NOAA's National Centers for Environmental Information
Visit:NCEI U.S. Tornadoes
According to preliminary data from NOAA's Storm Prediction Center, during September, there were 37 preliminary tornado reports. This is exactly half the 1991-2010 average of 74 tornadoes for the month of September. Of the tornadoes that did form during September, many occurred within the coastal regions of several southeastern states including Florida, Georgia, South Carolina, North Carolina and Virginia.
Given the below average during September, the only days with 10 or more tornadoes occurred on September 1 and 17. On September 1, there were 10 tornadoes scattered across Texas, Arkansas, Missouri and Tennessee. These were mostly weaker tornadoes (EF-0 and EF-1) that produced minimal damage to homes, vehicles and infrastructure. There was one EF-2 tornado in central Arkansas that impacted a rural area with little structural damage. There were no fatalities associated with these tornadoes. On September 17, 14 tornadoes were reported across eastern North Carolina and South Carolina. These were weaker tornadoes (EF-0 and EF-1) that did minor damage to trees, vehicles and infrastructure. There were no fatalities associated with these tornadoes.
Did You Know?
Tornado Count
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:
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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.