Will there be a debate on Katrinas intensity at landfall?

[senorpepr]

I can assure you they will not increase the winds in the analysis. As for those saying it was a category five... there were absolutely no winds of category five strength even several hours prior to landfall. The wind damage was not of category five power. Not even top-end category four. A majority of the damage was from the storm surge. The surge was remnant of category five intensity the day prior to landfall. As a storm weakens it takes quite a while before the surge can subside.

As for those talking about pressure... pressure does not directly dictate wind speed. Once again, it is the pressure gradient. This is why Katrina had lower winds and a lower pressure at landfall than Charley. It's storm size / pressure gradient that produces the winds.

As for recon data... the recon data wasn't removed from the data stream at 4am CDT. I should know... I was sitting and monitoring the four planes that were investigating the system at landfall. I received each observation with no problem. There was no deleted data. It was all there. There are transcripts available. They didn't adjust the data. C'mon now.

Here is a graphic of the sustained winds, as measured from the NOAA aircraft monitoring at landfall. The winds were much lower than most of you are saying.

http://www.aoml.noaa.gov/hrd/Storm_page ... ll_mph.pdf

Once again, maximum at landfall will be 140 at first landfall. They may bump the winds for the MS landfall to 145.

[NastyCat4]

Maybe the data wasn't so good? It was a 5--been through Andrew, and this one had far worse wind damage. I don't care what a limited profile of instruments said for ONE given moment.

[wxmann_91]

Large storms tend to have lower pressures.

Damage was from storm surge not from wind. But perhaps MS landfall might be bumped up a tad. Definately not LA landfall.

In summary, what Senorpepr said.

[senorpepr]

Maybe the data wasn't so good? It was a 5--been through Andrew, and this one had far worse wind damage. I don't care what a limited profile of instruments said for ONE given moment.

The wind damage was not from the wind speed, but rather the duration because of the large wind field. You cannot compare the damage from Andrew to that of Katrina. It like comparing the damage from being hit by a 90mph baseball to that of a 60mph basketball.

As for the "limited profile of instruments" -- I'd like to know what is so limiited about them. How can four aircraft with high-tech equipment report the same thing, but be wrong? Furthermore, it wasn't for "one" given moment. It was for several hours. I'm sorry, but this wasn't a five at landfall. The surge was the remnant of when Katrina was a five, but the winds were not.

[senorpepr]

I don't really... a lot of the catastrophic damage you've seen is from surge NOT wind.

Yes from a Cat 5 25-30 foot storn surge.

Once again... storm surge doesn't immediately adjust as the winds adjust. That's simple physics. You can take that to the bank. The surge hadn't slowed down to the winds yet. That is why you have a cat four system with a cat five surge. You're trying to make it sound like storm surge reacts instantly with winds, like an 18-wheeler being able to stop on a dime.

[Tampa Bay Hurricane]

I think it was the surge that did not decrease even though the winds
decreased that was the cause.

[wxman57]

I definitely agree with the other mets here that Katrina was in no way had Cat 5 wind speeds at landfall. Strong Cat 3 to lower Cat 4, certainly. All that damage you're seeing was from a geographically-enhanced storm surge, not from wind, which is how hurricanes are classified. Wind did not reduce those homes to slabs, as would have happened in a Cat 5. I used the old mariner's weather manual to manually calculate the storm surge at Pass Christien and Gulfport, MS based upon about a 90mb pressure difference from inside to outside the storm and came up with about 31 feet. The reason for the high value was a 1.9 multiplication factor for the coastal topography in the area. The multiplier farther down the coast was only 1.0.

One thing I did notice, however, is that it looks like Katrina strengthened between the mouth of MS River and the MS coast. You can see it on this satellite loop. Note the dark cold ring around the eye disappeared as it neared the mouth of the MS and returned at landfall in MS:

http://cimss.ssec.wisc.edu/goes/misc/05 ... ay_ir4.avi

[thunderchief]

Keep in mind that katrina was coming in directly perpendicular to the shore for about a day.

These are attributes that increase surge.

[Stormcenter]

I can assure you they will not increase the winds in the analysis. As for those saying it was a category five... there were absolutely no winds of category five strength even several hours prior to landfall. The wind damage was not of category five power. Not even top-end category four. A majority of the damage was from the storm surge. The surge was remnant of category five intensity the day prior to landfall. As a storm weakens it takes quite a while before the surge can subside.

