The 6 June 2020 Western U.S. Derecho

In the morning hours of 6 June 2020, a complex of severe thunderstorms formed in southeastern Utah. These thunderstorms organized into a northeastward-propagating line that produced severe winds over a large swath of eastern Utah, northern Colorado, eastern Wyoming, western Nebraska, western South Dakota, and southwestern North Dakota before finally dissipating, easily meeting derecho criteria. In total, 339 severe wind reports (67 damage and 272 measured, including 44 significant severe gusts), 12 severe hail reports ranging from 1.00 to 1.75 inch diameter, and 2 tornado reports related to the derecho were recorded by the Storm Prediction Center. The maximum wind report was a 96 kt gust at Winter Park, CO (NWS Boulder, 2020).

This derecho is especially notable as only two other derechos have been documented west of the Great Plains (Corfidi et al. 2016), and none have successfully crossed the Continental Divide. This research will investigate the meteorological factors that contributed to the formation, persistence, and intensity of this particular derecho, including synoptic-scale patterns and mesoscale influences.

Corfidi, S. F., R. H. Johns, and M. A. Darrow, 2016: The Great Basin Derecho of 31 May 1994. Wea. Forecasting, 31, 917–935, https://doi.org/10.1175/WAF-D-15-0178.1.

National Weather Service Boulder, 2020: June 6 2020 Derecho. Accessed 6 September 2023, https://www.weather.gov/bou/20200606Derecho.