Cat 4 hurricanes very unlikely north of Florida on E Coast

[Audrey2Katrina]

The observation states that the peak wind (i.e., a wind gust) of 107 kts

You seem to have erred here. I'm going by memory here and could be wrong but I believe this updated report mentions specific "gusts" but NOT in this case, it only refers to this as a "peak wind"... NOT a "gust".... so the wind-to-gust rhetoric is really not necessarily applicable here...

A2K

[Pearl River]

Wxman57 wrote

Pearl River wrote:

From the NWS Slidell, updated post Katrina report. Updated on Feb.17th.

GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2



So what's your point? The observation states that the peak wind (i.e., a wind gust) of 107 kts was observed. Wind gusts are not sustained winds, which is how hurricanes are categorized. To qualify as a sustained wind, that peak wind must be measured for 60 seconds or longer. Wind gusts are typically about 25-30% higher than sustained winds. In some cases, gusts can be nearly double the sustained wind (Lily in 2002 where sustained winds were 40-50 mph and gusts were recorded near 100 mph). Wind gusts can last anywhere from a few seconds to less than 60 seconds.

What's my point. Peak wind does not necessarily mean wind gust, as many other reports in the Katrina report so state the term wind gust. As a matter of fact in the official report, this GAGE 1 PEAK WIND 84 KT 1059UTC is listed as sustained 1 minute wind speed. I have a major in Aviation, I know what a gust is. So, that's what my POINT IS.

[Matt-hurricanewatcher]

So this must kill any chance of new york getting a cat3 or above? But 1938 storm that hit New york proves other wise.

http://weather.unisys.com/hurricane/atl ... /track.gif

Yes it raced up the gulf stream...But a quick moving storm moving 30+ mph as a cat4 can hit the outterbanks I believe.

[wxman57]

It does not mean that Cat 3 winds exist in all sections of the hurricane.

Really? Would you please direct me to the place where I even remotely intimated that it did? I never once said or even implied that these winds had to be "everywhere"... and even went so far as to show that by the HRD map, Buras itself did NOT get higher than cat 2 winds... it's exactly what THAT MAP shows.

You really needn't have provided a link to the report as I have a copy of it right here on the trusty 'puter; but thanks anyway as others may wish to check it as well. Bear in mind that even this has been "updated" with further data later on, specifically with the readings from the 2nd guage at Michoud--but that's irrelevant; if you check page 3 of this report on your Adobe reader, you'll find this quote: "The hurricane then made landfall, at the upper end of Category 3 intensity with estimated maximum sustained winds of 110 kt, near Buras,".... okay...ummm UPPER end of Cat 3 at Buras... and it maintains that it remained a 3 all the way till it moved inland over Mississippi... sorry, again this does NOT correspond to the contours of that map--it just simply doesn't jive at all, and I'm not buyin' it. I respect both your position and your right to accept it, please reciprocate the courtesy and grant me the right to see the contradictions that are rife amongst available data. I simply do not accept these contours at all. This by no means suggests I do not know what a Category 3, (or any other category classification for that matter) means--I most assuredly do.

A2K

You must not be looking at the same map that I am. The map clearly shows Cat 3 winds touching the LA coast near Buras. The 110 mph contour was a bit hard to follow along the coast near Buras, and there was a secondary contour of 115+ mph touching the coast near Buras on the map. The NHC post-storm report does say "near Buras", not in Buras, by the way. It appears that those peak winds were just to the north of Buras over the water.

The yellow outlined area would be the Cat 3 wind field. Can't you see the Cat 3 wind field extending all the way north to the MS coast at second landfall (between the Pearl River and Biloxi)? I indicated the position of Buras on this version of the map:

http://myweb.cableone.net/nolasue/KatrinaWinds2.gif

So I just don't see what you're trying to say. The map above clearly shows Katrina as a Cat 3 hurricane all the way to the MS coast. What are you seeing that tells you it wasn't a Cat 3 north of Buras?

[wxman57]

Wxman57 wrote

Pearl River wrote:

From the NWS Slidell, updated post Katrina report. Updated on Feb.17th.

GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2



So what's your point? The observation states that the peak wind (i.e., a wind gust) of 107 kts was observed. Wind gusts are not sustained winds, which is how hurricanes are categorized. To qualify as a sustained wind, that peak wind must be measured for 60 seconds or longer. Wind gusts are typically about 25-30% higher than sustained winds. In some cases, gusts can be nearly double the sustained wind (Lily in 2002 where sustained winds were 40-50 mph and gusts were recorded near 100 mph). Wind gusts can last anywhere from a few seconds to less than 60 seconds.

What's my point. Peak wind does not necessarily mean wind gust, as many other reports in the Katrina report so state the term wind gust. As a matter of fact in the official report, this GAGE 1 PEAK WIND 84 KT 1059UTC is listed as sustained 1 minute wind speed. I have a major in Aviation, I know what a gust is. So, that's what my POINT IS.

In the observation above (GAGE 2 PEAK WIND 107 KT 1415UTC VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2), I interpret the peak wind to be a wind gust, not a sustained wind. It's unlikely that the observer looking at a wind gauge watched the wind indicator stick at 107 kts for 60 seconds or longer. It is implied that the peak value that the needle reached was 107 kts. I've watched plenty of wind gauges in my time, and I'm sure that the observer reported the highest value that the wind indicator touched. I.E., the peak wind gust.

In the other table, it is clearly labeled as peak sustained wind. I'm sure you know what a gust is, but I think your interpretation of the observation is incorrect.

[Pearl River]

Geography lesson. Buras is south of the river, not north.

http://myweb.cableone.net/nolasue/KatrinaWinds2.gif

[Audrey2Katrina]

You must not be looking at the same map that I am. The map clearly shows Cat 3 winds touching the LA coast near Buras.

Umm no... I'm looking at EXACTLY the same map... problem is I know what Louisiana looks like down there, and this map ISN'T IT!... And saying Cat 3.. "touches" an area... Please! The hurricane report said "upper end"... now correct me if I'm wrong; but if a contour line barely "touches" an area, then where that line is would most certainly be the LOWER end of that category... certainly not the "HIGH" end.... sorry... I'm convinced that the map doesn't jive with the facts no matter how you try to spin it.

A2K

[Ivanhater]

This thread is getting juicy

[Pearl River]

Wxman57 wrote

In the observation above (GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2), I interpret the peak wind to be a wind gust. It's unlikely that the observer looking at a wind gauge watched the wind indicator stick at 107 kts for 60 seconds or longer. It is implied that the peak value that the needle reached was 107 kts. In the other table, it is clearly labeled as peak sustained wind. I'm sure you know what a gust is, but I think your interpretation of the observation is incorrect.

Look again. Copied directly from the NWS Slidell site.

EASTERN NEW ORLEANS - NASA MICHOUD FACILITY WIND EQUIPMENT 40 FT
GAGE 1 PEAK WIND 84 KT 1059UTC
GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2

Peak Wind...Peak Wind.

[wxman57]

Geography lesson. Buras is south of the river, not north.

http://myweb.cableone.net/nolasue/KatrinaWinds2.gif

The center of the "X" is south of the river, just about right over Buras. Might be a hair north of Buras. But Buras is only 2.13 miles from the coast (to the NNE). The Cat 3 wind contour goes inland to just about the MS River at Buras.

Buras:
http://myweb.cableone.net/nolasue/Buras.gif

[Matt-hurricanewatcher]

Very interesting thread to pass the time intill what ever storm forms.

[Audrey2Katrina]

So I just don't see what you're trying to say. The map above clearly shows Katrina as a Cat 3 hurricane all the way to the MS coast. What are you seeing that tells you it wasn't a Cat 3 north of Buras?

This is getting beyond ridiculous. In the first place, the "X" is nowhere "near" Buras. In the second... trying to play on words like "Near Buras"... umm it still clearly meant on LAND... and to claim that because it brushes about 50 feet onland would make it a bona-fide "HIGH" end Cat 3 landfall is so far over the edge that it's laughable. The report even mentions the possibility of Cat 4 winds near the mouth of the river... no such contour exists... I repeat... the "edge" of a countour would be the LOWEST end of that classification... not nearly the "highest"...

The map is quite simply...inaccurate... and regardless of how "you" may interpret the 2nd guage at Michoud, it's not how YOU or I "interpret" it that matters, the same exact data for guage 1 shows that the reading there was for a 1 minute sustained wind... NOT a gust... again.. inconsistent with the HRD map... and again.. like I've said before... you take your data... I'll take mine... (and regardless they're both viable data)... an it's obvious we're just not gonna agree on this one.

