Florida Major Hurricane Strikes: No Significant Increase in Intensity from Sea Surface Warming

Reposted from Dr. Roy Spencer’s Blog

September 4th, 2019 by Roy W. Spencer, Ph. D.

Summary: Twenty-two major hurricanes have struck the east coast of Florida (including the Keys) since 1871. It is shown that the observed increase in intensity of these storms at landfall due to SST warming over the years has been a statistically insignificant 0.43 knots per decade (0.5 mph per decade). Thus, there has been no observed increase in landfalling east coast Florida major hurricane strength with warming.

In the news reporting of major Hurricane Dorian which devastated the NW Bahamas, it is commonly assumed that hurricanes in this region have become stronger due to warming sea surface temperatures (SSTs), which in turn are assumed to be caused by human-caused greenhouse gas emissions.

Here I will use observational data since the 1870s to address the question: Have landfalling major hurricanes on the east coast of Florida increased in intensity from warming sea surface temperatures?

The reason I am only addressing landfalling hurricanes on the east coast of Florida is three-fold: (1) this area is a hotbed of major hurricane activity; (2) the record is much longer for landfalling hurricanes, since before the early 1970s the intensity of major hurricanes well offshore was much more uncertain; and (3) the coastal population there is now several million people, the region south of West Palm Beach is historically prone to major hurricane strikes, and so the question of whether hurricane intensity there has increased due to ocean warming is of great practical significance to many people.

First let’s start with the record of major hurricane strikes on the east coast of Florida, including the keys. There have been 22 such storms since 1871, occurring quite irregularly over time.

While there has been a slight increase in the intensity of these storms over time, amounting to +0.8 knots per decade, the correlation is quite low (0.21) and the quantitative relationship is only barely significant at the 1-sigma level.

But this doesn’t tell us the role of sea surface temperatures (SSTs). So, next let’s examine how SSTs have changed over the same period of time. Since all of these major hurricanes made landfall in the southern half of Florida, I chose the following boxed region (22N-28N, 75W-82W) to compute area-averaged SST anomalies for all months from 1870 through 2018 (HadSST data available here).


Since 18 of the 22 major hurricane strikes occurred in either August (4) or September (14), (and 4 were in October), I focused on the average SST anomaly for the 2-month periods August-September. Here’s the 2-month average SST anomalies for 1870-2018.

Note that the years with major hurricane strikes are marked in red. What surprised me is that the SST warming in this region during peak hurricane season (August/September) has been very weak: +0.02 C/decade since 1871, and +0.03 C/decade since 1950.

If we then compare SST anomaly with storm intensity at landfall, we get the following plot. Here I took into account which month the hurricane occurred in for the purposes of computing a 2-month SST anomaly. For example, if the storm hit in October, I used the September/October average. If landfall was in August, I used the July/August average.

There is a weak relationship between SST and storm intensity (correlation = 0.19), but the regression coefficient (+13.5 kts/deg. C warming) is not statistically significant at the 1-sigma level.

Now, if we just ignore statistical lack of significance and assume these quantitative relationships are mostly signal rather than noise, we can multiply the 0.03 C/decade SST warming trend since 1950 by the 13.5 kts/deg C “warming sensitivity parameter”, and get +0.43 kts/decade of storm intensity increase per decade due to SST warming, which is almost exactly 0.5 mph per decade.

This is an exceedingly small number. That would be 5 mph per century.

So, based upon the observed SST data from the Hadley Centre, and hurricane data from the National Hurricane Center, we conclude that warming SSTs have caused a tiny increase in intensity of landfalling major hurricanes by 0.5 mph per decade.

I suspect a statistician (which I am not) would say that this is in the noise level.

In other words, there is no observational evidence that warming SSTs have made landfalling hurricanes on the east coast of Florida any stronger.

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Jack Dale
September 5, 2019 10:12 am

Kerry Emanuel is the “go-to-guy” in hurricane research. He takes a global perspective, rather than cherry picking Florida.


Reply to  Jack Dale
September 5, 2019 10:52 am

Global Major Hurricane Frequency…

Global Tropical Cyclone Frequency…

Global and Northern Hemisphere Accumulated Cyclone Energy…


L G Brack
Reply to  David Middleton
September 6, 2019 6:43 am

Dr Emanuel shows a Peleo chart based on core samples which shows more intense hurricanes during the “little ice age” than current periods. He makes no mention of this except that we need cores at more locations and he then proceeds to modeling based on the assumption that more heat equals more frequent and stronger hurricanes. He never mentions that the difference in ocean and air temperature is a significant factor although he shows that there are NO hurricanes on the equator where water temperature is the highest.

Gary Pearse
Reply to  Jack Dale
September 5, 2019 11:27 am

Gee Jack, 1) where do you think the birth of real research into hurricanes was? 2) the study of Atlantic hurricanes actually has great utility for American citizens and 3) this is a research project in an area where there is the most data available in the world! Hint, hurricanes around the world work the same way, so this kind of study is a freeby benefit to the rest of the world (East Timor, for example doesnt have the resources to do this kind of thing).

Robert W Turner
Reply to  Jack Dale
September 5, 2019 11:45 am

After just 8.5 minutes he makes a claim that Hurricane Patricia was the strongest hurricane ever measured in the east Pacific or Gulf. That’s incorrect, I’m sure it was just an absent minded blunder, though a strange thing to get wrong.

Jack Dale
Reply to  Robert W Turner
September 5, 2019 12:45 pm

“That distinction (strongest on record) belongs to Hurricane Patricia, which formed in the eastern Pacific off Guatemala in 2015. Patricia’s barometric pressure was 872 millibars, and its peak winds were clocked at 215 miles per hour.”


Looking forward to the evidence supporting your assertion.

BTW – the video is from 2016.

