- Industry: Weather
- Number of terms: 60695
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The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, AMS has a membership of more than 14,000 professionals, ...
An oppressively uncomfortable state of the weather that results from the simultaneous occurrence of high temperature and high humidity. It is often enhanced by calm air and cloudiness. This term is gaining technical recognition in light of the increased study of human comfort and air conditioning. Sultriness has been expressed in terms of the values of various measures of comfort. Some of the lower limits are water vapor pressure of 14 mm; dewpoint of 19°C (65°F); equivalent temperature of 56°C (133°F); effective temperature of 24°C (75°F); and the following pairs of temperature and relative humidity, 35°C (95°F) and 25%, 30°C (86°F) and 40%, 25°C (77°F) and 65%. See comfort chart, comfort zone.
Industry:Weather
An often dangerous convective storm that consists primarily of a single, quasi-steady rotating updraft, which persists for a period of time much longer than it takes an air parcel to rise from the base of the updraft to its summit (often much longer than 10–20 min). Most rotating updrafts are characterized by cyclonic vorticity (See mesocyclone). The supercell typically has a very organized internal structure that enables it to propagate continuously. It may exist for several hours and usually forms in an environment with strong vertical wind shear. Supercells often propagate in a direction and with a speed other than indicated by the mean wind in the environment. Such storms sometimes evolve through a splitting process, which produces a cyclonic, right-moving (with respect to the mean wind), and anticyclonic, left-moving, pair of supercells. Severe weather often accompanies supercells, which are capable of producing high winds, large hail, and strong, long-lived tornadoes. See'' also'' convective storm, thunderstorm, splitting convective storm, cell, bulk Richardson number.
Industry:Weather
An observation (and report) of the occurrence, location, time, and direction of movement of severe storms.
Industry:Weather
An iterative numerical method for solving elliptic partial differential equations. For example, a Poisson equation, ∇<sup>2</sup>φ = ''F''(''x'', ''y''), where ∇<sup>2</sup> is the Laplacian operator and the function ''F''(''x'', ''y'') is given.
Industry:Weather
An international code word used to indicate a route forecast, units in the English system. See'' also'' ROFOR, ROMET.
Industry:Weather
An ionized gas composed of positive and negative charges (and possibly neutral atoms and molecules) of almost equal charge density. At least one kind of charge is mobile. The term was coined by Langmuir and Tonks (1929) “to designate that portion of an arc-type discharge in which the densities of ions and electrons are high but substantially equal. ” A more quantitative definition can be given in terms of the Debye shielding distance, the distance over which the density of negative charges can be appreciably different from that of positive charges: A plasma is an ionized gas for which the Debye shielding distance is small compared with a characteristic length (Spitzer 1962). According to this definition the ionosphere is a plasma, and so is a slab of aluminum, but in atmospheric usage it is limited to an ionized gas.
Industry:Weather
