Level of free convection

The level of free convection (LFC) is the altitude in the atmosphere where an air parcel lifted adiabatically until saturation becomes warmer than the environment at the same level, so that positive buoyancy can initiate self-sustained convection.

[1] The usual way of finding the LFC is to lift a parcel from a lower level along the dry adiabatic lapse rate until it crosses the saturated mixing ratio line of the parcel: this is the lifted condensation level (LCL).

If the temperature of the parcel along the moist adiabat is warmer than the environment on further lift, one has found the LFC.

If the airmass has one or many LFC, it is potentially unstable and may lead to convective clouds like cumulus and thunderstorms.

From the level of free convection to the point where the ascending parcel again becomes colder than its surroundings, the equilibrium level (EL), any air parcel gain kinetic energy which is calculated by its Convective available potential energy (CAPE), giving the potential for severe weather.