What factor would decrease the stability of an air mass?

Warming from below is a factor that decreases the stability of an air mass because it promotes vertical mixing and convection. When the lower layers of an air mass are warmed, the air expands and becomes less dense compared to the cooler air above. This reduced density allows the warmer air to rise, which can lead to the development of larger vertical clouds and potentially convective activity such as thunderstorms. In contrast, stable air masses tend to have a temperature inversion where warmer air acts as a cap, inhibiting vertical motion and keeping the air mass stable.

By increasing thermal instability through warming at the surface, the potential for turbulence and weather development increases, making the air mass less stable overall. In atmospheric science, understanding the stability of an air mass is crucial for predicting weather patterns and phenomena.