Dr. Philip Klotzbach writes via email:
Discussion of near impossibility of actually recording strongest winds in a hurricane
Brian McNoldy and I wrote a blog for Capital Weather Gang yesterday where we called out Matt Drudge about his claims that the National Hurricane Center was over-estimating the winds in Hurricane Matthew. As you know, it is nearly impossible to measure the strongest winds in a hurricane due to a variety of factors. Brian and I covered these in some detail in this blog.
Matt Drudge commented on our story last night, and since then, there have been hundreds of comments from individuals claiming that NHC is just a cog in the “global warming” machine. As you know, I’m certainly not a fan of over-hyping climate change and have published several papers showing no trends in intense hurricane activity over the modern observational period.
I feel that it would be incredibly useful for a well-respected climate skeptic website to pick up this story and give some additional credence to it. If the eyewall of Hurricane Matthew had been 50 miles further west, it would have been devastating for the east coast of Florida! We may not be so lucky next time, and I don’t want people to become armchair meteorologists and think the winds are much less than NHC reports.
Happy to help – Anthony
Hurricane intensity is not exaggerated to scare people, and here’s how we know
By Phil Klotzbach and Brian McNoldy
Hurricane Matthew brushed the East Coast as a Category 4 in early October. It scoured the Florida coast with a storm surge that washed out roads and flooded homes and businesses. It dumped over a foot of rain on the Carolinas and triggered deadly flooding. And before all of this, Matthew devastated Haiti and killed at least 600 people — it’s possible we’ll never knowthe final death toll.
But the hurricane’s deadly encounter with Haiti and multibillion-dollar brush with the East Coast wasn’t bad enough for some people — mainly, Matt Drudge, a political commentator and news aggregator, who tweeted skepticism about Matthew’s actual intensity as it barreled toward Florida. Perhaps, he suggested, the National Hurricane Center was overhyping the storm’s maximum winds.
Drudge deletes his tweets regularly, so here’s a screenshot from the morning of Oct. 7:
“The deplorables are starting to wonder if govt has been lying to them about Hurricane Matthew intensity to make exaggerated point on climate,” Drudge mused. (“The deplorables” refers to supporters of Republican presidential nominee Donald Trump.)
Then this (image saved by the BBC):
Drudge argued the point based on data from Caribbean weather stations and buoys that were not reporting winds as strong as what the National Hurricane Center used in its advisories. But the National Hurricane Center uses a lot of different methods to determine a hurricane’s actual peak intensity, and there are some serious issues with relying simply on weather stations and buoys.
The National Hurricane Center — or NHC — uses a variety of satellite-based tools to estimate a hurricane’s winds when the storm is far from land, and as the storm moves closer to land, additional devices are employed.
Hurricane Hunter aircraft are dispatched to investigate the storm in more detail. These planes measure winds both at flight-level, which is approximately 10,000 feet, as well as at the surface through the use of a device called a stepped-frequency microwave radiometer which measures radiation transmitted from the ocean surface back up to the airplane. When high winds churn up the ocean surface, the amount of microwave radiation measured is diffused compared with the amount of radiation measured when the ocean surface is calm.
NHC also utilizes devices called “dropwindsondes” that are dropped from the aircraft at about 10,000 feet and measure temperature, humidity, pressure and wind speed as they descend to the surface. When a storm nears shore, radars can also be utilized to estimate wind velocity.
All of these different measurement devices, combined with surface observations from ships and buoys, are combined to assess a storm’s intensity.
There are several reasons buoys are likely to underestimate a hurricane’s wind.
First, buoys utilize an eight-minute average maximum wind, and NHC uses one-minute average wind. The shorter the wind averaging time, the stronger the reported winds will be. The adjustment factor would be approximately 0.90, which means if a buoy measures 80-mph eight-minute average winds, the one-minute average wind would be about 89 mph.
A more significant bias in the buoy data is the insanely severe ocean conditions that it’s reporting from. Waves in a major hurricane can be as high as 50 feet, and consequently, a buoy experiences very large crests and troughs as the hurricane passes over. When a buoy is on the crest of a wave, it is exposed to the full force of the surface winds, but when it is in the trough of a wave, it is going to be sheltered from the strongest winds. These weaker winds measured in the trough of a wave get averaged into the eight-minute averaging period measured by the buoy, which therefore gives the buoy’s estimated wind speed in a hurricane a low bias.
Surface stations also have significant measurement challenges in hurricanes.
Often during strong wind speeds, the anemometers break. Storm surge can also wash away weather stations before the strongest winds come ashore.
Importantly, a hurricane’s wind field is a wide swath, and the strongest winds may only be found in a small region of the hurricane. The number of surface stations in any area struck by a hurricane is likely not dense enough to accurately measure the strongest winds. For example, one 2014 study found that on average, “a single perfect anemometer experiencing a direct hit by the right side of the eyewall will underestimate the actual peak intensity by 10-20% percent. Even an unusually large number of anemometers (e.g., 3-5) experiencing direct hits by the storm together will underestimate the peak wind speeds by 5%-10%.”
The number of surface weather stations reporting hurricane-force winds, even in notoriously strong United States landfalling hurricanes are surprisingly small. For example, in NHC’s post-storm report on Hurricane Katrina (2005), a Category 3 hurricane on the Saffir-Simpson Wind Scale, only five surface weather stations reported sustained hurricane-force winds, with the strongest sustained hurricane-force winds reported being 86 mph. Many of the surface stations reporting the strongest winds were also flagged by NHC as being incomplete, indicating failure of the station before the strongest winds likely occurred. For reference, NHC estimated Katrina’s Louisiana landfall to have had maximum winds of 125 mph and its Mississippi landfall to have had maximum winds of 120 mph.
The peak winds in a hurricane are confined to a small region of the storm called the eyewall, which is the ring of thunderstorms that surround the eye. Beyond the eyewall, the wind speed drops off relatively quickly.
In the case of Hurricane Matthew, while the southeast United States suffered significant flooding damage due to both storm surge and heavy rain, the east coast of Florida dodged a huge bullet. Had Matthew tracked 50 miles farther to the west, the eyewall of the storm would have come ashore, causing much more extensive flooding as well as significant wind damage.
In any case, Matthew’s strongest winds would likely not have been measured by a weather station. The National Hurricane Center provides the best analysis that science can offer.
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This is why all real scientists are paying the price for not standing up to the joke that climate science has become. Everyone is painted with suspicion now even if good data is being gathered and presented. I hate to say it but if these guys cried foul when so much bad science was being presented in the last 10 years, we wouldn’t have to now defend against such accusations.
BINGO!
And the worst is yet to come as this corruption continues.
I wish they would get of the Deplorables routine. “Deplorable” was a label created by a pathological liar and psychopath, who is amoral, arrogant, elitist, and foul to the core. To use “Deplorables” means you condone the actions of an evil person who looks down her nose at everyone.
How does the ” Deplorables” meme even fit into this discussion? As far as I can tell, your use of the term is first, unless there was a deleted comment which is unseen?
Steve R – try looking at the second Drudge tweet. He used the term.
Irony, perhaps. Possibly even sardonicism.
Well the psychopath is opposed for teh presidency by an economic genius who thinks that he can renegotiate the US national debt and create jobs by initiating a trade war with China. When asked by Sean Hannity how he would defeat ISIS and if he would need ground troops to do it, he replied that he would do it “swiftly and decisively.” The depth of military thought in this fool’s mind cannot be understated. This new Napoleon and embodiment of Julius Caesar noted that he knows more about ISIS than the generals. He absorbed his advanced knowledge in strategy and tactics while learning close order drill at military school. How could generals decades of experience and training stand up to a sharply done presnt arms on a military school parade ground.
Now think that this fool, whose only idea is whatever pops into his mind at the moment and whose relationship with the truth is so slight that it impossible to fact check the torrents of nonsense that flow from his mouth, has a credible chance of winning the US presidency
God a Like button or some such in the comments here…..
EXACTLY.
Thanks to Dr. Philip Klotzbach for the interesting article but the crisis of confidence reflected by Drudge’s comments is totally the fault of the scientific community as a whole.
