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Parameters & indices#sounding#moisture#tornado

LCL — Lifting Condensation Level

Also: LCL

At a glance

The height where cloud base forms if you lift a parcel from the surface. Lower LCLs mean wetter, cooler air near the ground — and they correlate with tornado potential.

Deep dive

Computed from surface temperature and dew point: roughly LCL (m) ≈ 125 × (T − Td) in °C. A 5 °C spread gives cloud base around 625 m; a 15 °C spread pushes it past 1.8 km.

For tornadic supercells, forecasters want LCL heights below ~1000 m — drier environments make it harder for a mesocyclone to reach the ground before evaporative cooling chokes the RFD. UK summertime supercells usually have low LCLs due to maritime moisture; our problem is shear, not moisture.

Low LCL + strong low-level SRH + moderate CAPE = tornado-favoured regime (see stp).