Jeff B says:
Are you using the maximum value for the entire storm system measured at 10m height from an unobstructed location? That’s the textbook standard for the Saffir-Simpson Scale. I was in Hurricane Rita near Houston and we saw mostly wind speeds like this at ground stations even though it came on shore as a Cat 3.
I pulled up every sea based weather station I could find. None showed sustained hurricane force winds, no matter how close or how far from the eye. I don’t know how much more unobstructed you can get from a sea based buoy or platform.
No, we use the accepted standard of a wetted finger held directly above the head to determine wind speed (ASTM 18439.211b). Saffir-Simpson has been proven unreliable.
NOAA’s press release says Irene is an unusual storm with higher winds at flight level, and lower winds at ground level….
They said to expect a 30% increase in winds 80-100 stories high.
They could not have measured 80 mph winds at ground level. If they did, you could have expected over 100 mph winds at 80-100 stories….and they would have measured at Cat 2 at flight level.
They measured 80 mph winds at flight level, a Cat 1
Using their own numbers, they could not have measured over 60 mph at ground level.
Unless someone is trying to say they measured a Cat 2 at flight level, and reported it as a Cat 1.
Hurricane Irene: Joe Bastardi interviewed on the Dennis Miller Radio Show, 8/25/11
A 4 to 8 foot storm surge is expected. and that is bad.
A 20 foot storm surge has hit New York before. And there has been 100 MPH winds in New York. A 50 foot storm surge (supposedly) hit Long Island in 1938.
http://www.youtube.com/watch?v=RwpW8JNrRdw
Extrapolation! A trick they learned from Big Jim or maybe he learned it from them as they Extrapolated historic values to get a global record when there were to few sites to have a reliable figure!
Chicken Little seems to be the fad of the day!
http://www.weather.gov/directives/sym/pd01006004curr.pdf
^^^The Saffir-Simpson Standard, not based on ground wind stations 20-80 miles away. Its a very specific standard. In Rita (Cat 3) we got max 50 mph sustained winds at most locations around Houston.
If you choose to use wind speed values at non-standard heights then look at the data from 4PM today when the Air Force WC-130J measured max sustained winds at 85-90 knots (104 mph) which would make Irene Cat 2. But the NHC doesn’t use wind values from arbitrary heights and arbitrary locations. They use max values sustained for one minute at 10m height from an unobstructed exposure.
That’s why you have this supposed difference between ground measurements and what the Air Force WC-130U pilots have measured.
And just in case you’re wondering, I’m a degreed chemist with 8 years experience in meteorological science and politically libertarian. This is not political for me.
I suppose the media would talk about the 104 MPH and not specify where it was measured and highlight the altitude differences in wind speed.
The wind speed at the surface is what determines the amount of wind damage, and the size of storm surge. Waves don’t care what is going on at 10,000 feet.
To be fair, winds slightly higher are important when considering Irene’s impact on NYC in terms of damage.
More comprehensive analysis in chart below. Reading buoys and AWOS data is going to skew your analysis too low, because the asymmetry in Irene’s eyewall led to the most intense surface winds manifesting on the right-hand side of the storm’s motion, where in situ measurements are sparse. Does remote sensing via satellite and radar not count as “observations” any more?
eh, chart is here: http://icons.wxug.com/hurricane/2011/irene_hwind_aug27.png
There is something seriously wrong with the output you provide. Compare the output to the contemporary observation at NWS station Manteo, NC. Output says 50 kts (57 MPH); observation says 37 MPH, at 1330Z, 0930L, 27 Aug.The output is inflating the winds by 55%. If this is a NWS product, it has a bad bug in it. I hope no one at NWS is relying on it or the subroutine which has the bug. The same inflation occurs at the Hatteras station.
