Anthropogenic Warming Weakens Mild Offshore Winds in Southern California but Not the Extreme Fire‐Weather Winds

This is the authors' abstract. We don't add key points for this paper.

Southern California's most destructive fires are driven by strong offshore winds, including the 2025 Los Angeles wildfires, among the deadliest in California's history. However, the influence of anthropogenic climate change (ACC) on extreme wind events remains unclear. Using high‐resolution simulations, we investigate the mesoscale katabatic pressure gradient, the primary thermodynamic driver of these winds. We show that this forcing arises from differential heating between interior and coastal regions, contributing to the strongest wind events and associated fire danger in recent decades. Using dynamically downscaled CMIP6 projections in which ACC weakens the average land–ocean temperature gradient, we find that this effect only reduces weak and moderate offshore wind events. Extreme events are unaffected. Observational analyses reveal this ACC fingerprint in the historical record. Together with robust warming‐driven increases in atmospheric aridity, these findings suggest that extreme wind‐driven wildfire threats in southern California will intensify despite weakened mean pressure gradients.