Quantification of the role of urbanization in changing the rainfall associated with tropical cyclones affecting Charlotte, North Carolina

The intensity and severity of tropical cyclones (TCs) continue to rise in the United States, with urban areas enduring the most damage, especially those close to the coast. However, much less is known about the impact of urban areas on changing the rainfall associated with these storms. To address this research gap, we focus on Charlotte, North Carolina, and explore the impact of urban areas on TC rainfall modification. We analyze five storms [Hurricane Ivan (2004), Tropical Storm Alberto (2006), Hurricane Florence (2018), Hurricane Michael (2018), and Hurricane Zeta (2020)] and use the Weather Research and Forecasting (WRF) model to quantify whether, the extent to which, and how urban areas can change TC rainfall. We find that the city's role is not uniform across all TCs. More specifically, urbanization notably impacts rainfall associated with stronger and wetter storms by increasing urban surface roughness and surface warming, as in the case of Hurricane Florence. However, the urban modification is not prominent for weaker storms associated with lower total rainfall, with the signal of change comparatively muted. This study expands the knowledge of TC rainfall modification by urban factors and provides critical information towards our future adaptation and mitigation strategies.