What makes clouds rain

Weather forecasters call this type of rain a shower, even though it may be quite heavy. Showers travel across a country, so they do not last very long in one place. Toggle text. Quiz yourself on weather! For example, hilly coastal areas are often wetter than flat coastal areas because as the wet air from the ocean rises to go over the hills, it condenses enough for rain to fall. When that happens the mass of warm air — and the water it's carrying — lifts up and over the air of the cool front.

As all that warm air rises it cools enough for water vapor to condense and fall in what can become heavy, intense rain. When conditions are correct, this can also be the mechanism that starts a summer thunderstorm rolling. Thunderstorms are caused by masses of warm air that rise, whether as the result of colliding weather fronts, mountainous topography or updrafts of warm air caused by the sun. If there's enough warm, rising air to keep feeding energy into the cloud, the combination of upward-rising warm, moist air and downward-falling dry, cool air creates the up-and-down cycle of air that forms a thunderstorm cell.

As you already know, precipitation can come down to Earth in many ways — and words like "fog," "mist," "drizzle" or "cloudburst" aren't just descriptive, they also have scientific definitions for the size of the water droplets, the speed of their fall, the inches of precipitation per hour, and their density or how many droplets there are in a square foot. From lightest precipitation to heaviest, those terms are:.

So when your friendly TV weatherperson says that "it's raining cats and dogs," they're embellishing a bit — but if they say you can look forward to "excessive rain," they're actually making a scientific statement. That's a complicated question. Here's one impressive fact: According to the United States Geological survey, enough rain falls on the continental United States to cover the land in 30 inches of water.

With that said, rainfall patterns vary enormously from year to year and between geographic areas. For example, the record for most rain in a year is held by the town of Cherrapunji, India, which received a whopping inches more than 75 feet of rain in The record for highest average annual rainfall belongs to Mt.

Then, as water vapor hit the cold metal bowl of ice, it turned back into tiny droplets of liquid water. The tiny droplets of water stuck to tiny bits of smoke in the air between the warm water and the ice.

In a real cloud, tiny pieces of dust floating in the air work the same way as the smoke did in your jar, and the water droplets form around the dust.

When water molecules warm up, they change from a liquid into a gas and rise up into the air, or evaporate. Water that has evaporated is called water vapor. Steam from a pot of water boiling on the stove is also water vapor. There is a lot of water vapor in the air we breathe.

Clouds are formed when water vapor rises high up into the air. When it reaches cold air, the vapor turns back into droplets of water! Clouds are just lots of drops of water all stuck together. Sometimes the water droplets freeze and fall to the ground as snow, sleet, or hail. Water or ice that comes from clouds is called precipitation. Besides bringing precipitation, clouds also keep the earth cool.

Warm air always rises and cool air sinks. On nights when there are lots of thick clouds, the earth does not lose its heat as fast because the clouds block the warm air from rising up as much. Warm air can hold more water vapor than cold air, so lowering the temperature of an air mass is like squeezing a sponge. Clouds are the visible result of that squeeze of cooler, moist air.

Moist air becomes cloudy with only slight cooling. With further cooling, the water or ice particle s that make up the cloud can grow into bigger particles that fall to Earth as precipitation.

Types of Clouds Because certain types of clouds are associated with certain types of weather , it is possible to forecast the weather by observing and understanding these different types of clouds. Clouds are classified into three main groups: cirrus , stratus , and cumulus.

Cirrus clouds are wispy, curly, or stringy. They are found high in the atmosphere—typically higher than 6, meters 20, feet —and are usually made of ice crystals. Cirrus clouds usually signal clear, fair weather. Their shape often indicates the direction the wind is blowing high in the atmosphere.

Stratus clouds are horizontal and stratified, or layered. Stratus clouds can blanket the entire sky in a single pattern. They usually occur close to the Earth. Stratus clouds often form at the boundary of a warm front , where warm, moist air is forced up over cold air. This movement produces clouds as the moist air is cooled across the entire front. The presence of stratus clouds usually means a chilly, overcast day.

If precipitation falls from stratus clouds, it is usually in the form of drizzle or light snow. Cumulus clouds are large and lumpy. Their name comes from the Latin word meaning "heap" or "pile.

Cumulus clouds are created by strong updrafts of warm, moist air. Most forms of heavy precipitation fall from cumulus clouds. The weather they bring depends on their height and size. The higher the base of a cloud is, the drier the atmosphere and the fairer the weather will be.

Clouds located close to the ground mean heavy snow or rain. Variations Clouds are also classified according to how high they are in the atmosphere and what kind of weather they produce. The prefix "cirro-" refers to clouds that lie more than 6, meters 20, feet above the Earth. The prefix "alto-" indicates clouds whose bases are between 2, and 6, meters 6,, feet above the Earth, such as altocumulus and altostratus clouds. They are considered "mid-level" clouds and are mostly made of liquid water droplets, but can have some ice crystals in cold enough temperatures.

The prefix "nimbo-" or the suffix "-nimbus" are low-level clouds that have their bases below 2, meters 6, feet above the Earth. Clouds that produce rain and snow fall into this category. Nimbostratus clouds bring continuous precipitation that can last for many hours. These low-level clouds are full of moisture. Cumulonimbus clouds are also called thunderheads.