Explore the different types of precipitation. Rain and snow are just the beginning
Precipitation is atmospheric moisture that falls on the ground, often in large quantities, which affects people's lives. It is classified by the nature of its origin: some types are formed from clouds — rain, snow, hail; others from the air: dew, frost, glaze ice; and others are colloidal suspensions: fog and mist. In this new lesson of the Windy.app Meteorological Textbook (WMT) for better weather forecasting you will learn more about different types of precipitations and their main features.
Precipitation formed from the clouds
Downpour (heavy rain)
Downpour is heavy torrential rain, which comes from cumulonimbus clouds — they can still be called thunderclouds or simply clouds. These are the сlouds with “vertical growth”. The more the cloud’s height, the more likely there will be rain, hail, thunderstorms, and squalls.
Monsoon rains
Monsoon rains are rains that occur during monsoons, one of the two major types of wind on planet Earth in pair with trade winds. They bring large amounts of rainfall and are considered to be the world’s main rains. In fact, monsoons bring record precipitation. For instance, London, which is considered a properly rainy town, gets 600 mm of precipitation a year.
Learn more about monsoon rains
Drizzle
Drizzle drops are already larger than cloud or fog drops, but smaller than rain drops. Drizzle drops are usually from 0.2 to 0.5 mm in diameter. Drizzle drops appear as a result of the merging of cloud drops and fall down before they grow into raindrops.
Acid rain
Acid rain is rain and other precipitation (snow, hail, and even fog) with a high acidic oxide content caused by air pollution from anthropogenic and natural sources. When we were young, many feared acid rain would eventually become part of everyday life. It is partly true. While it has disappeared entirely in some places, in others it will not go any where any time soon.
Snow on the top of the mountains
You’ve probably seen snow-capped mountains on a green background. Why doesn’t the snow melt? The reason is the freezing level. The freezing level is the height where the snow stops melting. That’s the “line” above which precipitation accumulates and simply does not have time to melt and evaporate.
Learn more about snow on the top of the mountains
Snow and ice pellets
Snow and ice pellets are two other common types of frozen precipitation after rain, snow, and hail. Snow pellets are common in autumn and spring, and they usually fall before it starts to rain or snow. It may start raining immediately after snow pellets have fallen, as pellets may melt before reaching the ground. Ice pellets are most likely to be found in autumn or spring, usually in advance of a warm weather front. Occasionally, however, they can be formed in other weather conditions, for instance, behind a cold front or with a stationary front.
Learn more about snow and ice pellets
Hail
Sometimes it rains from the clouds, and sometimes it turns into lumps of ice, called hail, that can break through the roof of a car. Like many other forms of precipitation, hail starts from a cloud — specifically, a cumulonimbus cloud. Typically, a hailstone is a piece of ice larger than 5 millimeters. Anything smaller is classified as sleet or powdery snow.
Slush — the mixture of snow and water
Slush, the mixture of snow and water, is a weather phenomenon familiar to anyone who lives in northern latitudes with a humid climate near the shore of a large lake, sea, or ocean. In nature, slush is usually formed when snow falls on the water's surface. If the water temperature is only a little above freezing point (about 0 °C), the snow barely melts on it. It remains to lie on the surface and gets wet, looking and feeling like “wet cotton”.
Types of precipitation. Valerya Milovanova / Windy.app
Precipitation formed from the air
Dew point
The dew point is the air temperature at which its relative humidity reaches 100% and water vapor begins to “precipitate”, that is to condense. In other words, the dew point is the temperature to which the air needs to be cooled so that water condensate is released from it (dew appears).
Precipitation as colloidal suspensions
Fog
Fog is made up of small water droplets which are so light that they don’t fall to the ground but remain suspended in the air. Dense fog significantly reduces visibility and can be a major nuisance to drivers and aviators. Depending on its severity, fog conditions pose a real danger to all those who have been affected.
Learn more about fog and its formation
Fog in the mountains
Fog in the mountains is a special type of fog, which occurs, as the name suggests, in the mountainous areas of Earth. Fog in the mountains is a very frequent phenomenon. It is both beautiful and dangerous. Fog can severely deteriorate visibility and make navigation very difficult.
Learn more about fog in the mountains
Precipitation measurement in weather forcasting
Total accumulated precipitation
Accumulated precipitation is the sum of precipitation over a certain period of time in a certain place, or how much rain has fallen or will fall in total. Yes, you can check cumulative precipitation not only as a forecast for the future but also as a statistic of past weather data or weather history.
Learn more about total accumulated precipitation
Precipitation probability (chance of rain)
Precipitation is usually calculated in exact values, namely millimeters (mm) or inches (in). These values mean a layer of water that would have formed from precipitation if it had not penetrated into the soil, did not flow or evaporate. As a general rule in meteorology and weather forecasting, 1 mm (0.03 in) of precipitation equals one liter (0.21 gallons) of water per 1 square meter (10.7 sq feet) of area.
Learn more about precipitation probability
Explore the different types of all the main weather phenomena:
Text: Windy.app
Cover photo: Kumar Rishabh / Unsplash
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