Temperature Scaling of Tropical Cyclone Precipitation in the North Atlantic

Tropical cyclones (TCs) and their post-tropical (PTC) counterparts show contrasting structural and extreme precipitation responses to surface warming. Using a dynamically derived wind-based radius (r6) from ERA5 near-surface winds, we quantify storm size and extreme precipitation characteristics for North Atlantic cyclones from 2001-2024. TCs are compact systems that contract under warmer and moister conditions, with extreme precipitation metrics increasing by more than 20% K⁻¹ for 2-m air temperature and dewpoint. In contrast, PTCs expand after extratropical transition and show weak thermodynamic sensitivity, consist with baroclinic control and more diffuse precipitation. Translational speed and latitude further modulate these patterns: slower, low-latitude TCs sustain intense, localized precipitation under warming, whereas faster, higher-latitude PTCs produce broader, asymmetric precipitation fields. These findings highlight the combined thermodynamic and dynamical controls on cyclone precipitation and structure, demonstrating that TCs and PTCs respond differently to surface warming. The r6 metric offers a physically consistent approach to assessing how cyclone precipitation extremes evolve in a warming climate.