Current Radar or Satellite Image

Flhurricane.com - Central Florida Hurricane CenterHurricanes Without the Hype! Since 1995


The Atlantic is mostly quiet
Days since last H. Landfall - US: Any 12 (Michael) , Major: 12 (Michael) Florida - Any: 12 (Michael) Major: 12 (Michael)
 


General Discussion >> Hurricane History

Jump to first unread post. Pages: 1
RedHurricaneRanger
Registered User


Reged: Mon
Posts: 6
Loc: Newport News, VA
Who thinks Katrina was a Cat. 5 at landfall.
      #74308 - Mon Feb 12 2007 08:01 PM

I started this thread to bring light on the dumbest thing the NHC has ever done: Downgrading Katrina to a Category 3.

First of all, who downgrades a storm that killed 1,000+ peope to a Category Three. Look at the damage, what was done to New Orleans. A Category Three couldn't have done this. And the levees were supposed to withstand Category Three strength storms, but they broke, and they are blaming bad structuring for the breach but it's obvious that Katrina was stronger than a three.

Another thing, Katrina was still a Category 5 by Midnight and even though rapid weakening can be the cause, they could have gotten a reading from another part of the storm. Also Katrina had the 3rd lowest pressure of a storm at US landfall. The two that are lower are the Labor Day Hurricane and Camille who had less damage than Katrina. The top 3 before Katrina were all Cat.5 hurricanes, which would seem strange for a Cat. 3 to take that record.

Also, the pressure. 918 mb is a pressure that is associated with Category 4 and Category 5 hurricanes not Category Three storms. The lowest pressure in a Category Three was 939 mb. Opal's 135 mph / 916 mb has an excuse to keep it a four at the time, since Opal's pressures were lower than the matching wind speed, while Katrina's wind speeds caught up every time.

So here is my evidence so far:

* Katrina was still a Category 5 hurricane, 6 hours before landfall.

* Landfall pressure was lower than Andrew's pressure at landfall.

* Costliest Hurricane

* Deadliest since 1928.

I now close my arguement.

Feel free to support or argue against my point.
How strong do you think Katrina was at landfall
You may choose only one
What the NHC Says
130 - 145
145 - 160
165 - 180
180 - 195


Votes accepted from (Mon Feb 12 2007 08:00 PM) to (No end specified)
View the results of this poll



--------------------
Just because I'm 13 years old...and autistic doesn't mean I can't be a expert hurricane tracker.


Post Extras: Print Post   Remind Me!   Notify Moderator  
RedHurricaneRanger
Registered User


Reged: Mon
Posts: 6
Loc: Newport News, VA
Theory 2: Dennis a Category 5 [Re: RedHurricaneRanger]
      #74309 - Mon Feb 12 2007 09:49 PM

My second theory is that Dennis was the first Cat. 5 of the season rather than Emily. I noticed a Cat. 5 signature on the satellite picture the night before it reached 150 mph.

So here is my second poll
Do you think Dennis was a Category 5
You may choose only one
No
Maybe it was at 155 mph
Yes


Votes accepted from (Mon Feb 12 2007 09:49 PM) to (No end specified)
View the results of this poll



--------------------
Just because I'm 13 years old...and autistic doesn't mean I can't be a expert hurricane tracker.


Post Extras: Print Post   Remind Me!   Notify Moderator  
allan
Weather Master


Reged: Thu
Posts: 468
Loc: Palm Coast, Florida
Re: Theory 2: Dennis a Category 5 [Re: RedHurricaneRanger]
      #74311 - Tue Feb 13 2007 01:03 PM

I'm 18 and have been studying storms for 6 years. I remember watching TWC when Katrina made landfall. It was a category 4 Hurricane with winds at 140 mph, and on the tip of Luisiana. It made a second landfall as a category 3 hurricane with winds at 125 mph around the coast of Missisippi. They went with the second landfall then going by the first. So you could be right but then yet, there are historic facts. Dennis was a very strong category 4 storm before it slammed Cuba, though it may have at some time reached winds greater then 155 mph. Though I doubt it.

--------------------
Allan Reed - 18,9,5


Post Extras: Print Post   Remind Me!   Notify Moderator  
ClarkModerator
Meteorologist


Reged: Wed
Posts: 1710
Loc:
Re: Who thinks Katrina was a Cat. 5 at landfall. [Re: RedHurricaneRanger]
      #74314 - Fri Feb 16 2007 09:31 PM

Strongly disagree.