Not only were the softy-lefty climate warriors allowed pervert the published literature and act as political activists whilst posing as scientists but when this was all exposed in Climategate emails, rather than being denounced by the majority of responsible scientists there was a resounding silent. They embarrassingly just looked to other way hoping it would all blow over and be forgotten.
Worse, when there finally were some “investigations” into the malfeasance they were a total whitewash. Fellow academics just circled the wagons and defended the indefensible.
So, if the science community now finds themselves with little credibility in the public’s eye, they only have themselves to blame.
While the science community is partially to blame for its complacency, much of the blame goes onto the universities that no longer educate people in science, but instead substitute activism. One can also point the finger at journalism, but honestly I think that all goes back to universities as well – you have atrocious journalism because journalists are taught to be activists instead of journalists. You have terrible scientific journals because the editors don’t know any better – they never learned what real science is.
Its amazing to me that good scientists continue to exist despite this backdrop of anti-scientific culture – so I guess I can’t bring myself to blame them too much for hiding in their fox holes and hoping they can continue to follow their work. They aren’t politicians after all. But they should not be surprised at the backlash as people start waking up to the fact they have been misled and exaggerated to.
Public opinion is like a pendulum – eventually it is going to swing the other way and be far more skeptical of everything no matter what the evidence suggests (like the distrust in common vaccines for example). Its up to people (not just scientists) trained in scientific methods and practicing healthy skepticism to keep the likely truth in the public discourse.
Yeah, well, a lot of people just want a get of jail free card to explain away how they rejected reasonable information that they obviously had little understanding of.
It is more than just tarred by bad science. Author specifically states they are now correcting via satellite and other data not available in the previous record. So new “estimates” or “adjusted” values are apples and oranges. If (like news media does constantly) the numbers are “unprecedented” and “worst ever”, they are comparing new to old that doesn’t match. Stop justifying this. You should be adjusting new methods Down to compare with historical methods, or ensure comparisons are not made. You sir, have no actual clothes on.
“This is why all real scientists are paying the price for not standing up to the joke that climate science has become.” Mr Nail, meet Mr Head.
@ur momisugly David
Yes, good point.
I have trouble believing ANY so-called scientist working in the climate field. There must be some honest people working in the field but the dishonest con-artists are such a vast majority that I don’t trust any of them.
I encouraged you to take a look at the paper that I wrote last year along with Chris Landsea at NHC discussing recent trends in Category 4-5 hurricanes. We show how some of the changing observational techniques likely led to underestimates in TC intensity prior to 1990 or so:
http://tropical.atmos.colostate.edu/Includes/Documents/Publications/klotzbachlandsea2015.pdf
That’s not the point, Phil. Have you, or anyone else, ever taken a public stand against Kevin Trenberth’s repeated public misrepresentations that intense hurricanes are the ‘new normal’ due to climate change(sic)? If so, when? We all missed it.
Phil, even if you are apolitical and you want your work (and referenced paper) to represent your professionalism, you still need to recognize that the information that you (through the NHC) release to the media, has been hyped and twisted by both the media and the politicians.
When the media and/or the politicians use you (through your NHC news releases) as a tool to push their separate agenda (be it hype to sell airtime, or an attempt shore up climate followers in an election) you need to protect yourself from that association. You need to say they are wrong for trying to interpret/twist your works in a manner that will ultimately harm your ability to communicate with the public in the future.
Please speak for yourself. You don’t appear to have read the Klotzbach/Gray hurricane forecasts, some of which I’ve posted here. As Phil became the lead author of them, Bill started writing more critically about claims that climate change was bringing bigger storms. I think he especially addressed Kerry Emmanuel’s claims. In terms of tropical storms, he was a more prominent voice than Trenberth.
I’m at work, so I don’t have time to link to one of the Klotzbach/Gray forecast or my posts here, where I probably pointed out Gray’s commentary. Perhaps you can take a little time and do a little reading yourself.
Ric Werme, my comments were addressed to Phil. I’m aware of Bill Gray’s critical comments and have watched one or two of his presentations. He’s a hero.
However, Phil was responding to the posts of Robert of Texas and markstoval, who asked where the honest scientists are who stand up publicly to the falsehoods loudly and incessantly promoted by AGW consensus science-impostures.
Phil’s reply was that he had published honest science. I’ve no doubt about that. But the field of battle for honesty and integrity in climate science is political and public, not in scientific journalism.
That was the point Robert and mark made, and that Phil (and you) apparently side-stepped.
Not quite sure what you mean here. Publishing in peer-reviewed journals is a scientific “public stand”. For example, I published a paper in 2006 discussing issues with papers published in 2004/2005 that received tons of media attention. Of course, publishing papers saying that TCs aren’t necessarily getting worse isn’t going to get the same kind of media attention. And, let’s just say, at the age of 26 (at the time), I wasn’t going to get the same publicity as someone with the stature of Dr. Gray received. Since I worked very closely with him at the time (and did until his death earlier this year), we decided that it made a lot more sense for him to handle most of the publicity aspects.
But if you prefer other public means, you can see many recent posts on my Twitter feed (@philklotzbach) where I discuss trends (or lack thereof) in TC activity. Dr. Gray and I also included a lengthy discussion on our seasonal hurricane forecasts for many years about TCs/climate change. Several of our press releases discussing our seasonal hurricane forecasts also delved into this issue. I also recently did an AMA on Reddit where that topic was discussed quite a bit. I’d say that I’ve done a pretty good job of stating my take on the issue publicly. Similarly, Ryan Maue at Weatherbell has also done an excellent job describing the TC/climate change both in published research as well as via his Twitter feed.
I remember a bedtime story about this as a kid.
The Boy Who Cried Wolf used this same storyline.
Who knew it was really possible to stir up a whole town?
Al Gore
“sustained winds” would indeed average their sustained number whether it was a one minute interval average or 8 minutes…….words do have meanings “sustained” means staying AT or ABOVE the stated wind speed…….the excuses used are an insult to intelligent people…..
The shorter the wind averaging time, the stronger the reported winds…of course, they are gabbing gusts..not sustained
It would have also helped their credibly if they had told people how small the eye was…it spun down, making eye wall winds faster (I hate “stronger”)
grabbing
“Grabbing” is clear in context, Latitude. “Gabbing gusts” is the politicians’ and TV journalists’ speciality.
“Stronger” is a legitimate descriptor. The problem with winds is what? They blow things down–with force. So, the relevant parameter of concern is the dynamic pressure of the wind, which is proportional to the SQUARE of the wind velocity. Works every time.
These aren’t going to be the same thing. For example, if you have one hour’s worth of wind measurements, you can naturally grab a 1-minute segment in that hour that is going to have a stronger wind speed (or alternatively lower wind speed) than if you grab an 8-minute segment. The World Meteorological Organization recommends a 0.88 correction for a 10-minute to 1-minute average, so for 8-minutes, we approximated 0.90.
The thing that caugt my attention was that the hurricane passed “almost” directly over the buoy but still gave “sub-optimal” placement. The excuses are build in even before the reporter finishes. Also other have commented on the adjustments between the 8 minute vs 1 minute data. How can you presume that it is 10-20 % higher wind speed because the lag is 1 minute vs minute, to me that is already suspected adjustments, could it not be lower?. Why not use 3 min data 6 min data and so on. To me this is manipulation As an aside would the storm mot have lost energy if it would have come on land sooner?
the lag is 1 minute vs minute” should be: “the lag is 1 minute vs 8 minutes”, sorry
Directly over is still suboptimal. Optimal would be a combination of being in the eyewall to the right of the path, perfect timing, and a moderate amount of luck.
Being in the right eyewall the vector addition of the storm’s forward motion and eyewall rotation is maximized. It would be least on the left side (a big break even at Florida’s distance) and in between for a direct hit.
The buoy problem is well known. It is a little like have your anemometer behind a building – when the wind is from the wrong direction you miss it altogether.
The Dropsonds have worked for 30 years at least (unless they have regressed since I used to work with them). The pre-mission calibrations are good assurance they will do what they were designed for. We had a few with dead transmitters, but that is what spares are for. Nothing worse than a crew coming back with no data from a dead transmitter.
