Bow Echo - On radar, a line of thunderstorms that bulges outward into a bow shape. Damaging thunderstorm winds often occur near the center of a bow echo. Convection - In meteorology, this term is used most often to describe the vertical transport of heat and moisture, especially by unstable air. Showers and thunderstorms are forms of convection. Downburst - A strong downdraft resulting in an outward burst of damaging winds on or near the ground.
Downburst winds can produce damage similar to a strong tornado.
Funnel Cloud - A funnel extending from the base of a towering cumulus or cumulonimbus cloud, associated with a rotating column of air that is NOT in contact with the ground. The terms funnel cloud and tornado are NOT interchangeable. A hook is often associated with a mesocyclone, and indicates favorable conditions for tornado development. Mesocyclone - A region of rotation, typically 2 to 6 miles in diameter, often found on the southwest part of a supercell. The circulation of a mesocyclone covers an area much larger than the tornado which MAY develop within it.