Katrina: Category 5

By: Dr. Jeff Masters , 12:24 PM GMT on August 28, 2005

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Katrina is in the midst of a truly historic rapid deepening phase--the pressure has dropped 34 mb in the 11 hours ending at 7am EDT, and now stands at 908 mb. Katrina is now the sixth strongest hurricane ever measured in the Atlantic. At the rate Katrina is deepening, she could easily be the third or fourth most intense hurricane ever, later today. The list of strongest hurricanes of all time includes:

Hurricane Gilbert (888 mb, 1988)

The Great Labor Day Hurricane (892 mb, 1935)

Hurricane Allen (899 mb, 1980)

Hurricane Camille (905 mb, 1969)

Hurricane Mitch (905 mb, 1998)

Hurricane Ivan (910 mb, 2004)

Katrina's winds and storm surge
Maximum sustained winds at flight level during the 7am Hurricane Hunter mission into Katrina were 153 knots, which translates to 160 mph at the surface, making Katrina a minimal Category 5 hurricane. The winds are likely to increase to "catch up" to the rapidly falling pressure, and could approach the all-time record of 190 mph set in Camille and Allen. Winds of this level will create maximum storm surge heights over 25 feet, and this storm surge will affect an area at least double the area wiped clean by Camille, which was roughly half the size of Katrina. Katrina has continued to expand in size, and is now a huge hurricane like Ivan. Damage will be very widespread and extreme if Katrina can maintain Category 5 strength at landfall.

Landfall projections
The computer models are very tightly clustered and have been so for almost a day. The data used to initialize the models is excellent, since all available hurricane hunter aircraft have been in the air continuously making measurements for several days. Katrina has already made her turn northward, which makes the task of landfall prediction for the models much easier. The offical NHC forecast of a landfall in SE Louisiana, on the western edge of New Orleans, is thus a high-confidence forecast. The spread in the landfall location is just 90 miles, meaning the eye of Katrina is very likely to hit somewhere between New Orleans and a point just east of the Mississippi-Louisiana border.

Intensity forecast
Katrina's intensity at landfall is likely to be Category 4, but could easily be Category 3 or 5. She will undergo another eyewall replacement cycle before landfall, and this will weaken her maximum winds by 20 - 30 mph for a 12-hour period. Additionally, some increase in shear is possible in the 12 hours prior to landfall, which could weaken Katrina's winds another 10 - 20 mph. If we are extrememly lucky, both factors will conspire to knock Katrina down to a Category 3 and she will hit at low tide. Given that the storm is so large and is already pushing up a huge storm surge wave in front of it, even a weakened Category 3 Katrina hitting at low tide will cause an incredible amount of damage. A stretch of coast 170 miles long will experience hurricane force winds, given the current radius of hurricane force winds around the storm. A direct hit on New Orleans in this best-case scenario may still be enough to flood the city, resulting in heavy loss of life and $30 billion or more in damage.

Dr. Jeff Masters

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559. mobilegirl
5:19 PM GMT on August 28, 2005
When does the next model data become available?
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558. sSnack
5:18 PM GMT on August 28, 2005
What was the Superdome designed to withstand? (in terms of wind, flooding, etc.)
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557. pseabury
5:17 PM GMT on August 28, 2005
Where you from Lefty? You a fellow New Orleanian? Those of us who've lived there know all too well that the city is full or people with very limited means. Why weren't/aren't they being bussed up to Baton Rouge?
Member Since: May 28, 2005 Posts: 0 Comments: 3
556. Orleans77
5:19 PM GMT on August 28, 2005
Lefty I cant believe the change since we last spoke last night...
555. Valence
5:17 PM GMT on August 28, 2005
Hurricane Gilbert (888 mb, 1988)

The Great Labor Day Hurricane (892 mb, 1935)

Hurricane Allen (899 mb, 1980)

Hurricane Camille (905 mb, 1969)

Hurricane Mitch (905 mb, 1998)

