Parameters & indices#sounding#instability
LFC — Level of Free Convection
Also: LFC
At a glance
The altitude at which a rising parcel becomes warmer than the air around it and can accelerate upward on its own.
Deep dive
On a skew-T, the LFC is where the parcel path (traced from the surface, first dry-adiabatically to the LCL then moist-adiabatically) crosses the environmental temperature curve from colder-to-warmer. Below the LFC the parcel is decelerating (contributing to CIN); above, it's accelerating (contributing to CAPE).
A low LFC (close to the LCL) means the parcel doesn't need much help to become buoyant — convection initiates readily. A high LFC implies a significant cap and often explosive storms once something breaks it.