Just in case you doubt the wind speeds we experienced from Hurricane Rita (Cat 3), check this data from LSU. Note this is peak gusts, not max sustained wind. Houston is Harris county on the map, max wind gusts were about 65mph.
http://lagic.lsu.edu/images/hurricanes/fema_advisories/rita/peakgusts.pdf
What is your point? Jefferson County was 125 MPH.
The point is that max sustained wind speeds from ground wind stations can be misleading in terms of storm strength. That’s not how you classify storms.
Well, no. First, this is re-analysis modeled winds reconstructed from the sparse data available while Rite made landfall – it’s not raw observations. Second, Based on this visualization, you aren’t justified in saying that Jefferson County experienced a maximum wind gust of 125 mph. At best, you can only say it experienced a max wind gust in the range of 111-125 mph. Choosing 125 mph is a dishonest inflation of the data in the chart by up to 10%.
Really, this entire episode you’ve taken the blog-o-sphere through this evening is an exercise in cherry picking. In situ observations of Hurricane Irene are sparse in time and space. It has already been pointed out that based on aircraft reconnaissance and doppler radar imaging, the most intense winds in Irene occurred offshore due to asymmetry in the storm’s eyewall – in a place where data is even MORE sparse.
If you want to allege that the NHC is engaging in fear-mongering by cherry-picking its own wind speed measurements so that it may continue to call Irene a hurricane, then go ahead and say it publicly and explicitly, and CC Bill Read on your allegation. The bottom line is that despite your incessant protests, Irene was observed to have a minimum central pressure in the range of a strong Cat 2 or weak Cat 3 hurricane during landfall, and both aircraft reconnaissance and remote sensing substantiated winds equivalent to a Cat 1 hurricane during landfall. So at the end of the day, you’re wrong, and Irene was (and still is) a Hurricane.
Jeff:
Take it up with NOAA as they changed the rules. A storm is determined by extrapolation rather than actual measurements! They looked at their satellite images, ran a few figures through a computer and said this storm has winds of X MPH! Extrapolation/ WAG!
“If you want to allege that the NHC is engaging in fear-mongering by cherry-picking its own wind speed measurements so that it may continue to call Irene a hurricane, then go ahead and say it publicly and explicitly,….”
I really don’t know how much more publicly and explicitly he can state it.
But John, here’s the thing, the divergence of the various reported wind speeds are too great. And while Steve’s approach may not have been to your liking, at the end of the day, it will be call a hurricane because some one believes some measurements over others…… or models…..or extrapolation ….. or whatever.
Maybe NHC is the exception to the rule, maybe there is an honest agency out there. But, I’m underwhelmed by the force of the argument.
In the end, it is because they say it is…….ok. Now, be sure to send the entire eastern sea board into a panic because wind speeds out in sea are scary, and ignore the reported wind speeds that actually effect someone. Nice.
suyts:
The asymmetry in the eye was noted by meteorologists – even TV guys like on the Weather Channel – over 16 hours before landfall, and was touted as call for a “sigh of relief” that Irene would pack less of a punch than feared. Your big problem is that you *don’t want* to place any trust whatsoever in the NHC or NOAA; you *want* them to fail at their mission of predicting Irene for some bizarre reason.
You can bemoan “extrapolations” and “models” all you want. But the reason we have them – as well as remote sensing via doppler radar and satellites and aircraft recon – is because in situ measurements are insufficient for understanding the atmosphere and for meteorological purposes.
Your entire argument is a null point. Steve is arguing that their isn’t evidence to support Irene being classified as a Hurricane. By definition, a hurricane needs to have sustained 1-minute, 10m AGL wind speeds greater than or equal to 74 mph. It doesn’t matter the provenace of those measurements – doppler radar is just as valid as you standing on a shed holding an anemometer in the storm. That requirement has been more than satisified over the past 24 hours, and continues to be satisfied to the present time.
JeffB:
The NWS is not measuring at 10M but extrapolating with a model. Since late last night this was just a big storm. I have been through a few storms and have seen what micro bursts can do. It was just considered wind damage because no one thought to name it.