The actual max windspeeds aren’t even throughout the eyewall, but only in a small area of that. A really compact storm’s max speeds can be missed if the station is not within a quarter of mile swath along the track.
I may have some doubts about the satellite estimates since they really depend on accurate modeling, but the aircraft estimates I am pretty certain of. When the two agree, I assume the model of the environment of the storm is pretty close and have more trust in the satellite estimates, but I am an amateur, although an experienced one, so take that opinion with the appropriate grains of NaCl.
Sure – and the average wind speed in a hurricane is only 5 mph, averaged over the month.
Sustained winds as opposed to gusts. That’s all it means.
As to insulting intelligent people, how would you know?
i DO “know” because my IQ falls in the top 1% of the population and indeed find their silly claims insulting…….i do note your lame attempt to insult me…..FAIL.
Top 1%? Is that all?
Regardless, your posts belies your claim.
I’d be more concerned about the hype promoted by the news media than reports made by the NHC.
+1
Buoys provide the most accurate measure of all the tools discussed. 8 minute is the standard! The Storm tracked along the coast barely breaking 20ft seas with winds less than 60 knot 8 min average; which is not what you would get from a Cat 4.. this from buoys that were within 20miles of the center and one that the storm tracked directly over. Even NHC normally uses buoy data when its available. an actual CAT 4 off the coast like that would have killed thousands, which is what happened last time a big storm rolled along that coast. It is very disturbing to see good buoy data being ignored. I personally think that hanging out for any hurricane is a serious mistake but when someone “survives a cat 4” getting them to evacuate becomes virtually impossible.
..exactly right David
Now they want to move the goal posts again……today’s cat 4 is yesterday’s cat 2….because buoys are no longer the gold standard
Now they have computer models to tell them the sustained winds.
Given that Matthew’s MSLP was ~940 mb at the time when the buoy was measuring those winds, it would require an extraordinarily large wind field (aka Sandy) to have winds that weak in the eyewall. In terms of size, Matthew was not particularly noteworthy for a hurricane with a 940 mb central pressure. If you look at most hurricanes of the past, very few sustained hurricane-force winds above about 85 mph are reported. For example, both the Freeport and Nassau Airport stations stopped reporting just as Matthew was coming ashore. Exuma Airport in the Bahamas did report a very impressive max wind of 119 mph with gusts to 144 mph as Matthew came ashore.
Phil, I have been at sea in hurricane force winds, 25ft seas for as long as Mathew was around is extra ordinarily small for a cat 4. A good gale can achieve that given time. My wind anemometer worked just fine and the buoys NOAA uses are not small and they also work fine. I get what your trying to say, there are certainly difficulties in measuring wind speed but Mathew did not leave the kind of damage behind that a prior to Safir Simpson hurricane (1972 or so) would have left. The primary determination of hurricane strength is not wind per se but destruction caused by that wind. Which is typically what the reanalysis will show since most of the time anemometers don’t last out a severe storm. Hype is awful when used over and over. Most of the people who live in hurricane prone areas completely ignore advice. That is the real danger! Bringing some truth to the hype is necessary to restore trust. NHC removed the Sampson part of the scale back in 2010 and they have gotten a bit weird about storm strength since then. They need to get back to a practical calculable means of forecasting the actual strength of a storm. Certainly the reanalysis of Mathew should be interesting unless politics have gotten involved in that as well.
Photos of surface damage confirm the buoy. Land based anemometers confirm the buoys and the actual surface damage.
Mathew was Category 1 over the Bahamas. Mathew was tropical storm at US landfall.
That’s a very confident assessment. I believe it takes a bit more than Category 1 winds to overturn cars:
https://twitter.com/donavoncurtis/status/784489432816685056
If you look a little deeper at damage photos from the Bahamas, they were pretty significant. Roofs ripped off of houses and trees virtually completed removed of foliage.
One overturned car, the rest are fine. That’s Category 1.
One photo of light weight aluminum awnings, some tree limbs. All consistent with Category 1.
I’ve looked at dozens of other photos of the Bahamas that are all consistent with Category 1, no exceptions. Gusts knock over vehicles on highways all the time. I’ve seen decades of midwest tornado damage and plenty of photos. I’ve looked at structural damage assessments by qualified engineers and insurance companies that know exactly and quantitatively what wind speeds and exposure times correlate with observed damage.
For those who don’t know about Saffir-Simpson Category 1. Here is the short definition.
Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.
Any photos of Category 2 damage in the Bahamas?? Any evidence or data showing Category 2 winds anywhere in the Bahamas?? Of course not, because there were no sustained winds of that force. The photos are selected by passers-by to show what they thought was significant damage.
One consistent theme, a hurricane (cat 1 too) have the potential to spawn tornados which can destroy a small area. so the strength of the storm is demonstrated by widespread damage not just a single car turned over. Tornado wind speed is not what the storm as a whole is rated by. so yes Bahamas were most likely hit with a cat 1. if Mathew had been major when it hit the Bahamas you would get more than roof damage. wide areas of homes would be gone areas would be treeless. When Katrina went north through Mississippi it even though it had calmed down a bit there was a near 30 mile wide area of total destruction that the media ignored because it wasn’t New Orleans.
Probably my own bias but it seemed to me the storm held a “cat 3” status well beyond what I would have considered reasonable. Seemed like there may have been a hope to break the cat 3/US landfall drought.
> cat 2 (by 2004 standards anyway) is where I dust off the generator.
I understand the precautionary principle but for whatever reason this was a blown forecast. It used to be that category was a combination of wind speed and pressure; I thought I read that they’ve dropped pressure from the parameters?
I had no idea the 8 minute average was a standard. For NWS ground measurements I was sure it was a 1 minute average, but I’m going to verify that before I make that claim again!
Thanks Phil – I learned something. 🙂
Ric, it appears that a 1-minute average is the standard, but buoys are only set up to record 8-minute averages. That seems like a mistake to me – if there exists a standard then buoys should be designed to meet that standard.
Klotzbach’s point about shelter from waves is interesting. It means that buoys should be principally used to determine gust strength, which itself can give some idea of plausible sustained winds.
Rich.
The standard set by the WMO is 10minute wind average. its been 8 on the buoys for ever so changing the standard means the buoy data is no longer comparable. 8 is the standard. NHC uses one minute because you can’t really get a 8minute reading from an aircraft (moving too fast to read in one area for that long) NHC likes their aircraft which all that info has to be inferred, There are many problems with aircraft data they don’t like to talk about but Phil was nice enough to put some of it out there.
David, thanks, that’s interesting, and I didn’t know that. So it becomes more apples and oranges again. Unless…
In this day and age we can be sophisticated enough to record multiple data streams. So, the 8-minute values could be kept for historical comparisons, and 1-minute values could be recorded as well for comparison with NHC (and with WMO who also use 1 minute values?). There is so much that could be done to get better data, but nobody seems interested.
Rich.
When we recorded weather data for the NWS at the Kennedy Space Center. The sustained wind program was written to record a 2 minute moving average updated every 5 seconds.
My quick read may have missed it but the hurricane quadrant being measured is also important. In the northern hemisphere the Coriolis force assures that the wind around a low will always be counter clockwise. Considering the direction of motion of the hurricane itself to be the ‘front’, the right hand quadrant will always have a greater ground wind speed than any other quadrant because the speed of the storm is added to this sector and subtracted from the opposite measurement. If a speed sensor is not placed there it will not be able to measure the highest wind speed. Similarly, if that portion of the hurricane doesn’t pass over the ground the apparent measured speed will be lower than the actual max sustained wind.
I recall that Nassau, Bahamas received a near direct hit when Matthew was still category 4. Here’s the aftermath:
http://eleutheranews.com/?p=6765
—
Bahamas Marinas Ready And Open For Early Fall-Winter Season
By Staff2 / in Business, Highlight / on Saturday, 22 Oct 2016 11:44 AM
NASSAU, THE BAHAMAS – The 47 marina and allied members of the Association of Bahamas Marinas are open for business and are anticipating a busy winter season, almost all members having experienced no significant damage during the recent hurricane Matthew.
