On Tropical Cyclone Fullness

Abstract A series of recent papers in Geophysical Research Letters and the Journal of Geophysical Research Atmospheres have explored the usefulness of a new “fullness” metric characterizing the ratio of the inner and outer core size of tropical cyclones and suggesting that this metric is better correlated with tropical cyclone intensity, and even intensification rate, than single size metrics. Given the potential importance of the fullness metric, we examine its dynamical significance in terms of the rotating‐convection paradigm, a new conceptual framework for understanding tropical cyclone behavior. We conclude that the silence of the fullness metric in characterizing the forcing of the overturning circulation by the aggregate effects of deep cumulus convection and the time evolution of this forcing raises questions about the value of the fullness metric as a physics‐based predictor of storm intensity.