CIN
Thunderstorms Convective Inhibition
CIN describes the energy needed to overcome a restraining layer of air. This inhibition can prevent thunderstorms even when buoyant energy would be available higher up.
The lid above warm air
A lifted parcel may initially be colder and denser than its surroundings, so it does not keep rising on its own. Convective Inhibition, or CIN, describes the work per kilogram needed to cross this barrier and reach a level where free ascent is possible.
Check the sign
The unit is J/kg. Some products display negative values, others positive magnitudes. A magnitude of 100 J/kg indicates stronger inhibition than 10 J/kg when the method and starting parcel are the same. Without the legend, the sign can be misleading.
How inhibition changes
- Sunshine can warm near-surface air and increase its buoyancy.
- A front or converging winds can provide extra lift.
- Changing temperature and moisture profiles can strengthen or weaken the barrier.
Read CIN together with CAPE
CAPE describes potential energy, while CIN describes the initial obstacle. CIN does not itself store storm energy. Strong inhibition also does not guarantee a particularly severe storm later. The lid may simply stay on.