D. J. Hawkins
Reply to  Jack Dale
September 5, 2019 1:29 pm

The wind speed is a little sketchy. After 1987, the US stopped flights into Pacific Basin hurricanes. So how was the speed measured?

Jack Dale
Reply to  D. J. Hawkins
September 5, 2019 1:43 pm

“Combined microwave brightness temperature measurements from recent
L- and dual C-band satellite radiometers provide new estimates of
surface wind speed structure in tropical cyclones.”


Robert W Turner
Reply to  D. J. Hawkins
September 6, 2019 9:30 am

They were measured to be only a PEAK (not sustained) of 160 kt and the data was later “reanalyzed” by NOAA to be 185 kt and said to be sustained for at least one minute. I’ll go with the actual operational measurements of a peak at 166 kt, revisionist data is not science, it’s data molestation.

This is like the claim of the 2.5 mile wide El Reno tornado was the largest and most powerful tornado evah. It only left EF-3 damage of about 1/8th mile wide on the ground, but let’s just ignore how things have always been measured for our Chicken Little headlines eh.

Michael Jankowski
Reply to  Jack Dale
September 5, 2019 5:04 pm

Nothing says “global perspective” like making a claim about “the strongest hurricane ever measured in the east Pacific of Gulf.”

Jack Dale
Reply to  Michael Jankowski
September 5, 2019 5:42 pm

What part of “strongest on record” do you not understand?

David Riser
Reply to  Jack Dale
September 5, 2019 7:15 pm

Wind Speed is very sketchy, since about 2008 the US and most other places use maximum 1 min wind speed instead of sustained winds. The scale still lists the wind speeds as sustained but that is too hard to figure out so the various MET organizations stopped estimating the average sustained and went for essentially a wind gust (WMO defines any max wind over a period as a gust). This means your guaranteed to be overestimating the wind speed. Of note look at Patricia’s wind field size and the damage caused. It was a smallish storm 24mile huricane force diameter and resulted in 6 deaths in a very populated area. I believe storm surge was about 14ft which is nothing for a major hurricane. To really get a sense of this change if you look at Dorians path, there is a weather buoy sitting right on it that never measured a sustained wind over 60kt. the eye went right over that buoy and so by definition did the eye wall. Pre 2008 dorian would have been downgraded to a tropical storm not upgraded to a major huricane. (small blip but kind of highlights the changes.)
Dave Riser

Robert W Turner
Reply to  David Riser
September 6, 2019 9:31 am

Exactly. All these strongest evah storms seem to be causing less damage than the purportedly weaker storms of the past.

Jack Dale
Reply to  Robert W Turner
September 6, 2019 9:47 am

Can we see the evidence for that assertion?

Jack Dale
Reply to  Robert W Turner
September 6, 2019 10:01 am

The major hurricanes CAT 3,4,5 account for only 24% of landfalls but 85% of normalized damage.


John Sandhofner
Reply to  Jack Dale
September 5, 2019 1:38 pm

Except hurricane formations are a regional thing which mostly depend on regional factors. If climate change happens on a global scale, all regions should be changed on a similar scale.

Jack Dale
Reply to  John Sandhofner
September 5, 2019 1:46 pm

Climate change DOES occur on a regional level. Check out the UAH temperature data by region.

Reply to  Jack Dale
September 5, 2019 4:06 pm

Jack Dale , How can we take you seriously when you cherry-pick your “go-to -guys” ???

Jack Dale
Reply to  Jm Steele
September 5, 2019 4:15 pm

How can we take you seriously when you think that is a cherry pick?

Reply to  Jm Steele
September 6, 2019 2:35 am

Kerry is your go-to guy just like Mann is a go-to guy. You “go to” the guy who says what you want to hear.

In the vid. Kerry shows how bad models are reproducing hurricanes compared to observation, then goes on to predict what the future may bring based on their lack of understanding.

If he is the worlds leading expert , it’s a testament of how little we understand. This does not seem to prevent everyone imagining we know all about this “basic physics” .

September 5, 2019 10:29 am

Way to be the skunk at the alarmists’ garden party (just kidding). Good work!! Real science beats a biased narrative every day. They couldn’t even wait until Dorian was gone before making their pronouncements to support their agenda.

Reply to  Dave
September 6, 2019 2:42 am

A little disappointed that Dr. Spencer can not do something better than trend analysis. Reducing everything to one scalar quantity throws almost all available information and makes it very likely that you will draw unwarranted conclusions and false attribution. This has been the trump card of the alarmist for the last 40 years. Everything “correlates” with everything else at the level of straight line analysis.

It would be more pertinent to note that only three storms on the entire graph are post 1970 when the OMG warming was supposed to be “majority” driven by AGW.

Reply to  Dave
September 6, 2019 6:35 am

The problem with focusing on one factor and only one factor – sea surface temperature – as the thermostat and sole energy source for hurricanes is just as silly as focusing only as CO2 as the sole thermostat for the planet’s atmospheric climate controls.

Clearly, after this past week and the performance of Dorian, it should be obvious that many factors control the performance of a cyclonic storm, not just sea surface temperature .. which itself varies spatially all over the world’s oceans and seas and is not just a singular measure of condition.

For instance, the upper atmosphere pressure cells, both high and low, serve to steer cyclonics storms. The interaction with land forms obviously affects storm strength. The presence of dry air masses vs. humid air masses affects storm strength. Wind sheer at various altitudes greatly affects storm strength.

As does the speed of the storm .. contrary to what many “experts” claimed, a slow moving storm is actually a weaker storm .. the “experts claimed that “a slow moving storm picks up more heat energy from the underlying waters.” But the contrary is actually true – a strong storm causes much more churning of the upper sea surface resulting in upwelling of colder deep waters, and that in turn weakens the storm.

That is precisely what happened with Dorian. As it held over one spot, at Grand Bahama, the upwelling caused the storm strength to fall from Cat 5 all the way down to Cat 2.

So much for the “experts”.

