulus congestus clouds continue to grow vertically. Their dark bases may be no more than 300 m (1000 ft) above the Earth's surface. Their tops may extend upward to over 12,000 m (39,000 ft). Tremendous amounts of energy are released by the condensation of water vapor within a cumulonimbus. Lightning, thunder, and even violent tornadoes are associated with the cumulonimbus.

Try to learn the names of the different clouds, and the next time you look up into the sky, take notice of what kind of clouds you see. And if you try, you might be able to guess what kind of weather they will bring.