A2K

[wxman57]

Wxman57 wrote

In the observation above (GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2), I interpret the peak wind to be a wind gust. It's unlikely that the observer looking at a wind gauge watched the wind indicator stick at 107 kts for 60 seconds or longer. It is implied that the peak value that the needle reached was 107 kts. In the other table, it is clearly labeled as peak sustained wind. I'm sure you know what a gust is, but I think your interpretation of the observation is incorrect.

Look again. Copied directly from the NWS Slidell site.

EASTERN NEW ORLEANS - NASA MICHOUD FACILITY WIND EQUIPMENT 40 FT
GAGE 1 PEAK WIND 84 KT 1059UTC
GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2

Peak Wind...Peak Wind.

Check that again - it's a visual observation of peak wind. That almost certainly means a gust, not a measured 1-minute wind. And it's quite likely that the first observation of the 84 kt wind was a gust as well. That's why the NHC classified the 84kt reading as "unofficial". The gauge most likely could only record the peak gust observed. Official gauges are able to calculate 60-second average winds. Also, the instrument is higher than the official 10 meter height.

[Budro999]

Opal storm wrote

Storm surge is not categorized, so there is no such thing as a "cat 5 storm surge".

Tell that to the pro-mets that do state there is such a thing.

They would be quite incorrect in saying such a thing. Saffir-Simpson is only a wind scale. There is no officially-associated storm surge for each category as such an association would be impossible and/or ridiculous. Very early on, the NHC tried to associate a storm surge with SS categories, but that was dropped after a short time because peak wind speed is only a tiny part of the storm surge equation.

For example, a Category 3 hurricane could produce a storm surge anywhere from 3-5 feet to 30-35 feet, depending upon radius of max winds, forward speed, angle it hits the coast, offshore topography, and coastal topography. Same thing for a Cat 4 or 5, but with a bit higher surge on the high-end.

Actually, every published version of the SS scale that I have ever seen does have surge estimates along with each category. Now, those estimates have been shown to be inadequate with plenty of storms over the years, and there are currently other methods being worked on in the community currently in an effort to replace the current SS scale.

[Pearl River]

A2K wrote

Quote:

So I just don't see what you're trying to say. The map above clearly shows Katrina as a Cat 3 hurricane all the way to the MS coast. What are you seeing that tells you it wasn't a Cat 3 north of Buras?



This is getting beyond ridiculous. In the first place, the "X" is nowhere "near" Buras. In the second... trying to play on words like "Near Buras"... umm it still clearly meant on LAND... and to claim that because it brushes about 50 feet onland would make it a bona-fide "HIGH" end Cat 3 landfall is so far over the edge that it's laughable. The report even mentions the possibility of Cat 4 winds near the mouth of the river... no such contour exists... I repeat... the "edge" of a countour would be the LOWEST end of that classification... no nearly the "highest"...

The map is quite simply...inaccurate... and regardless of how "you" may interpret the 2nd guage at Michoud, it's not how YOU or I "interpret" it that matters, the same exact data for guage 1 shows that the reading there was for a 1 minute sustained wind... NOT a gust... again.. inconsistent with the HRD map... and again.. like I've said before... you take your data... I'll take mine... (and regardless they're both viable data)... an it's obvious we're just not gonna agree on this one.

A2K

Yes, what you just said. I'm tired.

[wxman57]

A2K wrote

Quote:

So I just don't see what you're trying to say. The map above clearly shows Katrina as a Cat 3 hurricane all the way to the MS coast. What are you seeing that tells you it wasn't a Cat 3 north of Buras?



This is getting beyond ridiculous. In the first place, the "X" is nowhere "near" Buras. In the second... trying to play on words like "Near Buras"... umm it still clearly meant on LAND... and to claim that because it brushes about 50 feet onland would make it a bona-fide "HIGH" end Cat 3 landfall is so far over the edge that it's laughable. The report even mentions the possibility of Cat 4 winds near the mouth of the river... no such contour exists... I repeat... the "edge" of a countour would be the LOWEST end of that classification... no nearly the "highest"...

The map is quite simply...inaccurate... and regardless of how "you" may interpret the 2nd guage at Michoud, it's not how YOU or I "interpret" it that matters, the same exact data for guage 1 shows that the reading there was for a 1 minute sustained wind... NOT a gust... again.. inconsistent with the HRD map... and again.. like I've said before... you take your data... I'll take mine... (and regardless they're both viable data)... an it's obvious we're just not gonna agree on this one.

