Lifecycles of Coastal Urban Thunderstorms from a Modelling Perspective

Coastal cities across the world have been increasingly exposed to severe storms which threaten and strain their populations, infrastructure, and economies. Despite nearly 40% of the global population residing in these cities, the processes that drive coastal urban rainfall modifications are poorly understood. During its warm season Houston, the fourth most populated city in the United States, frequently experiences intense and isolated convective thunderstorms making it an ideal region to study these urban-storm interactions. The primary goal of this research is to understand the dynamic role of the built environment -particularly its urban heat island (UHI) and building mechanical effects- in altering these coastal and convective processes. Sea breeze thunderstorm cases, from the summer 2022 DOE Tracking of Aerosol Convective Interaction Experiment (TRACER) and NSF-funded Convective-clouds Urban Boundary-layer Experiment (CUBE) field campaigns, were simulated using an ensemble of microphysics schemes with the fully urbanized Weather Research and Forecasting model (uWRF). Model performance was validated with field campaign and NEXRAD observations. Model results illustrate how urban thermal and momentum tendencies impact sea breeze front propagation and circulation. Ensemble results will connect the environmental feedback between the urban boundary layer and thunderstorms, especially its microphysical and rainfall properties from an Eulerian viewpoint. Future work will utilize a Lagrangian storm-cell tracking algorithm across ensemble members to understand how this urban rainfall modification may differ between clouds of varying maturity.