Lack of correlation between tornadoes and temperature increase in the USA

Guest essay by Alberto Z. Comendador

Temperatures in the USA have generally increased since the 1950s. Of course, anything that mostly increases over time will have a positive correlation with everything else that also increases; in the USA this includes tornado counts. And of course most correlations are utterly meaningless and devoid of causation. For a hilarious take on the issue, see spurious correlations.

The problem , as NOAA itself says, is that there is a bias: just because we observe more tornadoes than before, doesn’t mean their number has actually increased.

‘With increased National Doppler radar coverage, increasing population, and greater attention to tornado reporting, there has been an increase in the number of tornado reports over the past several decades. This can create a misleading appearance of an increasing trend in tornado frequency.’

They illustrate this by excluding the weakest tornadoes (the F-0 category), which is the one most affected by this observation bias. If one does so, there doesn’t seem to be a long-term increase.

From the NOAA Storm Prediction Center:


And if you look only at strong tornadoes, F3 and up, they’ve actually declined.


Today I want to look at the issue from another angle: changes in temperature. I have seldom seen this kind of analysis in climate and it seems to me temperature provides a good opportunity, because the yearly changes are so large compared to the long-term trend. By contrast, any observation bias has to be small. The population of states, coverage of Doppler radar, etc. are virtually identical from one year to the next.

NOAAs’ temperature data page shows this:


Temperature swings from one year to the next are sometimes in excess of 1ºC. In fact, that’s about as much as total warming since 1979.

Now, there are some aspects of climate for which yearly temperature swings are not very relevant; for instance, glacial melting depends mostly on the absolute temperature, not the change from the year before. Sea level rise depends both on water expansion (through heat accumulation) and additional water mass (through glacial melting). So it shouldn’t surprise us if we don’t see any correlation between temperature swings and sea level rise.

Still, I wanted to see if there’s something about tornadoes that makes them increase or decrease when temperatures go up. We’re always hearing about the 2ºC target, so I figure changes of over 1ºC should be enough to cause some change in the tornado count.

How I counted

NOAA’s storm database is here. As of this writing, at least the files for 2015 and 2016 have a new weird format that apparently removes the ‘event type’ column (and a lot of other things); I haven’t looked at all the files, for obvious reasons, but fortunately I downloaded the data a few months ago and those do indicate the event type (tornado, hail, etc).

So the files and R-Code I actually used are stored here. The link is only missing the data for 2016, which I got from Wikipedia. If anyone knows of a more ‘official’ answer I can plug it in – though honestly it wouldn’t change the results. In the Dropbox link you’ll also find my R-code and the temperatures for 1951-2016.

The 1951-2016 period has 66 years, but since we’re looking at changes, there are 65 ‘points’. And as you can guess looking at the chart…


…the correlation is 1.5%, which is to say effectively zero.

The problem with using changes in temperature is that, obviously, absolute temperature also plays a role. Perhaps going from 14ºC to 15ºC has no effect on tornadoes, but moving from 15ºC to 16ºC does cause an increase. To test this I checked only the years since 2000: an increase in temperature from that baseline leads to higher absolute values than one from earlier dates.


In that case the correlation is -33%. I don’t think this really means there is a negative relationship between tornadoes and temperature – it’s just that with so few points you will get skewed results.

What this doesn’t mean

This simply shows there is no correlation between tornado change and temperature change. Of course, in reality any change in temperature will affect tornadoes somehow; perhaps the changes that increase this count are offset by others that decrease it, or perhaps the influence of temperature is simply too small and gets lost in the noise of variability. To probe deeper, one could also look at trends depending on regional temperatures, or comparing day time with night time and so on.

For now that is beyond my means, in terms of both skill and free time. I hope you enjoyed this post – feel free to tinker with the data and code provided in the references.


Tornado Climatology:

NOAA/NCEI Storm event data:

NOAA USA Temperature Data:

Data files and R-code used to make counts:

R graphical language (free):


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March 20, 2017 4:51 pm

I am suprised that there was not an increase in low-rated tornadoes due to the increase in coverage of Doppler radar. There could be an actual decrease in count masked by better detection due to radar, but determining that would require seeing if the count of older radar installations changed over time.

Reply to  Tom Halla
March 20, 2017 7:51 pm

There was a major increase of F0/Ef0 tornadoes. Ones F1/EF1 and stronger had no significant up or down trend during the period covered.

Reply to  Donald L. Klipstein
March 21, 2017 1:22 am

In that case the correlation is -33%. I don’t think this really means there is a negative relationship between tornadoes and temperature – it’s just that with so few points you will get skewed results.

What this doesn’t mean

This simply shows there is no correlation between tornado change and temperature change.

So you found a strong correlation, then dismissed it and concluded that there was no correlation : presumably the basic assumption which you started out with.

Congratulations, you have qualified as an “expert” for the next IPCC report.

If you want to dismiss the correlation on the grounds of the number of data points then provide some kind of significance test.

I looked at this several years back and it seems like there is a strong negative correlation.
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There was a marked drop throughout the late 20th c. warming period and somewhat what higher activity during the warming “hiatus”.

Reply to  Donald L. Klipstein
March 21, 2017 6:19 am

33% isn’t statistically significant with that few points, Greg. Besides, all the correlation comes with the two outliers on the top-left and bottom-right.

Reply to  Donald L. Klipstein
March 21, 2017 11:45 am

33% isn’t statistically significant with that few points, Greg.

Significance at what level, against what noise model? How many points?

Prove it, don’t try to lecture me while making bland assertions/ assumption like the author.

Robert B
Reply to  Donald L. Klipstein
March 21, 2017 5:58 pm

There is no physical reason for a correlation so unless its well and truly not just a coincidence you assume no connection. Your plot shows that a warming climate means a low tornado count so the criticism is that he should have looked at the correlation of the change in temp with the actual tornado count. Just eyeballing the plot, there doesn’t seem to be a good correlation there.

