low-pressure area
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GC: n

S: https://content.meteoblue.com/en/meteoscool/large-scale-weather/high-low-pressure (last access: 2 July 2015); http://usatoday30.usatoday.com/weather/tg/wlowpres/wlowpres.htm (last access: 2 July 2015).

N: 1. – low (adj): “not high, below the usual level,” late 13c., earlier lah (late 12c.), “not rising much, being near the base or ground” (of objects or persons), also “lying on the ground or in a deep place” (late 13c.). This is not found in Old English, so the word is probably from Old Norse lagr “low, low-down, short; humble,” or a similar Scandinavian source (compare Swedish låg, Danish lav), from Proto-Germanic *lega- “lying flat, low” (source also of Old Frisian lech, Middle Dutch lage, Dutch laag “low,” dialectal German läge “flat”), from PIE root *legh- “to lie down, lay.”
– pressure (n): late 14c., “suffering, anguish; act or fact of pressing on the mind or heart,” from Old French presseure “oppression; torture; anguish; press” (for wine or cheeses), “instrument of torture” (12c.) and directly from Latin pressura “action of pressing,” from pressus, past participle of premere “to press, hold fast, cover, crowd, compress” (from PIE root *per- (4) “to strike”).
– area (n): 1530s, “vacant piece of ground,” from Latin area “level ground, open space,” used of building sites, playgrounds, threshing floors, etc.; which is of uncertain origin. Perhaps an irregular derivation from arere “to become dry” (see arid), on notion of “bare space cleared by burning.” The generic sense of “any particular amount of surface (whether open or not) contained within any set of limits” is from 1560s. Area code in the North American telephone systems is attested from 1959.
2. Low pressure areas (depression): Because of the insolation, the Earth’s surface is warming up and acts like a heating to the surrounding air. The air expands while heating and, because of the expansion, has a lower concentration than the cold air. As a consequense of this, the warm air raises up and warms also the regions above. Simultaneously, the air takes off from the “heating” – the ground – and is thus cooling down. If this process occurs in a greater area, there will arise a great packet, warmer, expanded air, which is now more stratified (towering) than the surrounding air. If this height difference grows, the warmer air starts to flow laterally over the adjoining cooler air packets. Because of this, the air is cooling down further, getting heavier and finally sinking to the ground when it hits the less cool regions.
3. low-pressure system; low-pressure area; low: terms officially approved by the Avalanche Bulletin Terminology Standardization Committee.

S: 1. OED – https://bit.ly/2VZQXld (last access: 19 October 2019). 2. https://content.meteoblue.com/en/meteoscool/large-scale-weather/high-low-pressure (last access: 2 July 2015). 3. TERMIUM PLUS (last access: 2 July 2015).

GV: low pressure area

S: https://content.meteoblue.com/en/meteoscool/large-scale-weather/high-low-pressure (last access: 2 July 2015); http://weather.about.com/od/pressureandtemperature/a/What-Is-A-Low-Pressure-Area.htm (last access: 2 July 2015).

SYN: 1. depression. 2. low-pressure system. 3. low.

S: 1. https://content.meteoblue.com/en/meteoscool/large-scale-weather/high-low-pressure (last access: 2 July 2015); TERMIUM PLUS (last access: 2 July 2015). 2. http://usatoday30.usatoday.com/weather/tg/wlowpres/wlowpres.htm (last access: 2 July 2015); TERMIUM PLUS (last access: 2 July 2015). 3. GDT (last access: 2 July 2015); TERMIUM PLUS (last access: 2 July 2015).

CR: cold air pool, cyclogenesis, explosive cyclogenesis, natural disaster, storm, thunderstorm.