Increased persistence of warm and wet winter weather in recent decades in north-western Europe

Changes in weather persistence have important implications for flood risk and regional climate resilience. In recent decades, the winter North Atlantic Oscillation index has shown a sustained shift toward more strongly positive values, exceeding the range projected by climate models under high greenhouse gas scenarios. Here we investigate whether this shift has influenced the persistence of warm and wet winter conditions in north-western Europe. We use daily temperature and precipitation records from weather stations across Europe and daily values of the North Atlantic Oscillation index from 1950–1980 and 1990–2020. Using quantile autoregressive models applied to the temperature data, we find significant increases in the persistence of warm weather. Moreover, we observe a rise in precipitation persistence. To assess the robustness of our findings, we also evaluate the influence of the Scandinavian teleconnection pattern and the Atlantic Multidecadal Oscillation. The increased persistence of warm and wet winter weather in north-western Europe increases the likelihood of prolonged wet spells and associated flood risk. Strongly positive phases of the North Atlantic Oscillation increased the persistence of weather events in northwest Europe between 1950-1980 and 1990-2020, amplifying the risk of persistent precipitation and flooding, according to a statistical modeling framework.