Climate performance, and the performance of cyclonic storms, is vastly more complex than the simpletons who call themselves experts will ever admit to as they flog their “one thing only” stupid models of unreality.

John Q Public
September 5, 2019 10:33 am
Reply to  John Q Public
September 5, 2019 11:59 am

What absolute horrendous garbage. Roger Pielke has gone right off the rails.
Pielke is a warmist, but also was a voice for moderation. This is very disappointing.
He starts:

Before proceeding, let me make a few things perfectly clear: Human-caused climate change, driven by accumulating greenhouse gases, is real and poses significant risks. Aggressive action is needed to decarbonize the global economy and to improve adaptation to climate.

He takes what is the most contentious and disputed assertion in all of science, and presents it as an absolute accepted fact. “Human-caused climate change”: Sure, now prove it.
He goes on:

Let’s start with the obvious and uncontested. Humans have fundamentally altered the climate system. This means that all weather on planet earth is influenced by climate change.

No, it is not obvious, no it is not uncontested. Show us your data, and prove it.
Here we go again:

It has also become common to see claims that sea level rise – again, undoubtedly true and caused by accumulating greenhouse gases

Categorically false, absolutely proven that accumulating greenhouse gases have had no effect on sea level rise.
And finally:

although we note that no TC climate change signal has been convincingly detected in sea level extremes data.” It is happening, but the effect is not yet so large that we can observe it.

He wants to claim an effect exists, yet admits that such an effect is too small to measure.
You can not claim the existence of an effect if you can not measure it.

Reply to  TonyL
September 5, 2019 12:51 pm

…. and another one:

“Of course, when it comes to scientific claims, don’t take my word for it or anyone else’s, you can access the consensus assessments directly.”

Farcical Dr. Pielke. How about accessing the effing data ?? Accessing the “consensus assessments” IS taking “anyone else’s word for it.”

Joel O'Bryan
Reply to  philincalifornia
September 5, 2019 1:36 pm

Pielke Jr really gave an anti-science “Emperor’s New Clothes” explanation about SL rise effects when he wrote, “It is happening, but the effect is not yet so large that we can observe it.”

He’s a true-believer apparently in seeing what can’t (or hasn’t been) seen and then still calling what he says as “science” just “trust me.”

Then there was the garbage statement he made, “Both fringes are at odds with central-tendency consensus views, and care must be taken to distinguish where scientific claims sit with respect to that consensus from the worth of the causes being advocated for by those making the claims.”

What the “Bullish” fringe wants is a totally rejection of uncertainty that is at the heart of scientific principle. That he doesn’t recognize the “bullish” rejection of any uncertainty is his main failure here IMO.

But he is humorously correct to call out Trenberth’s waffling statement as an “inkblot.” Readers can read whatever they want to into that nothing-burger statement from Trenberth was simply trying to ride the line between science (telling the truth about uncertainty) and remaining in the Alarmist Camp full of lies and distortions.

Gary Pearse
Reply to  Joel O'Bryan
September 6, 2019 9:41 am

Joel, this author is Pielke Sr.

Jack Dale
Reply to  Gary Pearse
September 6, 2019 9:52 am

Nope it is Pielke Jr.

The contributor link in the article.


Joel O'Bryan
Reply to  TonyL
September 5, 2019 1:42 pm

That last one you quoted really got me. He’s convinced its all happening including SLR as a consequence of humanCO2 additions, he says so, then says “not yet so large we can observe it.”

Pielke Jr has lost all credibility with me as a straight shooter. Did someone on the Left get to him? Are they threatening his university tenure again unless he falls in line?

Kristi R Silber
Reply to  TonyL
September 5, 2019 9:00 pm

Funny that when Pielke writes a paper that skeptics agree with, he gets all kinds of praise. When he writes about general issues, things he believes to be true, he is lambasted.

The part about “It is happening, but the effect is not yet so large…” is simply a restatement of what the quote is saying. All the quote said is that sea levels are rising, so sea level extremes will rise, but that the climate change signal for those rises is not yet statistically detectable. It’s really quite a simple statement. Pielke then goes on to talk about predictions, putting it all in context.

I thought his article was excellent. It says to beware what the media tell you. Beware extreme views. Beware quote by single scientists. Sure, it supports AGW. That’s because AGW is well-supported.

I often wonder what it would take for deniers (I feel perfectly free calling them that, when they call anyone who takes AGW seriously “alarmists”) to finally believe. How long are deniers going to believe the small minority of climate scientists who are themselves deniers, the most vocal of whom also talk about the terrible cost of doing something about it and are usually affiliated with conservative think tanks – that is, there is a political aspect to their rhetoric.

What will it take for deniers to ignore the politics, ignore the economics, and just assess the data – not cherry-picked data, but the data as a whole, with an open mind?

What changes would be convincing? What evidence do you need?

Reply to  Kristi R Silber
September 5, 2019 9:13 pm

Great questions Kristi.

Please show any scientifically valid empirical data that demonstrates that atmospheric carbon dioxide going from pre-industrial levels of 280 ppm to current levels of around 415 ppm has had any effect on any global climate parameter.

J Mac
Reply to  Kristi R Silber
September 5, 2019 9:22 pm

Ahhhhh Buhlieeeeve, Kristi! Say Halellujah!

Reply to  Kristi R Silber
September 5, 2019 9:29 pm

Why does it matter it will be settled over time in the future as it isn’t as if anything is going to happen CO2 levels will continue to rise well past 2050. Unless a better plan than the crazy emission control plan is put up the increasing levels are a guarantee.

Joel O'Bryan
Reply to  Kristi R Silber
September 5, 2019 10:38 pm


How do you square Pielke, Jr saying”“It is happening, but the effect is not yet so large that we can observe it.” with anything about science as an observational based method of inquiry?

If sciuence is to based on observation of the natural world around us, then how can anything but “fauth” be invokded with that statement? And faith is the realm of religion. Not science.

