A term coined by Brooks (1949) to describe a surface low pressure area in a convective storm that, with its attendant winds, has a radius of about 8–16 km and is associated with, but is larger than, a tornado. Starting with Agee (1976), the tornado cyclone has been redefined as a distinct circulation with a scale larger than that of the tornado but smaller than that of the mesocyclone (although embedded within it and smaller in scale than the mesolow). The intermediate-scale tornado cyclone is sometimes inferred from high-resolution Doppler radar observations, but at other times it is not apparent.