Rapid versus slow intensification of idealized tropical cyclones using soundings from reanalysis

Abstract Low vertical wind shear and high mid‐tropospheric humidity are accepted to usually be conducive for the rapid intensification of tropical cyclones (TCs). Climatologically averaged environmental wind and moisture profiles around intensifying TCs are used to be more representative of TC environments than previous idealized studies. The structural and thermodynamic differences between ensembles of rapidly (RI) and slowly (SI) intensifying storms are analyzed. On average, RI storms have lower vertical tilt, are more symmetric, and less ventilated at onset than SI storms. SI is characterized by abundant downdraft ventilation left of shear and inner‐core radial ventilation upshear right. RI events contain more points with greater reflectivities and updrafts compared to SI events, which have more points with lower reflectivity values and downdrafts. Despite these significant differences at onset, the RI and SI ensembles are nearly identical just 24 hours prior. Most notably, the rapid vertical alignment and symmeterization of precipitation in the 12 hours prior to onset was found to be a better indicator of RI versus SI. This result suggests that it is the evolution of these variables that provides a signal to the expected intensification rate, and not simply a standalone value or pattern.