Linking weather regimes to the variability of warm-season tornado activity over the United States

Graber, Matthew; Wang, Zhuo; Trapp, Robert J.

doi:https://doi.org/10.5194/wcd-6-807-2025

Articles | Volume 6, issue 3

https://doi.org/10.5194/wcd-6-807-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/wcd-6-807-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 6, issue 3

Research article

|

28 Jul 2025

Research article |

| 28 Jul 2025

Linking weather regimes to the variability of warm-season tornado activity over the United States

Matthew Graber, Zhuo Wang, and Robert J. Trapp

Supplement

https://doi.org/10.5194/wcd-6-807-2025-supplement

Data sets

ERA5 hourly data on pressure levels from 1940 to present Hans Hersbach et al. https://doi.org/10.24381/cds.bd0915c6

ERA5 hourly data on single levels from 1940 to present Hans Hersbach et al. https://doi.org/10.24381/cds.adbb2d47

Severe Weather Database Files (1950-2024) Storm Prediction Center https://www.spc.noaa.gov/wcm/#data

2018 Preliminary Killer Tornadoes P. Marsh and J. Guyer https://www.spc.noaa.gov/climo/torn/STATIJ18.txt

2019 Preliminary Killer Tornadoes P. Marsh and J. Guyer https://www.spc.noaa.gov/climo/torn/STATIJ19.txt

2020 Preliminary Killer Tornadoes P. Marsh https://www.spc.noaa.gov/climo/torn/STATIJ20.txt

2021 Preliminary Killer Tornadoes M. Elliott https://www.spc.noaa.gov/climo/torn/STATIJ21.txt

2022 Preliminary Killer Tornadoes M. Elliott https://www.spc.noaa.gov/climo/torn/STATIJ22.txt

2023 Preliminary Killer Tornadoes M. Elliott https://www.spc.noaa.gov/climo/torn/STATIJ23.txt

Model code and software

Matt0604/Kmeans: Weather Regimes Graber et al. 2025 (Version 1) Matthew Graber https://doi.org/10.5281/zenodo.16043868

Short summary

This study identifies five warm-season weather regimes (WRs) to investigate the link between tornado activity and large-scale atmospheric circulations. Certain WRs strongly affect tornado activity due to their relationship with the environment. When a WR that positively affects tornado activity persists over multiple days, it further increases the tornado activity probability. The links found highlight the potential application of WRs for developing better seasonal prediction of tornadoes.