But then I also spent the night with Fran in North Carolina! I know why she got a name!
“Since late last night this was just a big storm. I have been through a few storms and have seen what micro bursts can do. It was just considered wind damage because no one thought to name it.”
I’ve seen too. Microbursts (by definition) affect an area of < 3 miles. Although they tend to do damage in a straight line, let's be generous and say that they affect a land surface area of about 9 square miles. They also tend to last a few minutes at most before their gust front dissipates.
Irene had a radius of hurricane-force winds at landfall of about 100 miles, which means that an area of 10,000 square miles could experience sustained hurricane-force winds – about equivalent to a mid-grade microburst. Irene is moving at about 20 mph, so if you lie directly on a diameter of the storm, that means that you'd be experiencing hurricane force winds for about 10 hours.
So by our crude estimate, Irene is 1,000 times bigger than a microburst and lasts about 300 times longer. If that's your criteria for "just a bit storm", then the thought of what might constitute dangerous weather really terrifies me.
My wind speed was bigger than your wind speed. Nah, nah, nah-nah. I love this blog
Biff:
Wind speed is the deciding factor in determining the category of a storm and it is the difference between a hurricane and a tropical storm. At any speed damage is done but this one has been overblown and unnecessary precautions were called for. Even when the NOAA had numerous chances to downgrade the storm they used the extrapolation method rather than surface observations.
Okay, I’ll buy all of that. But you are basically arguing that the government over-prepared for a catastrophe. That’s a bad thing why? What if the Hurricane was worse than expected? I just don’t get this entire line of thinking.
If you seriously think that surface observations are the be-all end-all of meteorological observations, then you very clearly know very little meteorology or atmospheric science.
Biff:
What if a meteor falls on your house tomorrow? What are you doing to prepare for that possibility? What if a semi truck drives through your house next week? What precautions did you take to prepare for the results? What if a sink hole opens up and swallows your house? What did you do to prepare? WHAT IF pigs had wings? They could fly!
Biff – Exaggerating the severity of a tropical system in order to encourage unnecessary precautions is irresponsible. The public will begin to discount the severity of the threat of similar storms in the future. If the authorities “Cry Wolf” and to induce people to take unncessary precautions, there are consequences. How often do we hear of individuals who refuse to take precautions because they think the threat is exaggerated? Should NOAA act in a manner that makes that thought process rational in any way?
John:
I did not set the standards the NWS / NOAA uses to determine the strength of a storm! They did. And it was not the wind speed at 5,000ft because the wind speed at 5,000 ft does little damage at the surface. It is the wind speed at or near the surface that does the damage. That would mean the speed near the surface is the important number.
Unless you live at 10,000 feet and in that case the wind conditions at that altitude would be important!
lol, who are you going to believe? The ingenious mathematical methodology or your own lying eyes?
Mike Davis:
You’re right. The standard set by NWS/NOAA is that to be a Hurricane, Irene needs to pack 1-minute sustained winds at 10m AGL of greater than or equal to 74 mph. The problem with your argument is that it doesn’t matter where this estimate of wind speed comes from. It can be extrapolated from dropsondes, it can be taken from doppler radar, it can be taken from the fancy probes that the Dominator shoots into storms, or it can be taken from a stationary anemometer. This criterion has been and continues to be satisfied for Irene.
Mike, that was worst analogy in history. If I live next to a hairpin turn where semi-trucks speed by, then I probably take precautions,maybe even erect a wall.
This was a known probability, not a random event as your analogy suggests.
Biff, the thing is the constant fear mongering has to stop. It paralyzes our society. I think what Mike was saying, is that you can’t live in fear of the great “what if”. Should people take precautions? Sure! And, its a great thing that we have people watching such stuff for us. But, we must have people we can believe when they sound the alarms. Another thought would be, to have a level of preparedness before the alarms. Is trick but, that’s how some of us do it.
