National Climate Data Center Katrina Report

[HurricaneBill]

What about Eloise?

She appeared to be strengthening up until landfall.

However, Eloise never really underwent rapid intensification. In fact, Eloise wasn't upgraded to a hurricane until she was well into the Gulf.

[Normandy]

how about the fact that its possible that the north GOM cannot support anything above a marginal cat 3. Notice which systems have weakened in the NGOM... all cat 4's and 5's, while the 1's and 2's have managed to intensify or at least maintain their intensity

BUT, if the conditions are right and that is what the data shows, Camille was a 5.

Data shows Camille having gusts to 190...which equates to 150 mph winds inland. That is a Cat 4 my friend. I completely disregard the 224 mph gusts reported (somewhere in MS) because never since then has a hurricane produced those gusts (not even in Andrew, which I feel was probably stronger than Camille at landfall).

In my opinion Katrina shows that Camille is probably the most overrated storm in history (in terms of intensity). It caused far more damage, produced 10 more feet of surge. I know people sill say that "Oh Camille was a small hurricane, size of Charley"......no, it wasn't. Try comparing to Ivan (like Ortt said in previous threads). If Camille was really 190 mph in the gulf, the surge it would have carried should have been even more tremendous than it was (near Katrina). Ive yet to see wind damage from Camille that proves it was a Cat 5 (much less 190 mph).

[Derek Ortt]

Eloise was a 3, which can be supported

There was no EWRC in either Katrina or Dennis. Dennis, had it have been Katrina's size, likely would have made it as a 4, because where it approached, the shelf is very close to the coast. Larger hurricanes are quicker to spin down

[Margie]

There was no EWRC in either Katrina or Dennis.

Could you clarify...there was a second eyewall starting to form prior to Katrina's landfall. Take a look at the radar images in the NCDC report. However an ERC had barely begun.

To answer the earlier question...Kat reached max strength Sunday morning and was steady state until early afternoon, if memory serves, when dry air started being entrained and the smooth "platter" look of the clouds of a Cat 5 gave way to the original spiral banding features. The area with the dry air rotated around. Kat was quite large. The process of pulling in the drier air from the land side of the storm continued. By the time the upper third of the storm was over land, Sunday evening, only the eastern side of the storm was able to regenerate over the GOM, and the western side was dramatically attenuated before landfall...except near the eyewall, there was hardly anything left on the western side. The eastern side continued to be quite strong even after landfall; there was a large feeder band covering Jackson and Mobile Counties until about 6pm in the evening pulling in moisture from the GOM.

[Pearl River]

Read Special Advisory 16 on Camille. Air Force recon estimated winds of 190 mph near the center. NOT gusts to 190 mph. You can find it in the NHC archives. We all have to remember that several things have changed since 1969, mostly a building boom along the MS coast. That's why there appears to be more damage caused by Katrina.

I can remeber every hurricane that has hit Southeast LA and Southern MS since Hilda in 64 and Katrina is by far the worst. If you have not seen it with your own eyes, tv pictures do not do it justice. Pressure at Buras,LA at landfall 920 mb. Pressure in Slidell, LA at 2nd landfall at the mouth of the Pearl River, 934 mb. Both pressures Strong CAT 4. Some camn argue and say 920 mb is CAT 5. Either way the damage was explosive.

[Derek Ortt]

air force estimated? So we are relying on estimates? Remember, Ethel was estimated to be a cat 5 when it was really a cat 2. If all we have is an estimate of the wind speed, we have no idea as to how strong the winds are.

In Katrina, there was not a secondary wind maximum present, which is the definition of a secondary eye wall, and this feature was not wrapped at leats 50% around the center. It may hve been in the formative phases; however,far too soon for a decrease in the wind speeds in the primary eye

[Pearl River]

The one thing I have not been able to see in the NWS preliminary report was wind information given by the Mayor of Slidell,LA. He was on a local radio station 2 weeks after Katrina hit and said that the NWS in Slidell advised him, that the city had max sustained winds of 174 mph and gusts to 192 mph, and this story has been repeated several times. This goes against all that has been said about Katrina weakening. Now, if you look at the Mobile radar sequence just before the 2nd landfall, you will notice that there appears to be some strengthening in the northern eyewall over the marshes of se LA just east of N.O. The oranges start turning bright red.