Reply to  Donald L. Klipstein
March 22, 2017 6:41 am

Assuming 33% means that r=0.33 for the estimated correlation coefficient, then the standard test for spurious correlation using that value and the count of 16 points says that the probability of spurious correlation is greater than 20%. Given the usual 95% confidence interval (ie probability of spurious correlation < 5%), that result is not remotely statistically significant. I agree with the author's conclusion.

Reply to  Donald L. Klipstein
March 26, 2017 9:50 pm

Using cor.test I get basically the same p-value ThinkingScientist reported (0.21)

Reply to  Tom Halla
March 21, 2017 10:24 am

One thing that could easily be subjected to observation bias is the way in which the number of tornadoes are counted since there is a “new” one every time they “lift”. A (what I would call) single tornado can go 30 miles and be counted as 30 tornadoes (or more). The rules for this count procedure, especially with radar, would be very important. Then add in whatever the rules were (if any) before or where there was no radar or the addition of “improved” radars and I would think that common ground becomes rather confused.

March 20, 2017 4:58 pm

Observers’ bias.
As always.
Not good. Not bad. But, I guess, it is real.
I wish I could suggest a way to avoid this.
Unhappily, I cannot do so. Sorry.


March 20, 2017 5:09 pm

Increased CO2 DEFINITELY causes more tomatoes!!

Reply to  Aphan
March 20, 2017 7:00 pm
Bryan A
Reply to  Aphan
March 20, 2017 9:59 pm

Big EF-ing tomatoes

Rob Dawg
March 20, 2017 5:09 pm

One would think that as people and radar expand with ever better coverage that the number -reported- would increase even as the number of -occurrences- remained the same.

Steve Case
March 20, 2017 5:16 pm

Storms operate off of the difference in temperature between air masses. Maximum summer time temperatures have decreased in the U.S. for over 80 years while the minimums have increased. The decrease in U.S. Summertime maximums is especially true in states in the Mississippi and Ohio River Valleys.

Steve Case
Reply to  Steve Case
March 20, 2017 5:23 pm

Here’s NOAA Climate at a Glance for Maximums June through September for the contiguous U.S. with the trend since 1930:

Steve Case
Reply to  Steve Case
March 20, 2017 5:26 pm

The alarmists dwell on average temperatures, and ignore the fact that the averages are pushed up by the minimum temperatures. And the folks on the other side of the debate let them get away with it.

Reply to  Steve Case
March 20, 2017 5:44 pm

Steve, thanks for pointing that “error” out. I’v always noticed that their data collection methods are garbage, but that was one item I never thought of.

Reply to  Steve Case
March 20, 2017 6:58 pm

Steve, exactly
Global warming was supposed to make nights warmer, and not effect day temps too much

Reply to  Steve Case
March 21, 2017 1:28 am


…and ignore the fact that the averages are pushed up by the minimum temperatures.

This was the basis of Karl et al SST frawd. They decided to “correct” daytime SST using nocturnal ( NMAT) which shows more warming. They spuriously assume that the two should be the same and obviously this means that the one showing less warming must be “wrong”.

Samuel C Cogar
Reply to  Steve Case
March 21, 2017 4:09 am

If the Average Summer Temperatures had been increasing at the same rate as the Average Winter Temperatures, which they should have been if atmospheric CO2 is the culprit, then 100+ degree F days would now be commonplace throughout the United States during the Summer months. But they are not commonplace and still only rarely happen except in the desert Southwest where they have always been commonplace.

Now, instead of saying that “the Earth is warming” it is more technically correct to say “the earth has not been cooling off as much during its cold/cool periods or seasons”.

One example of said “short term” non-cooling occcurs quite frequently and is commonly referred to as “Indian Summer”.

Given the above, anytime the earth’s average calculated temperature fails to decrease to the temperature recorded for the previous year(s), it will cause an INCREASE or spike in the Average Temperature Calculation results for that period ….. which is cause for many people to falsely believe “the earth is getting hotter”.

[All blockquoted ? .mod]

Tom O
Reply to  Steve Case
March 21, 2017 10:46 am

I have been making this point as often as possible. I moved to Phoenix, AZ 20+ years ago. There were often 120 degree days years past, but even with the expanded urban heat island, there are few 120 days now, if any. I’ve always wondered how we could have “warming” while the maximum and daily average highs are in decline. And when you consider that the overnight low has increased, thus lifting the bottom from which the Sun’s heat must lift to the next day’s high, you would expect an increasing trend in highs, which we are not seeing, instead of just an increase in average daily temperature.

Samuel C Cogar
Reply to  Steve Case
March 22, 2017 4:08 am

[All blockquoted ? .mod]

mod, …. I was quoting myself.

I plagiarized (copied) the above verbiage from an MS Word file that I authored long time ago.

Samuel C Cogar
Reply to  Steve Case
March 22, 2017 4:23 am

@ mod, ….. in reference to my above blockquote:

Here are the 1st three (3) paragraphs which I omitted from the above posted blockquote.

If one looks at most any multi-year Annual Average Temperature graph it will likely show an increase in the Average Temperatures for the specified time frame, …… but how does one know if said increase is due to an increase in the Average Winter Temperatures or an increase in the Average Summer Temperatures?

If the Average Winter Temperatures were steadily getting less cold (warmer) over the past 60 years …. which we know is an observational fact …… and the Average Summer Temperatures remained about the same, ……. then wouldn’t that produce an increase in Average Temperatures over said 60 year time frame?


And if so, wouldn’t that rule out the presumed “greenhouse” effect of atmospheric CO2?


If the atmospheric CO2 is increasing but the Summer temperatures are not getting hotter then atmospheric CO2 is not affecting near earth temperatures.

Cheers, Sam C

ron long
Reply to  Steve Case
March 21, 2017 3:25 am

Steve C., yes I think your statement “Storms operate off of the difference in temperature between air masses.” is correct, but it’s not the daytime and nighttime temperatures. Tornados are basically produced when two air masses of different temperture and humidity, collide at an oblique angle. The cooler, and usually drier, air mass comes down from generally Canada and the warm, and always moist, air comes up from the Carribbean, and the two meet at Tornado Alley. So the noted decrease in EF1 and greater strength tornados means that the difference in the characteristics between these two different air masses is declining? Is one changing or are they both changing? I personally don’t want to be homogenizied.

