CAPE is effectively the positive buoyancy of an air parcel (mass of air) and is an indicator of atmospheric instability, which makes it very valuable in predicting severe weather. Values from 1000 to 2000 can indicate forming of moderate thunderstorms, and over 2000 severe ones.

What is the lifted index in meteorology?

The lifted index (LI) is the temperature difference between the environment Te(p) and an air parcel lifted adiabatically Tp(p) at a given pressure height in the troposphere (lowest layer where most weather occurs) of the atmosphere, usually 500 hPa (mb).

What is a lifted index used for?

The lifted index is a stability index to help measure the buoyancy of the atmosphere. Atmospheric temperature generally decreases with height. When surface air rises, it also cools. However, sometimes it cools more slowly than its surounding environment.