Pielke’s own words in that one line are anti-science, a “take it on faith” expression of his belief. That’s not science.

Every past expression to the CO2-AGW hypothesis has posited an acceleration of SLR. Since that is obviously in 2019 is still not happening, they now invoke all SLR as a result of AGW. I call BS.

Reply to  Kristi R Silber
September 5, 2019 11:23 pm

“What changes would be convincing? What evidence do you need?”

For some here; none. The “hiatus” gets shorter and shorter but never goes away, the “cycles” get longer and longer and we climb further and further out of the LIA. Anyway, how can there be evidence if climate scientists are communists?

Refreshing to read your posts again btw.

Reply to  Loydo
September 6, 2019 4:44 am

You could start by addressing my response to Kristi instead of trying (unsuccessfully) to hide behind climate bafflegab. Here it is again; Don’t be shy now:

Please show any scientifically valid empirical data that demonstrates that atmospheric carbon dioxide going from pre-industrial levels of 280 ppm to current levels of around 415 ppm has had any effect on any global climate parameter.

Tom Abbott
Reply to  Kristi R Silber
September 6, 2019 5:23 am

“What evidence do you need?”

What evidence do you have? Lay it on us.

The fact is you won’t lay any evidence on us because there is no evidence that CO2 is doing anything to change the climate of the Earth.

You could prove me wrong with some evidence. But I’m betting you can’t.

I constantly ask the alarmists to supply even one bit of evidence showing CO2 is doing anything the alarmists claim it is doing, and to date, have *never* recieved a reply from an alarmist that had any evidence contained in it.

Perhaps you can break this string of silence with evidence. Show us what convinced you that CAGW is real. Then we can determine whether that is actually evidence or not.

Reply to  Tom Abbott
September 6, 2019 7:26 am

It’s amazing what you can find on the internet, but one thing you cannot find is the statement regarding “man-made climate change” that there is overwhelming evidence for it, and where this statement is actually followed by any evidence.

Tom Abbott
Reply to  Tom Abbott
September 7, 2019 4:44 am

No CAGW evidence is presented. Just what I expected. It couldn’t be otherwise because there is nothing to present.

This demonstrates again how weak the CAGW argument is, when its proponents can’t even mount a defense of it when challenged. And this applies to ALL alarmist arguments, not just a few individuals. No alarmist can produce evidence of CAGW because there is no evidence, as ought to be obvious by the lack of response every time the challange is issued. If there was evidence, you can safely bet your paycheck that the Alarmists would be all over such a challenge. That they don’t do that ought to tell you all you need to know about the science of climate change. The science is *not* settled. Not even close. Not even enough for an alarmist to shut a skeptic up, which they would dearly love to do.

Yet millions of people are scared to death that CAGW is real. Why? Because there is a concerted effort on the part of authoritarians in our societies to make them believe this fantasy in an effort to gain political power, and the authoritarians are very effective at applying their propaganda to the public mainly because the Leftwing News Medias of the Western Democracies are all onboard with pushing the CAGW lie because they want their political side (Left) to gain political power, and/or they have been fooled by the lie themselves.

Bottom line: There is NO evidence of CAGW (Catastrophic Anthropogenic Global Warming) happening on the Earth. If anyone says there is, tell them to prove it.

Tom Abbott
Reply to  Tom Abbott
September 7, 2019 5:18 am

“It’s amazing what you can find on the internet, but one thing you cannot find is the statement regarding “man-made climate change” that there is overwhelming evidence for it”

The only problem for the average person is the alarmists will tell them they *do* have evidence, and then they will present them with the fraudulent Hockey Stick chart. Anyone looking at that chart would think the Earth’s temperature was climbing higher and higher and higher and would be convinced that what the alarmists say is true. The average person would not know the Hockey Stick is a purposeful fraud created by people with political motives. We actually have on record the conspiracy the Hockey Stick creators entered into in their own emails (Climategate). The average person doesn’t know about Climategate.

Of course, these ploys wouldn’t happen on the WUWT website because the alarmists know such a claim would be shot down quickly, so they don’t make that argument here. And there is nothing else they can present confirming CAGW because the estimates of how much CO2 raises the temperatures are all over the map. They are educated guesses, and they are all over the map.

Neither educated guesses or fraudulent Hockey Sticks are evidence of anything, other than evidence of fraud, in the case of the Hockey Stick chart. The alarmists know this and that’s why they don’t use these arguments here because they know we know it, too.

Jack Dale
Reply to  Tom Abbott
September 7, 2019 3:41 pm

Does your assertion apply to each of the more than 3 dozen replications of Mann;s hockey stick that have been published by different researchers using different methodologies with different data sets?

Here is a link to them:


Tom Abbott
Reply to  Tom Abbott
September 8, 2019 6:10 am

“Does your assertion apply to each of the more than 3 dozen replications of Mann;s hockey stick that have been published by different researchers using different methodologies with different data sets?”

No, the Hockey Stick charts I’m talking about are the modern-era Hockey Stick charts, the ones that disappear the hot decade of the 1930’s, and disappear the hot El Nino year of 1998.

I have made this distinction on more than one occasion. You should be able to tell what I’m talking about because I *always* refer to the 1930’s decade.

Mann’s Hockey Stick Chart Lie was focused on erasing the Medieval Warm Period and the Roman Warm Period both of which were warmer periods than today, with less CO2 in the air then than now.

Warm periods in the past didn’t fit in with Mann’s CAGW scaremongering, so he attempted to erase the evidence that would blow up his CAGW science fiction story by creating his famous Hockey Stick chart, the one Al Gore used in his movie.

Similarly, the warm periods of the 1930’s and 1998 did not fit with the CAGW claims, because if it was just as warm in the recent past as it is today, then that means we are not experiencing unprecedented warmth today, which means there is no CAGW, so the Climategate conspirators got together and erased all that warmth from the global temperature chart in an effort to make CAGW look real. The Data Manipulators are cooking the books to this very day.

