Changes in Flood Frequency and Seasonality Across Midwestern U.S. Watersheds Under a Warming Climate: Insights From Convection‐Permitting Climate Simulations and Physics‐Based Hydrologic Models

Abstract We combine CONUS404 convection‐permitting climate simulations with the physics‐based WRF‐Hydro model to assess how climate warming may influence flood frequency and seasonality across the Midwestern United States. This framework captures interactions among precipitation, soil moisture, and snowpack that shape flood generation. Both simulated warming and historical records show a regional shift toward more extreme warm‐season, rainfall‐driven floods. This regional signal, however, does not translate uniformly to individual watersheds, where flood responses reflect not only warming but also the influence of subregional climate variability and sampling uncertainty. Local flood‐frequency changes thus remain highly uncertain despite the thermodynamic tendency toward stronger convective precipitation. Ensembles of convection‐permitting simulations are needed to constrain plausible local outcomes. These findings suggest that flood risk communication under climate warming should distinguish broad climate‐driven tendencies from uncertain local responses.