The Influence of North Pacific Variability on Recurving EPAC Tropical Cyclones

Enhancing our understanding of the atmospheric dynamics governing the recurvature of tropical cyclones (TCs) in the eastern North Pacific (EPAC) is crucial for improving track forecasting accuracy and mitigating potential impacts along the Western North American coastline. This study investigates the linkages between Rossby wave breaking (RWB), large-scale flow patterns, and the recurvature of EPAC TCs, with a specific focus on unraveling the underlying dynamic processes across the North Pacific (NPAC) that drive EPAC TC recurvature. By investigating these relationships, we aim to acquire valuable insights into the dynamical mechanisms responsible for EPAC TC recurvature, contributing to enhanced forecasting capabilities and improved hazard mitigation strategies.

To achieve this objective, we will utilize 6-hourly best-track data from the National Hurricane Center's (NHC) HURDAT2 spanning the period from 1979 to 2021. By using the methods detailed in Archambault et al. (2013), we will identify EPAC TCs that undergo recurvature. To detect RWB events favorable for downstream EPAC TC recurvature, we will utilize a RWB tracking algorithm formulated by Bowley et al. (2019) and apply it to the ERA5 reanalysis data.

In addition to identifying and characterizing TC recurvature events, storm-relative composite analyses of large-scale flow patterns will be constructed and linked to EPAC TC recurvature events using ERA5 reanalysis. We will also present a representative case study to illustrate the methodology employed in this study and to showcase a notable instance of EPAC TC recurvature. We anticipate that our findings will provide valuable insights into the chosen methodology, allowing us to further elucidate the clarity and applicability of our research.