Quote:

"First of all, who downgrades a storm that killed 1,000+ peope to a Category Three. Look at the damage, what was done to New Orleans. A Category Three couldn't have done this. And the levees were supposed to withstand Category Three strength storms, but they broke, and they are blaming bad structuring for the breach but it's obvious that Katrina was stronger than a three."




The Cat. 5 version of Katrina was the one which created most of that surge. The fast translation speed coupled with the winds provided an ideal growth scenario for the waves and surge. It takes a lot longer for seas to subside than for winds to subside, and thus tons of wave energy hit the coastline. The levees were in poor condition before the storm and were breeched once the water became significant in the vicinity of the city. That, IMO, is not an argument that Katrina was stronger than a category 3 at landfall.

Quote:

Another thing, Katrina was still a Category 5 by Midnight and even though rapid weakening can be the cause, they could have gotten a reading from another part of the storm. Also Katrina had the 3rd lowest pressure of a storm at US landfall. The two that are lower are the Labor Day Hurricane and Camille who had less damage than Katrina. The top 3 before Katrina were all Cat.5 hurricanes, which would seem strange for a Cat. 3 to take that record.




1. Rapid weakening was the cause. They measured the winds all over the storm as it was approaching the coast with multiple airplanes taking both dropsonde and SFMR instruments, allowing for complete scanning of the storm. In fact, the analyses from the post-storm wind products suggest that the winds were even weaker than the NHC analyzed as it made landfall! (e.g. ftp://ftp.aoml.noaa.gov/hrd/pub/hwind/2005/PostKatrina/0829/0600/col08deg.png -- 108kt max surface wind, middle of category 3 intensity)

2. Pressure and maximum wind are not correlated directly. More important is how the pressure field is spread out over a short distance within the storm as well as how the pressure of the storm compares to that in the outer environment. Katrina had a very broad pressure and wind field distribution and thus supported a low pressure but relatively low wind speeds.

3. The Labor Day Hurricane and Camille were storms from different eras. If either hit in 2005, as did Katrina, it's a different story. Katrina was unique in that it leveled the most vulnerable city in the SE US with tons of water damage; the Labor Day hurricane was known merely for its intensity while Camille hit in a time period when the coastline was not nearly as developed as today. The storms are not directly comparable.

Quote:

Also, the pressure. 918 mb is a pressure that is associated with Category 4 and Category 5 hurricanes not Category Three storms. The lowest pressure in a Category Three was 939 mb. Opal's 135 mph / 916 mb has an excuse to keep it a four at the time, since Opal's pressures were lower than the matching wind speed, while Katrina's wind speeds caught up every time.




See my comments above (point 2) regarding the pressure-wind relationship. Katrina's wind speeds did not "catch up" every time to its pressure, either; while pressure changes generally do precede wind field changes, wind field changes can occur independent of numeric pressure changes -- such as by a broadening of the storm's circulation or entering into a different background environment. There's no indication in the data that Katrina's winds matched the low pressure it continued to display until landfall.

Values like damage and death toll are important values, but they are only partially correlated with storm intensity. The number one killer from tropical systems is water -- particularly inland flooding from torrential rains. Damage totals can be heavily skewed based upon where a storm made landfall -- a category 4 storm into S. Texas (like Bret a few years ago) will likely cause a lot less damage than a weak hurricane into S. Florida (like Katrina itself) solely because one area is relatively uninhabited while the other is heavily populated.

In summary, the data only supports Katrina as a category 3 hurricane at landfall and it is quite possible that the NHC's post-storm and post-season analyses are too high given the available data. The water which caused the decimation of much of the coastline started to get going while Katrina was a few hundred miles west of Key West; it did not just suddenly appear when the storm made landfall.

--------------------
Current Tropical Model Output Plots
(or view them on the main page for any active Atlantic storms!)


