Tropical Cyclone Stalling Shifts Northward and Brings Increasing Flood Risks to East Asian Coast

Abstract

Tropical cyclone (TC) stalling has been widely perceived to yield a greater threat of flooding. Understanding the effect of stalling and its long-term trends will enhance adaptation strategies to cyclone-associated disasters. We show that stalling prolongs western North Pacific TCs to live 24 hr longer and produces 23% greater 24-hr rainfall accumulations in a more concentrated area, which is more prominent over a 72-hr rolling period. More importantly, we discover a northward migration of TC stalling (∼0.7°N decade−1) over 1979–2020, bringing increasingly higher flood risks to the highly-populated East Asian coast. Further diagnoses suggest the role of binary cyclone interactions in TC stalling, whereby the second larger TC slows down the smaller one by weakening the northwestward steering flows. The northward shift of TC stalling can be explained by a similar trend in binary TC cases and environmental fields. Our findings are robust across various best track and precipitation products.