clouds, called "mother-clouds"; two cases can be distinguished. Alto: means height or upper air, in meteorological context = medium level. The classification of clouds is based on a book written by Luke Howard, a London pharmacist and amateur meteorologist, in 1803. cloud, its outline is clearly discernible. They are called multi-level clouds because of their ability to spread through the lower, middle, and upper cloud levels. sheet or layer. mother-cloud with the addition of the suffix "genitus" (e.g. Spissatus (spi) (to make thick): Cirrus of sufficient optical thickness to appear menacing arc. The cloud genera are ten in number: the upper part are beginning to lose their cumuliform outlines but in which no above or attached to the upper part of one or several cumuliform clouds which Strato, from which stratus is obtained means "layer" or"layered". Varieties of clouds. clouds are mostly brilliant white; their base is relatively dark and nearly GCSE Geography revision section covering Weather terms. Pileus (pil) (cap) also called cap cloud, scarf cloud: An accessory cloud of small The WMO International Cloud Atlas is the reference for the classification of clouds and meteorological meteors. Fine, Clear or Sunny ‘Alomalie, Tafitonga. Clouds with this designator appear to be piled up. manner suggestive of vertebrae, ribs, or a fish skeleton. etc. The higher the base of a cloud is, the drier the atmosphere and the fairer the weather will be. lifting. Arcus (arc) (bow) often called roll or shelf cloud: A dense, forced (mechanical) lifting, such as; orographic, frontal or convergence They are given Condensation nuclei, such as in smoke or dust particles, form a surface upon which water vapor can condense. or inclined trails of precipitation attached to the under surface of a cloud, Nebulosus (neb) (full of horizontal extent, in the form of a cap or hood above or attached to the top of a Protuberances and sproutings tend to form halo phenomena. A cloud that extends through all three heights is called a cumulonimbus. Stratus (St): Generally grey cloud layer with a fairly uniform base, which may the shape of an anvil with smooth, fibrous or striated appearance. features, the last three accessory clouds. Vertebratus (ve) (having vertebrae): Clouds, the elements of which are arranged in a These charts show the amount of cloud cover forecast. Fogs which are mainly composed of water droplets are generally classified according to the physical process which produces saturation or near-saturation of the air. cloud does not show halo phenomena. Base usually 20,000 ft or above, over the British Isles. Cumulo, from which cumulus is obtained means "heap". the form of a mountain or huge towers. enough to reveal the Sun at least vaguely, as through ground glass. often pierce it. rounded masses, rolls, etc., which are non-fibrous (except for virga) and which Calvus (cal) (bald): Cumulonimbus in which at least some protuberances of The turrets, some of which Clouds are one of nature's most consistently visible wonders and can also tell us a lot about what is going on up in the atmosphere. Sun. We hope this helps clear the clouds! This work was pioneered by Luke Howard at the beginning of the 19th century. The main types of clouds … Many times when you look at a satellite picture especially one with animation and during the night time for that area, you will be looking at a picture that is taken using the infrared wavelength. They ceiling A mea… Lahi ‘alomalie. greater part of which is sufficiently translucent to reveal the position of the may form. Low clouds, 2 to 0 km (6,500 to 0 feet), are stratocumulus, stratus, and nimbostratus. Microscale: A scale that covers phenomena smaller than those in the mesoscale range. apparent width of less than one degree. their upper part, cumuliform protuberances in the form of turrets which phenomena except, possible, at very low temperatures. from a cloud and reaching the earth's surface. transformation of clouds should not be confused with changes in the appearance falling Subdivision of cloud genera and their species, determined by taking into undulations. 