In an unstable environment, the temperature of rising air can be traced and compared to the vertical profile of the environmental temperature.

The area between these two lines is representative of the available energy a storm could use to grow. This energy is call CAPE (Convective Available Potential Energy) and comes from the energy released when water condenses.

Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.