NOAA's National Centers for Environmental Information
Visit:NCEI U.S. Tornadoes
According to data from NOAA's Storm Prediction Center, during November, there were 17 preliminary tornado reports. This is well below, about one-third, of the 1991-2010 average of 58 tornadoes for the month of November. This represents the lowest count of monthly tornadoes for any month so far this year.
The vast majority (14) of these November tornadoes occurred across northern Illinois on November 10 in association with a severe weather system. There was also an isolated tornado in eastern Oregon on the same day. All of these tornadoes were rated as EF-0 or EF-1, with scattered damage to structures, homes, vehicles and infrastructure. There were no fatalities for these tornadoes. Additionally, there were no tornado fatalities during the month of November. This continues a 3-month continuation where no tornado fatalities have occurred dating back August.
There was only one other day during the month of November that had any reported tornadoes. This was on November 14, in which two EF-1 tornadoes impacted central Arkansas damaging homes and causing several injuries but no fatalities.
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.