It is shown that axisymmetric steady-state theory, generalized to permit gradient-wind and hydrostatic imbalance, provides a reasonably accurate value for the maximum wind speed Vmax of a mature TC up to surprisingly high levels of inner-core convective asymmetry (CA). The smallest values of CA are found to coincide with the highest degrees of imbalance (largely connected to supergradient flow) near the radius of maximum wind. On the opposite end of the spectrum, an excessive level of CA coincides with substantial violation of the key theoretical assumption of slantwise convective neutrality in the main updraft of the basic state. A reliable curve-fit is obtained for the anticorrelation between a simple measure of CA and Vmax normalized to a classic estimate of its balanced potential intensity that is based solely on environmental conditions and air-sea interaction parameters. The importance of imbalance in simulated TCs whose wind speeds are within observational limits is assessed.
This work is supported by NSF grant AGS-1101713.