Potential instability refers to a layer that is lifted as a whole.
If it slopes to the left with increasing height, more than the saturation adiabats, the layer is potentially unstable. If none of the potential curves intersect the sounding, thunderstorms are not likely to occur. This method is a reasonably simple method for forecasting air-mass thunderstorms in the Eastern United States. It does require prediction of short-range changes in the vertical distribution of temperature and moisture. . The Dewpoint depression is 13 C or more at any level from 850 through 700 hPa. .