http://www.theweatherprediction.com/habyhints2/462/
Dit is wat ik kon vinden op het web....
CISK stands for Convective Instability of the Second Kind. Not only does a changing temperature profile lead to more or less instability. Instability is also influenced by the moisture profile. Instability will increase further when the dewpoint near the surface increases. The addition of moisture makes the air less dense near the surface but more importantly releases more latent heat when air rises and condenses into precipitation. Air that is less dense and is warmer due to latent heat release will produce a more significant convection. Severe thunderstorms often have an environment with warm and humid air near the surface with cool air aloft.
In conclusion, instability is influenced by the temperature and moisture profile. The three factor that will increase instability are warming air near the surface, cooling air aloft and increasing dewpoints near the surface.