Met Dr. Steve Lyons: his thoughts on Katrina, etc.

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Audrey2Katrina
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#61 Postby Audrey2Katrina » Fri Feb 24, 2006 11:32 pm

Yup... found a good site with info on the '47 storm, also called the "Fort Lauderdale Storm" of Sept 4, 1947.



http://today.answers.com/topic/1947-fort-lauderdale-hurricane

And yes, it also mentions Cat 3 in Louisiana with gusts of 125 in New Orleans as the eye passed directly over the city--from the east... this would be a truly frightening scenario for a Katrina-like storm. Pearl River, I bet your dad could say a lot about that one!

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#62 Postby Extremeweatherguy » Sat Feb 25, 2006 12:30 am

Pearl River wrote:Rock wrote

skysummit wrote:
I'm not saying that there were stronger winds than Cat 1 or 2 IN New Orleans, but that doesn't mean there's no wind damage either. I have seen entire brick walls that have collapsed where there was no flooding.


we had brick walls fall in Galveston with Rita. Didn't even see cat 1 winds...


EWG- I agree with all your points. Kat offically was a 3 at landfall. Wind damage seen in NO was not even close to sustained cat 3 winds.


There maybe other reasons why the brick walls fell in Galveston.

Here we go again. If you are talking downtown New Orleans, more than likely cat 2 gusts. New Orleans is not just the French Quarter. It's Michoud, Lake Catherine, Rigolets, Fort Pike, New Orleans East. Those are all the city of New Orleans. Orleans Parish is the city of New Orleans.

Maybe when someone talks about New Orleans, they need to clarify they are speaking of downtown. There was an update to the Post Storm report dated Feb 17th. Second wind gauge at Michoud, 107 knots peak wind. Does not mention or call it a gust, and yes it is unofficial.

All I ask is don't base your facts or opinions on videotape. You don't and cannot see everything that has happened. It also depends on where one's location was when they shot the video. I know what cat 1/2 winds can do to trees. I'm almost 50yo and have been thru many storms. Cat 2 wind gusts did not do the type of damage that has occured to a lot of these trees. My dad who is 83yo and has lived in Slidell all his life except for 1942-1944, has said he has never seen anything like this and I trust his judgement more than someone sitting and viewing videotapes.
I was talking about downtown New Orleans. I saw a CNN live report from Mardi Gras in N.O. today and it looked like there was very little damage in the city. Also, the video I was talking about seeing that was taken right after the storm came from the downtown area of N.O. too. My opinion is that North and west of downtown they saw TS force or Cat. 1 force winds...downtown they saw Cat. 1 force winds...and in eastern N.O. (inluding Michoud) they saw Cat. 2 force winds from Katrina. This is based off of video, pictures, eyewitness accounts, and a few people I know that live in parts of N.O. and have told me this.
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#63 Postby Derek Ortt » Sat Feb 25, 2006 12:40 am

H-Wind also indicates that the cat 3 winds remained east of New orleans. Plaquemines, was not as fortunate though
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#64 Postby skysummit » Sat Feb 25, 2006 1:15 am

No, as far downtown, there is little damage. The French Quarter is basically untouched. I was there the morning after Katrina. Other than a few signs down here and there it wasn't bad at all....except for a lot of windows being blown out of the taller buidlings.

I was just west of Slidell, La. for the storm. Our office's annemometer broke during a 121mph gust. That's the highest gust I saw there. It's not an "official" NWS station, but it is an extremely expensive weather station.
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#65 Postby Audrey2Katrina » Sat Feb 25, 2006 1:51 am

Let's see, Steve Lyons feels Katrina was a 4 at least at first landfall, if not at both. Max Mayfield, the director of the NHC said this very month, Feb, 10 I believe, from the following article:

"Mayfield pointed out that New Orleans was to the west of where Katrina made landfall, which is supposed to be on the weak side of the hurricane. He said the strongest winds hit Mississippi. Katrina reached category five velocity before going ashore, but Mayfield said New Orleans felt category three winds from the storm."