Post Extras: Print Post   Remind Me!   Notify Moderator  
dem05
User


Reged: Wed
Posts: 368
Loc: Port Charlotte, FL
Re: Who thinks Katrina was a Cat. 5 at landfall. [Re: Clark]
      #74318 - Wed Feb 21 2007 06:51 AM

I agree with Clark's analysis. While speaking of wind in sum, strengthening storms translate more of their strong winds to the surface, weaker systems translate far far less. While the storm surge from storms such as Katrina, Dennis and Ivan were large, all three were a case of a ball being set in motion well before landfall. Katrina was categorized as a category 3 at landfall wind wise, but the surge that came with it was reflective of the ocean buildup during peak intensity. Due to weaker wind readings, some have even suggested that Katrina was a category 2 at landfall. Either way, this does not discount or discredit high wind damage, tornado damage, and excessive storm surge effects. Likewise, Dennis was a category 4 at one point, but landfall as a cat 3 is almost a stretch. Outside of some gusts and winds in Santa Rosa County, there is little evidence to support a weakening category 3 hurricane produced a lot of category 3 wind. Dennis himself may have been a category 2 in a smallarea when you look at the observations. On a side note, Ivan was a similar beast. It was a Cat 4 hours before landfall, but as a weakening hurricane...It probably brought some category 3 wind while the cat 4 tide continued to reach and devestate the coast. Conversely, A well known hurricane hit this neckof the woods before I lived here...While Charley hit at its wind maximum...it strengthened late, moved extremely fast, and lacked the wind diameter to create a true category 4 storm surge. In an area that is highly vulnerable to this threat, the surge was actually confined tothe coastal areas.

A track record has been built over the last several years. The Saffir-Simpson Wind scale is very important...however...it may be time for something like the Enhanced Fujita when it comes to hurricanes. Something that is not confusing to the public (I.E. Hurricane "X-whatever" :Cat 3 Winds/ Cat 5 Tide and Surge/Rain-Flood Risk: High). That may help the public. Furthermore, science may refine wind speeds in strengthening and weakening storms. From my personal experience, I have been in enough of them to say that a strengthening Category 1 at landfall almost seems stronger than a weakening category 3 at landfall. While that is a personal sensation, it is proven that weakening storms do translate less of the stronger winds to the surface.

From the aspects of death toll and dollar damage, both of these are highly unfortunate truths with hurricanes and tropical storms. However, it is really impossible to correlate a storm category with these figures. A massive flood event tropical storm in Houston can create similar damages to a category 3 hurricane in another place. Likewise, a category 1 hurricane can kill thousands in Mexico or Central America, while a similar storm may only injure a handfull in the US. These are aspects of topography/geography, population and demographics. Maybe the social sciences world will have a way to categorize hurricanesin that respect someday , but for now...the best we can go on is an actual strength and an areas vulnerability to its impacts.

As devastating and horrific as Katrina, Dennis, and Ivan were...I can't imagine the devastation we would have seen had these storms hit full steam. The same can be said for Hurricane Charley. As horrific as these events were, each one of them did have some silver lining. God forbid the day that we ever see one of these storms hit at their full force with the promise of a full tidal surge.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Lysis
User


Reged: Thu
Posts: 451
Loc: Hong Kong
Re: Who thinks Katrina was a Cat. 5 at landfall. [Re: RedHurricaneRanger]
      #74897 - Fri May 18 2007 04:18 PM

While ultimately flawed, this thread does bring one interesting point to mind.

Katrina was by all accounts catastrophic, both in terms of monetary loss, and loss of life. You could therefore argue that the net effect was that of a category five. Therefore, what does the NHC do in the face of impending catastrophe from a weakening storm? Downgrade said storm resulting in an equally lesser regard from the public? Now you see the dilemma forecasters face with each decision in the hours prior to landfall.


The facts are still the facts however, as Clark pointed out.

--------------------
cheers


Post Extras: Print Post   Remind Me!   Notify Moderator  
Rabbit
Weather Master


Reged: Sat
Posts: 511
Loc: Central Florida
Re: Who thinks Katrina was a Cat. 5 at landfall. [Re: Lysis]
      #74898 - Fri May 18 2007 04:26 PM

im going to have to agree with NHC's landfall intensity, and with one addition: New Orleans' structural wind damage was not what you would find in teh western eyewall of a cat v--most of the damage was limited to roof damage, and New Orleans itself only experienced 90-95 mph winds (definately not Cat V eyewall, even if on teh weaker side)

i am willing to agree that Dennis may have been 155 at landfall in Cuba though, as NHC's only stated reason for not classifying it so was the pressure of 937 mb (even though Charley was classified in 2004 at 150 mph with 941 mb pressure), and both had very small eyes and tight circulations


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1



Extra information
0 registered and 3 anonymous users are browsing this forum.

Moderator:  CFHC, Ed Dunham, Colleen A., danielw, Clark, RedingtonBeachGuy, Bloodstar, tpratch, typhoon_tip, cieldumort 

Print Topic

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled

Rating:
Topic views: 10331

Rate this topic

Jump to

Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at
Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center