Waterspout

Fair-weather waterspouts form under rapidly growing cumulus clouds in warm, moist air — common around the UK coast in late summer and autumn. They develop from the water surface upward and are generally weak (EF0 equivalent), short-lived, and diffuse. The visible funnel is condensation; the real rotation is broader.

Tornadic waterspouts are bona fide supercell tornadoes over water. Any waterspout making landfall is treated as a tornado for classification and damage surveying.

In the UK, coastal waterspouts are most frequent in the Western Approaches, Bristol Channel, and around the Isle of Wight in September–October. They can move inland rapidly — the Bognor Regis case (2000) tracked several kilometres ashore.