2) The whole or large part of a cloud may undergo complete internal unstable layers of air. REFERENCE MATERIAL. Weather prediction: Rain or snow will arrive within 24 hours! However, according to the National Weather Service, partly cloudy and partly sunny mean exactly the same thing.The NWS definition states that between 3/8 and 5/8 of the sky is covered by clouds when it's classified as partly cloudy or partly sunny. In the list below the first Most of our names for clouds come from Latin and are usually a combination of the following prefixes and suffixes: Cumulus/cumulo = heaped up/puffy, like cauliflower. At a Glance. Humilis (hum) (small size-low): Cumulus clouds of only a slight vertical extent. Several new cloud classifications have been added by the World Meteorological Organization. origin, but may also occur in regions without marked orography. then given the name of the appropriate genus, followed by the name of the genus Translucidus (tr) (transparent): Clouds in an extensive patch, sheet or layer, the the bulging upper parts often resembles a cauliflower. They may also form or grow from other Where these names are combined, we can often build up an idea of that cloud's character. elements usually have an apparent width of between one and five degrees. Minor Trough: A pressure trough in the upper air of smaller scale than a long wave trough. part of certain clouds and having, when extensive, the appearance of a dark, Altostratus TP.150 & WMO publication No. Variations Terms include Atmosphere, Air Masses, Types of Cloud, cirrus, cumulus, stratos, nimbus, el nino and la nina, high pressure, low pressure, anticyclones, depressions, temperature differences, winds, cold fronts, warm fronts, occluded fronts and weather systems Average cloud cover equal 6 oktas, rainfall less … No clouds or with a few light clouds (<0 to 2 okta or less than 1/8 to 2/8 of sky covered with cloud) and no rain. Otherwise known as The King of Clouds, cumulonimbus clouds exist through the entire height of the troposphere, usually characterised by their icy, anvil-shaped top. Cloudy: Cloudy for most of the time. Scud clouds Small, ragged, low cloud fragments that are unattached to a larger cloud base and often seen with and behind cold fronts and thunderstorm gust fronts. Sometimes, a \"mix of sun and clouds\" is used by some forecasters instead of \"partly sunny\" during the daytime hours, though it is no… Today it is known in numerous methods to be able to predict the weather that is going to be and cloudiness plays an important role. of the sky resulting from the relative movement of clouds and observer. For example, if we combine nimbus and stratus we get 'nimbostratus' - a cloud which is flat and layered and has the potential for rain. Mamma (mam) (udder-breast) also called mammatus: Hanging protuberances, like pouches, them altogether); The arrangement of their macroscopic elements (clouds whose constituent Altocumulus, altostratus, and nimbostratus are the main types of middle clouds. Definitions of commonly used terms used at the Tonga Meteorological Service. Generally lots of low or medium clouds. The latest breakthroughs, research and news from the Met Office. The new classifications are the first in 30 years for the International Cloud Atlas. Stratiformis (str) (to spread out): Clouds spread out in an extensive horizontal arranged in lines. This splits clouds into three main types - stratus, cumulus and cirrus. Mediocris (med) (medium size): Cumulus clouds of moderate vertical extent, the tops Thus,nimbostratus and cumulonimbus are clouds from which precipitation occurs. ( ) = abbreviations of the genera, species, varieties & supplementary features and accessory clouds, ( ) = meaning of Latin names of species, varieties & supplementary features and accessory clouds, Source: WMO publication No. At the higher altitudes, they may also have some ice crystals, but they are composed mainly of water droplets. Meteorology: The study of the phenomena of the atmosphere. in clouds composed of elements, separate or merged. sun or moon. distinct details. Cirrus cirrostratomutatus, Stratus stratocumulomutatus). Species of clouds. 407. Cumulonimbus capillatus is usually accompanied by self-exclusive except for opacus and translucidus. frequently produces very well-defined virga. horizontal roll with more or less tattered edges, situated on the lower front Nimbo: means "rain". In aviation forecasts and reports it is coded as BKN. Pannus (pan) (rag): Ragged shreds, sometimes constituting a continuous of which show fairly small protuberances. which do not reach the earth's surface. The World Meteorological Organization (WMO) has extended Luke Howard's classifications to make 10 main groups of clouds, called genera. The spaces allow Fractus (fra) (to fracture) : Clouds in the form of irregular shreds, which have a diffuse and which may or may not be merged; most of the regularly arranged small Cumulonimbus (Cb): Heavy and dense cloud, with a considerable vertical extent, in Their form (cloud in banks, veils, sheets, layers, etc. account one or other of the two following characteristics: The varieties of a given genus or species are 9 in number and are not The higher clouds are depicted as white and lower darker grey, so keep this in mind when looking at these charts. A cloud layer that covers between 3/8ths and 1/2 of the sky. with a cumuliform appearance, the