As for those talking about pressure... pressure does not directly dictate wind speed. Once again, it is the pressure gradient. This is why Katrina had lower winds and a lower pressure at landfall than Charley. It's storm size / pressure gradient that produces the winds.

As for recon data... the recon data wasn't removed from the data stream at 4am CDT. I should know... I was sitting and monitoring the four planes that were investigating the system at landfall. I received each observation with no problem. There was no deleted data. It was all there. There are transcripts available. They didn't adjust the data. C'mon now.

Here is a graphic of the sustained winds, as measured from the NOAA aircraft monitoring at landfall. The winds were much lower than most of you are saying.

http://www.aoml.noaa.gov/hrd/Storm_page ... ll_mph.pdf

Once again, maximum at landfall will be 140 at first landfall. They may bump the winds for the MS landfall to 145.

There were never any winds measure higher than 140mph for Andrew at landfall but he was still reclassified. The damage WAS a cat.5 type damage why argue what it so obvious despite what the NHC measured. They made a mistake with Andrew initially and they made a BIG mistake with Katrina. What do you or anyone else gain from it? You need to ask those poor people in La.,Ms. or Al. whether it was a Cat.5 or not and see what they tell you.

[Stormcenter]

I definitely agree with the other mets here that Katrina was in no way had Cat 5 wind speeds at landfall. Strong Cat 3 to lower Cat 4, certainly. All that damage you're seeing was from a geographically-enhanced storm surge, not from wind, which is how hurricanes are classified. Wind did not reduce those homes to slabs, as would have happened in a Cat 5. I used the old mariner's weather manual to manually calculate the storm surge at Pass Christien and Gulfport, MS based upon about a 90mb pressure difference from inside to outside the storm and came up with about 31 feet. The reason for the high value was a 1.9 multiplication factor for the coastal topography in the area. The multiplier farther down the coast was only 1.0.

One thing I did notice, however, is that it looks like Katrina strengthened between the mouth of MS River and the MS coast. You can see it on this satellite loop. Note the dark cold ring around the eye disappeared as it neared the mouth of the MS and returned at landfall in MS:

http://cimss.ssec.wisc.edu/goes/misc/05 ... ay_ir4.avi

I'm sorry wxman57 I usually agree with your posts but I think you and other posters are off base on this one. This storm's pressure speaks for itself. The NHC will correct their mistake with Katrina in due time as they did many years later with Andrew. The same arguements were made with Andrew concerning his strangth back 97 and many of the same mets that argued he wasn't a cat.5 back then are the same ones arguing the point today concerning Katrina. Gentlemen the NHC was wrong back then and they are wrong today. The damage speaks for itself.

[senorpepr]

There were never any winds measure higher than 140mph for Andrew at landfall but he was still reclassified. The damage WAS a cat.5 type damage why argue what it so obvious despite what the NHC measured. They made a mistake with Andrew initially and they made a BIG mistake with Katrina. What do you or anyone else gain from it? You need to ask those poor people in La.,Ms. or Al. whether it was a Cat.5 or not and see what they tell you.

First... winds were measured at cat 5 level for Andrew... it's called recon. Initially they thought it was 140... that was because they were using an incorrect conversion. However, new technology was used with Katrina that has a much higher accuracy than the tecnology used with Andrew. Once again, the winds were cat four.

Now, I do agree that the damage was cat five. That was because the surge hadn't decreased yet. The NHC didn't make a "BIG" mistake with Katrina. Grasp the facts... we're dealing with a cat four with surge that hadn't decreased.

What do I, or anyone, have to gain from it? Plenty. Many people kept harping over how Ivan was a cat four. Yeah, the damage was pretty bad, but the damage was cat two on the majority. The cat three damage was limited because, the cat three winds were limited. See, now people think they've "rode out" a cat four when in fact they didn't. Now these people will be hit by a "real" cat four, like Katrina, and be in a world of hurt.

Furthermore, why would I ask a resident from LA or MS or AL if it was a cat five? Did they have the scientific evidence in front of them that proves it was a cat four? For the most part, no. I'm sorry, but the observations don't lie. Sorry to put a tear in your eye, but that's how it is.