[Derek Ortt]

the story has been discounted as no other obs (either aircraft, doppler, or readings from the east eye wall where the strongest winds are) showed this, Maybe if that report is true, it was from a tornado or something

[Margie]

In Katrina, there was not a secondary wind maximum present, which is the definition of a secondary eye wall, and this feature was not wrapped at leats 50% around the center. It may hve been in the formative phases; however,far too soon for a decrease in the wind speeds in the primary eye

Well I thought there was a secondary wind maximum associated with this band, which can be clearly seen in the northern portion of the storm at landfall.

The SW portion of the storm was eaten away by dry air and that is a separate circumstance. If we could find some images to view look a little further before landfall, I have to go back to my notes but I think it was quite clearly defined at one point. If you look at the radar loop, the outer band did reform briefly and was completely around at MS landfall, but there was not strong convection all the way around, not quite 50%.

I agree totally with your last statement. I didn't mean to imply the inner eyewall had lost strength. Just that I did believe there was a secondary wind maximum in the NE at MS landfall.

My brother was very close to shore on the eastern coast of Biloxi Bay and they did experience a short period of very strong winds accompanied by lower darker cloud cover at the time period that this band would have been passing just to the west of them. Also storm chasers holed up in the Biloxi Coliseum a couple miles to the west did experience a short period of lighter cloud cover after intense winds (this was videotaped), at this same time, which I believe was the break between the eyewall winds, which passed to the west of them, and what I am seeing as the beginnings of the second eyewall, which passed just to the east of them. At the time the storm chaser stated he thought they were just on the edge of the eye, but that is not possible as the eastern eyewall was some distance away over the Pass Christian / Long Beach area. He did see a wind maximum and did interpret it as an eyewall based on his experience.

[rtd2]

Wow, looking at that pic of Camille approaching leads me to believe it was no where near 190 mph. The western side of it seems to have dry air intrusion just like Katrina did.....looks like Camille might have weekened just like Katrina did. Also amazing to see how Katrina just dwarfs Camille.

WOW I have to disagree! Infact if you ZOOM in on the Camille pict. you will see a Tight- vertical stacked Eyewall......Very Healthy!That said I DOUBT camille hit @ 190 but So what Even 160 is/was Bad! I bet she was Atleast 160!(In a Small area 10-20 miles)

[Margie]

NWS in Slidell advised him, that the city had max sustained winds of 174 mph and gusts to 192 mph, and this story has been repeated several times.

Well remember that also every media report talking about any location where Katrina hit mentions 140mph sustained winds, even (well, especially) media reports about NOLA!

There was a very virulent chunk of the strong northern eyewall that rotated over Pearlington / Slidell area as Katrina made landfall. I watched it happen. I had no doubt in my mind that Slidell was hit hard; I figured Slidell was demolished. Aerials show extensive blowdown in the forests of that area. But those wind numbers you quote are way too high to be associated with the eyewall winds.

Doesn't it seem much more likely that Slidell was hit with very strong eyewall winds, but not that strong.

[rtd2]

NWS in Slidell advised him, that the city had max sustained winds of 174 mph and gusts to 192 mph, and this story has been repeated several times.

Well remember that also every media report talking about any location where Katrina hit mentions 140mph sustained winds, even (well, especially) media reports about NOLA!

There was a very virulent chunk of the strong northern eyewall that rotated over Pearlington / Slidell area as Katrina made landfall. I watched it happen. I had no doubt in my mind that Slidell was hit hard; I figured Slidell was demolished. Aerials show extensive blowdown in the forests of that area. But those wind numbers you quote are way too high to be associated with the eyewall winds.

Doesn't it seem much more likely that Slidell was hit with very strong eyewall winds, but not that strong.

I know Gen Lord at Keesler was Quoted saying the Base saw winds Atleast 140mph.... Now I would suspect he ment Gust.

[Derek Ortt]

gusts to 150 m.p.h. would be expected from a landfalling marginal cat 3 hurricane.

On Virginia Key at RSMAS during Wilma, we had sustained winds of about 81 m.p.h., but the gusts were between 110-115 m.p.h. Traveling over land reduces the surtained winds greatly, but the gusts are much slower

[Pearl River]

The winds reported were not reported by the media, rather a live conference with the mayor of Slidell. It could well have been a tornado. I do believe though, that we did have sustained 140 mph.