Matthew’s small eye passed over Old Bahama Bay Resort & Yacht Harbour. Even at category 4, the marina and resort did extremely well and suffered little damage. The marina continues to receive and welcome yachts, although power is yet to be restored. Many yachts have their own-power generating capacity. The resort itself escaped damage and will open once power is back.
ABM members were reporting full restoration of power and water to their docks and resorts within a day or two of the hurricane, the small eye of which traveled over the Exumas, Nassau, Chub Cay and Grand Bahama Island. All the Exuma marinas including Highbourne Cay and The Marina at Emerald Bay (Sandals) reported no or slight damage with Safe Harbour at Cave Cay soon to repair two damaged docks and fully operational with other docks.
In Nassau and Paradise Island, all marinas escaped unscathed. In the harbour, Bay Street Marina and Nassau Yacht Haven reported no damage and are fully functional. Palm Cay on the southeast coast of New Providence only had a couple of channel markers misplaced while marinas at Lyford Cay and Albany were undamaged. Albany chose to close temporarily to cleanup foliage and make the luxury estate pristine.
—
Photos of damage everywhere confirm that Mathew was not as strong as the NHC claims. Amazing that such a “powerful” hurricane can pass directly over populated areas with little wind damage.
That’s the point of the Saffir-Simpson scale, even if there were no measurements of wind speeds, the strength of the storm is determined by the surface damage. Trees, poles, roofs, metal signs, etc. all have known structural properties, over the years the known wind speeds are calibrated to the actual damage. Photos of the actual damage confirm the actual wind forces acting to create the damage. The actual wind forces causing the damage are recorded by the photos of the damage. Mathew was Category 1 at most over the Bahamas. The surface damage observed in Florida to North Carolina show less wind force, so the storm was weaker, tropical storm level.
In a sense it doesn’t matter who gets the velocities right. The impact of a revolving tropical storm can be extremely destructive. Certainly, as the good folk of Darwin found at Christmas 1974, a category 2 cyclone can destroy a whole city. I have experienced a category 5 cyclone in a company town that was designed to withstand 135mph winds. There was significant damage but, fortunately, no lives were lost, primarily because of building design and company rules which dictated how their employees protect themselves. I have no wish to ever encounter conditions in the eye of a cyclone again.
‘The northern Australian city of Darwin was devastated early on Christmas morning 1974 when hit by the tropical weather depression that was given the name Cyclone Tracy. As the eye of the cyclone passed over the city between midnight and 7am on Christmas morning, torrential rain fell and the winds were officially recorded at 217 kilometres per hour prior to the Bureau of Meteorology anemometer being destroyed.’
Hardly a Cat 2, Gary.
No way cyclone Tracey was a Cat 2 storm. They barely had low resolution sat pics back then and the destruction of the buildings and port were more consistent with a major cat 3 or 4 storm. My next door neighbour lived through it and told me how they survived by lying in a cast iron bath tub whilst watching their house explode around them. My sister lived through Cat 5 cyclone Vance in Exmouth Western Australia. She described watching a big 4×4 vehicle blowning down the road like a toy smashing into a house. She left town and never went back.
No way cyclone Tracey was a Cat 2 storm. They barely had low resolution sat pics back then and the destruction of the buildings and port were more consistent with a major cat 3 or 4 storm. My next door neighbour lived through it and told me how they survived by lying in a cast iron bath tub whilst watching their house explode around them. My sister lived through Cat 5 cyclone Vance in Exmouth Western Australia. She described watching a big 4×4 vehicle blowning down the road like a toy smashing into a house. She left town and never went back. Darwin post cyclone Tracey.
http://www.nma.gov.au/__data/assets/image/0011/448526/Wagaman-685w.jpg
This is a true, but, a highly-likely-to-mislead statement. It strongly implies, falsely, to the average reader, that hurricanes ARE getting worse, but, that we just “got lucky,” this time.
The truth of the matter is: regardless of how strong the winds were, there have not been any >= Cat. 4 hurricanes to make landfall in the United States for over 11 years. That fact is the significant one. To say, “we just got lucky,” is to say essentially, “Yes, hurricanes are ramping up, it’s just that they are all out at sea.”
THAT THEY ARE ALL OUT AT SEA (v.a v. the U.S.) IS THE POINT! 🙂
Language is important — always remember, we are fighting a battle for TRUTH (give the enemies of truth NO foot hold to launch an attack at you):
The AGWers run with such statements and will use it in their propaganda that hurricanes are worsening and that it is due to human CO2 emissions.
All you lukewarmers who like to talk about how human CO2 “causes” “some” warming — heads up:
if you do not at the same time, every time you say something like that, carefully (as a good scientist always does) clarify what you mean (i.e., that such “causation” is theoretical only, not measured (in the climate system called “earth”) AND that such theorized “warming” would be, if it is not, indeed, overwhelmed by natural warming, so slight as to be negligible vis a vis a climate shift on earth) YOU ARE HELPING THE ENEMIES OF SCIENCE.
The term “lucky” was in the colloquial email that I sent to Anthony, not in the article I wrote for CWG. But, if Matthew had come ashore, the results would have been much different for the state of Florida. That’s the challenge of forecasting a hurricane tracking parallel to the coastline. Very small changes in track have very large differences in impacts.
Dear Dr. Klotzbach,
You were BRILLIANT in your forecasting of Matthew. We, here, were so very impressed.
Thank you for taking the time to respond. I think you may have (due to my not writing clearly enough) not quite seen my point, but, that’s okay. I am often misunderstood around here!
Yes, indeed. It would have been a very bad situation if it had been farther west.
Dr. Gray would be so proud of you, carrying on the torch with such painstaking care to be accurate, and with such a bold willingness to stand up for what you know is right.
With admiration,
Janice
The FACT is that it didn’t come ashore … so why try and scare the bejesus out of people?
very early on, the climate catastrophists started prancing around with their rattles in great anticipation of what was to come- chanting numbers and predicting more freakin alpaca lips. and then, AS USUAL, it didn’t happen.
was anybody not expecting the fallback to be ‘we were so lucky to dodge the bullet but we will get our heads smashed like pumpkins dropped from the parking ramp NEXT TIME for sure!
hype is hype. no apology is acceptable.
Streetcred, because the next one might come ashore.
Matthew would have certainly been worse had it come ashore. We *were* lucky it stayed out to sea.
The Governor of Florida was criticized for supposedly hyping the threat, but it wouldn’t have been hype had the storm moved far enough west, no matter what category of hurricane it was. The Governor was properly cautious in such a situation.
What I glean mostly from this article, is measuring wind speeds inside hurricanes is not as precise as we might prefer.
MarkW … and they will all stay put because they’ve become desensitized to alarmism.
I think that the Bahamas tell us what Matthew would have been like if it had made landfall in Florida. Namely, Category 1 damage (as per bw’s comments upstream) in a few areas.
Richard.
I enjoyed reading this. Most folks think you attach an instrument and get a measurement … end of story. Instrumentation is an art and a science. If you don’t understand what you’re doing, you can be led seriously astray. The consequences range from embarrassment to death.
Dr. Klotzbach tells it like it is and gets my respect. The people who don’t get my respect insist that their results are +/- 0.1% when the data that they are using doesn’t even support +/- 10%.
+100 commieBob. I’ve had to try to figure out what the measurements meant from flight tests for a couple decades – instrumentation, IMHO, is much more art than science. I took a one-semester undergrad course in instrumentation – one of the most practical course I ever took.
Dr Klotzbach, thank you for your detailed article, and please recognize that for many here it has been so long since they’ve seen real science that they tend to suspect everything and everyone. As a lad on Long Island (NY), I spent several days in the basement, on several occasions, when major hurricanes passed over. I have gone out during the passage of the eye on two occasions and enjoyed how calm they were, especially since we then knew that the worst of the storm had passed.
Keep up the good work, keep warning people of the storms and the possible damage and loss of life, and keep providing regular updates to the storm track.
“I have gone out during the passage of the eye on two occasions and enjoyed how calm they were, especially since we then knew that the worst of the storm had passed.”
