Slow environmental evolution and fast inner-core reorganization during Super Typhoon Mawar's eyewall replacement cycle

Eyewall replacement cycles (ERCs) can interrupt tropical-cyclone intensifica- tion within hours while the environment evolves over days. We test whether such reorganization leaves a robust wind-tendency signal once slowly varying environmental effects are represented. We analyze Super Typhoon Mawar (2023) using 3-hourly best-track intensity, seven environmental records, six geolocated 88.2–89.0-GHz brightness-temperature swaths, and an independent operational chronology. Inner-core morphology reorganized over an estimated 3–6 h, compared with 24–48 h for the sampled environment, and the trailing 24-h rapid-intensification metric lagged both weakening and renewed strength- ening. A reduced equation decomposes wind tendency into environmental and morphology-conditioned terms. In a 2000-member perturbation ensemble with no imposed coefficient signs, the closed-state residual was negative in 99.3% of members, whereas the closing-state sign was not robust. State conditioning reduced calibration RMSE from 11.3 to 8.7kt, but the 42-h post-ERC extrapolation RMSE was 10.2 versus 8.9 kt for the environmental baseline. The paired 95% block-bootstrap interval for this difference was −4.4 to 6.6 kt. Because the structural correction was zero throughout this interval, the extrapolation cannot independently test the inferred ERC-state residual. Mawar therefore supports a case-specific slow–fast description, but not process attribution or added forecast skill. Independent-storm validation, objective microwave metrics, and closed dynamical budgets are required.