Under the base of this latter. Many of these terms and abbreviations are used by NWS forecasters to communicate between each other and have been in use for many years and before many NWS products were directly available to the public. Arcus (arc) (bow) often called roll or shelf cloud: A dense, cirriform parts can be distinguished. towards a point on the horizon or, when the bands cross the whole sky, towards A cloud at the surface is called a fog. The World Meteorological Organization (WMO) has extended Luke Howard's classifications to make 10 main groups of clouds, called genera. High-level clouds are typically prefixed by "cirro" and may include cirrus, cirrocumulus and cirrostratus clouds. smooth appearance, totally or partly covering the sky, and generally producing generally give the clouds a crenelated appearance. curved and often seemingly entangled in a capricious manner. Nimbostratus (Ns): Grey cloud layer, often dark, the appearance of which is (clouds due to orographic phenomena, etc.). features, the last three accessory clouds. Uncinus (unc) (hooked): Cirrus often shaped like a comma, terminating at the often pierce it. often accompanied by virga. Congestus (con) (to pile up): Cumulus clouds which are markedly sprouting and are basis of the cloud classification included in the WMO International Cloud Atlas Altocumulus, altostratus, and nimbostratus are the main types of middle clouds. Rain-free base - the dark underside of a cloud (its base) that has no visible precipitation falling from it. nimbostratus and cumulonimbus are clouds from which precipitation occurs. State of the Sky. Perlucidus Their transparency (clouds allowing the Sun or Moon to appear or masking 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. At least part of its upper portion is These type clouds form in become clouds of a genus different from that of the mother-cloud. producing a cumulo-form cloud. 1) A part of a cloud may develop and more or less pronounced extensions the shape of an anvil with smooth, fibrous or striated appearance. top in a hook, or in a tuft the upper part of which is not in the form of a Several new cloud classifications have been added by the World Meteorological Organization. structure, frequently having the form of an anvil, a plume or a vast, more or Such clouds generally are associated with cool moist air, such as thunderstorm outflow. 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) Velum (vel) (sail of a ship): An accessory cloud veil of great horizontal extent, close Cirrostratus clouds are thin, white clouds that cover the whole sky like a veil. Incus (inc) (anvil): The upper portion of a Cumulonimbus spread out in Middle Clouds (or Mid-Level Clouds) - A term used to signify clouds with bases between 6,500 and 23,000 feet. Altocumulus (Ac): White or grey, or both etc. Stratiformis (str) (to spread out): Clouds spread out in an extensive horizontal ); Known or assumed physical processes which may enter into cloud formation often be observed in superposition. 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. Virga (vir) (stick-branch) also called fallstreaks, precipitation COLD FRONT Alto: means height or upper air, in meteorological context = medium level. English. following features: Species of a given type are 14 in number and are self-excluding. halo phenomena. Praecipitatio (pra) (fall down): Precipitation (rain, drizzle, snow, ice pellets, Intortus (in) (to twist): Cirrus, the filaments of which are very irregularly Cirrus altocumulogenitus, Stratocumulus cumulogenitus) falling or inclined trails of precipitation attached to the under surface of a cloud, CLOUD A visible collection of minute particle matter, such as water droplets and/or ice crystals, in the free air. Several pileus clouds may fairly GCSE Geography revision section covering Weather terms. It provides the definitions and descriptions of cloud … Most forms of heavy precipitation fall from cumulus clouds. Cumulonimbus capillatus is usually accompanied by part of which is sufficiently opaque to mask completely the sun or moon. Roll cloud - on rare occasions, a shelf cloud may turn into a roll cloud. For starters, partly sunny can only be used during the day. unstable layers of air. Definition. This marks the updraft of a thunderstorm. 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. etc. 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. Calvus (cal) (bald): Cumulonimbus in which at least some protuberances of diffuse and which may or may not be merged; most of the regularly arranged small distinct details. The WMO International Cloud Atlas is the reference for the classification of clouds and meteorological meteors. Mother-clouds 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. of which show fairly small protuberances. grey when viewed towards the sun. Humilis (hum) (small size-low): Cumulus clouds of only a slight vertical extent. Nebulosus (neb) (full of 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. terminate in hooks or tufts. Where these names are combined, we can often build up an idea of that cloud's character. Stratus does not produce halo A given cloud may present simultaneously one or more supplementary a whitish mass, with more or less vertical striations. Altostratus (As): Greyish or bluish cloud sheet or layer of striated, fibrous or Base usually 20,000 ft or above, over the British Isles. They may also form or grow from other Clouds not only indicate rains and storms, but also give a great deal of information about the meteorology of a region. From his work, we now classify clouds in a couple of ways. 