lower part of which is more or less ragged and Congestus (con) (to pile up): Cumulus clouds which are markedly sprouting and are Supplementary features and accessory clouds, Clouds attached to the main part of a cloud, generally smaller than the basis of the cloud classification included in the WMO International Cloud Atlas less disorderly mass of hair. A cloud forms in the atmosphere as a result of condensation of water vapor. Perlucidus Their bulging upper part frequently resembles a Cirrostratus clouds are thin, white clouds that cover the whole sky like a veil. The many possible variations in the shape of clouds and differences in their internal structure have led to the subdivision of most of the cloud genera into species. Main characteristics mutually exclusive forms of clouds, constituting the Mother-clouds Cirro, from which cirrus is obtained means "wisp of hair". are taller than they are wide, are connected by a common base and seem to be white or mostly white patches or narrow bands. composed of very small elements in the form of grains, ripples, etc., merged or Hail: Precipitation in the form of balls or irregular lumps of ice, usually produced by convective (cumuliform) clouds. (hair-like) appearance, or a silky sheen, or both. of laminae, rounded masses, rolls, etc., which are sometimes partly fibrous or hail, etc.) Can be uniform appearance, totally or partly covering the sky, and having parts thin Altostratus (As): Greyish or bluish cloud sheet or layer of striated, fibrous or Such clouds appear most often in cloud formations of orographic Tongan. Cumulus clouds are created by strong updrafts of warm, moist air. The sunlit parts of these Here are some of the more common and basic meteorological terms, concepts, and phenomena. At any time there are many weather systems weaving around the globe, however when averaged over many years a global pattern of air movement emerges. The International Cloud Atlas currently recognizes ten basic cloud “genera,” which are defined according to where in the sky they form and their approximate appearance. This marks the updraft of a thunderstorm. These terms are used frequently in both the Towns and Cities forecasts and the Rural/Regional forecasts. Radiatus (ra) (having rays): Clouds showing broad parallel bands or arranged in parallel bands, which, owing to the effect of perspective, seem to converge Cirrus (Ci): Detached clouds in the form of white, dedicate filaments or Everything you need to know about the forecast, and making the most of the weather. Cirrocumulus clouds usually create patterns of patchy cotton balls high in the sky. Stratocumulus (Sc): Grey or whitish, or both grey and whitish, patch, sheet or "layered". may or may not be merged; most of the regularly arranged small elements have an top in a hook, or in a tuft the upper part of which is not in the form of a They may also for… producing a cumulo-form cloud. most cases reaches the ground. Mountain waves are often standing or nearly so, at least to the extent that upstream environmental conditions (and diurnal forcing) are stationary. nearly straight or more or less irregularly curved filaments which do not These clouds are most commonly seen in the winter, and can cause the appearance of a halo around the sun or the moon. slightly different levels, sometimes partly merged. often of great vertical extent. BROKEN CLOUD. The latter may cover the sky with a milky blanket, still allowing some weak sunlight and moonlight to filter through. Multi-level Clouds are clouds that have a large vertical buildup. CLOUD A visible collection of minute particle matter, such as water droplets and/or ice crystals, in the free air. The internal The classification of clouds into types was first proposed by Luke Howard in 1802 and we largely use the same system today. following features: Species of a given type are 14 in number and are self-excluding. often accompanied by virga. apparent width of more than five degrees. Two divisions of mountain wave are recognized, vertically propagating and trapped lee waves.Vertically propagating mountain waves over a barrier may have horizontal wavelengths of many tens of kilometers or more, usually extend upward … Most forms of heavy precipitation fall from cumulus clouds. mist): A cloud like a nebulous veil or layer, showing no Amount of clouds generally increasing/decreasing to/from cloudy or overcast with only light showers or rainfall less than 0.05 inch or 1.27 mm. Strato, from which stratus is obtained means "layer" or C. climate: average meteorological conditions in a certain area over a certain period. By the end of this lesson, you will be able to predict rains by studying clouds too. towards a point on the horizon or, when the bands cross the whole sky, towards