Well, that's at least two fairly well versed experts IMHO. I know, I know, you can spare me all the "gusts" speak, been there done that. Eye of the beholder thing I guess. I don't need CNN videos from an area of downtown surrounded by tall buildings and relatively quickly back up and running (desperately trying to regenerate tourist revenue), I see the REST of the city every day. I don't need a few acquaintances from there, I live among thousands. I stand in accord with what Lyons seems to have stated, and feel Mayfield knows what he's speaking of as well, as far as whether one wants to talk gusts or sustained... all that's moot as the definitive proof one-way or the other is beyond our abilities at this time... to each, his or her own.

Keeping my perspective:

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#66 Postby Aslkahuna » Sat Feb 25, 2006 4:32 am

I suspect that this debate will go on until the next really big storm hits.
But just to point out a couple of things-what the sustained winds do is soften things up. It's the gusts that do the damage since they can be,in a hurricane, a full two categories above the sustained. Again, watch the long form video of Typhoon Omar by Jim Leonard-that was a true Cat 3 storm and note also that the roofs and things come apart during the big gusts.

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#67 Postby wxman57 » Sat Feb 25, 2006 8:17 am

Audrey2Katrina wrote:Let's see, Steve Lyons feels Katrina was a 4 at least at first landfall, if not at both. Max Mayfield, the director of the NHC said this very month, Feb, 10 I believe, from the following article:

"Mayfield pointed out that New Orleans was to the west of where Katrina made landfall, which is supposed to be on the weak side of the hurricane. He said the strongest winds hit Mississippi. Katrina reached category five velocity before going ashore, but Mayfield said New Orleans felt category three winds from the storm."

A2K


I suspect that eastern parts of New Orleans may have seen peak gusts above 111 mph, but certainly Max Mayfield didn't mean that anywhere near downtown New Orleans experienced sustained 111+ mph winds. Ignore it if you will, but there's a HUGE difference between sustained winds 111 mph and a gust to 111 mph. Here's the final HRD wind analysis of Katrina at landfall. I've highlighted the Cat 1, 2, and 3 wind fields. The blue "X" marks downtown New Orleans.

Image
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#68 Postby vbhoutex » Sat Feb 25, 2006 9:22 am

Questions and comments on the wind chart. How are the wind fields determined for these charts? Are actual readings used? Are areas assumed? I do know that interaction with land(land friction)slows wind speeds down considerably, but I find it had to believe that the Cat3 winds followed the LA coastline as depicted. I guess I am wondering how much of these wind charts are a "guess" as opposed to "actual".
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#69 Postby senorpepr » Sat Feb 25, 2006 9:52 am

vbhoutex wrote:Questions and comments on the wind chart. How are the wind fields determined for these charts? Are actual readings used? Are areas assumed? I do know that interaction with land(land friction)slows wind speeds down considerably, but I find it had to believe that the Cat3 winds followed the LA coastline as depicted. I guess I am wondering how much of these wind charts are a "guess" as opposed to "actual".


As for the "guess vs actual"... these charts are rather accurate. Many people tend to hear a wind speed and assume it's a sustained speed when it's a gust. The affects of land usually quickly lower the sustained speeds while actually increasing the margin between sustained and gusts. (You'll see higher gusts right at landfall). While the sustained winds are decreasing, they are still "weakening" structures while the 'increased' gusts tend to do the damage. That is whatever the surge isn't taking care of.

As for how the charts are determinded...

...from the HRD website regarding the above H-wind profile:

An HRD wind analysis requires the input of all available surface weather observations (e.g., ships, buoys, coastal platforms, surface aviation reports, reconnaissance aircraft data adjusted to the surface, etc.). Observational data are downloaded on a regular schedule and then processed to fit the analysis framework. This includes the data sent by NOAA P3 and G4 research aircraft during the HRD hurricane field program, including the Step Frequency Microwave Radiometer measurements of surface winds, as well as U.S. Air Force Reserves (AFRES) C-130 reconnaissance aircraft, remotely sensed winds from the polar orbiting SSM/I and ERS, the QuikScat platform and TRMM microwave imager satellites, and GOES cloud drift winds derive from tracking low level near-infrared cloud imagery from these geostationary satellites. These data are composited relative to the storm over a 4-6 hour period. All data are quality controlled and processed to conform to a common framework for height (10 m or 33 feet), exposure (marine or open terrain over land), and averaging period (maximum sustained 1 minute wind speed) using accepted methods from micrometeorology and wind engineering (Powell et al., 1996, Powell and Houston, 1996). This framework is consistent with that used by the National Hurricane Center (NHC), and is readily converted to wind load frameworks used in building codes.
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#70 Postby Scorpion » Sat Feb 25, 2006 9:57 am

Has a chart for Wilma been made yet?
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#71 Postby senorpepr » Sat Feb 25, 2006 10:01 am

Scorpion wrote:Has a chart for Wilma been made yet?


http://www.aoml.noaa.gov/hrd/Storm_page ... /wind.html

Choose the time you want and what resolution. (4 degrees is the better, but as Wilma was developing... try 2)
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#72 Postby Opal storm » Sat Feb 25, 2006 10:32 am

senorpepr wrote:
vbhoutex wrote:Questions and comments on the wind chart. How are the wind fields determined for these charts? Are actual readings used? Are areas assumed? I do know that interaction with land(land friction)slows wind speeds down considerably, but I find it had to believe that the Cat3 winds followed the LA coastline as depicted. I guess I am wondering how much of these wind charts are a "guess" as opposed to "actual".


As for the "guess vs actual"... these charts are rather accurate. Many people tend to hear a wind speed and assume it's a sustained speed when it's a gust. The affects of land usually quickly lower the sustained speeds while actually increasing the margin between sustained and gusts. (You'll see higher gusts right at landfall). While the sustained winds are decreasing, they are still "weakening" structures while the 'increased' gusts tend to do the damage. That is whatever the surge isn't taking care of.

As for how the charts are determinded...

...from the HRD website regarding the above H-wind profile:

An HRD wind analysis requires the input of all available surface weather observations (e.g., ships, buoys, coastal platforms, surface aviation reports, reconnaissance aircraft data adjusted to the surface, etc.). Observational data are downloaded on a regular schedule and then processed to fit the analysis framework. This includes the data sent by NOAA P3 and G4 research aircraft during the HRD hurricane field program, including the Step Frequency Microwave Radiometer measurements of surface winds, as well as U.S. Air Force Reserves (AFRES) C-130 reconnaissance aircraft, remotely sensed winds from the polar orbiting SSM/I and ERS, the QuikScat platform and TRMM microwave imager satellites, and GOES cloud drift winds derive from tracking low level near-infrared cloud imagery from these geostationary satellites. These data are composited relative to the storm over a 4-6 hour period. All data are quality controlled and processed to conform to a common framework for height (10 m or 33 feet), exposure (marine or open terrain over land), and averaging period (maximum sustained 1 minute wind speed) using accepted methods from micrometeorology and wind engineering (Powell et al., 1996, Powell and Houston, 1996). This framework is consistent with that used by the National Hurricane Center (NHC), and is readily converted to wind load frameworks used in building codes.

I don't think these charts are that accurate.The chart of Dennis showed T.S force winds in Pensacola when actaully Pensacola had hurricane force winds.That might not be a big deal but that tells me these charts can't be 100% accurate on everything.
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#73 Postby senorpepr » Sat Feb 25, 2006 10:46 am

Opal storm wrote:I don't think these charts are that accurate.The chart of Dennis showed T.S force winds in Pensacola when actaully Pensacola had hurricane force winds.That might not be a big deal but that tells me these charts can't be 100% accurate on everything.


Hmmm... they show hurricane force winds in Pensacola...
It matches up very well with the reports listed in the NHC Report.

[img]ftp://ftp.aoml.noaa.gov/pub/hrd/hwind/2005/al04.2005/0710/1930/col02deg.png[/img]
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#74 Postby Audrey2Katrina » Sat Feb 25, 2006 10:48 am

wxman57 wrote:
Audrey2Katrina wrote:
"Mayfield pointed out that New Orleans was to the west of where Katrina made landfall, which is supposed to be on the weak side of the hurricane. He said the strongest winds hit Mississippi. Katrina reached category five velocity before going ashore, but Mayfield said New Orleans felt category three winds from the storm."

