Characteristics of precipitation associated with post-tropical cyclones in the North Atlantic

ETCs share characteristics with frontal cyclones, such as faster translation velocities and larger radii than TCs. Hourly precipitation data from Integrated Multi-satellitE Retrievals for Global precipitation measurement ( IMERG) (2001–2020) shows lower intensity during ETC phases compared to TC phases but with broader areal coverage – precipitation shields -, with ETCs consistently producing more total rainfall over 24 h.

The centroid of precipitation regions during ETC phases shifts northeast of the cyclone centers for short-duration rainfall and west-southwest for longer durations, indicating widespread precipitation further from the cyclone centre. We found asymmetric precipitation distributions favoring the left side of the cyclone track during ETC phases, especially for lower-intensity events. Our results provide valuable insights into the evolving nature of PTCs, and their impact on precipitation patterns, which are crucial for hazard assessment models and mitigation strategies to safeguard communities and minimize the risks associated with these potential hazards.