pretornadic

Pretornadic is an adjective used in meteorology to describe the phase of a convective storm in which a tornado is possible but not yet observed. It refers to conditions and processes that precede tornadogenesis, including developing rotation within a thunderstorm and environmental factors such as wind shear and instability that favor tornadic development. The term is commonly used in storm-scale analysis, field campaigns, and weather reporting to distinguish storms that have not yet produced a tornado from those that have already become tornadic.

Typical pretornadic features include a developing mesocyclone evidenced by radar velocity couplets, organization into a supercell with a persistent updraft, and visible indicators such as funnel clouds or a wall cloud while the tornado is still absent. Radar signatures and sustained rotation, even without a confirmed tornado, are commonly discussed in this context.

In forecasting and warning operations, recognizing pretornadic characteristics helps meteorologists monitor for potential tornadogenesis and issue timely alerts. Not all pretornadic storms produce tornadoes; some dissipate or fail to tighten rotation, ending the potential for tornadic development.

See also: Tornado, Tornadogenesis, Mesocyclone, Supercell, Funnel cloud.