Initiation: moisture, instability and lifting is needed for deep convection to develop
However, instability is often not well predicted by models.
Outflow from earlier convection may focus lifting (none of the models now handle outflow well).
The surface data may be too sparse to detect some important low level boundaries.
- Satellite and radar helps fill in the gaps.
The scale of the lifting may be too small to be resolved by the model.
A Cap (the negative area on a sounding) may inhibit development. Convective inhibition is often not well predicted by the models