Tail cloud

From Glossary of Meteorology

tail cloud

Colloquial expression for a horizontal cloud band, often laminar and tube-shaped, but sometimes ragged and turbulent, that is attached to a wall cloud.

Fujita, T. 1959. A detailed analysis of the Fargo tornadoes of June 20, 1957. U.S. Wea. Bur. Res. Paper 42. p. 15.