This analysis is based on preliminary data available from the Storm Prediction Center. Final tornado counts published by the Storm Prediction Center and NCEI's Storm Events Database might differ from this report. For a more detailed climatology, please visit our tornado climatology page.
According to data from NOAA's Storm Prediction Center, during May, there were 555 preliminary tornado reports. This is well above, more than double, the 1991-2010 average of 276 tornadoes for the month of May. In fact, based on preliminary data, May 2019 eclipses May 2003 for the most reported May tornadoes on record. Moreover, May 2019 has the second highest number of reported tornadoes for any month on record, only behind April 2011, which produced several tornado outbreaks across the Southeast and Midwest. A majority of the May 2019 tornadoes occurred over many of the Central Plains and Midwestern states in three multi-day events (May 17-18, May 20-22 and May 26-29).
In addition, the May 2019 tornado production was persistent, as 28 of the 31 days in May had at least one tornado reported. Moreover, this resulted in a daily average of 19.8 tornadoes per tornado-producing day. However, the majority of May's tornadoes occurred during the second half of the month. To the credit of NOAA forecasts, there were remarkably few tornado-related fatalities given the high number of tornadoes during the month of May.
The first tornado outbreak occurred during May 17-18, in which 67 tornadoes developed. On May 17, many of the tornadoes formed in western Nebraska and Kansas. On May 18, the tornadoes were more scattered affecting Texas, Oklahoma, Arkansas and Louisiana. There were no reported fatalities associated with these tornadoes.
The second tornado outbreak of the month occurred during May 20-22, in which 119 tornadoes developed based on preliminary reports. This outbreak consisted of 35, 41 and 43 reported tornadoes, respectively, during the 3-day event. A majority of these tornadoes were clustered from west central Texas through Oklahoma and into Missouri. This multi-day outbreak of tornadoes caused property damage and injuries and three reported fatalities resulting from an EF-3 tornado.
The third and most prolific tornado outbreak of the month occurred during May 26-29, in which 190 tornadoes developed. This outbreak consisted of 42, 77, 26 and 45 reported tornadoes, respectively, during the 4-day event. This was a widespread outbreak of tornadoes from eastern Colorado to Pennsylvania, with more than one dozen states impacted. Of particular note was the EF-4 tornado that produced heavy damage near Dayton, Ohio on May 27. There was just one tornado-related fatality in Ohio during this 4-day outbreak despite the large number of tornadoes.
Did You Know?
Final monthly tornado counts are typically less than the preliminary count. This can be due to some phenomena being inaccurately reported as tornadic activity or a single tornado being reported multiple times. Tornado accounts are reported to the local National Weather Service forecast offices who are responsible for going into the field and verifying each tornado reported. This process often takes several months to complete. Once all reports have been investigated, the final count is published by the Storm Prediction Center (SPC).
The Tornado Monthly Climate Reports are written using the preliminary numbers because the final data is not available at the time of production. Historically, for every 100 preliminary tornado reports, at least 65 tornadoes are confirmed. An error bar is depicted on the tornado count graphic representing this uncertainty in the preliminary tornado count.
The following U.S. studies performed by SPC meteorologists offer deeper context and discussion regarding the frequency and distribution of tornado intensity climatologies:
- Edwards, R., H. E. Brooks, and H. Cohn, 2021: Changes in tornado climatology accompanying the Enhanced Fujita scale. J. Appl. Meteor. Climatol., 60, 1465-1482, DOI: 10.1175/JAMC-D-21-0058.1.
- Mccarthy, Daniel & Schaefer, Joseph. (2004). Tornado trends over the past thirty years. paper presented at 14th Conference on Applied Meteorology.