[senorpepr]

I'm sorry wxman57 I usually agree with your posts but I think you and other posters are off base on this one. This storm's pressure speaks for itself. The NHC will correct their mistake with Katrina in due time as they did many years later with Andrew. The same arguements were made with Andrew concerning his strangth back 97 and many of the same mets that argued he wasn't a cat.5 back then are the same ones arguing the point today concerning Katrina. Gentlemen the NHC was wrong back then and they are wrong today. The damage speaks for itself.

Once again... PLEASE STOP COMPARING STORMS BY THEIR PRESSURE. Katrina's pressure DOES NOT speak for itself. PLEASE understand that it's pressure gradient. The NHC will not correct "their mistake," because they didn't make one. You cannot compare Andrew with Katrina. I'm sorry, but I believe you're the one off base here.

[Geomagnetic Man]

Well as you all know you have the Fujita Scale for Tornadic measurements. It doesn't measure the size, or strength of the winds at all. It actually measures how much the tornado destroys. If you use the same concept in Katrina, the damage was Catagory 5.

Katrina came in from due south. The winds on the northern end rotated and went westward, piling more and more gulf water along the coast. When it was time for the surge wind to take over, all the water piled came inland when the winds turned due North. That's what I saw happening that morning, which happened to be My Birthday, lol, August 29th. I wanted a hurricane to hit LA. I even wished it earlier this year, but not LA as in Louisiana, I meant Los Angeles. So maybe a global warming climate change would have been proven. Non-the-less, Katrina was a Catagory 5 to me rating that damage.

Geo

[senorpepr]

Well as you all know you have the Fujita Scale for Tornadic measurements. It doesn't measure the size, or strength of the winds at all. It actually measures how much the tornado destroys. If you use the same concept in Katrina, the damage was Catagory 5.

Katrina came in from due south. The winds on the northern end rotated and went westward, piling more and more gulf water along the coast. When it was time for the surge wind to take over, all the water piled came inland when the winds turned due North. That's what I saw happening that morning, which happened to be My Birthday, lol, August 29th. I wanted a hurricane to hit LA. I even wished it earlier this year, but not LA as in Louisiana, I meant Los Angeles. So maybe a global warming climate change would have been proven. Non-the-less, Katrina was a Catagory 5 to me rating that damage.

Geo

See, if you're going to use a damage-producing scale, yes... Katrina was definately a five. No doubt about it. However, unfortunately, a Fujitaisque-scale isn't used with hurricanes. They are simply judged by wind speeds. That is why I'm saying this was a category four. Why? Because the winds were only category four. Yes the surge was of a cat five calibur. That is because the surge doesn't immediately die down after the winds die down. Yes the pressure was of a typical cat five. However, it wasn't because of the pressure gradient. The pressure gradient with Katrina was much lower than with Charley or Andrew.

[SouthernWx]

There were never any winds measure higher than 140mph for Andrew at landfall but he was still reclassified. The damage WAS a cat.5 type damage why argue what it so obvious despite what the NHC measured. They made a mistake with Andrew initially and they made a BIG mistake with Katrina. What do you or anyone else gain from it? You need to ask those poor people in La.,Ms. or Al. whether it was a Cat.5 or not and see what they tell you.

There are big differences in how wind data is obtained today vs when hurricane Andrew struck in 1992. For example, Katrina was probed by Nexrad doppler radar as it approached the coast......from the NWSFO's in Mobile and New Orleans. Nexrad velocity data that was unavailable in 1992 gives us a very good estimate of a true wind velocity; also, eyewall dropsondes hadn't been invented in 1992.....if they had been available, I'm very confident hurricane Andrew would have been classified cat-5 immediately.

Based on the limited nexrad radar, surface reports, and recon data available thusfar, I rate hurricane Katrina a category 4 hurricane at landfall......120-125 kt in Plaquimenes Parish, Louisiana (Boothville area) and 115-120 kt near the Mississippi/ Louisiana border west of Gulfport.

**FYI** Based on recon data, Katrina at her peak was still not as intense as Andrew....at least wind speed. The peak 700 mb wind measured in Katrina was 166 kt....compared to 170 kt during hurricane Andrew (which was due to Andrew's exceedingly small eyewall).

