Tuba
From Glossary of Meteorology
tuba
(Obsolete; commonly called funnel cloud;
also called pendant cloud, tornado cloud.) In meteorology, a cloud column or inverted cloud cone, pendant from a cloud base. This supplementary feature occurs mostly with cumulus and cumulonimbus; when it reaches the earth's surface it constitutes the cloudy manifestation of an intense vortex, namely, a tornado or waterspout.
also called pendant cloud, tornado cloud.) In meteorology, a cloud column or inverted cloud cone, pendant from a cloud base. This supplementary feature occurs mostly with cumulus and cumulonimbus; when it reaches the earth's surface it constitutes the cloudy manifestation of an intense vortex, namely, a tornado or waterspout.
See cloud classification.