Abstract The role of upper‐level outflow in tropical cyclone (TC) rapid intensification (RI) remains poorly quantified compared to thermodynamic drivers. Combining high‐resolution satellite observations and statistical modeling, this study reveals distinct outflow dynamics and cloud properties differentiating RI from slow‐intensifying (SI‐1/SI‐2) TCs. A novel vortex flow ratio, defined as the ratio of tangential to radial wind, demonstrates RI TCs maintain a distinctly larger mean vortex flow ratio of 0.7, which is 1.8 (2.5) times higher than SI‐1 (SI‐2) TCs, correlating with deeper vortices and energy accumulation in the upper troposphere. RI TCs further exhibit a 10.8% (36.4%) greater radial decrease in ice cloud cover than SI‐1 (SI‐2) TCs, accompanied by a 4.9% (24.4%) greater radial increase in high cloud cover than SI‐1 (SI‐2) TCs, indicative of enhanced vortex contraction and outflow transporting hydrometeors. These findings identify the upper‐level vortex flow ratio and associated cloud radial variation as key intensification regime indicators.
Ou et al. (2025) studied this question.