CAPE - Convective Available Potential Energy, defined as the amount of energy a parcel of air would have if lifted vertically through the atmosphere, the higher the number the better.

LI - Lifted Index, defined as the temperature of a parcel of air at 500hPa (~ 18,000ft) subtracted from the temperature of the air surrounding it at the same height. In order for thunderstorms to develop, it requires parcels of air to continue rising, the bigger the difference of the air surrounding the rising parcel equates to how forcefully that parcel of air rises, the lower the number the better.