A2K


I suspect that eastern parts of New Orleans may have seen peak gusts above 111 mph, but certainly Max Mayfield didn't mean that anywhere near downtown New Orleans experienced sustained 111+ mph winds. Ignore it if you will, but there's a HUGE difference between sustained winds 111 mph and a gust to 111 mph. Here's the final HRD wind analysis of Katrina at landfall. I've highlighted the Cat 1, 2, and 3 wind fields. The blue "X" marks downtown New Orleans.


Nice map; and while I respect the effort put into it, I do question its accuracy. The preliminary report from the HRD which showed this map, (not very different from the one above) showed the "surface" stations they got wind speeds from totalled 12, from SE. Louisiana, all the way through Mississippi--not very many, and additionally ALL of those windspeeds measured were from instruments that failed long before highest windspeeds could have reached them.

Personally, I find it inconceivable that Buras, Louisiana, the point of initial landfall didn't even fall into cat 3 range of winds, and this is exactly what that map shows. The map also contradicts Mayfields conclusion as it doesn't even show the gusts of cat 3 in New Orleans, and flies in the face of both instruments at Michoud which reported peak winds of 84 KT, and 107 KT respectively, and NOAA's own report says the first is a measured "sustained one-minute" wind.

Perhaps it's as Lyons already noted; some authorities simply live or die by their charts, graphs, models and estimations, with which I believe neither he nor I am finding fault--only disagreement, while others go on their own experience, their own instincts, and a "different" interpretation of pretty much the same data. I still agree with Lyons about landfall and Mayfield that NO received cat 3 winds (seems Mayfield would take issue with these data and I think he's a fairly qualified authority)...already brought up that it's pointless to continue the argument of gusts/sustained... gets us nowhere.

A2K
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#75 Postby MiamiensisWx » Sat Feb 25, 2006 10:51 am

Audrey2Katrina, Buras might have received at least sustained Category Two winds, if not higher. The land there is flat and sparsely populated; also, the highest sustained winds in a storm are almost never recorded. Do you agree with these points?
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#76 Postby Audrey2Katrina » Sat Feb 25, 2006 10:51 am

Opal storm wrote:I don't think these charts are that accurate.The chart of Dennis showed T.S force winds in Pensacola when actaully Pensacola had hurricane force winds.That might not be a big deal but that tells me these charts can't be 100% accurate on everything.


I agree with you, Opal. This chart doesn't even have the site of initial landfall as inside the Cat 3 windfield. That is beyond the inconceivable IMHO, and I take a measure of consolation in that neither the remarks of Mayfield who directs the NHC, nor a well respected nationally syndicated meteorologist like Steve Lyons would agree with it either. Still, everyone is entitled to their own opinions and/or interpretation of what data they have.

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#77 Postby Pearl River » Sat Feb 25, 2006 10:53 am

IMHO, I don't believe that the charts are that accurate either. The Katrina chart shows the outline of cat 3 over open water, yet it outlines the SE coast of LA. Most of the area that is outlined in cat 2 is watery marshland. There is not enough actual landmass there to cause that much friction. I also know that the following isn't from the "official report", but I thought it was rather interesting that the 2 vortex messages from Katrina, the first message was probably over Lake Borgne, but the later shows a 7 kt increase after it moved inland:

URNT12 KNHC 291500
VORTEX DATA MESSAGE
A. 29/14:42:40Z
B. 30 deg 11 min N
089 deg 36 min W
C. NA mb NA m
D. NA kt
E. NA deg nm
F. 179 deg 120 kt
G. 097 deg 019 nm
H. 928 mb
I. 18 C/ 2435 m
J. 19 C/ 2435 m
K. 19 C/ NA
L. OPEN SW
M. E210/35/25
N. 12345/NA
O. 0.12 / 2 nm
P. AF306 2112A KATRINA OB 30
MAX FL WIND 120 KT E QUAD 14:36:40 Z
MAX FL TEMP 20 C, 99 / 13NM
FLIGHT ALTITUDE 8000 FT