Linda MacLeod Goodman
September 5, 2019 10:40 am

It’s futile to try to convince liars and true believers, so it’d be helpful to know the % of fence-sitters, imo.

Reply to  Linda MacLeod Goodman
September 5, 2019 9:34 pm

The largest group don’t get a say because they live under authoritarian rules. Of democracies the I don’t care group, which have more pressing things to worry about in there life is probably the largest. The only group this noise plays out with are greens and self guilt inner city yuppies and government workers in most developed nations.

Gary Pearse
September 5, 2019 11:14 am

Roy: I note a speed up of intensity after Dorian resumed its forward motion onto warmer waters, leaving no doubt about the direct relationship of SSTs to intensity (including the drop in intensity as it used up the available heat during its pause). I think intensity picked up about 10knots back into major hurricane territory. Perhaps noting the difference in SSTs and the resulting spin-up of Dorian is a diect experiment in the relationship with more certainty if it.

September 5, 2019 11:20 am

Roy W. Spencer, Ph. D.

All storms are caused by the intensity differences of temperature when warm/hot meets with cool/cold air currents. When you’re only looking at warming you miss the cooling part that’s different. If the cool/cold air and water from the poles is lower than the warm/hot at the Equator it will change the intensity of the storm. We are in a Solar Minimum that is causing cooler polar climates. That although the warmth at the Equator is not changing by much. These cooler polar temperatures has extended toward the Equator. I don’t have anywhere near your education or access to the data that you have. But it would be advantageous if you can research the temperature difference at each of these 22 hurricanes.

Reply to  JOHN CHISM
September 5, 2019 12:22 pm

John, you write, ‘We are in a Solar Minimum that is causing cooler polar climates.” I’m in Alaska and although I suspect that the South Pole is getting cooler despite claims to the contrary, the North Pole is not at the moment cooler than it used to be. It is warmer and I have a hell of a time explaining that to my alarmist brother — how the polar vortex is pushing our normally cool and cold weather south so that we are experiencing generally warmer temps while the lower 48 is actually cooling.

Reply to  Shelly
September 5, 2019 1:28 pm

Meridional vs. zonal jetstream. What you described is normal for meridional flow. Has nothing to do with CO2.

Tom Abbott
Reply to  Shelly
September 7, 2019 5:28 am

“the North Pole is not at the moment cooler than it used to be. It is warmer and I have a hell of a time explaining that to my alarmist brother — how the polar vortex is pushing our normally cool and cold weather south so that we are experiencing generally warmer temps while the lower 48 is actually cooling.”

It’s even less complicated than that, Shelly. Look at the link below which centers on Alaska and you can see a high-pressure system over Alaska (I marked the center of it), which if you are under it, would explain why your temperatures are warmer.

High-pressure systems have been hovering over Alarska for many months and that is the cause of the warmer weather. Why the high-pressure systems have been persistent over Alaska is another question.


September 5, 2019 11:31 am

As regards the oft cited ‘more and more frequent hurricanes’ there was a hurricane drought over the last 12 years, noted in 2016 by the ‘Washington Post’ the U.S. equivalent of the excitable ‘Guardian’. The highly respected American GFDL, contributed 14 scientists on six chapters of the IPCC assessment in 2013 and noted; (edited for brevity)

“Existing records of past Atlantic tropical storm or hurricane numbers (from 1878 to present) in fact do show a pronounced upward trend…. However, the density of reporting ship traffic over the Atlantic was relatively sparse during the early decades of this record, such that if storms from the modern era (post 1965) had hypothetically occurred during those earlier decades, a substantial number of storms would likely not have been directly observed by the ship-based “observing network of opportunity.”

We find that, after adjusting for such an estimated number of missing storms, Statistical tests indicate that this trend is not significantly distinguishable from zero (Figure https://www.gfdl.noaa.gov/global-warming-and-hurricanes/

The 12 year Hurricane dearth since 2006 is the longest in the 140 year record. The phraseology usefully illustrates that, as with ships, there are far more people and sophisticated equipment to observe significant weather events today than in the past .

So it is remarkable that numerous records still exist to illustrate the often severe nature of historic weather even though, statistically, many more events must have occurred than we are aware of. Floods are undoubtedly a serious problem as so many people insist on living next to water. Should the weather of the past recur, this has obvious implications as the worst occurrences of floods appear not in modern times but historically, as those examining centuries long weather records- rather than modern satellite records –recognise.


Reg Reynolds
Reply to  tonyb
September 5, 2019 6:30 pm

On August 3, 1926 Reuters reported that a hurricane struck the Bahamas killing 126 and leaving 400 missing. At the time the population was approximately 60,000 today it is closer to 400,000.

Robert W Turner
September 5, 2019 11:32 am

At those “correlation” values, it’s safe to say there is no correlation. Correlation with ENSO and WAMI, that has been long established.

Clyde Spencer
Reply to  Robert W Turner
September 5, 2019 12:51 pm

With a correlation coefficient of 0.71, the r^2 value is 50%, meaning that only half of the variance can be explained by the parameter being correlated. That is like flipping a coin many times.

A correlation coefficient of 0.19 means that <4% of the variance can be explained or predicted. That is almost useless, even if valid and not just noise.

Reply to  Clyde Spencer
September 5, 2019 1:41 pm

Yep. Best to avoid trend line abuse by not showing a fit or slope when correlation is poor.

Crispin in Waterloo
Reply to  Bernie
September 5, 2019 3:57 pm

There is nothing more misleading than a trendline on a sine wave.

September 5, 2019 11:55 am

Not in Florida, no…

but the Bahamas? Puerto Rico? Dominica?

would somebody like to acknowledge your neighbours are getting their homes mashed flat by hurricanes which are of record destructivity in recent years?