Hurricane Ivan (910 mb, 2004)
554. pseabury
5:14 PM GMT on August 28, 2005
Valence, unfortunately Airlines care more about their infrastructure investment (mainly planes) to risk having them in a target area like that. My guess is that MSY will depart as many scheduled flights as they can, but inbound flights will trickle and/or stop if they haven't already. Once the planes are gone, they are gone.
Member Since: May 28, 2005 Posts: 0 Comments: 3
553. Orleans77
5:15 PM GMT on August 28, 2005
Hey Folks ..was away last 8 hrs...cant believ the change since yesterday evening...went to church this morning to pray for all those pour souls in NO...God help them
552. weatherboyfsu
5:15 PM GMT on August 28, 2005
At her current speed.....which I dont think will slow.....outside chance increases.....were looking at about 15 hours give or take a couple hours.....
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551. leftyy420
5:15 PM GMT on August 28, 2005
its really diheartneing to see that most those people who are puring into the superdome are black and all look dirt poor. there are young kids and babies. may god protect the children
Member Since: August 24, 2005 Posts: 35 Comments: 1987
550. leftyy420
5:14 PM GMT on August 28, 2005
sometime mid morning tomm but the effects will be felt as early as this afternoon in no
Member Since: August 24, 2005 Posts: 35 Comments: 1987
549. leftyy420
5:14 PM GMT on August 28, 2005
thousands are pouring into the suprdome. those poor folks in no
Member Since: August 24, 2005 Posts: 35 Comments: 1987
548. weatherboyfsu
5:13 PM GMT on August 28, 2005
Lefty....what time do you see Katrina making landfall?
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547. leftyy420
5:12 PM GMT on August 28, 2005
we will no mor once she turns north. that would tell us landfall and better forcast inpacts to people to the east of no
Member Since: August 24, 2005 Posts: 35 Comments: 1987
546. mkm1960
4:44 PM GMT on August 28, 2005
Please, please, please do not start gathering your yard sale inventory for the American Red Cross unless they request it. I am a former diaster relief worker. The logistics of sorting and transporting goods would be a nightmare, the ARC is already at work and is currently on the move to staging areas. The best thing to do is donate, they will be showing a toll free number if you have a credit card or send a check to your local chapter with Hurricane Katrina on the memo. It doesn't take a big donation believe me a buck or two will do. The Red Cross will appreciate it.
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545. pseabury
5:09 PM GMT on August 28, 2005
WeatherboyFSU - I think that it will technically make landfall sometime early yes, but that will be the Delta region....points south of NO. I feel sorry for the beautiful Venice, LA area....... and possibly Houma, Thibodeaux, LaRose depending on impact point.
Member Since: May 28, 2005 Posts: 0 Comments: 3
544. Valence
5:10 PM GMT on August 28, 2005
Question about evacuations:

Can airports add additional flights in a situaion like this? I know they'll probably close the airport at 6pm or so, but im just wondering about before then. Just fly in every plane in the area to get people out!
543. icebear7
5:11 PM GMT on August 28, 2005
i'm guessing the trof won't do much
Member Since: August 20, 2005 Posts: 0 Comments: 5
542. leftyy420
5:11 PM GMT on August 28, 2005
here is a link to the live webcast from nop. lets u see whats is happening in that poor city

Link
Member Since: August 24, 2005 Posts: 35 Comments: 1987
541. killdevilmax
5:09 PM GMT on August 28, 2005
Bush just declared Miss. disaster area as well as LA
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540. leftyy420
5:09 PM GMT on August 28, 2005
she will turn ne eventually but that might not happen to after landfall. thats my best bet right now cause we still need to seee how much influence the trof will have
Member Since: August 24, 2005 Posts: 35 Comments: 1987
539. afs
5:04 PM GMT on August 28, 2005
I wasn't discussing politics. I was discussing emergency management. An important political figure just went on national TV with a chance to convince a massive amount of people to get out of the path of one of the powerful hurricanes on record to save their lives...

... and he tossed that opportunity aside to promote a seperate political agenda.

At least neither Governor of Louisiana or Mayor of New Orleans has discussed anything but emergency management information since the spotlight started focusing on them yesterday.
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538. tmichelle1979
1:07 PM EDT on August 28, 2005
With the question posed on whether or not Katrina could make it to 200mph I have a question...
What was the strongest in history??
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537. Valence
5:07 PM GMT on August 28, 2005
From the article someone posted a line for a little bit ago

"Researcher Jay Combe has reached a troubling conclusion. He's told his supervisors at the Army Corps of Engineers that if The Hurricane hits New Orleans, most of the buildings in the city would probably be destroyed. If the water didn't demolish them, the hurricane's horrific winds would. And Combe says that raises a question: How many people would die?

Some researchers say 40,000. Some say 20,000. This Army Corps researcher says those figures are probably too low.

Combe worries, "I think of a terrible disaster. I think of 100,000."

Do you dream sometimes about a hurricane?"

I think you call that a nightmare - and its here.

Good luck to everyone in NO, MS, AL, and even FL.

536. leftyy420
5:08 PM GMT on August 28, 2005
the real tragedy is the tourists in no. lots of them have no way out and will have to ride it out with limited supplies in the hotel. thast sickening.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
535. CFLweather
5:07 PM GMT on August 28, 2005
The wave that emerged off of Africa has a definite spin, you can already see the convection wrapping around the center of circulation in a symmetrical fashion.

The wave further to the west isn't looking like a good scenario either at this point. We may see more major hurricanes in the coming weeks as these waves are fairly impressive coming from the Cape Verde islands.
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534. K8tina
12:04 PM CDT on August 28, 2005
Valence -- I just took a look... very impressive, almost beautiful (as odd as that must sound!).

I still do not know if my friends in New Orleans were able to evacuate. Phone lines seem to be busy (as I am sure everyone is trying to call their loved ones there).

Thanks to whoever it was that updated on their situation in the NO area. I'm sure you know our prayers and thoughts are with you!!!
533. PascMississippi
12:07 PM CDT on August 28, 2005
Hey Lefty, In your opinion, do you see anything that might push this thing more east as it nears the coast? They are already predicting 125 - 130MPH where I am.
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532. weatherboyfsu
5:07 PM GMT on August 28, 2005
Im thinking about 4am to 6am in the morning for landfall....what do you guys think....shes moving at 12....about 200miles away from the tip of Louisiana....
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531. Carbo04
5:05 PM GMT on August 28, 2005
When is the next recon plane getting there? It has to be stronger by now looking at it.