Reply to  ron long
March 21, 2017 5:25 am

Much more likely for warm moist air to come up from the Gulf. To reach the US from the Caribbean, air would have to move against the prevailing winds.

Reply to  ron long
March 21, 2017 6:16 am

“So the noted decrease in EF1 and greater strength tornados means that the difference in the characteristics between these two different air masses is declining?”

That would be my guess, ron.

March 20, 2017 5:26 pm

See Tony Heller’s site. It is doubtful that temperatures have increased at all before “adjustment”.

Steve Case
Reply to  Mike Borgelt
March 20, 2017 5:30 pm

Oh yeah, and there’s that.

Here’s the changes made to the data from 2005 to 2015. In the last two years there’s been even more.

Reply to  Steve Case
March 21, 2017 6:17 am

Yeah, cool the past and warm the present. It’s criminal.

Janice Moore
March 20, 2017 5:32 pm


…. 1ºC. In fact, that’s about as much as total warming since 1979.

Where do you get this figure? ONE DEGREE warming since 1979 (implied is “to present,” i.e., 2017)??

All the reliable data analysis I’ve seen says it is MUCH less (sometime, even negative).
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Note to author: This WILDLY INACCURATE assertion about surface temperature may be a simple mistake. However, your post, mostly just a “gee whiz,” conjectured, “say, this looks interesting about tornadoes” with little else *appears* to be mainly not to discuss tornadoes but to promote the falsity that there is certainty about “global warming.” That is, your job for the AGW gang is apparently to just hammer home the falsity that great warming has occurred to keep alive the “GW” part of AGW.

Shrug. I’m not saying I KNOW your real point in writing the above was to promote AGW, only that it appears that way. Prove me wrong.

Reply to  Janice Moore
March 20, 2017 6:45 pm


Reply to  Janice Moore
March 20, 2017 7:08 pm

Hi Janice,
I got curious, so I ran UAH TLT for USA48, last months version, latest and greatest.
The overall slope, beginning to end, is 0.164 deg./decade.
So for 38 years, warming is just about 0.64 deg.
I did not run the NOAA data presented here, but I can if you really want to see it. By my eyeball, the statement of ~1 degree seems OK, given the dataset. Comparing the two, in round numbers, the NOAA data shows a slope ~50% greater than the UAH data. Just about what we have come to expect from NOAA.
Whether you believe them is another matter entirely.

March 20, 2017 5:41 pm

Since temps are not increasing of course there is no correlation.

Jeff Alberts
March 20, 2017 5:57 pm

The problem with using changes in temperature is that, obviously, absolute temperature also plays a role.

You’ve got bigger problems. There is no US average temperature, any more than there is a global temperature. Both are physically meaningless. Temperature is an intensive property of the location the specific temperature reading was taken. Averaging it with readings from different locations is bogus.

Tornadoes are also very rare in many parts of the country. So you’d be better off using regional averages instead of including places that, for all intents and purposes, get zero tornadoes.

Samuel C Cogar
Reply to  Jeff Alberts
March 21, 2017 4:38 am

Jeff Alberts – March 20, 2017 at 5:57 pm

There is no US average temperature, any more than there is a global temperature. Both are physically meaningless.

But, …. but, ….. but, ….. Jeff, ……….. iffen everyone quits “talking” the asinine silliness of “average surface temperatures” …… and ……. ”CO2 causing increasing temperatures”, …… then a majority of the people won’t have anything climate related to talk about.

Jeff Alberts
Reply to  Samuel C Cogar
March 21, 2017 7:03 am

Wouldn’t that be AWESOME?!?

As much as I love WUWT, I’d rather there had never been a need for it.

Nick Stokes
March 20, 2017 6:00 pm

“This simply shows there is no correlation between tornado change and temperature change.”
Well, that no change could be shown. And that is pretty much the conclusion of the IPCC (AR5) as Roger Pielke noted here at WUWT. At least they did not claim any correlation.

The relevant AR5 section is here.

Reg Nelson
Reply to  Nick Stokes
March 20, 2017 6:14 pm

And where is that ever reported in MSM outlets, who disingenuously, exaggerate anecdotal evidence?

Reply to  Nick Stokes
March 20, 2017 11:52 pm

Nick, I wouldn’t want to exploit your free time, but perhaps you know of a way to automate reading of CSV files? I had to write the same 2 lines with a couple changes 66 times, one for each year. I asked on Stack Overflow but so far I haven’t been able to fix this.

Thanks in advance.

Reply to  Alberto Zaragoza Comendador
March 21, 2017 12:08 am

A programming environment can do that for you, such as MATLAB (free versions exist), many now use “R”.

Nick Stokes
Reply to  Alberto Zaragoza Comendador
March 21, 2017 11:25 pm

I see you are using R, and I presume you have a vector of filenames. I see at Stack that you run a loop over the names. I would, as they suggest, put them into a series of dataframes – probably have to be a list rather than a vector. Then you can extract the files by heading, eg

x[[i]] <- read.csv…

for(i in 1:62){
s <- x[[i]]$EVENT_TYPE # s is vector of event types
or whatever
You can also extract by column number, if they are consistent, eg

s<- x[[i]][,22]

Michael Jankowski
Reply to  Nick Stokes
March 21, 2017 10:42 am

“…Well, that no change could be shown…”

You call a lack of statistically-significant warming “strong warming,” and a few days later imply that a lack of observed change could still be a change.

What won’t you say to support your bias?

March 20, 2017 6:11 pm

Re 2hotel9

But if temperatures are not increasing, and the number of tornadoes is not increasing, there is perfect 100% correlation!

Reply to  dudleyhorscroft
March 20, 2017 6:59 pm

Now I am going to open that box and see if the cat is there!

Reply to  2hotel9
March 20, 2017 9:40 pm

Check the bag.

Reply to  eyesonu
March 21, 2017 5:58 am

Poppa got a brand new bag!