A2K

Yes, what you just said. I'm tired.

I'm tired, too. Let's argue about Rita's intensity at landfall tomorrow.

Have a good night, everyone.

[Audrey2Katrina]

Have a good night, everyone.

Nytol... it's been fun.... and interesting!

A2K

[weathernic]

If this thread hits 25 pages and gets locked...I might puke.

Here are the facts.

KATRINA was a DEVASTATING storm, and it occurs to me at this late hour that the brilliant minds on this board should make better use of their time than lambasting each other about geographical points of interest and/or arguments about storm surge and wind speed.

There are lots of people dead.
There are lost of people living in trailers (some of which are reading this garbage in utter dismay)
and even more displaced semi-permanently or even worse, living in tents.

So lets get back to the topic of this thread or use our infinite wisdom to talk about what might happen somewhere, versus what DID happen to countless lives, regardless of accepted or perceived data,

PRETTY PLEASE!?!?!?!

[Pearl River]

Wxman57 wrote

Pearl River wrote:
Wxman57 wrote

Quote:
In the observation above (GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2), I interpret the peak wind to be a wind gust. It's unlikely that the observer looking at a wind gauge watched the wind indicator stick at 107 kts for 60 seconds or longer. It is implied that the peak value that the needle reached was 107 kts. In the other table, it is clearly labeled as peak sustained wind. I'm sure you know what a gust is, but I think your interpretation of the observation is incorrect.


Look again. Copied directly from the NWS Slidell site.

Quote:
EASTERN NEW ORLEANS - NASA MICHOUD FACILITY WIND EQUIPMENT 40 FT
GAGE 1 PEAK WIND 84 KT 1059UTC
GAGE 2 PEAK WIND 107 KT 1415UTC
VISUAL OBSERVATION OF READOUT DISPLAY FROM GAGE 2



Peak Wind...Peak Wind.


Check that again - it's a visual observation of peak wind. That means a gust not a measured 1-minute wind. And it's quite possible that the first observation of the 84 kt wind was a gust as well. That's why the NHC classified the 84kt reading as "unofficial". The gauge may have simply recorded the peak gust observed, as it may have been unable to calculate 60-second average winds. Besides, the instrument is higher than the official 10 meter height.

You know, it's your opinion, not mine. Only the person that was there can verify whether he looked at the gauge for 1 minute or not. I don't believe that 7 feet will knock that much off of the wind speed. My opinion, which I'm entitled too. The first gauge does not state visual, even in the Katrina report.

So since we are going to get technical about all of this.

While the intensity of Katrina was Category 3 as the center of the eye made its closest approach (about 20 n mi) to the east of downtown New Orleans, the strongest winds corresponding to that intensity were likely present only over water to the east of the eye. The sustained winds over all of metropolitan New Orleans and Lake Pontchartrain likely remained weaker than Category 3 strength. The strongest sustained wind in New Orleans is subject to speculation since observations are sparse, due in part to the power failures that disabled ASOS stations in the area before peak wind conditions occurred. However, the NASA Michoud Assembly Facility in eastern New Orleans measured a 1-minute sustained wind of 84 kt (at an elevation of about 12 m) near 1100 UTC 29 August.

This is from the Katrina report and they even speculate about the strongest winds over New Orleans. This is also before the 2nd gauge reading was available.[/b]

[Sean in New Orleans]

Lordy, lordy, lordy...this is too much to read. I don't care what category the storm was, who says how strong it was, the winds, the surge, etc....it doesn't matter. What is the truth? That it is the worst hurricane to ever strike the United States in history when it comes to damage and debris. When all is said and done Katrina debris will total over 12X that of the next hurricane and debris clean-up. Over 1600 people died. My own parents had 17' of water in their home...etc. etc. It doesn't matter what anyone argues or says or states. Whether it be official or not. What matters is the truth...it's the worst one yet...EVER, BY FAR. No questions, at all regarding this...Bicker about whatever, all that really matters is the truth of what occurred. It doesn't even need a man-made label, IMO...it just takes a little common sense, open eyes and understanding to see what is in our face...the worst one ever. Hopefully, no one will have to go through this, again, anywhere, for a long, long time....