Passage: A lee trough, also known as a dynamic trough, is "A pressure trough formed on the lee side of a mountain range in situations where the wind is blowing with a substantial component across the mountain ridge; often seen on United States weather maps east of the Rocky Mountains, and sometimes east of the Appalachians, where it is less pronounced." It can be formed either as a result of the adiabatic compression of sinking air on the lee side of a mountain range, or through cyclogenesis resulting from "the horizontal convergence associated with vertical stretching of air columns passing over the ridge and descending the lee slope."

Question: How can a lee trough be formed?
either as a result of the adiabatic compression of sinking air on the lee side of a mountain range, or through cyclogenesis resulting from "the horizontal convergence associated with vertical stretching of air columns passing over the ridge and descending the lee slope