Hang on, if you are in the eye of the storm doesn’t that mean that you have suffered the winds in one quadrant of the eyewall, but are soon to suffer the winds in a different quadrant?
Rich.
OK, if they are going to do this they need to change the stated standards for classification. They says Buoys are not accurate because of masking by waves. And common sense rules out a dropsonde hanging at 10 meters above the surface for 1 minute to get a sustained wind reading. And satellite measurements at 10 meters above the surface are corrupted from spray, spume, and waves. Wind speeds at higher altitudes above the surface in these storms are much higher because of the lack or friction with the surface but there is no scale which grades the winds to say that if the wind is at a certain velocity at a particular level it will be at a particular velocity at another level. Their “estimates” are guesses and not hard data. So we see that they have positioned themselves to declare the strength of a tropical cyclone without anyone else being able to validate their claims.
It is simply impossible to state with definitive certainty the intensity of a hurricane at any point and time. The max winds typically are in only a small portion of the eyewall. NHC forecasts estimate that their error is about +- 8 mph with aircraft reconnaissance. With tropical cyclones out in the open ocean and estimations from satellite, these uncertainties are even larger. There is much more confidence in measurements of the central pressure of a hurricane than there are in the max winds given the relative ease of measuring this parameter.
yet that doesn’t seem to stop anybody from stating with lurid conviction the horrible devastation in store, does it?
first it was doom and now we’re gonna get precious about eyewalls and confidences?
what a swift pivot from ‘State of Emergency’, eh?
if nothing else, you suckers can dance a fandango like a burning spastic.
I suspect, that much like tornadoes, the true relative intensity should be from analysis of on ground destruction (or lack thereof), after the passing. From the number of people remaining behind after being required to leave by authorities, it would appear that some locals had also been “fooled” one too many times by the weather “experts” wild guesses and decided to take their chances. I remember when the predicted path of Katrina changed so many times that when they did decide that New Orleans was finally truly at risk, it was essentially too late. Would anyone argue from watching regular storm forecasts that they routinely heighten the risk just in case they are wrong? Another thing I hate is the propensity to play with weather radar color intensity so that when it’s supposed to be “pouring” there is not even a sprinkle (or the radar area location is fouled up which is also believable). Much like the 7 day (or even 3 day) forecasts, it’s no wonder that many who actually pay attention treat these predictions as numerology..
Correct, surface damage directly measures wind force. Just test a stop sign in a wind tunnel. The sign bends over consistently because the bending forces are known for the type of steel pole. Same for a wood wall, damage is proportional to wind forces. Over years of photographic evidence in different storms, with nearby anemometers, the strength of the storm is observed. Mathew was not a hurricane over the southeast US. The damage is entirely consistent with tropical storm force winds.
If we determine the “intensity” of a hurricane based solely upon ground destruction that leaves a few holes.
How do you measure intensity where the is no ground to be effected such as out-at-sea?
How do you measure destructive damage? Reverse engineer the force needed to create such damage?
Surely one cannot categorize ground damage based upon monetary damages or else Haiti will never see anything larger than a Cat 1 as there isn’t enough valuable property to damage.
Other than in the Atlantic (and very rarely in the NE Pacific), all estimates of hurricane intensity at sea are derived from satellite imagery. Aircraft reconnaissance are a luxury for us in the Atlantic basin, and in the NW Pacific through 1987. On a positive note, the NW Pacific will start up limited aircraft reconnaissance again next year.
In the early 80s we used to fly them out of Guam. Even when we closed that squadron the unit at Keesler used to deploy a plane out to fly the peak of the season. Of course that all wrapped up by the late 80s
I am sorry, but your analysis and report have one really massive glaring problem.
Historical Data.
The Hurricanes/Typhoons/Tornadoes that DID devestate areas of the US and the Pacific had ground based Wind Speed measurements comensurate with the damage that they caused.
So basically you are bringing in to question all that historic data which was measured using just ground based instruments and the very Grading Systems currently in use.
It is therefore incumbent on the Scientists to try and ensure that other methods match those ground based instruments for Grading Purposes.
Modern Techniques may be better for understanding Weather Events but should not be used to Hype (compared to ground measurements) current and future events.
It is much like modern Electronic Thermometers that pick up Transient temperatures that the old Mercury ones could not, should not be used for establishing “Record” temperatures unless they can be verified by the old technique.
Otherwise we are trying to compare apples & oranges.
A C Osborn; that was exactly my thoughts as I was reading. While I don’t see any errors in the essay, what I got from it is that historic hurricane data needs to be padded up, which would suggest that hurricanes are actually trending down.
“If the eyewall of Hurricane Matthew had been 50 miles further west, it would have been devastating for the east coast of Florida,”
This statement looks like hype to me. Are we being no asked to consider that if the storm would have cost great havoc across the entire coast? If the eyewall of Hurricane Matthew had been 50 miles further west, it would have been devastating for “some portion of the” east coast of Florida – but hitting land would have slowed it down. It would not have traversed the entire length of Florida at the same speed and intensity if it were 50 miles further west. Am I. Issuing something?
Sorry-most glaring typos fixed.
“If the eyewall of Hurricane Matthew had been 50 miles further west, it would have been devastating for the east coast of Florida,”
This statement looks like hype to me. Are we being asked to consider that the storm would have caused great havoc across the entire Florida coast? If the eyewall of Hurricane Matthew had been 50 miles further west, it would have been devastating for “some portion of the” east coast of Florida – but hitting land would have slowed it down. It would not have traversed the entire length of Florida at the same speed and intensity if it were 50 miles further west. Am I missing something?
missing nothing. 50 miles west would have been a major speedbump.
only thing i think you left out is IT DID NOT HAPPEN- which, after all, is the reality that brings forth the apologia for the sick fantasies.
and next time a kitten sneezes it will have a name like HURRICANE TROGDOR because they are such careful scientists, doing their best. they only need more resources, you know. some airplanes would be great. learjets, maybe. and some lavish funding. maybe a supercomputer. because
HEAP BIG WARMY.
Why not also announce what would have happened if the hurricane had been 50 mi further east too? I agree the 50 mi west statement and the “luck” statement are hype.
“If the eyewall of Hurricane Matthew had been 50 miles further west, it would have been devastating for “some portion of the” east coast of Florida – but hitting land would have slowed it down. It would not have traversed the entire length of Florida at the same speed and intensity if it were 50 miles further west. Am I missing something?”
That “some portion” of Florida would have been hit very hard. As far as I know, noone has claimed a hurricane would maintain its intensity the full length of Florida, once it hit land.
Of course the hurricane will lose intensity as it moves inland, but the people who get the direct hit from a hurricane will get the full intensity of the hurricane. Since you don’t know the exact path of the hurricane, you have to warn the whole area because somewhere in that area the hurricane will hit that “some portion”.
I don’t think the hurricane warnings were overblown at all. They were reasonable under the circumstances.
What was overblown was the supposed connection between hurricanes and human-caused climate change, that Hillary Clinton and other alarmists were trying to make.
If, as stated, the hurricane was moving parallel to the coastline, a little distance makes a big difference.
Think of it this way: cyclones are vortices, and the winds subject to vortex flow have a velocity that is inversely proportional to the distance from the center of the vortex (eye of the hurricane). The closer to the eye, the faster they go–up to a point where vortical flow breaks down and the core of the vortex must actually rotate like a phonograph record (velocity linearly declines with radius). But the blowing force of a wind is simply its dynamic pressure, which is proportional to the square of its velocity. This means that the wind force is inversely proportional to the SQUARE of the distance from the center of the hurricane. I don’t know how far that 50 mile point would have been, but this means that if the hurricane came close enough that the distance to its center dropped in half, the force of the winds would have been 4 times greater.
To press the point, a 40 mph wind has 4 times the dynamic pressure of a 20 mph wind. And an 80 mph wind has 4 times the dynamic pressure of a 40 mph wind. It grows rather fast.
Al Gore greatly disappointed. He was waiting in the wings to gloat.
==============
I am not qualified to post an opinion here — but when did that ever stop me?
