Lifecycles of Coastal Urban Thunderstorms from an Observational and 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 metropolitan area in the United States, frequently experiences sea breeze fronts (SBFs) and intense convective thunderstorms, which makes it an ideal region to study coastal urban-precipitation modification. The primary goal of this research is to understand the dynamics of the built environment -particularly its urban heat island (UHI) and building mechanical effects- in altering these coastal and cloud processes. An isolated thunderstorm sea breeze case from the summer 2022 NSF-funded Convective-clouds Urban Boundary-layer Experiment (CUBE) and DOE Tracking of Aerosol Convective Interaction Experiment (TRACER) field campaigns was simulated and evaluated against field campaign and radar observations. The tool used in the current investigation is the urbanized Weather Research and Forecasting (uWRF) model linked to the MYNN scheme. Results illustrate the formation of a UHI “plume” circulation in response to both urban SBF bowing and downwind rainfall. The role of this circulation in vertical moisture transport and updraft enhancement is explored. Future work will use Lagrangian storm-cell tracking software to understand how these clouds are changed by traversing the urban environment.