I did watch the landfalls constantly from Slidell radar until it's failure, then switching to Mobile's radar for the 2nd landfall. The eye was very large. NE eyewall landfall was in MS and NW eyewall landfall in SE St Tammany Parish. Slidell experienced the western edge of the eye.

The forestry destruction is unbelievable. The size of the trees snapped in half or blown over you just can't imagine. The arial photo's do it no justice. I live here and I see it every day.

A lot of Slidell's damage was from storm surge from Lake Pontchartrain. The surge went into Slidell, as far inland as 4 miles and as high as 8 feet. Most areas of Slidell average 10 ft asl. So we are looking at a surge of 18 ft.

[MGC]

The worst wind damage I've observed from Katrina was in western Harrison County and Hancock County. There I would estimate wind gusts of 150mph or so. I've seen roofs ripped off of well constructed homes with hurricane straps flapping in the wind. It didn't look like a tornado but could have been a meso-vortice. Slidell didn't get close to 174mph winds. Wind damage there is no where near as bad as Mississippi......MGC

[Margie]

I reviewed my notes and looked around online, no mention of an additional ERC starting with Kat just before landfall, I had even noted it myself.

The strongest winds onshore were most definitely to the east of the eye, from about the eastern border of Pass Christian into Long Beach past Gulfport and MS City into western Biloxi, and a little ways up 49. Also there were definitely some strong winds assoc with the northern and NW eyewall for a period of time at landfall that is evident by the massive blowdown in Hancock County.

Also Cat 4 surge occured basically all along the shoreline of Hancock County, and, in the bay, at the north at Diamondhead, and along the western portion of Harrison County (parts of Pass Christian and a little to the east). That is also an indicator of where the strongest winds occured.

It still looks to me on the radar that there were fairly strong winds, or a particular band, east at about Ocean Springs, not as strong as the winds to the immediate east of the eyewall, at landfall, sometime around 11am CDT. That area of wind moved inland, along the border of Jackson and Harrison Counties, into George County (which is north of Jackson County), which, although inland, had I believe over 50% of trees downed by the wind. Those forestry stats are somewhere on line on one of the NOAA websites.

But as far as roofs coming off...I think there were very strong gusts right along the entire MS coast. The roof of the EOC in Pascagoula came off and that was from a very strong gust, early in the morning, and that is eastern Jackson County, at least 70 miles to the east of the storm center. Most of Pascagoula is right on the coast, it is only about a mile or so deep. The EOC was also right by the wide Pascagoula River inlet. In other words it was very near the onshore winds. My opinion is that it is likely that Pascagoula received extremely strong gusts as well. The highest gust recorded by the EOC before roof failure, recorded in the post tropical cyclone report, was 108kts (124mph).

[Lindaloo]

Pascagoula is not a mile deep. I do not know where that comes from. I am 2 miles from the beach in Pascagoula and I had water in my home.

The EOC is not the only structure in Pascagoula that had roof failure.

[Margie]

Pascagoula is not a mile deep. I do not know where that comes from. I am 2 miles from the beach in Pascagoula and I had water in my home.

The EOC is not the only structure in Pascagoula that had roof failure.

OK...it is almost two miles inland up to about Hwy 90. One mile, two miles, I remember I could ride my bicycle around the entire town and still not get enough exercise.

The point I was making was that most of the city is so close to the water that it could experience strong winds coming onshore. Locations further inland such as Trent Lott airport did not experience winds that were nearly as strong.

This point has nothing to do with flooding. As a matter of fact Jackson County had flooding right up to the George County border.

[Normandy]

Wow, looking at that pic of Camille approaching leads me to believe it was no where near 190 mph. The western side of it seems to have dry air intrusion just like Katrina did.....looks like Camille might have weekened just like Katrina did. Also amazing to see how Katrina just dwarfs Camille.

WOW I have to disagree! Infact if you ZOOM in on the Camille pict. you will see a Tight- vertical stacked Eyewall......Very Healthy!That said I DOUBT camille hit @ 190 but So what Even 160 is/was Bad! I bet she was Atleast 160!(In a Small area 10-20 miles)

She looks just like Katrina, no western side.

[f5]

Katrina clobbered the most surge prone area in the country the ERC was timed just right the windfield spread out mobile was flooded.as far as the western side i saw that with Ivan last year he was getting booted by dry air&shear