000

URNT12 KNHC 291527
VORTEX DATA MESSAGE
A. 29/15:16:50Z
B. 30 deg 19 min N
089 deg 38 min W
C. 700 mb 2497 m
D. NA kt
E. NA deg nm
F. 178 deg 127 kt
G. 90 deg 031 nm
H. EXTRAP 932 mb
I. 11 C/ 3049 m
J. 17 C/ 3049 m
K. 17 C/ NA
L. OPEN SW
M. C33
N. 12345/ 7
O. 0.02 / 1 nm
P. AF300 2212A KATRINA OB 28
MAX FL WIND 127 KT E QUAD 15:06:20 Z
SLP EXTRAP FROM 700 MB
FIX MADE OVERLAND
EYE RAGGED
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#78 Postby senorpepr » Sat Feb 25, 2006 10:55 am

Audrey2Katrina wrote:The map also contradicts Mayfields conclusion as it doesn't even show the gusts of cat 3 in New Orleans, and flies in the face of both instruments at Michoud which reported peak winds of 84 KT, and 107 KT respectively, and NOAA's own report says the first is a measured "sustained one-minute" wind.


First... it doesn't contradict cat 4 gusts in NO. This map does NOT show gusts.

Second... Michoud instruments are not certified/initialized and... therefore... considered unofficial. Therefore, they will not appear on the map. That is pointed out on NOAA's report.
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#79 Postby MiamiensisWx » Sat Feb 25, 2006 10:56 am

Pearl River wrote:IMHO, I don't believe that the charts are that accurate either. The Katrina chart shows the outline of cat 3 over open water, yet it outlines the SE coast of LA. Most of the area that is outlined in cat 2 is watery marshland. There is not enough actual landmass there to cause that much friction. I also know that the following isn't from the "official report", but I thought it was rather interesting that the 2 vortex messages from Katrina, the first message was probably over Lake Borgne, but the later shows a 7 kt increase after it moved inland:

URNT12 KNHC 291500
VORTEX DATA MESSAGE
A. 29/14:42:40Z
B. 30 deg 11 min N
089 deg 36 min W
C. NA mb NA m
D. NA kt
E. NA deg nm
F. 179 deg 120 kt
G. 097 deg 019 nm
H. 928 mb
I. 18 C/ 2435 m
J. 19 C/ 2435 m
K. 19 C/ NA
L. OPEN SW
M. E210/35/25
N. 12345/NA
O. 0.12 / 2 nm
P. AF306 2112A KATRINA OB 30
MAX FL WIND 120 KT E QUAD 14:36:40 Z
MAX FL TEMP 20 C, 99 / 13NM
FLIGHT ALTITUDE 8000 FT





000

URNT12 KNHC 291527
VORTEX DATA MESSAGE
A. 29/15:16:50Z
B. 30 deg 19 min N
089 deg 38 min W
C. 700 mb 2497 m
D. NA kt
E. NA deg nm
F. 178 deg 127 kt
G. 90 deg 031 nm
H. EXTRAP 932 mb
I. 11 C/ 3049 m
J. 17 C/ 3049 m
K. 17 C/ NA
L. OPEN SW
M. C33
N. 12345/ 7
O. 0.02 / 1 nm
P. AF300 2212A KATRINA OB 28
MAX FL WIND 127 KT E QUAD 15:06:20 Z
SLP EXTRAP FROM 700 MB
FIX MADE OVERLAND
EYE RAGGED


I agree... I find it rather hard to believe that portions of the sparsely populated regions of southeast Louisiana did not receive at least some sustained Category Three winds.
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#80 Postby senorpepr » Sat Feb 25, 2006 10:57 am

Pearl River wrote:There is not enough actual landmass there to cause that much friction.
You would be amazed what little land can create enough friction. The circulation can be over water, but the shear proximity to land creates enough friction.
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