Did NOAA or someone else have their thumb on the scale regarding this hurricane? I honestly don’t know. Are there people that have a vested interest in this storm being greater than what it really is? I do know that, and the answer is yes.
Look, no one wants people to be caught unawares, but 30-40-50 mph winds? That’s national news? Oh, wait, I forgot, they flew a plane out to sea thousands of feet in the air, took a measurement, and extrapolated much higher speeds…….. ok, fine. But, when they do this, it must be realized that the actions the citizens take comes at a great cost. Will it be justified? I don’t know. We’ll see.
John says:
August 28, 2011 at 4:44 am
…………
@ John,
Sigh, I’ll respond and then call it a night. First, you are entirely incorrect on your assumptions about me. But, I’m used to it. I’d like nothing more than to believe NOAA or NHC. But, if your arguments are representative of theirs, then I find little reason to deem them believable. More on that in a second. As to my wishing for the prediction of a hurricane making landfall in the U.S. to fail……….. guilty. I really hope hurricanes don’t make land fall on U.S. soil. Every time one is predicted I hope it doesn’t. Yeh, that’s bizarre, I know.
Thanks for letting me know measurements aren’t entirely sufficient for understanding…… anything, much less atmospheric and meteorological purposes……gosh….whodda thunk it?
But this is where you really fall of the rails. Sorry, neither models nor extrapolations are as credible as observations. As far as the definition of a hurricane or its categories, I don’t really care, but when a model tells me I’m experiencing winds at 70+mph and I’m on my roof with an anemometer only getting 40……. there’s something wrong with the model….extrapolation….or whatever.
I’ll leave you with this. Observation is king. It always was and always will be. In any science one deals with. You cannot disregard observations because it doesn’t fit with what you think may or may not be happening.
Best wishes
James
So you think observation beats DNA for instance?
lol, was and is there observed information that lead to our knowledge of DNA?
“You cannot disregard observations because it doesn’t fit with what you think may or may not be happening.”
ROFL!
So sayeth the person who rejects doppler radar measured windpseeds.
Oh my, how did you misinterpret my statements so poorly?
Does Doppler use actual measurements?
Biff, you should probably use a different handle since you already fibbed about the hurricane damage to your fictitious home……nothing you say now will be taken seriously.
Hurricane Rita….
The only measured wind speed that met the 10m unobstructed requirement showed <100mph at Buras, LA.
If you read the NHC discussion a 9PM the storm doesn't qualifiy as a hurricane. If you look at the radar the storm hasn't met the definition of a hurrican since early this evening….
rian says:
August 28, 2011 at 10:38 am
So you think observation beats DNA for instance?
What the hell does DNA tell you about the Weather?
You can tell if they are related to Chicken Little! 😉
You’ve sort of overused the “chicken little” bit.
You have overused the excesses of the Chicken Little Mindset so live with the title!
And you guys have overused the old man yelling at the sky while clinching his fists mindset.
Brian:
Yes I am an OLD MAN! However I have lived through a few situations and know that shaking my fist at the sky does not settle anything.
I happen to know that the sky is falling and have made preparations for the event. I expect others to do the same without claiming Whoa is me I am afraid of life whatever shall I do!
I could tell you what would be your best way forward but you must find that answer for yourself!
The guy said that the human eye is better than the science. Always.
He didn’t say that you and you know it.
lol, Thanks Scott, Brian knows I didn’t state such, but I am given an insight as to why models are believed more than actual measurements.
I’m more and more beginning to believe the whole CAGW discussion has more to do with psychology than anything else. Just like this intense desire for a storm to be categorized as a hurricane.
How dare those dern kids take a hurricane seriously! Back in my day we had picnic’s in these dern hurricanes!
As a matter of fact there have been many events in weather conditions worse than what is being experienced in the majority of the area that is currently under Hurricane warning!
It is not a hurricane by any acceptable measurements and it barely qualifies as a tropical storm!