SIOUX FALLS, S.D. (KELO) –During storm season we talk a lot about storm energy. But what does that mean?

Storm energy is the convective available potential energy, also known as CAPE.

CAPE is directly related to the maximum potential updraft speed in a storm. So, the higher the value, the greater the potential for severe weather. CAPE is, formulated using the temperature and dew point.
CAPE values may exceed 1000 joules per kilogram (J/kg) in a thunderstorm, and extreme cases can even exceed 5000 J/kg.

Looking back to May 12th of last year when we had the wall of dirt with the derecho, the CAPE value was expected to be 3500 to 4500 J/kg.

During our second derecho on July 5th of last year, the CAPE values were near 3000 J/kg over South Dakota.

And on Tornado Tuesday in 2003, when 67 tornadoes touched down in South Dakota, CAPE values ranged between 3500 to 4500 J/kg.

We are keeping an eye on the CAPE values for the rest of this week. There’s a chance we’ll see thunderstorms that could become severe.