Thermodynamics: adiabatic
Self-tutoring about thermodynamics and weather: the tutor mentions adiabatic.
Adiabatic refers to the concept that a system can heat or cool without heat flow between itself and the environment.
In such a case, the exchange is of energy. If the system in question expands, for instance, it does work according to W=PV, where W=work, P=pressure, and V=volume. Yet, doing this work means it expends energy, which ultimately means it must lose energy. What happens is that its molecules lose kinetic energy as they impart it to the surroundings. Hence, its temperature lowers.
Source:
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.