PW

[Stormcenter]

I'm sorry wxman57 I usually agree with your posts but I think you and other posters are off base on this one. This storm's pressure speaks for itself. The NHC will correct their mistake with Katrina in due time as they did many years later with Andrew. The same arguements were made with Andrew concerning his strangth back 97 and many of the same mets that argued he wasn't a cat.5 back then are the same ones arguing the point today concerning Katrina. Gentlemen the NHC was wrong back then and they are wrong today. The damage speaks for itself.

Once again... PLEASE STOP COMPARING STORMS BY THEIR PRESSURE. Katrina's pressure DOES NOT speak for itself. PLEASE understand that it's pressure gradient. The NHC will not correct "their mistake," because they didn't make one. You cannot compare Andrew with Katrina. I'm sorry, but I believe you're the one off base here.

Of course you can compare Andrew to Katrina. Come on now they both were major hurricanes. The big difference is that Andrew was a smaller storm and can not compare to the shear size of Katrina. What damage Katrina has done will dwarf anything Andrew ever did when the final horrible numbers come in. It's almost like some of you guys haven't seen the images on TV. The path of destruction Katrina left is NOTHING like anything Andrew left. Yes it was as destructive but not as wide. Don't you guys see the eerie similarities in the destruction both left? Did any of you see the Superdome or the Hyatt Regency in N.O.? All of this damage by the way was on the "weak" west side of the storm! For one second forget the technical crap and accept the obvious. Katrina was a more intense storm than Andrew. I don't care what anyone says including the NHC and their pressure and wind correlation. Which basically means she was a Cat.5 at landfall. If the NHC the comes back and changes their tune what will you say then? Anyway unless you were in the storms path measuring the actual winds this will ALWAYS be left for debate.

[senorpepr]

Of course you can compare Andrew to Katrina. Come on now they both were major hurricanes. The big difference is that Andrew was a smaller storm and can not compare to the shear size of Katrina. What damage Katrina has done will dwarf anything Andrew ever did when the final horrible numbers come in. It's almost like some of you guys haven't seen the images on TV. The path of destruction Katrina left is NOTHING like anything Andrew left. Yes it was as destructive but not as wide. Don't you guys see the eerie similarities in the destruction both left? Did any of you see the Superdome or the Hyatt Regency in N.O.? All of this damage by the way was on the "weak" west side of the storm! For one second forget the technical crap and accept the obvious. Katrina was a more intense storm than Andrew. I don't care what anyone says including the NHC and their pressure and wind correlation. Which basically means she was a Cat.5 at landfall. If the NHC the comes back and changes their tune what will you say then? Anyway unless you were in the storms path measuring the actual winds this will ALWAYS be left for debate.

I'm sorry that you live in a fantasy world. Of course I've seen the news. Notice how most of the damage was surge related and not windborne related? The windborne damage that did occur was due to duration. Andrew was different. The damage at the Superdome and the Hyatt was from cat 3 winds for the most part. The reason why there was damage, however, was duration. The storm was so big that the duration was much longer than in Andrew.

Sorry, but you cannot compare the pressures between these storms. Yes, the pressure was lower in Katrina, but the winds were much lower. It's not technical crap... were actually accepting the obvious. Consider a figure skater. Andrew was spinning with his arms tucked close thus spinning faster... Katrina had her arms out. Her winds were lower. I'm sorry you cannot accept facts. While I wasn't in the storm myself, the observations don't lie. The recon crew isn't making junk up.

Have you really looked at the damage from aloft or have you just relied on the media? A large majority of the damage was surge related. As a matter of fact, less than a mile inland from Biloxi, there was relatively little damage. Why? The elevation was too high -- no surge. What little damage occurred was from the long duration of high winds. This is a location that picked up as estimated 110-120kt winds. (Surface observing equipment broken, but there were meteorologists on the ground, but I guess they don't count.)

I don't understand why you cannot accept the fact that this wasn't a category five. I guess some folks can't accept the truth.

[Hurrilurker]

It sounds like we need to be using a more accurate system to describe the complete effects of a hurricane at landfall. Wind speed, wind field, central pressure, storm surge, topology, damage are perhaps not adequate when taken alone, one at a time. Katrina is a bit strange because she defies the conventional wisdom of a weakening storm (which she clearly was) being much weaker than indicated by the strength at landfall.

[Matt-hurricanewatcher]

She was not weaking at landfall. The whole western quad had rewraped at lanfall. In the storm was becoming alot more organized. Given more time she would of been back where she was earlier.

[superfly]

140-145 MPH sounds about right from the data.