Extratropical transition pathways of tropical cyclones and their associated storm intensity and destructiveness

Abstract

Tropical cyclones (TCs) undergoing extratropical transition (ET) can have widespread impacts; however, the differences in their evolutionary pathways remain incompletely understood. In this study, the cyclone phase space is applied to classify TCs in the western North Pacific from 1979 to 2022 into three distinct types. Type 1 exhibits the most pronounced asymmetry changes and retains the strongest surface winds, whereas Type 2 undergoes more modest asymmetry changes and maintains a weaker wind field. Type 3, in contrast, preserves a relatively symmetric wind field throughout the transition and occurs in a more baroclinic environment. Among the pathways, Type 1 demonstrates the highest post-transition destructiveness. Sensitivity analysis indicates that while most findings are robust across classification thresholds, Type 3 is particularly sensitive to threshold selection and requires careful interpretation. The present results enhance our understanding of ET variability and its implications for mid-latitude storm impacts. © 2025 Elsevier B.V., All rights reserved.