Unraveling the roles of jet streams on the unprecedented hot July in Western Europe in 2022

Abstract Western Europe experienced an unprecedentedly hot July in 2022, which significantly impacted ecosystems and society. Our observational and numerical modeling study reveals that this event was influenced by anomalous North Atlantic and Eurasian jet streams. The northeastward shift of the North Atlantic jet stream, driven by sea surface temperature gradients, and the curving of the Eurasian jet stream, affected by rainfall anomalies in Pakistan, enhanced atmospheric subsidence over western Europe. This research highlights the crucial role of the synergistic behavior of the North Atlantic and Eurasian jet streams in driving extreme heat over Western Europe. Furthermore, CMIP6 climate model projections suggest that under the SSP585 scenario, similar jet stream configurations could lead to even more intense extreme temperatures (~7.02 ± 0.61 °C) compared to the current climatological mean.