Tornado Studies | The Patterns Of Tornadoes In The U.S.
This will be another post about tornado studies. We will talk about the patterns of U.S. tornadoes using 5 maps. Learn more further in the post…
There are a few things that the majority of the U.S. population knows about tornado patterns, like that tornado season is in the spring. This is pretty basic weather knowledge and there are still variations in the amount of facts known by the public. I looked through many tornado climatology maps online and here are some interesting graphs. *some may be outdated*
This post is all about U.S. tornado patterns.
American Tornado Patterns
Max. Probability Days for Significant Tornadoes
Our first tornado pattern map will be the days of the year with the most significant tornadoes from 1921 to 1995. The numbers on the side are the days of the year (not accounting for 02/29 on Leap Years) in the numerical sense. For example, the 91 on the side is April 1st, because April 1st is the 91st day of the year. So, let’s start. One of the first trends I noticed was how there was a little bit of a pattern. The earliest max probability is mainly in Dixie Alley, and when you go further away from Dixie Alley, the dates generally go further in the year. Another way to look at this is from Tornado Alley. In Tornado Alle, the farther you go north, the later the dates are.
Total Days with Tornadoes 1953-2020
This is a graph of the total number of EF-5s from 1953-2020. When I looked at this graph, after a while, I noticed something interesting. When there are two complete cycles on the graph, where the tornado days go up and down. This isn’t the most interesting thing though. When you look at when the two cycles start climbing to the peak, the years are VERY similar. For this case, I will use the end of the very high stage. For the first cycle, it is 12 years. The second, it is 13! So some people would say this is just a random occurrence. But some of those people might change their minds after they see THIS.
When you do the same thing for the decline, you find 12 & 15 years! So what I am saying is that maybe there is a full cycle of tornado days that is 24-30 years long. I just noticed this and created a quick not evidence-based theory. This might have a scientific reason, but I wouldn’t know of that. This is just a random theory so do not use this theory for any scientific purposes. The last note that I would like to add is that the peaks were within a few years of major tornado events like the 1974 Super Outbreak and the 1999 Moore Tornado.
Tornado Warnings 2012-2022
This map is of all the tornado warning events from 2012 to 2022. While this may not directly be a tornado pattern map, it can still say some things. Like when you see that the most tornado warning events are in SW Dixie Alley. That shows us that based on what the NWS spotted, most storms with tornadic potential of any NWS office are right there. Another thing to spot is the offices with over 200 tornadoes are mostly in the Midwest, Tornado Alley, and Dixie Alley
2023 Tornado Reports
It is a map of all the tornado reports of 2021 *not actual tornadoes, the reports*. You can see the tornadoes are concentrated in three areas. One of those areas is the WY-NE-CO border area, the second is the eastern part of the Upper Midwest, and the last is Dixie Alley. The lower Tornado Alley area does have some tornadoes to see but there aren’t many reports. There are also probably many tornadoes that humans just do not see and because of that, go unreported. One place on the map I see that is in Central & Upper Wisconsin. There is just a stop to all the tornadoes up there probably for that reason. The elevation does rise quite a bit up there too though.
Tornado Days Per Year Within 25 Miles
The final map that I will show you is one of tornado days per year within around 25 miles of any given point. This one might be much different today since this one is from 2003-2012. In this graph, the highest number in in South-Central MS, with a number of 5. Other places with a high number on the map include the Denver area and Northern Alabama. The shaded areas cover a lot of the area within the 48 states. The heart of Dixie Alley can easily be seen on the map but not as much for Tornado Alley. This map doesn’t explain everything about U.S. tornadoes though.
