The name Instant Occlusion results from the resemblance of the mature stage of development of the cloud system with that of an Occlusion. But the meteorological background of the development is completely different from an Occlusion process where warm air is lifted from the surface (see
Occlusion: Warm Conveyor Belt Type
). The process of the Instant Occlusion is characterized by the mergence of a distinct cold air, Comma-like cloud feature
) with a cloud band associated with the polar front (Cold Front).
The adjective instant represents the fact that the Occlusion appearance is assumed suddenly without the usual development at a front.