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Sharpening of cold-season storms over the western United States


Winter storms are responsible for billion-dollar economic losses in the western United States. Because storm structures are not well resolved by global climate models, it is not well established how single events and their structures change with warming. Here we use regional storm-resolving simulations to investigate climate change impact on western US winter storms. Under a high-emissions scenario, precipitation volume from the top 20% of winter storms is projected to increase by up to 40% across the region by mid-century. The average increase in precipitation volume (31%) is contributed by 22% from increasing area coverage and 19% from increasing storm intensity, while a robust storm sharpening with larger increase in storm centre precipitation compared with increase in storm area reduces precipitation volume by 10%. Ignoring storm sharpening could result in overestimation of the changes in design storms currently used in infrastructure planning in the region.

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Fig. 1: Response of extreme precipitation events to future climate change over the western United States.
Fig. 2: Responses of composited storms to future climate change.
Fig. 3: Future changes for different storm metrics.
Fig. 4: Constructed future storms over the western United States.
Fig. 5: Changes in infrastructure design ARFSC.

Data availability

The precipitation object dataset is available and deposited at Zenodo ( The intermediate data necessary to reproduce the results are deposited at Zenodo (

Code availability

The codes used to generate the figures in this study are available at Zenodo (


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This research is supported by the US Department of Energy Office of Science Biological and Environmental Research as part of the Regional and Global Model Analysis and Multi-Sector Dynamics programme areas. The WRF simulations were supported by the Strategic Environmental Research and Development Program (SERDP) under contract no. RC-2546 and performed using computing resources of the Pacific Northwest National Laboratory Research Computing and the National Energy Research Supercomputing Center (NERSC), which is supported by the DOE Office of Science under contract no. DE-AC02-05CH11231. Pacific Northwest National Laboratory is operated for the Department of Energy by Battelle Memorial Institute under contract no. DE-AC05-76RL01830.

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Authors and Affiliations



X.C. and L.R.L. designed the research. X.C. performed the analysis, drew all figures and wrote the first draft of the paper. L.R.L. provided comments on the analysis and contributed to the writing of the paper. All authors discussed and commented on the first draft of the paper. X.C. and L.R.L. revised the manuscript with inputs from other authors.

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Correspondence to Xiaodong Chen or L. Ruby Leung.

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The authors declare no competing interests.

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Nature Climate Change thanks Dongyue Li, Deepti Singh and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–6 and Table 1.

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Chen, X., Leung, L.R., Gao, Y. et al. Sharpening of cold-season storms over the western United States. Nat. Clim. Chang. 13, 167–173 (2023).

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