Meteorology (Weather)/Atmospheric Stability
Is it possible for convective instability to exist within an absolutely stable layer?
See if this helps:
"•Potential (convective) instability:
Exists when Qe or Qw (equivalent and wet bulb potential temperature, respectively) decreases with height (dQe/dz < 0). When this occurs, an initially stable layer will destabilize as it is lifted, since the top of the layer will cool faster than the bottom, thereby steepening the lapse rate. In reality, whole layers may not be lifted at once; instead, parcels often lift from the boundary layer to their level of free convection (LFC) to form thunderstorms. Thus, the physical process that potential instability represents may or may not occur often during convection. However, Qe (which is more sensitive to moisture than temperature) decreasing with height IS important, since it represents the presence of dry air above moist air which enhances downburst and possibly hail potential if thunderstorms develop."