Also, i asked earlier, but I'll try again. Was there ever a recorded pressure for hurricane dog at peak intensity. Because if there isn't I'd guess it was stronger than Gilbert. 185 MPH winds, and a Cat 5. for 50+ hours.
530. pseabury
5:05 PM GMT on August 28, 2005
Yes jayhawk.....that place still is a dump. In all honesty, most places there are...but these are people's lives, livelihoods, etc. Not nly immediate danger to life and limb, but workplaces, careers, family histories gone literally.

Member Since: May 28, 2005 Posts: 0 Comments: 3
529. CFLweather
5:05 PM GMT on August 28, 2005
Thats true Valence. It should stay up for a while though.
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527. leftyy420
5:05 PM GMT on August 28, 2005
next recon will reach the storm around 230 est. so the next update will just likley be a position statement as the winda and pressure will not be changed due to noe rcon data
Member Since: August 24, 2005 Posts: 35 Comments: 1987
526. boiredfish
5:02 PM GMT on August 28, 2005
Quote from Nagin press conference this morning......."I am declaring a, uh, uh, state of mandatory evacuation this morning".

Oh, and Pres. Bush has already declared Louisiana and Mississippi as disaster areas, clearing the way for what will be much needed federal aid.

I think he already had that declared before Nagin issued his mandatory evacuation of New Orleans.
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525. pseabury
5:05 PM GMT on August 28, 2005
I'd say slightly higher waves Mr. Lefty, but yeah.......that is terrible.
Member Since: May 28, 2005 Posts: 0 Comments: 3
524. flajayhawk
5:04 PM GMT on August 28, 2005
CNN just gave a 25-28 ft surge for Metairie.....where my family is. Ouch.

maybe it will clean up the days inn then, that place was a dump the last time i stayed there.. that was a joke to lighten the mood....
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523. Valence
5:01 PM GMT on August 28, 2005
CFL-

That links not going to be active for very much longer. Not gonna make it.

When was the last time the wind/pressure was updated? Was it at the 11am advisory, or did they issue a special statement? And when is the next set of data expected from the recon flights?
522. leftyy420
5:04 PM GMT on August 28, 2005
and there will be 25-45 ft waves ontop of that surge
Member Since: August 24, 2005 Posts: 35 Comments: 1987
520. pseabury
5:02 PM GMT on August 28, 2005
CNN just gave a 25-28 ft surge for Metairie.....where my family is. Ouch.
Member Since: May 28, 2005 Posts: 0 Comments: 3
519. leftyy420
5:02 PM GMT on August 28, 2005
hey discoboy all i did was make a comment on his speach. thats all i asaid and since than i have disscissed the storm. thank you

the eye is really round now and quite impresssive. she looks stronger than she was at the last update for sure
Member Since: August 24, 2005 Posts: 35 Comments: 1987
518. pseabury
4:59 PM GMT on August 28, 2005
Man, the last IR image I looked at is impressive. NW quadrant getting squeezed a bit, but her eye is very impressive. Waiting for the 2pm model runs from NHC. Here's my latest imagery/model overlay.

IR + Model Runs 1pm EST
Member Since: May 28, 2005 Posts: 0 Comments: 3
517. weatherguy03
5:00 PM GMT on August 28, 2005
Yeah valence when they are this big they create there own environment. people keep thinking its gonna do a charlie and move right, i dont think so. Remember Charlie was small and strong, BUT Kat is soooo much larger. two different storms.
Member Since: July 5, 2005 Posts: 592 Comments: 29708
516. SEFL
12:59 PM EDT on August 28, 2005
I do grief counseling. I just got a call from one of the agencies I work with asking if I would go to Louisiana (somewhere don't know where yet) next week.

Obviously a lot of resources are already starting to be mobilized for the aftermath.
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513. CFLweather
4:58 PM GMT on August 28, 2005
Link New Orleans RADAR, bookmark it if you haven't already.

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512. weatherboyfsu
4:54 PM GMT on August 28, 2005
The only thing that ive noticed with katrina is the cloud tops are not as cold.....still impressive....and i understand thats normal in the scheme of things....tonight, like last night, I think it will look better....im thinking that the winds will level off or even drop at the next update at 2 and 5 and 8, then increase again tonight....just a guess but i think you will see katrina peek tomorrow morning at 5am, then its decreasing from then on.....
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511. stmarylalady
4:45 PM GMT on August 28, 2005
We spent the morning boarding the store and shuttering the house. We just came inside, the last 20 minutes or so outside a breeze kicked up and was blowing pretty good.

I looked at the radar(hadn't had a chance for the last 5 hours or so) and was surprized to see how close she has gotten.

Well hubby wants to take a quick drive to the bay before I get ready for work and he and the kids hunker down. Will try to log on later guys.
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509. Valence
4:56 PM GMT on August 28, 2005
Katina-

Have you seen to lateast satellite pictures? Katrina basically stopped the trof dead in its tracks- like running into a brick wall.

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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