Cyclone (depression, low, low-pressure area) Area in the atmosphere in which the pressures are lower than those of the surrounding region at the same level. It is represented on a synoptic chart by a system of isobars at a specified altitude level (or a system of contours at a specified pressure level) which enclose relatively low values of pressure (or altitude). In its development a cyclone usually has the following phases. A wave (young) cyclone forms and moves along a front. Mature cyclone has well-developed warm sectors and both cold and warm fronts. Occluded cyclone is that within which there has developed an occluded front. |
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