Definition
A rotating, cone-shaped column of cloud extending downward from the base of a thunderstorm but not reaching the ground. It contains violently rotating winds and is the visible portion of a vortex that has not yet made surface contact. If the rotating column touches the ground, it becomes a tornado; if it touches water, it becomes a waterspout.
Plain English
A spinning, funnel-shaped cloud hanging down from a thunderstorm that has not yet reached the ground. It is a tornado in the making — if it touches down, it becomes one.
Context Anchor
Seen in aviation weather discussions, weather briefings, and visual weather avoidance near thunderstorms.
Derivation
‘Funnel’ comes from the Latin ‘infundibulum,’ meaning a vessel for pouring liquids — narrow at the bottom, wide at the top. The cloud is named for its shape, which mirrors that of a kitchen funnel held upside down.
Why Pilots Care
Indicates possible tornado formation and requires immediate avoidance to maintain safety.
Grounding Statement
Picture a dark storm cloud with a rotating cone hanging below it, not yet touching the ground.
Intuition Check
A funnel cloud is not automatically a tornado. In this aviation weather use, it becomes a tornado only when the rotating column of air is in contact with the ground or water surface.
Example Sentence 1
The pilot diverted well around the storm cell after ATC reported a funnel cloud descending from its base.
Example Sentence 2
ATC reported a funnel cloud near the approach path, so the flight held until the weather cleared.