It seems to me that searching out the highest wind speed of a storm is sort of “cherry picking’. That is made plain in the article where the highest wind speed of Matthew was located in a small area of the storm. So the methodology seems to be — keep looking till you find what you want to find.
Such a small area was affected by this “highest wind speed” that you have to wonder how highest wind speed has come to define the potential destructive power of a hurricane? Has anyone ever shown that this metric, highest wind speed, in any way relates to the storm’s average intensity? Would not the “average wind speed” of a hurricane be a better metric for determining its potential destructive power?
I think “highest wind speed” is a bit of useless data that tells very little about a hurricane. I think Phil Klotzback is just defending the “old ways of doing business” rather than questioning the old ways and looking for better. He needs to rethink his approach.
And that is my unqualified opinion.
Eugene WR Gallun
This would pose very challenging. You would have to decide a specific radius in which to average wind speeds. Some hurricanes may have very strong winds in the eyewall (like Hurricane Seymour in the NE Pacific recently), but these hurricane-force winds may only extend ~10-20 miles out from the center. Also in highly sheared situations, hurricanes may have strong winds on one side with much weaker winds on the other side. The average wind would represent a wind that was actually unlikely to occur in that region.
There is also a great variance in the actual diameter of a tropical cyclone even within a given category. Andrew was a very compact CAT V for example. With that in mind and making it clear that I am now sure how well pressures correlate to wind velocities I’m thinking your correct about pressure being the metric for classification but not just minimum pressure as measured at a point in the eye wall. Perhaps pressures taken at set of standard distances from the eye wall?
Now should have been “not”. Sorry for the fat finger.
Dr. Phil Klotzbach — Thank you for your reply. Almost everybody just ignores me.
But “highest wind speed” is likely to occur almost no place doing a hurricane.
Giving your reply some very quick thought — Deciding on a specific radius in which to average wind speeds
seems wrong for the reasons you stated.
!) The destruction caused by a hurricane cannot be used post facto to measure its potential destructive level. When I was a kid when a hurricane was going to hit Florida this question was always asked — was it going to hit a city or come ashore somewhere on the undeveloped and unpopulated coastline? That question is no longer askable. For Katrina a levee broke in New Orleans and the flooding caused most of the damage, New Orleans being below sea level. Hurricane Sandy and the Hurricane of 1938 (the worser hurricane) had one thing in common. They both came straight out of the Atlantic and headed due west and drove straight inland. (Sandy, the weaker storm, just picked a terrible time and place to come ashore.) All other hurricanes in that area came up along the coast, half of the storm still over the water and not affecting the land.
2) So maybe what we need is the size of the round area in which hurricane level winds blow.. This would be broken down into lesser circles of higher wind speeds as the center was approached. (There could be a still problem because I believe hurricane winds speeds are somewhat lopsided.) But hurricanes are not stable. They get bigger and stronger and they also shrink and get weaker. So that metric would constantly need remeasuring. And since it is a new metric it would take time to figure out what it is actually telling us, if anything.
3) There has got to be a better method than “highest wind speed”. Hey, you’re the hurricane scientist so go do your thing and figure it out and maybe win yourself a Noble Prize. The pinko, socialist, commies of the left are just licking their chops desperately wanting to hand out a Noble for climate work.
Well, now you know why almost everybody just ignores me. Did i mention to you that I am the world’s ONLY expert on how to translate Biblical Hebrew? They ignore me also.
Eugene WR Gallun
PS — I have spent the last three days passing, not one, not two but three gall stones. I claim the pain has driven me crazy.
Hi, Mr. Gallun,
Hope you are feeling okay, today.
Your neighbor to the distant north,
Janice
P.S. Being ignored is tough and I can empathize. To help yourself realize that it is the lot of 90% of the commenters (to be ignored most of the time), notice how many, MANY, interesting and or witty remarks go unresponded to day after day. And also, to help yourself realize that you are being READ, note how many comments you smile at or nod your head at, thinking, “That was a good comment (or the like)” but do not say anything. Sometimes, I think there should be more threads where conversation is encouraged. I have heard (C.S. Lewis believed this to be true) that men are much less “epistolary” than women on the average (he received FAR more letters from female readers), thus, they do not enjoy “correspondence” of ANY sort. There is a fairly high percentage of men, here. HANG IN THERE, Mr. Gallun — there are some who will write back (Marcus would be a fun pen pal for you — but, sadly, he is still on moderation).
P.P.S. And some of us would write more in response to more people, but we are regularly castigated for it by the WUWT curmudgeons.
Phil, then how about a range of wind speeds n/s & e/w of the eye?
NHC provides much more information in their forecast advisories than just the max wind/minimum pressure. They provide radii of 34-knot, 50-knot and 64-knot winds in four quadrants (NE, NW, SW, SE). They also provide a wide variety of graphical tools of potential wind and surge impacts.
Janice wrote to Eugene: “To help yourself realize that it is the lot of 90% of the commenters (to be ignored most of the time), notice how many, MANY, interesting and or witty remarks go unresponded to day after day. And also, to help yourself realize that you are being READ,”
That’s right, Eugene. You are being read. And there are SO many witty posts on this website. Many, many, times I feel like complimenting someone on something, or telling them how funny they are, but I refrain for one reason or another. I bet there are a lot of people like me.
Lots of good comments on this website. I laugh out loud a LOT reading here. It’s a lot of fun. And educational.
I don’t want to pose as an expert, but I have had some education in statistics, and two things I learned apply here:
(1) summarising data with just one number is always misleading. Real phenomena vary. Even a range is misleading, but at least it’s less misleading.
(2) (estimates of) extremes are unreliable.
In particular, while it’s true that “the average wind would represent a wind that was actually unlikely to occur in that region”, the maximum wind represents a wind that is ALMOST CERTAIN to fail to occur in most of the hurricane. It is, if you like, one of the *least* representative measures possible.
I can imagine, but I hope the NHC have some real data we could be enlightened by, that the maximum wind speed of a hurricane might vary a lot over time even while its total energy remained fairly constant.
Of course, if I’ve read the article correctly, while the maximum wind speed is hard to measure, measuring ANYTHING inside a hurricane is fraught with difficulty, so it’s not clear what could be done that’s better.
Safir designed his scale idea based on wind speed damage from an engineers perspective. Since then a team of folks at NHC have been updating this standard. This standard was designed in the 70’s and we have category estimates that discuss stoms in terms of categories back in before the standard also determined by damage. What I am not sure about is if Safir intended for a one minute average to be used. It would be interesting to see his original math.
David Riser
No matter what the math says what is in question is the NOAA standard for classifying storms based on the Safir-Simpson scale. Here is the NOAA standard as stated here:
http://www.nhc.noaa.gov/pdf/sshws.pdf
” The maximum sustained surface wind speed (peak 1-minute wind at the standard meteorological observation height of 10 m [33 ft] over unobstructed exposure) associated with the cyclone is the determining factor in the scale.”
As we have been informed by multiple authorities now, it is most often impossible to obtain the wind speed data for this metric.
Maybe some one should design an instrument that can survive the strongest hurricane, while measuring wind speed using that metric.
anemometers rarely fail due to wind speed per se. I have certainly watched my anemometer on the ship clock steady 100+ knot winds. The failure is almost always related to flying objects. In the case of buoys its spray or dunking that does it. NOAA buoys are built to hang tough in the roughest environment without dumping the package into the water. Failure for anemometers is of two types, catastrophic and age. age related they slow down relative to wind. but they have to be pretty old for that to happen.
Janice Moore —
Thank you for your kind words of comfort. Have you ever heard the expression — “sympathy for the Devil”? Here is a poem i wrote a number of years ago.
THE DEVOUT OF DELA
As evening over Dela spreads
We heed the Temple horns
And bind the roses round our heads
Still guarded by their thorns
For in the holy songs we sing
The prophets make it plain
Whatever gifts the gods may bring
They also bring us pain
The gods create, the gods destroy
We live beneath their sword
The gods will do what brings them joy
We pray to be ignored
Here is another poem that deals in one part with a similar idea.