March 20, 2017 6:26 pm

That is one Hypothesis that bit the dust, there are two other ones right now, the Artic Ice and Cosmic Ray theories that are also being tested. Here is a short article on the topic.
Climate “Science” on Trial; The Moment of Truth

March 20, 2017 6:28 pm

That is however pretty funny. The more they “adjust” the data fewer and fewer of their claims will be proven correct. “Adjusting” the data simply won’t change reality.

Reply to  co2islife
March 20, 2017 6:55 pm

Worst part about it…..they are tuning their models to it
The models will never be right

Reply to  Latitude
March 20, 2017 6:56 pm

LOL, that is what happens when you start with a lie, you have to stick with it. They just keep digging deeper and deeper.

Reply to  Latitude
March 20, 2017 7:07 pm

wellllll…….what tells me the temp adjustments are fake is that all the models say almost the same thing
Models are tuned (hind cast) to the adjusted temps…so they show warming that isn’t happening
That many people, that many super computers….can’t all be that wrong/stupid

Myron Mesecke
March 20, 2017 6:36 pm

I want to point out that the two largest tornado outbreaks occurred in 1974 and 2011. Remember that the ’70s was the global cooling scare.
What both years had in common were strong La Nina’s, colder Pacific water off the west coast.

Being an amateur radio operator I have attended the Skywarn storm spotter training presented by the National Weather Service many times. They talk about how and why severe weather forms.

Two of the atmospheric conditions which lead to the potential for severe weather are cold dry air aloft and warm moist air below. The greater the temperature difference between these air masses, the greater potential for both storm chances and storm strength.
Since the tropics do not change temperature much, the warm moist air moving up from the Gulf of Mexico will not fluctuate to any great degree. That is the constant.
But the temperature of cold fronts moving across the US to collide with the tropical air can vary quite a bit. Now if the cold air doesn’t warm as much off the west coast it can get colder and stay colder longer after it moves over the Rockies.
Strong La Nina’s are just what you need to give a boost to severe weather.

The alarmists love to promote warm air as a cause of severe weather. But it isn’t.
Cold is the key.

Jeff Alberts
Reply to  Myron Mesecke
March 20, 2017 9:17 pm

“I want to point out that the two largest tornado outbreaks occurred in 1974 and 2011. ”

That we know of, in the VERY short time we’ve been able to “see” them accurately/

Don K
Reply to  Myron Mesecke
March 20, 2017 11:13 pm

Not disagreeing, but elaborating a bit. I believe that the coldest airmasses come from the Arctic, not the Pacific and are propelled South and East by winds circulating around low pressure centers near Hudson Bay. I’m not that big a weather buff and I could be wrong. But I believe that unmodified Pacific air is a rarity here in New England and probably well to the West of here.

Another factor that may to be accounted for is that Winters have been getting a bit warmer and a bit shorter in New England, and probably elsewhere in Eastern North America since Colonial times. For example, in 1776, General Carleton backed off from investing the Colonial forces at Ticonderoga because the winter snows had started in late October. Nowadays that probably wouldn’t happen until mid-November at the earliest.

That suggests to me that the average location of the potentially tornado spawning frontal boundaries at any given time of the year may well be shifting Northward. That is to say, that the start (and end) of “Tornado Season” in any giver area might be a bit earlier in the Spring than it used to be

And finally the dearth of landfalling hurricanes in the last decade has possibly affected the tornado count some.

Myron Mesecke
Reply to  Don K
March 21, 2017 9:58 am

I admit that I haven’t mapped out how many Continental polar (land underneath) and Maritime polar (oceans underneath) air masses there are that enter the US. Nor how many of them lead to tornadoes.
But geography dictates that the cold fronts that move over the Rockies to enter the US plains would be those that are closer to the west coast where ocean temperature could have some effect.
My thinking is that an El Nino would sort of counter-act the cold charge the fronts would get going over the Rockies while a La Nina would sort of boost the cold charge of the Rockies.

It will take someone with actual knowledge to say I am sort of right or that I am dead wrong.

Don K
Reply to  Don K
March 21, 2017 10:30 am

You may well be right Myron. This is not an area I know much about. But if you look at and look at the temperature plot, you’ll see a large mass of arctic air being pulled down into the Eastern prairies of Canada by a low (indicated by counter clockwise wind circulation) currently centered centered near the Southern tip of Baffin Island. The current temperature at Flin Flan on the Saskatchewan-Manitoba border is around 4F (-15C) whereas whereas along the Rocky Mountain foothills in Alberta temperatures are in the 20sF (-5C give or take)

Reply to  Don K
March 23, 2017 9:57 am

The only way winters can get shorter or longer is precession of the equinoxes. Axial tilt affects the amount of incoming solar radiation near the poles. Combine those, the local weather will change.

Indeed, I recall well the big outbreak in 1974 and 2011. Locally, the 2011 one was worse. [Incidentally, the Blizzard of ’93 was enhanced in strength by the same processes, giving me thundersnow and parts of Florida a major tornado outbreak.]

IR active gases affect the lapse rate (the change in temperature with height above the ground). Differential mass air flows can do this as well, but that will not affect the IR related screening in both directions. Consider an upper level high pressure area. It will lower the lapse rate and cap convection. Consider an upper level low pressure area. It will increase the lapse rate and increase the convection. Consider that the dry standard US atmosphere’s calculated lapse rate is about -9K/km. Consider that a water saturated one, with the other constituent’s molar mass unchanged, the lapse rate is about -6.5K/km. This we measure directly. That the other IR active gases, which should lower the lapse rate (the tropospheric hot spot that supposedly requires a higher altitude for effective IR emission, which makes no sense to me chemically from the IR and Raman spectroscopy that I am aware of) apparently can’t be measured, well, that makes me question the theory. Water’s effect is two-fold here. There is the direct IR effect of the vapor and the liquid/solid aerosols, plus the effects of the latent heats of sublimation/vaporization and their inverses deposition/condensation.

Reply to  Myron Mesecke
March 21, 2017 6:31 am

Good post, Myron.

