The white region is called the "positive energy" region. The area of this region is CAPE and is expressed in Joules/kg values. The larger this area, the more CAPE, and the more energy that is available to rising parcels. A CAPE value that is more concentrated in the lower half would produce a stronger updraft than an equal CAPE value that is stretched higher and narrower. Also, CAPE is directly related to the maximum potential vertical speed within an updraft. Faster updrafts means more powerful updrafts. Powerful updrafts aid in the creation of large hail, supercells and violent tornadoes.