What is the condition for conditional instability in the atmosphere?

The correct condition for conditional instability in the atmosphere is that parcels will rise if saturated but sink if unsaturated. This scenario indicates that when an air parcel is saturated (meaning it contains moisture and can condense), it will rise because it becomes less dense than the surrounding environment, driven by buoyancy forces. As it rises, it cools and can potentially release latent heat due to condensation, which further enhances its buoyancy.

On the other hand, if the air parcel is unsaturated (not containing enough moisture), it will be denser than the surrounding air and will sink back down. This difference in behavior between saturated and unsaturated conditions is key to understanding how certain atmospheric conditions lead to cloud formation and precipitation, as it highlights the role of moisture in air stability.

Other options describe scenarios that do not align with the concept of conditional instability, such as all parcels rising regardless of saturation, which depicts absolute instability, or all parcels cooling faster than the environment, which would suggest stable conditions, where neither saturated nor unsaturated air would typically rise. Therefore, the specified condition accurately captures the essence of conditional instability in the atmosphere.