The Jet Stream postion has a lot to do with how strong a tornado outbreak gets. The strongest tornado outbreaks form when the jet stream is flowing diagonally across the U.S. from southwest to northeast. As the jet stream slowly moves east, tornadoes break out along the leading edge of the jet stream. When the two warm and cold fronts and the jet stream come together just right, they can create really strong tornadoes.

March 20, 2017 6:48 pm

Might be because the temperature, even with all the adjustments and fudging….is so small the tornadoes didn’t notice…
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tony mcleod
Reply to  Latitude
March 21, 2017 5:36 am

The numbers on the left would be a little different but that could also be the graph of a ton of water being boiled of into steam. But that would be a silly way to depict it.

Reply to  tony mcleod
March 23, 2017 10:01 am

Actually, it isn’t. Add in the inherent uncertainly in the underlying measurements, it actually shows, with in the limit of the actual meaningfulness of ‘average’ temperatures, that the whole thing is “a tempest in a teapot”, so to speak.

March 20, 2017 7:06 pm

Having lived in every major region of the US I noticed that locals always thought they had the most unusual weather. Also the worst allergies and a few other things. Climate change and weather porn simply expand upon that existing harmless bias. Of course now it’science so that’s different.

Regular folks being lead around by the nose certainly isn’t a new phenomenon. The tornado scarves an easy sell in 2011. Same sales force is working on selling ice to the Eskimos.

Reply to  troe
March 21, 2017 6:35 am

“Having lived in every major region of the US I noticed that locals always thought they had the most unusual weather.”

I’m reminded of the old saying: “If you don’t like the weather in (name of State here), just wait a few minutes.” It seems people in a lot of states use that old saying as their own. And why not.

Reply to  TA
March 21, 2017 1:27 pm

Of course in So Cal, we say “… you better move.” For 80% accuracy, just use one forecast all year. For > 90%, forecast yesterday again. (only fails twice per storm).

Paul Penrose
Reply to  troe
March 21, 2017 7:45 am

Yeah, I had a discussion with my dad about CAGW and he defended using the following as his basis for belief in it: “I know it’s real because I’ve seen it get warmer though my life. It was colder when I was a child.” I tried to tell him that while his 77 year lifespan was admirable, it wasn’t nearly long enough to qualify as “climate” relevant. I also pointed out that he has lived in the same part of the same state his entire life, so at best his experiences are only related to regional changes, not global. I didn’t even get to talk about how inaccurate decades old memories were and how easily they are influenced by current beliefs (confirmation bias), because he cut me off and told me in no uncertain terms that I was wrong and he was right.

I love my dad, but he has always been pretty stubborn. Not only that, but like most people, he allows himself to become emotionally invested in the issues he supports. This makes it much more difficult to accept new facts and change his position if the facts warrant it. He simply retrenches, leaning back on confirmation bias and appeals to authority, and rejects any attempt at rational debate. Plus, it’s just easier to accept other people’s conclusions than study the relevant issues, collect data, and come up with your own conclusions.

Reply to  Paul Penrose
March 23, 2017 4:57 am

“emotionally invested”

I think most people are prone to do that at times. Some more than others. The Left more than the Right, imo. It does tend to cutoff the debate.

My experience is the weather has gotten much milder over the years. Not that an extremely hot year doesn’t pop up once and a while, like the summer of 2011 around here where it was as hot as I ever remember it, but that was just one year and one weather system. But when I was a kid in the 1950’s it was much hotter than today by a good measure. That’s what I think about when I remember the 1950’s: It was hot. Today is like a walk in the park in comparison. And think about how hot it must have been in the 1930’s which was even hotter than the 1950’s. The Official “Hottest Year Evah!” pronouncements are a joke. We should appreciate the good weather we have been having.

Reply to  TA
March 23, 2017 5:28 am

You got that right! I constantly ask people why they are complaining, I remember much worse winters and summers and I am only 56. I remember hurricane Camille, the Real Worst Hurricane of the last 100 years. Galveston was so far off the scale it qualifies as a singularity in the record. As for winters, I moved north cuz I like winter and I been getting ripped off! Damned uncooperative climate. grumblegrumblegrumble.

Lance Wallace
March 20, 2017 7:44 pm

Tornadoes, like temperature, are local events. There is no conceivable reason why they should have any relation to an annual average across the US.

Since you have the actual dates and locations of the tornadoes, why not pick the closest thermometers for analysis?

Reply to  Lance Wallace
March 21, 2017 5:36 am

” no conceivable reason” is a sweeping generalisation which implies you consider that you know what everyone else may conceive.

Tornadoes are caused by interactions of large weather fronts. It is foolish to announce that those conditions are totally unrelated to nation averages. How about this links to the strength of the polar vortex which determines how deeply large scale weather features descend in latitude. This will also affect nation average temps.

There, I “conceived” one.

Reply to  Lance Wallace
March 21, 2017 6:38 am

“Since you have the actual dates and locations of the tornadoes, why not pick the closest thermometers for analysis?”

You also need to know about moisture content of the air and jet stream location when talking about tornado strength.

March 20, 2017 8:13 pm


-“This simply shows there is no correlation between tornado change and temperature change.”

– “It shouldn’t surprise us if we don’t see any correlation between temperature swings and sea level rise.”

– “Of course, in reality any change in temperature will affect tornadoes somehow”



Principally potential difference is the source of all displacements in nature. “Force” and “Displacement” are always together. The biggest variable here is the temperature difference between day and night. Seasonal changes should be added to the variables. Earth’s rotation around its axis is the dynamo, creates the necessary potential difference.
Earth’s atmosphere is a fluid environment. So this quality should be considered in the calculations. The definition of high and low pressure areas according to meteorological science is correct. The number and quality of tornadoes are very criterion by records.
In a fluid environment equilibrium conditions is important. Conditions in each location can be affected by the prevailing situation of neighboring areas contrary to our expectations. That is why we see some misleading results in the article.

-“This simply shows there is no correlation between tornado change and temperature change.”

This is not a key result.