THE BEST OF A BAD GENERATION
or
THE POETIC CAREER OF A DIRTY OLD MAN
On stage butt-naked with his cock getting hard
Berating old Moloch and burning the flag
A closet pedophile — in public a fag
Crazy like his mommy with her Commie card
And then after forty years of avant-garde
As con-artist, Zen-fakir and Beatnik scag
The old humbug pulled a last trick from his bag
And donned cap and gown — an academie bard?????
Life, perhaps, does make hypocrites of us all
Our best shot may be the shallowness of fame
But when Time, the slow reader, speaks of his name
The godhead of Ginsberg — will get very small
He was one part a poet, nine parts a fake
Vachel Lindsay in vitro — no William Blake
Eugene WR Gallun
If you prepare for average winds, those who get hit by the highest winds are going to die.
But if you *predict* the highest winds based on measured averages, at least you will have predictions based on more data.
When I was working on https://wattsupwiththat.com/2016/06/05/summer-of-1816-in-new-hampshire-a-tale-of-two-freezes/ I was intrigued that the average temperature back then was typically the average of morning, afternoon, and evening temperatures, e.g. 6:00 AM, 1:00 PM, and 9:00 PM, with the evening temperature counted twice. Presumably that was because the evening temperature was more representative than the morning or afternoon temperatures.
Once Max/Min thermometers were invented, I presume that helped encourage our continuing focus on extremes. For future metrics, it may be worth looking at less extreme measurements, but for things with a long historical record we pretty much need to stick with what we do now.
Dr. Klotzbach is absolutely correct in his assessment, and we can be assured that he is no warmist “adjusting” data for nefarious purposes. So modern methodologies use a variety of airborne, satellite, radar, and surface observations to define a more precise peak wind within a hurricane. My concern is that modern measurements of a hurricane categories at landfall are being compared to hurricanes a century ago whose landfall strength would be underestimated by a category or two due to much less complete data (no satellites or aircraft, less coastal development to indicate the peak damage, and only scattered anemometers that often failed). Which leaves us with recent hurricanes being “accurately” categorizd, being compared climatologically with older hurricanes that are underestimate.
Unwittingly, this is statistically comparable to lowering early temperatures relative to recent ones to up the trend. Unless, of course, the assessments of earlier hurricanes somehow take the sparse data into account – perhaps by informed interpretation of pressures?
BTW, I’d like to thank Dr. Klotzbach for carrying on the good work of our late hero, Dr. Bill Gray.
Very good.
This.
Plus as I wrote up post, the current Grading/Rating System is based on those old ground based measurements.
To be consistent we should have 2 grading systems one continuing the use of Ground based Instruments and another for Satellite “ESTIMATED” values.
Or as mentioned by Mr Keen are you going to go back and increase all the old Values to get a proper single scale
As I mentioned before, in all other global tropical cyclone basins (except for the NW Pacific from the late 1940s to 1987), satellite is the only tool used to estimate hurricane intensity. The majority of North Atlantic hurricanes and tropical cyclones also have their intensity estimated from satellite imagery. It’s only when they threaten land (or encounter a ship) that these other techniques are employed. The reason that the Hurricane Hunter planes are employed is to measure winds both at flight level (10000 feet), but also to release dropsondes and utilize the stepped-frequency microwave radiometer which estimates surface winds based on the state of the sea. The utilization of the sea state for estimating surface winds is a practice that has been long-utilized by the National Hurricane Center (since the 1950s).
For The Sake Of Argument:
I accept Dr. Klotzbach’s arguments at face value. There are better ways of measuring wind speed than previously existed.
Now:
We have a long history of hurricane data upon which the intensity scale, damage assessments (both before and after), historical patterns, number of storms, numbers of intense storms, etc., etc. are based. This data is sustained ground speed and is formally defined as as such. Note that whatever under-registering of wind speed is happening now has always happened in the record, and the record is based on it. Fair enough.
Now we introduce a new, improved method which produces results which are systematically higher. How much higher? Make up a number, perhaps 20%, perhaps 30% or more. In other words, a lot. Enough to be at odds with the whole of the historical record. Any scientist would recognize that you have introduced a systematic bias into the record. Without an attempt to create a cross calibration between the two measurement methods, this is about as bad an error as you can introduce into a data collection system.
At Best:
Use the traditional measurement for the traditional uses, particularly for likely damage. Use the new measurements for any new purposes.
Going Forward:
Sounds like a surface measurement to me. Take these readings where there are deep water buoys, shallow water buoys, and close by land stations. Compare data sets.
In other words:
Calibrate, Calibrate, Calibrate
Having two measurement systems which routinely differ by one full category on the S-S scale, and frequently differ by 2 full categories, is just not acceptable.
By relying on the new, higher values without any attempt to calibrate to historical data on the S-S scale, you trash the value of the historical hurricane record.
This is why we work so hard to eliminate systematic errors in long running data sets which so commonly occur when there is a change in instrumentation or methodology.
Also very good.
Absolutely spot on.
There must be some reason why the winds, once they reach land, are only 50% of that projected from the satellite measurements.
A most recent example being Hermine? I still have serious doubts it was a hurricane when it made land fall.
I too have serious doubts about Hermine.
hermine went right over top of me.
it rained.
some spanish moss blew off the oaks.
the weather gangsters shifted to a tale of how lucky we were and skulked off to look for another tyfun of doom so they could party on paranoia again asap.
hermine went right over top of me.
it rained.
some spanish moss blew off the oaks.
the doom mongers got precious about how it might would could may should next time.
So the strength of pre-satellite analysis hurricanes have been adjusted?
NHC has conducted a reanalysis of Atlantic hurricanes going back as far as 1851. Obviously there are large underestimates, especially as one goes back in time. There were also some over-estimates of winds in the late 1950s-early 1960s, when the MSLP/max wind relationship they were using was poorly chosen. Gabe Vecchi at GFDL has done some good work looking at potential underestimates in named storms and hurricanes prior to the satellite era using ship track measurements. When you include his estimates of missed hurricanes with the observed hurricanes, you see no trend in Atlantic hurricane activity since the late 19th century.
We can only estimate the winds in a hurricane. There is no way to consistently measure the peak winds in a hurricane, and even if we could, the peak wind probably fluctuates fairly rapidly in such dynamic storms.
There is another way to estimate the winds in a storm: by surveying the damage. If I remember correctly, that is how Hurricane Andrew in 1992 was raised from an estimated Category 4 storm at the time it hit southern Florida to a Category 5 storm after post analysis.
Since the hurricane winds are estimated, that means there is larger uncertainty than if we had direct measurements. My guess is that the uncertainty is somewhere around 10 to 20 percent most of the time, and sometimes larger, depending on the information available for making the estimates. Uncertainty of the peak wind estimates for historical hurricanes before the satellite era is probably much larger.
For hurricanes striking land, the peak winds are most likely to occur at the immediate coast where wind is blowing onshore. Even if there is a weather station right on the coast, like NOAA’s CMAN stations, if that measurement is at 10 meters above the surface in normal conditions, hurricane high tides may decrease the measurement height above the surface and wind driven waves may create surface roughness that decreases the winds substantially from what would be measured at 10 meters above the wave crests. As the wind moves inland from the coast, surface roughness increases rapidly in most populated areas, because of buildings and trees, and thus winds at 10 meters are almost always much lower even a few miles inland than on the immediate coast. There are always exceptions, and one I remember is Hurricane Celia which hit the Corpus Christi area in 1970. In that storm the Corpus Christi National Weather Service Office, about 22 miles inland from the Gulf of Mexico, measured a peak sustained “fastest mile” wind of 125 mph and peak gust to 161 mph according to the annual hurricane summary for 1970 reported in Monthly Weather Review. In those days the “fastest mile” wind was estimated from a chart recording of the anemometer output.
