Climate Models Tend to Underestimate Scaling of UK Mean Winter Precipitation With Temperature

Abstract Changes to seasonal precipitation can have dynamical and thermodynamic origins and disentangling these processes is challenging. To evaluate observed changes in UK winter precipitation from 1901 to 2023, we separate the signal into dynamical and non‐dynamical components by applying a dynamical adjustment using European weather patterns. We find long‐term changes in the non‐dynamical component are tied to temperature, with a 7% increase in UK winter precipitation per degree of local warming, in line with expected increases in atmospheric moisture content. We find this significant increase in non‐dynamical winter precipitation is attributable to anthropogenic forcing according to the CMIP6 global climate model simulations. Notably, most CMIP6 models produce a much weaker intensification of the non‐dynamic (thermodynamic) component relative to observations, with a model ensemble mean scaling of 4% °C −1 . The results show that projections based on CMIP6 models could underestimate the scaling of precipitation with temperature and increase in flood risk.