Reply to  Max
March 21, 2017 5:38 am

It’s not even “a result” since he found exactly the opposite , then dismissed it out of hand and ignored it !

Reply to  Greg
March 22, 2017 6:54 am

The correlation is not statistically significant – I left the spurious correlation calculation result upthread. It has not been “dismissed out of hand”, its been rejected on the basis of not statistically significant.

From a purely physical basis, I would not exact tornadoes (or hurricanes) to be fundamentally related to absolute temperature. Temperature gradients, yes and local gradients in the case of tornadoes. On the topic of hurricanes, as Lindzen has pointed out, the effect of global warming might be expected to decrease the temperature gradient between the poles and the equator, leading to fewer and less potent hurricanes or extreme storm weather. There is some research that supports this, suggesting it was stormier during the little ice age.

So the dearth of cat 5 hurricanes making US landfall since Katrina would be entirely consistent with a warming world. Just not a catastrophe, so it gets little traction as a physically plausible hypothesis because it means warming might be benign.

Joel O’Bryan
March 20, 2017 9:39 pm

I suspect with a cooling NH, this April-June springtime will be an above-normal tornado season. Unfortunately. (Clash of the airmasses thing… weather).

And the Alarmists will cheer nonetheless the destruction and human misery as evidence of their CO2 religion.

tony mcleod
Reply to  Joel O’Bryan
March 21, 2017 5:44 am

You’ve actually seen people cheering the aftermath of a tornado? No, I know, of course you haven’t. It’s just something hateful to say that you think will seem inciteful.

Reply to  tony mcleod
March 21, 2017 10:54 am

I’ve seen them get quite gleeful at the thought of violent weather.

Jeff Alberts
Reply to  tony mcleod
March 22, 2017 7:03 am

I’ve seen some AGW faithful seem glad that tornadoes have hit in areas governed or represented by Republicans, saying they got their just desserts for failing to believe and take action. Not sure I would call it cheering, but it certainly seemed like they were glad it happened. There have been stories about it here on WUWT.

Reply to  tony mcleod
March 23, 2017 5:45 am

Oh, I see these “weatherpersons” on TV and they are absolutely orgasmic over violent weather, destruction and injuries/deaths. They got nothing else since they can not predict weather in a 72 hour time frame, so destruction/death porn is all they got.

Reply to  Joel O’Bryan
March 21, 2017 5:55 am

“And the Alarmists will cheer nonetheless the destruction and human misery as evidence of their CO2 religion.”

A very salient point. The left uses such things to push their political agenda, the rest of us use it to raise funds to assist or actually go there and help.

Javert Chip
March 20, 2017 9:47 pm

I don’t know about you guys, but I’m thinking all that as-yet-unseen tornado energy is being stored in the deep ocean.

There is also a terrific correlation between NYC ice cream sales and homicides. Just saying.

Neil Jordan
Reply to  Javert Chip
March 20, 2017 11:40 pm

It’s getting awfully crowded down there in the abyss: Bathybius haecklii, Polywater, Godzilla, the missing heat, latent sea level rise, immaculate convection, and now tornado energy.

Samuel C Cogar
Reply to  Javert Chip
March 21, 2017 5:07 am

Me thinks that iffen one defines the root cause of a “dust-devil” ….. then they will also have defined the root cause of a “tornado”.
comment image

The primary difference between a dust-devil and a tornado is: 1) “point” of origin, …. and 2) “energy” content.

Reply to  Samuel C Cogar
March 21, 2017 5:39 am

brilliant example , thanks.

Reply to  Samuel C Cogar
March 21, 2017 9:09 am

Tornadoes are formed by thunderstorms, rarely also by convective showers that are not producing thunder. Dust devils form in clear air and derive their energy from buoyancy of a thin layer of very hot air adjacent to sun-baked ground.

Mickey Reno
Reply to  Samuel C Cogar
March 21, 2017 12:53 pm

Dust devils form close to the ground. They don’t have enough power to form, move out over the ocean, pick up sharks, move back over land and fling the sharks into major urban centers. Good thing, too, because my chain saw is in the shop.

Reply to  Samuel C Cogar
March 23, 2017 5:17 am

I got a good laugh out of that one, Mickey!

Ron Williams
March 21, 2017 12:03 am

It would be interesting if it were possible to go back in time and observe the actual tornado record data, complete with temps and F force. Of course we can’t do that, but what would have been the albedo been of the affected area prior to European settlement compared to a natural prairie grass ecosystem? Now, massive farm landscapes and the city urban heat sink everywhere, this has to have an effect on the warm moist air rising ready to do battle with any cool sinking air mass. CO2 or average global temps have nothing to do with this scenario. So as mentioned already, this is really somewhat of a localized event.

There is a lot of excess local thermal heat being generated by our advanced civilization that is clearly observable-some such that big cites are 7-8 degrees warmer than the surrounding country side or more. This accomplishes half of the equation with more man made heat present in the lower atmosphere, waiting to clash with the cooler upper level lows/fronts that advance down from the north. So the other interesting question would be whats up with this cold weather advancing south, if the AGW theorists are saying the northern climes are warming exponentially faster than mid and equatorial latitudes?

Another question I have is why do tornados seem to frequently hit a mobile home park? Presumably the tornado would damage any other housing subdivision just as bad. Even in Edmonton at 54 degrees north lat in 1987, an F4 tornado roars thru the country side into the city… “The tornado persisted as it headed northeast toward the Evergreen Mobile Home Park. There, the tornado completely destroyed nearly 200 mobile homes in the area, killed 15 people and injured numerous others.”

Reply to  Ron Williams
March 21, 2017 2:24 am

This has been an interesting thread.
Your own comments and questions. Tornado season starts in the south mainly and works its way north. The southern states have two peaks to the season, the first in the spring and the latter in late summer.
This coincides with the seasonal rise and fall of the tropopause. This movement is not smooth, with large areas moving vertically by about 3 km in 12 hours. This draws in the cold and hot air and a fight breaks out called a tornado. That is why they are predominantly in the centre of the country. It’s an annualized pumping action causing different temperatures to meet, plus causing atmospheric flow and air movement.