clouds: a suspended mass of water vapor in the atmosphere. A given cloud may present simultaneously one or more supplementary Middle clouds, 7 to 2 km (23,000 to 6,500 feet), are altocumulus and altostratus. nimbostratus and cumulonimbus are clouds from which precipitation occurs. cloud which is often very dark, there are frequently low ragged clouds ether Verification, impacts and post-processing, Climate information for international development, Science for Impacts, Resilience and Adaptation (SIRA), Atmospheric processes and parametrizations, Regional model evaluation and development, Environmental Hazard and Resilience Services, National Meteorological Library & Archive. developing vertically in the form of rising mounds, domes or towers, of which a shower or by a thunderstorm, often with squalls and sometimes with hail; it Precipitation shaft - a visible column of rain or hail falling from the base of the cloud. rendered diffuse by more or less continuously falling rain or snow, which in layer, situated below another cloud and sometimes attached to it. two opposite points on the horizon, called "radiation point(s).". elements are associated in a particular way). the sun, the moon, the blue of the sky or over-lying clouds to be seen. manifestation of more or less intense vortex, namely, a tornado or waterspout. The terms he used were readily accepted by the meteorological community and are still used across the world today. Altocumulus (Ac): White or grey, or both Nimbostratus (Ns): Grey cloud layer, often dark, the appearance of which is The clearest way to understand this system is to examine the Latin roots of the words. At least part of its upper portion is National Weather Service Glossary This glossary contains information on more than 2000 terms, phrases and abbreviations used by the NWS. with fringed edges. Uncinus (unc) (hooked): Cirrus often shaped like a comma, terminating at the Middle Clouds (or Mid-Level Clouds) - A term used to signify clouds with bases between 6,500 and 23,000 feet. the name of the appropriate genus, followed by the name of the genus of the Undulatus (un) (wave): Clouds in patches, sheets or layers, showing These are divided into three levels - cloud … It is thick enough throughout to blot out the (pe) (allowing light to pass trough it): An extensive cloud patch, sheet or layer, with Glossary of Weather Terms. Clouds with this designator form in stable layers of air; These undulations may be observed in fairly uniform cloud layers or structure, frequently having the form of an anvil, a plume or a vast, more or Cirrostratus (Cs): Transparent, whitish cloud veil of fibrous (hair-like) or The castellanus character is especially evident when the Sometimes a double system of The clouds are characterized by vertical air movements called updrafts. When the sun is visible through the Cloud Types common cloud classifications Clouds are classified into a system that uses Latin words to describe the appearance of clouds as seen by an observer on the ground. of the mother-cloud with the addition of the suffix "mutatus" generally appear flattened. A cloud species that displays at least in its upper part cumuliform protuberances resembling the turrets of a castle, giving a crenellated aspect. often spreads out in the shape of an anvil or vast plume. Clouds make those shadows. separate, and more or less regularly arranged; most of the elements have an BUOYANCY. The new cloud is State of the Sky. Their transparency (clouds allowing the Sun or Moon to appear or masking Cirrocumulus (Cc): Thin, white patch, sheet or layer of cloud without shading, The initial lifting may be due to convective lifting or undulations is in evidence. Volume I & II of 1956, and Volume I of 1975 & Volume II of 1987. Bureau of Meteorology › Weather Services › Aviation Lenticularis (len) (lentil): Clouds having the shape of lenses or almonds, Low-level clouds (cumulus, stratus, stratocumulus) that lie below 6,500 feet (1,981 m) Middle clouds (altocumulus, nimbostratus, altostratus) that form between 6,500 and 20,000 feet (1981–6,096 m) High-level clouds (cirrus, cirrocumulus, cirrostratus) that form above 20,000 feet (6,096 m) Stratus does not produce halo grey when viewed towards the sun. Clouds with this designator form in stable layers of air;except the stratocumulus type which forms in a thin, unstable layer of air. (e.g. Praecipitatio (pra) (fall down): Precipitation (rain, drizzle, snow, ice pellets, Find out what clouds are made of, how they form and all the names for the many and magnificent types in these pages. Manner suggesting a net or a honeycomb from 7,000 meteorological terms for clouds 25,000 feet in elevation cumulus clouds are created strong! 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