Reply to  griff
September 5, 2019 6:13 pm

As usual you do NOT do research, just shoot from the hip with wild statements and guesses. Here is a listing of many Hurricanes that have swept through the islands:

“Hurricanes in Puerto Rico”

Kaiser Derden
Reply to  griff
September 5, 2019 9:15 pm

not my neighbors … live on an island in a common hurricane zone and there are consequences … thier problem, not mine … I don’t go crying to them when a bad winter storm hits me in Pa. … and frankly they could care less about my problems … so why should I care about their problems … enough with your virtue signaling nonsense …

September 5, 2019 12:09 pm

We can stop any future strikes by giving Trump a sharpie and getting him to track a new path around Florida and straight to Alabama.

Tom Abbott
Reply to  Simon
September 6, 2019 5:39 am

Trump was just going by the early computer models, with some showing Dorian moving across Florida and into Alabama.

If there were no computer models showing Alabama in the crosshairs, then you might have a point, but the models did show that, and you don’t have a point.

The sharpie-doctored chart doesn’t change the facts and Trump said he didn’t use the sharpie.

More ridiculous, truth-twisting, leftwing, hate-Trump BS.

Reply to  Tom Abbott
September 6, 2019 7:55 am

It shows how desperate the anti-Trumpers have become. I saw some models that showed the storm crossing the Florida peninsula, emerge into the Gulf, and head as far west as Louisiana.

Tom Abbott
Reply to  jtom
September 7, 2019 5:43 am

“It shows how desperate the anti-Trumpers have become.”


Reply to  Tom Abbott
September 6, 2019 3:02 pm

“Trump was just going by the early computer models, with some showing Dorian moving across Florida and into Alabama.”
Even if that were true, what on earth is he doing being so out of date with his “proclamations?” That map he showed (and doctored) was days before he made his tweet about Alabama. He’s the president for goodness sake, why isn’t he giving people quality up to date information? I’ll tell you why…. he was off playing golf and actually doesn’t give a flying fig about weather. Unless he can make money from it.
This is a life threatening storm and he’s telling the wrong people to be ready. And then to use a sharpie like he can just move a hurricane’s path with his pen? And it was so easy to see he was making it up as he dug a whole defending himself. Seriously folks, even by his low standards, this is weapons grade “stupid” and the fact you try to defend it shows how blind you are.

Tom Abbott
Reply to  Simon
September 7, 2019 5:47 am

“Seriously folks, even by his low standards, this is weapons grade “stupid” and the fact you try to defend it shows how blind you are.”

Something is weapons-grade stupid, but it isn’t Trump.

Frank Acme Jr.
September 5, 2019 12:10 pm

I find it very interesting that the four hurricanes that enjoyed the largest positive SST anomaly were actually ‘below average in intensity (from the SST Anomaly vs. Intensity graph).
While I understand that the energy that powers a hurricane is derived from oceanic heat (and we frequently see the intensity of a given hurricane change as it traverses warmer or cooler water), the intensity must rely on many other factors that are critical in enabling or inhibiting the hurricane from tapping into that energy.

Joe Chang
September 5, 2019 12:34 pm

The AGW/CC people like to claim that global warming provides more energy to feed tropical storms. But do not cite temp data specific to tropical waters where storms form. They also say the bulk of the warming occurs at the higher latitudes. Um, where do tropical storms form again?

September 5, 2019 12:35 pm

1500’s. 1600’s. 1700’s etc..and all those Spanish galleons..sitting on the bottom…all up and down Florida’s east coast and all around the Keys
were a mechanical problem

Reply to  Latitude
September 5, 2019 1:57 pm

Latitude. That’s incredible, so in theory these storms/hurricanes have been happening for hundreds if not thousands of years?

Jack Dale
Reply to  Sunny
September 5, 2019 2:12 pm

There is now a field of study covering historical hurricanes.

Paleotempestology is the study of past tropical cyclone activity by means of geological proxies as well as historical documentary records. The term was coined by Kerry Emanuel.

Reply to  Jack Dale
September 5, 2019 4:34 pm

..or just pick up any good book on the history of Florida
Florida was settled by people…shipwrecked…and stranded…because of hurricanes

Joel O'Bryan
Reply to  Jack Dale
September 5, 2019 7:55 pm

If it paleo/proxie data, then aren’t they pre-historic hurricanes?
Even hurricanes pre-satellite era that were far out in the Atlantic or Pacific basins, we have sparse data if knew of them at all.

Trying to Play Nice
Reply to  Jack Dale
September 6, 2019 8:14 am

He must be trying to corner the market on adjusting the historical storms out of existence.

Norman Blanton
September 5, 2019 1:14 pm

I wonder how much heat Dorian pulled out of the water while it was stalled over the Bahamas, and if that will affect the storms (Fernand and Gabrielle) that are following it.

Tom Abbott
Reply to  Norman Blanton
September 6, 2019 5:45 am

Good question. Several posters have asked this question.

It makes sense that Dorian might steal a little strength from following hurricanes. I know that during a tornado outbreak, one tornado can move through an area and suck the energy out of adjacent storms systems diminishing their ability to spin up into tornadoes..

Joel O'Bryan
September 5, 2019 1:16 pm

Drilling in on the 5 post-1960 hurricanes that Dr Spencer plotted:

Name Year Dates of RI ENSO3.4 Ap ApSpike?
Donna 1960 9/03 – 9/04 +0.3 120 yes

Betsy 1965 9/02 – 9/04 +1.9 4 no (ElNino)
1965 9/09 – 9/10 +1.9 5 no (ElNino)

Andrew 1992 8/23 +0.1 74 yes

Jeanne 2004 9/25 +0.7 4 no (ElNino)

Irma 2017 9/04 – 9/05 -0.3 106 yes

My Ap-Hurricane Rapid Intensification (RI) hypothesis predicts a rapid hurricane strengthening coincident with an Ap spike ≧20 … IF ENSO neutral conditions exist: that is an ENSO 3.4 is below |+/- 0.5|. Between ENSO 3.4 |+/- 0.5 to 0.7| the correlation begins to break, and is completely lost for full blown El Nino-LaNina state in the equatorial Pacific.