Those are my conclusions, for what they are worth.

Reply to  ozonebust
March 23, 2017 10:11 am

Given that I live in the Southeastern US of A, we do indeed have two tornado seasons; but we may have one on any given day in any given month. Ours peaks in late March or early April (spring) and in late November/early December (autumn). Summer and early autumn months, lacking tropical systems, typically do not have the dynamics necessary for tornadoes. We tend to not have any from late May/early June through October, when the HHH sets in due to the semipermanent subtropical highs sitting over us,

Reply to  Ron Williams
March 21, 2017 6:56 am

“So as mentioned already, this is really somewhat of a localized event.”

Yes. Tornado outbreaks depend on where the jet stream is located. Tornado outbreaks will begin in the spring in parts of Tornado Alley like Texas, Oklahoma, Kansas, Nebraska, and over the course of the spring the center of the jet stream’s energy will push farther east and north and bring the center of tornado activity to south of the Great Lakes area. The northeast U.S. usually doesn’t get too many tornadoes before summer begins and tornado activity declines.

Which brings up another thought. The heat per se doesn’t drive tornadoes, otherwise we would have huge outbreaks during the very hot summers of Tornado Alley. But we hardly ever have any tornadoes during a very hot summer. Without warm, moist Gulf air, there won’t be any tornadoes, no matter how hot it gets.

Reply to  Ron Williams
March 21, 2017 9:16 am

Tornadoes generally do not damage housing subdivisions other than trailer parks as severely as they damage trailer parks. Trailer homes are easier for a strong wind to damage or destroy than other homes. Even more so, people get killed or seriously injured by tornadoes more easily in trailer homes than in other homes that are more sturdily attached to the ground and that have stronger or multiple walls and stronger roofs and upper floors to better block flying debris.

Reply to  Donald L. Klipstein
March 23, 2017 5:23 am

Many trailer homes in trailer parks have lightweight skirting around the bottom exterior of the house which doesn’t provide much protection from wind getting up under the house and lifting it in very strong winds.

Reply to  TA
March 23, 2017 5:42 am

That is a fact. You can strap a mobile home down as required by code, tornado don’t care. I have installed a lot of skirting, mostly vinyl, and it is flimsy. I try to convince people to go with plywood or plank skirting well anchored along the bottom. Not just tornadoes, microbursts and straightline winds are hard on mobile homes and modulars. And then their are crappy contractors who skimp and cut corners and leave you with a substandard home.

Schrodinger's Cat
March 21, 2017 1:16 am

According to the BBC this morning, WMO have issued a report on recent weather. The BBC didn’t give details but the familiar phrases such as severe weather events, sea level rise, coral bleaching and carbon dioxide were somehow contained in just a couple of sentences.

March 21, 2017 3:09 am

I published the results of my study in 2014 which showed a tornado frequency correlation

My results showed some very interesting connections only my coauthor agreed with.

March 21, 2017 5:35 am

“Temperatures in the USA have generally increased since the 1950s.”

You mean since the late 1970’s, don’t you. Temperatures generally increased and decreased during this time period. Saying temperatures generally increased since the 1950’s doesn’t tell the whole story.

Here’s Hansen’s 1999 temperature chart which shows temperatures decreasing from the 1950’s to the 1970’s.
comment image

Reply to  TA
March 21, 2017 5:42 am

Thanks, do you have a citation/source for that image. Well worth keeping as a reference.

Reply to  Greg
March 21, 2017 7:26 am

It’s on the realclimatescience website. Just click on the image for a larger version.

As far as I’m concerned, the 1999 Hansen chart is about as close as we are going to get to a real U.S./Global temperature profile. Combine the 1999 Hansen chart and the UAH satellite chart to get a reasonable representation of the historic global temperature profile.

The bastardized surface temperature charts that NASA and NOAA produce are garbage and should not be put forward as representing reality. These charts have been manipulated for political purposes to support the CAGW narrative. They represent wishful thinking, not reality. Anyone basing their research on these charts has already gotten off on the wrong foot.

1999 Hansen + UAH = A reasonable representation of the global temperature profile. No “hotter and hotter” or “hottest year evah!” here. That’s why NASA and NOAA fiddled with the charts and changed them to fit their CAGW narrative.

Reply to  Greg
March 21, 2017 1:23 pm

Thanks TA, I meant a paper citation or original URL. If I am going use that graph to present anything I need something more credible “Hansen’s 1999 temperature chart”.

Reply to  Greg
March 23, 2017 4:16 am

“Thanks TA, I meant a paper citation or original URL. If I am going use that graph to present anything I need something more credible “Hansen’s 1999 temperature chart”.”

This is probably what you are looking for:

This shows the same Hansen 1999 U.S. temperature chart alongside the bastardized Global surface temperature chart, on the official NASA website.

Reply to  TA
March 21, 2017 8:07 am

Here is the US GISS + UAH (2011) I put together six years ago.

Reply to  stevekeohane
March 21, 2017 1:19 pm

Interesting. You really need to use compatible datasets though. It appears that you are dumping monthly “anomalies” on top of annual averages and 5y mean ( which is an incorrectly labelled running mean : not the same thing ).

Use UAH annual mean for a less noisy, more relevant comparison.

Reply to  stevekeohane
March 21, 2017 1:25 pm

Do you have a link to the orginal dataset for GISS or is that just photoshop collage?

Reply to  stevekeohane
March 23, 2017 4:24 am

“Here is the US GISS + UAH (2011) I put together six years ago.”

I love ya, man!

Yes, that’s the temperature profile we have all been living under all this time. Nothing scary here. No “hotter and hotter”, no “hottest year evah!”, none of that bs (bad science).

It was hotter in the 1930’s than today and since that time, the temperatures have been going down a little, and then up a little, and then down a little and now we are at the top of the “up a little” phase, and logic would tell you that we will probably go down a little now, but the CAGW promoters say, “No! Wait a minute! Because we have more CO2 in the atmosphere we won’t go “down a little” anymore, we are going to go straight up!