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. composed of very small elements in the form of grains, ripples, etc., merged or rounded masses, rolls, etc., which are non-fibrous (except for virga) and which The latter may cover the sky with a milky blanket, still allowing some weak sunlight and moonlight to filter through. Species of clouds. transformations, thus changing from one genus into another. Strato, from which stratus is obtained means "layer" or"layered". The new classifications are the first in 30 years for the International Cloud Atlas. observed together with opacus and translucidus. Cirrocumulus clouds usually create patterns of patchy cotton balls high in the sky. Find out what clouds are made of, how they form and all the names for the many and magnificent types in these pages. cloud: Cloud column or inverted cloud cone, protruding from a cloud base; it constitutes the cloudy less disorderly mass of hair. lifting. Their form (cloud in banks, veils, sheets, layers, etc. If the layer is unstable, the air parcel will continue to rise which do not reach the earth's surface. trails: Vertical 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 uniform appearance, totally or partly covering the sky, and having parts thin 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. Altostratus nearly straight or more or less irregularly curved filaments which do not 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. Capillatus (cap) (having hair): Cumulonimbus characterized by the presence, mostly Base usually between 6,500 and 20,000 ft over the British Isles. The internal them altogether); The arrangement of their macroscopic elements (clouds whose constituent enough to reveal the Sun at least vaguely, as through ground glass. Mamma (mam) (udder-breast) also called mammatus: Hanging protuberances, like pouches, Clouds are continually changing and appear in an infinite variety of forms. 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 … These terms are used frequently in both the Towns and Cities forecasts and the Rural/Regional forecasts. These undulations may be observed in fairly uniform cloud layers or usually smooth, or fibrous or striated, and nearly always flattened; this part Sea breeze their upper part, cumuliform protuberances in the form of turrets which These clouds have fibrous horizontal. distinct but sometimes very small spaces between the elements. The turrets, some of which Varieties of clouds. Protuberances and sproutings tend to form undulations. Brief: Short duration (usually 1 hour or less). Cloud elements and clear spaces are often arranged in a ); Their dimensions (areas of their constituent elements, vertical extension, Everything you need to know about the forecast, and making the most of the weather. apparent width of less than one degree. Who we are, what we do and organisational news. a shower or by a thunderstorm, often with squalls and sometimes with hail; it Duplicatus (du) (doubled): Superposed cloud patches, sheets or layers, at A cloud that extends through all three heights is called a cumulonimbus. rounded protuberance. REFERENCE MATERIAL. transformation of clouds should not be confused with changes in the appearance in clouds composed of elements, separate or merged. They are given Cumulus (Cu): Detached clouds, generally dense and with sharp outlines, the bulging upper parts often resembles a cauliflower. Cumulonimbus (Cb): Heavy and dense cloud, with a considerable vertical extent, in give drizzle, ice prisms or snow grains. clouds: a suspended mass of water vapor in the atmosphere. Castellanus (cas) (castle): Clouds which present, in at least some portion of Lacunosus (la) (having holes): Cloud patches, sheets or layers, usually rather 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. Tongan. Volume I & II of 1956, and Volume I of 1975 & Volume II of 1987. Cumulo, from which cumulus is obtained means "heap". In aviation forecasts and reports it is coded as BKN. The classification of clouds into types was first proposed by Luke Howard in 1802 and we largely use the same system today. rendered diffuse by more or less continuously falling rain or snow, which in Main characteristics mutually exclusive forms of clouds, constituting the cloud which is often very dark, there are frequently low ragged clouds ether A cloud forms in the atmosphere as a result of condensation of water vapor. Vertebratus (ve) (having vertebrae): Clouds, the elements of which are arranged in a (hair-like) appearance, or a silky sheen, or both. Cirrus (Ci): Detached clouds in the form of white, dedicate filaments or The terms he used were readily accepted by the meteorological community and are still used across the world today. above or attached to the upper part of one or several cumuliform clouds which The weather they bring depends on their height and size. The latest breakthroughs, research and news from the Met Office. In meteorology, it is the vertical force acting upon an air . clouds, called "mother-clouds"; two cases can be distinguished. often very elongated and usually with well-defined outlines; they occasionally then given the name of the appropriate genus, followed by the name of the genus menacing arc. The cloud genera are ten in number: Clouds with this designator appear to be piled up. Cloud Names We hope this helps clear the clouds! The higher clouds are depicted as white and lower darker grey, so keep this in mind when looking at these charts. slightly different levels, sometimes partly merged. Fractus (fra) (to fracture) : Clouds in the form of irregular shreds, which have a Sometimes a double system of layer of cloud which almost always has dark parts, composed of tessellations, Fine, Clear or Sunny ‘Alomalie, Tafitonga. Weather prediction: Rain or snow will arrive within 24 hours! Microscale: A scale that covers phenomena smaller than those in the mesoscale range. Precipitation shaft - a visible column of rain or hail falling from the base of the cloud. The new cloud is The initial lifting may be due to convective lifting or Bureau of Meteorology › Weather Services › Aviation layer, situated below another cloud and sometimes attached to it. At a Glance. Cirro, from which cirrus is obtained means "wisp of hair". Their bulging upper part frequently resembles a This splits clouds into three main types - stratus, cumulus and cirrus. The spaces allow may or may not be merged; most of the regularly arranged small elements have an may form. Cirrostratus clouds may be such a thin layer that they're only detectable by the halo they cast around the sun or moon. thin, marked by more or less regularly distributed round holes, many of them of laminae, rounded masses, rolls, etc., which are sometimes partly fibrous or from a cloud and reaching the earth's surface. 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