Even going back all the way back to 1950: Major Hurricane Able Aug 17-19,1950 and Major Hurricane Dog Sept 3-5, 1950 using NOAAs HurDatV2 dataset, the Potsdam historical K/A indices data base, and NOAA’s ONI back to 1950, I find:

Name Year Dates of RI ENSO3.4 Ap ApSpike?
Able 1950 8/17 – 8/19 – 0.4 136 yes (a huge spike)
Dog 1950 9/03 – 9/05 -0.4 64 yes

Now jump to 2018 just for fun:
Michael 2018 10/09 – 10/10 +0.6 20 yes (barely, ElNino was starting).

Conclusion, these strong Atlantic basin hurricane’s strengthening phases correlate to geomagnetic disturbances when ENSO neutral conditions exist.

Why has no one spotted this Ap-hurricane RI correlation before?
My guess would be because no one thought to look at (use) the ENSO state as a 3rd variable in a 3-way ANOVA. Without ENSO 3.4/ONI taken into consideration, there is no correlation between Ap spikes and hurricane strengthening. Why is that? I don’t know.

Reply to  Joel O'Bryan
September 5, 2019 2:37 pm

Joel O’bryan. I’m totally new to the science and understanding of weather, climate, hurricanes.. May I humbly ask if you could explain what you have written in a more simpler way please, especially the “geomagnetic disturbances when ENSO neutral conditions exist”… Does this have something to do with the current weak earths magnetic field? Many thanks.n.

Joel O'Bryan
Reply to  sunny
September 5, 2019 8:38 pm

Google is your friend.

“The joy of an education is being able to teach oneself new things and not depend on others to tell you how to think or learn.”
– me (and probably a whole lot of other peole)

ferd berple
September 5, 2019 2:52 pm

Sorry, but warming alone cannot make hurricanes, or any engine more powerful. All engines run on the difference in potential between an energy source and sink. Be it a gas engine, electric engine, water wheel, etc., etc.

You need to warm the water but not warm the air to make hurricanes more powerful. The exact opposite of what GHG theory predicts.

If anything, hurricanes would have been more powerful during the LIA than today.

Joel O'Bryan
Reply to  ferd berple
September 5, 2019 4:19 pm

Hurricanes are heat engines that move energy at higher temperature to lower temperature. The energy transfer to produce the work comes from mass transfer, i.e. convection, the working fluid is water vapor, and the energy is in the form of latent heat of evaporation of water.

And as you note it’s the T difference that matters. So the Carnot cycle best describes the heat engine of a hurricane. Thus the efficiency, 𝓷, of the Carnot Cycle is:

𝓷= 1 – (T2/T1),

where T1 is the temperature of the hotter surface, and T2 is the temperature (both in Kelvin) of the cooler surface. Thus if T2 were absolute 0K, then the engine could run at 100% efficiency. It could do no more. This is a direct outcome of entropy, the 2nd Law of Thermodynamics.

T1 is the sea surface water temperature that directly determines the saturated air temperature immediately above the sea surface. The saturated air is at the temperature of the water, that is fueling the hurricane, typically 26 C to 32 C, or 299.15K to 305.15K for tropical cyclones to form and grow. T2 is the temperature of the top of the tropopause-stratosphere interface, usually about -68 C to – 73 C, or 205K to 200K, where the heat is transported and released by the condensing water vapor.

Inserting these values into the efficiency equation provides a range for hurricane operating efficiency where, 𝓷 = 0.315 to 0.345. Within that 3% differential range is a huge capacity of a hurricane to stagnate or strengthen.

We do have evidence that the stratosphere is cooling since at least 1979 from the AMSU data that Dr Spencer and Dr Christy provide (along with radiosonde balloon data too). A cooling stratosphere also lowers the tropopause and slightly increases the wet adiabatic lapse rate (makes the decrease in temperature greater with an increase in altitude, i.e. more negative).
Lowering the tropopause also helps the towering cumulonimbus heat towers to connect the fluid flow between the surface to the optimally coldest temperature at the tropopause-stratosphere boundary. It is this boundary interface (top of tropopause) where the hurricane’s cloud tops spread radially outwards into a very large radiating surface area to continuing releasing the latent to sensible heat, where radiative transfer takes over to move the heat energy as phtons finally back to space. It is also the reason hurricanes tend to strengthen at night, becasue the stratosphere cools and lowers a bit, allowing 𝓷 to increase.

So even if SST (T1) is nearly the same, a cooling (cooler) stratosphere (T2) can greatly aid in making for stronger tropical cyclones. This is irregardless of “why” the stratosphere cooled and the tropopause lowers.

Jack Dale
Reply to  Joel O'Bryan
September 5, 2019 4:34 pm

The tropopause is increasing in altitude.

Thus the sky is not falling

Joel O'Bryan
Reply to  Jack Dale
September 5, 2019 8:49 pm

A cooling stratosphere is documented by multiple independent lines of evidence.
A cooler stratosphere at the stratopshere-tropopause interface must increase the lapse rate of the troposphere, especially with a warming near surface temp (TLT).

The models predict this will ead to a Tropical hotspot due to increase water vapor convection. The hot spot is not observed. Something is opposing it (negative feedback). Clouds come to the front of the suspect list, as they can block SW to the sea surface impeding further warming. Deep ocean thermal inertia and Water vapor-cloud negative feedback on SW absorption is the likely dominate feedbacks that have kept our Earth’s climate stable on geologic time scales.

pCO2 is irrelevant. A minor +feedback that is well compensated and regulated for on our water world.

