Decreasing trends in consecutive‐day tornado events in the United States

Days with many tornadoes in the United States have become more common over time. These days tend to occur in consecutive‐day tornado events, but trends in the characteristics of consecutive‐day tornado events have not been documented. The Mann–Kendall trend test and Theil–Sen slope estimator were used in this study to detect trends and estimate rates of change over time in multiple metrics of consecutive‐day tornado events. Results show that the number of consecutive‐day events, the number of days occurring in consecutive‐day events, and the number of tornadoes occurring in consecutive‐day events have decreased over time. The percentages of annual tornadoes and tornado‐days occurring in consecutive‐day events have also decreased over time. These trends suggest that the percentage of tornadoes occurring on isolated days has, alternatively, increased over time. Over time, the numbers of consecutive‐day tornado events and the numbers of tornadoes occurring in these events have decreased. This has, in turn, decreased the percentage of annual tornadoes occurring in consecutive‐day events. These decreases suggest that the percentage of annual tornadoes occurring on isolated days has increased over time.