The effect of surface roughness is to greatly increase turbulence, which drags down wind speed averages much more than peak gusts. However, it is the gusts that cause most of the wind damage and probably provide the best indication of what damage might occur. The exposure of a 10 meter anemometer also plays a roll. Poorly exposed sites with nearby buildings and trees usually measure lower winds than well exposed sites in wide open spaces, like airport runways. Nearby buildings can sometimes cause very localized higher winds because of the Venturi effect. I remember an extreme wind gust measurement of 236 mph made in Guam during Typhoon Paka in 1997 was suspected of being enhanced by the position of the instrument relative to nearby buildings, and thus not representative of the larger area around the measurement location. Many anemometers are blown away or damaged before peak winds occur in a hurricane landfall and often power outages precede the peak winds so that wind measurements are lost from lack of backup power. So it’s tough to get good wind measurements during a hurricane landfall, even in a populated area.
At least Andrew had the decency to rip the anemometer off the NHC with a final reading of 200mph.
Well said.
Andrew damage was beyond anything in my 60 years. I went there a month after the storm, and saw what happened with my own eyes. In the damage path, almost everything above the surface was scraped clean. All trees were gone, some palm stumps. Mountains of debris were piled at every street corner. Over a 10 mile path, I saw one structure made of steel reinforced concrete that survived, it looked like someone had built a NASA blockhouse. Heavy steel girders and beams, such as those holding metal roofs over service stations and commercial buildings were twisted and mangled. Light steel structures were gone. All wood structures were gone. Temporary street lights were rigged, some of the heavy steel poles survived. And the structures in that area were mostly new enough to have been constructed under rules that are supposed to anticipate a direct hurricane strike.
It was a very grim scene, because it reminded me of photos of Hiroshima after the bomb.
It does not matter what talking heads say on TV, or politicians blather, you need to stay far away from any strong hurricane.
bw, it’s a miracle there was not a greater loss of life with Andrew. If the eyewall had hit the center of Miami instead of well to the south, damage and deaths would have been much higher. Thankfully the highest winds in the eyewalls of the most intense hurricanes usually impact an area not more than about 20 to 50 miles across and most commonly hit areas that are not as heavily populated as city centers. But like many natural disasters looming in the future, sooner or later a Category 5 hurricane will hit the center of cities like Miami, Tampa, New Orleans, and Houston. It’s just a matter of time. We don’t have a long enough record to estimate the frequency with much confidence, but my guesstimate would be about once every 200 to 500 years for such an event somewhere in the southeastern US. As coastal cities grow in population, the average recurrence interval will decrease just because there will be more and larger targets.
Please be careful about advocating a damage-based measurement system, First, for any given storm, it has no predictive value, as the damage has not yet occurred. But more importantly, damage will vary, for a given storm intensity, based upon the standards to which a building was built, how the area was affected by any storm surge and for such things as stop signs and trees, how well they were installed (the stop sign) and how saturated the ground was at the time (for trees). Damage assessment can be rather subjective.
Some of you may remember the great hurricane of 1987 that hit England – it uprooted thousands (maybe tens of thousands) of old-growth trees. I don’t think it did much other damage – can anyone comment on that? Does anyone have any assessment of the strength of that storm?
The Saffir-Simpson scale has been consistently confirmed for decades. Wind damage is proportional to wind speed.
Jim, I certainly don’t advocate a damage only assessment of hurricane wind strength at landfall. It’s just one more piece of the puzzle and occasionally a decisive piece as in the case of Andrew. It’s also all there is for estimating hurricane wind strength back before the days of wind instruments.
I was living in Broadstairs, Kent at the time and experienced the Great Storm of 1987. Though easily of hurricane force, technically it was not actually a hurricane but a very deep mid-latitudes depression. The anemometers at Dover Docks were rated to 110 knots, and were constantly off-scale at the height of the storm. Had it not struck in the small hours, hundreds of people would have died.
In the example above where an anemometer is hit by the eye wall, why would it measure low? Would we also conclude that all anemometers in every situation read low? If not, why just in huricanes?
I’m not trying to poke a hole in the explanation, I’m just trying to understand.
An anemometer is a physical device, and it may read low during high winds for many reasons:
– it may break if wind speeds exceed some threshold
– it may be unable to report wind speeds above some threshold (e.g., limitations on electronic signalling)
– it may be inaccurate for wind speeds outside a specific range (e.g., too much friction for turning paddles)
Once in the eye, not much wind. Resumes from another direction on leading the eye.
Anemometers are pretty sound. if they get the wind they will be accurate. Some silly model has no way to prove that t wind anemometer is not accurate. That being said the sources of error for a anemometer relates to a few things. bearing failure caused by age and wind not hitting the thing square. When you realize that wind is in three dimensions if it has a bit of updraft to it or downdraft your still just reading the forward part of the vector. Buoys have a vain that keeps them roughly into the wind but a confused sea can spin them a bit and they can get some blockage sometimes. overall though they are accurate up to failure unless they are already failing but you can usually spot this problem since at low wind speeds they wont spin at all. NOAA (NDBC) buoys manage this through paired sets of Anemometers which reduces error significantly.
The relevance of a hurricane varies with intensity, dwell time and location.
“If the eyewall of Hurricane Matthew had been 50 miles further west”
If I had some ham I could make a ham & cheese sandwich if I had some cheese.
Any discussion about hurricanes and their impact must consider the practical effect on populations. There are hurricanes that manifest off-shore that never hit land fall… and it is as if they never happened.
Matt Drudge recognized that the democrat party activists were aching for a devastating climate related event. Many people were hyping it, and Hillary was planning a trip to the projected landfall location.
voice of reason. rara avis.
Hah – I think we would have seen a landfall of Hillary instead, had she gone.
> The adjustment factor would be approximately 0.90, which means if a buoy measures 80-mph eight-minute average winds, the one-minute average wind would be about 89 mph.
Wouldn’t an adjustment factor of 0.90 with a measurement of 80 mph be 87 mph? (0.9 * 80 = 7.2)
Then Phil also wrote:
> The World Meteorological Organization recommends a 0.88 correction for a 10-minute to 1-minute average, so for 8-minutes, we approximated 0.90.
If you just rounded it to 0.9, that’s fine, but if you “made it a little bigger” because of the 10-8 minute difference, the adjustment-to-the-adjustment-factor went the wrong way. An 8-minute average should be closer (smaller adjustment) to a 1-minute average than adjusting a 10-minute to 1-minute.
Divide by 0.9 and you get 88.89 mph
When did satellite-measured wind speeds become part of the standard, and how did the agency ensure continuity with pre-satellite measurements?
That is, once satellite measurement is added to the mix, the greater precision appears to bias wind speed measurements up by removing some of the negative bias (AMSU measurements are outliers significantly above the line from 10/6-10/8), so if a storm would have previously been measured at wind speed X, would it now be reported as wind speed X + something, because of these more precise measurements?
I doubt that Matt Drudge is arguing that Hurricane Matthew was not harmful. It clearly was. I think his point is that National Hurricane Center has modified their measurement systems in such a way as they report storms at a higher wind speed than they did several decades ago.
The National Hurricane Center is constantly tweaking their methods. Their intent is to ensure more reliability. However, the result could be a bias in hurricane levels which would lead scientists to draw inappropriate conclusions from this biased data. The simple, obvious example is “Hurricanes are getting worse — therefore climate change is a contributor.
Personally, I think Drudge is right. Air pressure at the eye is not a perfect determinate of hurricane strength, but it is pretty reliable. Of the 31 category five Atlantic storms which have occurred since the beginning of record keeping, only three have had pressure higher than 934 millibars — Edith in 1971 (943 millibars); New England Hurricane of 1938 (940 millibars) and Matthew (934 millibars.)
Historically, those numbers are closer to the pressure in category 4 storms (these typically run 930-950 millibars). Category 4 storms can still cause plenty of damage — the only ones who really care about such differences are those trying to calculate ocean energy content for a research paper.
For those interested the wind map for the east coast is on page 37, other areas are on other pages,
The problem is this… Now you have hundreds of thousands of people from Cape Canaveral to Mayport who think they rode out a “Major” hurricane within a few miles of the beach. My own parents carried out one of the most stupid evacuations, from their house on the beach to a motel ONE MILE from the beach, and they think that was just great. A real “major” hurricane would have destroyed that motel.
What happens when alarmists keep crying wolf. Just like claim of 250mph winds off the Northwest coast about 2 weeks ago. Total B.S.