instability

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instability Atmospheric condition in which displaced air tends to maintain its movement away from its original level. This occurs, for example, when rising air cools at the moist-adiabatic lapse rate while a greater environmental lapse rate allows the air parcel to remain warmer than surrounding air (or even increases the temperature difference) so that continual buoyancy prevails. See also CONDITIONAL INSTABILITY; POTENTIAL INSTABILITY; and STABILITY.

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