Joel O'Bryan
Reply to  Joel O'Bryan
September 5, 2019 10:31 pm

HA!! A 2003 paper that was junk attempt to find something the manipulator Ben Santer needed to cover his ass. In the 2006 NCA the alarmists still tried to hand-wave away the “Tropical Hot Spot” as “largely settled”. But it was far from it. Now they’ve just gone silent on that failure. Moved on to other stupid attribution fingerprints like “seasonal heartbeats” nonsense that onl exposed the lack of a tropical hotspot. Tiresome attempts in a vainglorious attempt at justification. Now they are simply depending a corrupt/incompetent/uninformed media not to ask deep, hard questions about past failures of predictions.

But the Lack of a Tropical Hot Spot forming, as predicted by both CMIP3 and CMIP5 AOGCM ensembles, is blatantly obvious in the AMSU and radiosonde data of today. Despite the earlier hand-waving attempts in the NCA authors, it is still there for everyone to see if they ask.

Nice try though, an A for effort. But I award you zero points (an F) for that effort to gas-light me on the Missing Tropical Hot Spot. It’s still missing in 2019.

James Galloway
September 5, 2019 2:59 pm

Hurricane Dorian sat over the Bahamas for an extended period and was weakened by a combination of upwelling of cooler waters due to it’s sitting over 1 location and land interaction ( although not a major factor it still was not sitting entirely over the ocean ). The hurricane eye sustained much weakening and the hurricane wind field was considerably stretched and Dorian weakened in intensity before it’s jaunt up the eastern US coast. Even though the sea surface temperatures were very warm along the east coast the hurricane also encountered significant shear as it headed north – so, the eye structure suffered considerably and intensity increased slightly but could never totally recover.

September 5, 2019 3:05 pm

Dorian that’s a pretty scary weapon they have there.

But can they use it else where that is the question. Could they do that in the Baltic sea?

Spraying Chemicals and using Ionic Sphere heaters all along the path and creation of Dorian.

Read Dorian Gray.

It’s rather disturbing when you see the videos of them openly talking about creating hurricanes.

Joel O'Bryan
Reply to  Divine
September 5, 2019 9:00 pm

It’s a pretty ugly picture IMHO.

ferd berple
September 5, 2019 3:07 pm

The tropospheric hot spot ensures that GHG will warm the tropical air FASTER than the ocean, which means there is less potential to drive hurricanes which means that GHG will reduce hurricane intensity.

Of course this assumes that climate models are correct in their prediction of the hot spot.

September 5, 2019 4:21 pm

Before hitting the Bahamas a forecaster from Accuweather predicted Dorian’s intensity could increase because there was a path without wind shear. Wind shear is the critical variable that is often overlooked when alarmists want to blame temperature in order to keep a focus on CO2 warming.

So I have a question for the alarmists:

How does rising CO2 affect windshear? If at all?

And perhaps Roy Spencer can answer my 2nd question, or anyone else :

Is there any correlation between low wind shear and anomalously warm surface temperatures? Less surface wind likely cause less cooling, as we say with the Blob in the northeast Pacific. But wind shear is determined by the difference in wind speeds at low and higher altitudes.

Joel O'Bryan
Reply to  Jim Steele
September 5, 2019 8:33 pm

Persistent high pressures correlate with a clear blue sky due to downward flow of air, and its adiabatic warming and thus (relative humidity) drying. Persistent high pressure correlates with modest steering winds at the periphery, and gentle surface winds closer to the center of the high because their CW-NH rotation is being opposed by CCW Coriolis effect (CCW-SH).
Thus everything points to warming SST as UV/SW solar radiation penetrates to depth with reduced overturning.

Low Pressures are in-flowing CCW-steered surface winds, associated clouds blocking SW to the surface. The clouds are forming as moist air rises to it saturation point. Releasing atent heat driving further bouyancy and convection. If the layers are unstable cumulonimbus clouds form.

CO2 is posited to bring on global warming. Global warming is posited to shift the hemispheric tropical Hadley cell polewards, squeezing the mid-latitude and polar circulations, amplifying the jet streams between and causing a meridonal-pattern (rather than zonal) of meandering jet streams as angular momentum is trying to be conserved as they get squeezed polewards.

The wind shear you are describing though is more likely tied to the Madden-Julian Oscillation. The MJO, wind shears, and climate change… is as clear as mud.
Bob Tisdale highlighted that unclear topic of wind/precipitation variations with MJO-climate change here at WUWT with a confusing paper that tried to tie back in January this year.


Johann Wundersamer
September 5, 2019 4:37 pm


Caribbean tropical storms / hurricane exist in geological times

since both americas colliding closed

the isthmus of Panama

that before lay under sea level.

Reg Reynolds
September 5, 2019 6:33 pm

On August 3, 1926 Reuters reported that a hurricane struck the Bahamas killing 126 and leaving 400 missing. At the time the population was approximately 60,000 today it is closer to 400,000.

Joel O'Bryan
Reply to  Reg Reynolds
September 5, 2019 10:09 pm

They (1926 folk) probably didn’t have the warning time or the hardened shelters that many had with Dorian.
But you are correct in pointing out that this is nothing “new” unfortunately for islands that lie in hurricane zones during peak hurricane season. To call what happened on 1 September to the Abaco Island as “climate change” is simply a ruse to sucker people into believing in a scam. A scam intentionally designed to drain their wallets today and their future economic and personal freedoms.

September 6, 2019 4:10 pm

Overall, the original measurement errors in wind speeds (constantly changing through the course of a tropical storm or hurricane) coupled with the impossibility of quantifying the general wind speed of a given hurricane, makes the whole argument moot.

Even thinking that a few miles per hour higher wind speed (when, where, for how long????) in Hurricane Sally over Hurricane Martha is something we can measure and talk about is computational hubris writ large.

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