3. Stability

Determining Stability » Potential Errors The Net Effect of Non-Adiabatic Processes

Since the parcel method does not take into account the effects just discussed, we must use it with some degree of caution. Generally, the parcel assumption of continuous adiabatic ascent within clouds results in much higher values for updraft speed, water content, and temperature than we would typically observe. Nevertheless, empirical forecast techniques that use sounding analyses were derived by correlating actual weather events with parcel-method-derived parameters. For example, parameters such as CAPE and stability indices such as lifted index, both of which are derived using parcel methods, have empirically derived thresholds for assessing the strength and severity of convection. Therefore, these techniques indirectly incorporate these diabatic effects.