Convective Cold Pools and Their Influence on Hurricane Intensification: A Case Study of Hurricane Helene (2024)

Convective cold pools—regions of cooled, dense air formed by evaporating rainfall—play a pivotal role in modulating atmospheric convection, yet their influence on hurricane dynamics remains insufficiently explored, especially in real-world simulations. In this study, we investigate the role of convective cold pools in the evolution of Hurricane Helene (2024) using a modified version of the Hurricane Weather Research and Forecasting model (HWRFxUT). Hurricane Helene formed in the Caribbean and intensified to become one of the deadliest hurricanes in recent history, offering a unique opportunity to study cold pool–hurricane interactions. The model setup includes nested domains at 9 km, 3 km, and 1 km resolution over the contiguous United States and employs a set of sensitivity experiments. Specifically, the rainfall evaporation rate in the Ferrier–Aligo microphysics scheme is altered by 20%, 50%, 150%, and 180% relative to a control run to assess how changes in cold pool characteristics affect the storm.

Cold pools are identified using a watershed algorithm, enabling systematic comparisons of their spatial extent and thermodynamic properties across all experiments. Analyses show that modifications to the rainfall evaporation rate significantly influence the development and distribution of cold pools in the vicinity of Hurricane Helene, with consequent impacts on storm rainfall, intensity, and track. The results underscore how changes in cold pool strength can yield marked differences in hurricane structure and evolution. These findings highlight the importance of accurately representing cold pool processes in numerical models to enhance tropical cyclone forecasts and underscore the need for continued research into this critical yet under examined aspect of hurricane physics.