And the CAGW promoters are correct in saying there is more CO2 in the atmosphere, but that steadily rising heat they predict because of it is nowhere to be seen going on 20 years now.

March 21, 2017 6:09 am

See also another important facts about tornadoes
How large, and fast, can tornadoes (storm,cyclone) become, and when do they occur? How are tornados ranked?How are they spotted?What was the most devastating tornado? How to stay safe during tornado?
All answers in this video ->

Killer Marmot
March 21, 2017 11:10 am

People think of heat as energy. Thus the warmer things are, the more energetic the system.

Not quite. The ability to do work, which drives weather systems, is not a function of temperature but of temperature gradient — that is, of spatial differences in temperature.

Thus one should not immediately assume the rising temperatures produces more energetic weather systems.

Reply to  Killer Marmot
March 23, 2017 10:19 am

And that’s partly due to the fact that the thermodynamic temperature is the geometric mean of a defined sample of matter’s internal kinetic energy *and* nothing else. The thermodynamic temperature, by itself, tells you next to nothing without the other relevant information, other than the constituents of the sample at the higher one are generally moving faster than they are at a lower thermodynamic temperature. The temperature tells you a little bit about the total energy within the sample.

March 21, 2017 11:53 am

So why do most tornadoes occur in the US? Why doesn’t the rest of the world get some of this action?
I can’t see temperatures causing these things less or more when they occur over a wide temperature band.

Reply to  Martin457
March 21, 2017 1:15 pm

Well if you know nothing of what causes them, that is not a very surprising result.

Reply to  Martin457
March 23, 2017 5:44 am

“So why do most tornadoes occur in the US? Why doesn’t the rest of the world get some of this action?”

I think it is a matter of topography.

The U.S. is a big, wide area, and a lot of moisture available to certain parts of it during the spring and fall.

A strong cold front comes into the northwest U.S., and causes a lot of rain but few if any tornadoes because the temperature differential isn’t large enough in that area. As the cold front passes through Arizona and New Mexico there is a bigger heat differential but still no tornadoes because there is no moisture to work with. Then as the cold front passes over the Rocky Mountains and enters the Great Plains, it starts running into warm, moist air, and the warmer moist air is usually located in Texas, Oklahoma, Arkansas, Kansas, Missouri, and Nebraska as the cold front pumps moisture and warm air up from the Gulf as part of the process. And all these forces meet right in Tornado Alley. As the season gets closer to summer the focus of tornado activity moves east from Tornado Alley, because there is usually a big high pressure system forming over the center of the nation. Then the heat of summer sets in and that’s the end of tornadoes until the heat breaks.

Reply to  TA
March 23, 2017 6:55 am

Very well put. You should take over for B Nye, last I heard him speaking about this very question he mangled it all to hell.

Reply to  TA
March 24, 2017 4:33 am

We have a potential tornado maker of a weather front coming into Tornado Alley now, although, right now, it looks like the storm fronts are pushing south to north along the front, which means they won’t have as much potential for big tornadoes. If the Storm Fronts were moving from southwest to northeast along the weather front (the jet stream), then the potential for large tornadoes is much greater. The angle the jet stream takes makes a lot of difference in the strength of these storms.

The wind has been blowing fairly hard here for the last two days, but not as hard as the weather front that went through here a couple of weeks ago which clobbered the east and northeast U.S. Those winds were “howling”. Not so much this time.

Reply to  TA
March 24, 2017 4:36 am

Here’s the weather radar map I use:

Reply to  TA
March 24, 2017 4:57 am

B Nye seems to mangle all things science. Bill is very confused.

Reply to  TA
March 24, 2017 5:34 am

When my son was young he watched the early B Nye videos for kids, they were OK, then he expanded into AGW advocacy and you could really see the difference. Still have a couple of VHS tapes of his elementary school type shows, stuck to basic science at kid level, fun experiments and such. Then BANG, loony tune time. Makes me wonder what, medically, happened? Early onset Alzheimer’s? Traumatic brain injury? Some sort of chemical imbalance? Something happened.

Reply to  TA
March 24, 2017 5:41 am

And thanks for that active weather map link! Put it right below AccuWeather in my book marks.

March 21, 2017 1:14 pm

BTW thanks to Sr. Comendador for archiving and sharing this data. We were warned that data would start disappearing when Trump was elected.

I pointed out that it would not be Trump which was behind but the alarmist, activist scientists.

Samuel C Cogar
March 22, 2017 3:55 am

What is the direction of the “rotational spin”, …… clockwise or counterclockwise, …. of a tornado and a “dust devil”?

Are they the same or opposite?

Is the “rotational spin” reversed for tornadoes or “dust devils” that form in the Southern Hemisphere?

Reply to  Samuel C Cogar
March 23, 2017 10:23 am

The tornadoes that I’ve seen rotate counterclockwise, but could rotate either way, depending on local conditions. Dust devils definitely may be seen rotating either clockwise or counterclockwise; but once a rotation direction is established, it maintains it until it dissipates.

Samuel C Cogar
Reply to  cdquarles
March 24, 2017 4:10 am

Thanks for your response, cd, …… I was curious if there was a specific rotational direction because I had never researched it or ever heard/read anyone say anything about it,

Anyway, I was just wondering if their rotational direction was in any way related to or determined by the N/S hemisphere in which they formed, …… like the rotational direction of water flowing down a drain.

Reply to  cdquarles
March 24, 2017 7:51 am

I don’t think that there is a preferred direction, either, for drains. I’ve seen them rotate either way. I’m in the Southeastern US of A. I would say that, since there isn’t enough of a differential in the local Coriolis force for such small areas, that it is the local factors that give the initial direction. For large circulations, such as hurricanes/cyclones or mid-latitude baroclinic systems, which span 500 to 1000 miles, there would be enough of a differential in the northern and southern ends to make them have a preferred rotation dependent on the bulk pressure differential. So high pressure areas have winds that change direction in a clockwise fashion and low pressure systems have the inverse direction.

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