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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1459. IrememberFredrick
5:01 AM GMT on August 29, 2005
Hey everyone first post been reading for hours. I live just west of Mobile in Irvington. Wondering if anyone thinks it will get bad here.
1458. GRDRATNAVARRE
2:54 AM GMT on August 29, 2005
bands passing nothing serious yet.
1457. Solo
1:30 AM GMT on August 29, 2005
This is truly amazing! I've lived along the Gulf Coast (from Houston/Galveston to Baton Rouge to Panama City and now Tampa) for nearly 18 years, and this is simply the scariest thing I've ever seen. Even if NOLA dodges the direct bullet, there are going to be major after-effects for a huge swatch of the coast. Good to see that W is on the ball, too. Best wishes and best of luck to the folks in the track.
1456. cajunkid
1:04 AM GMT on August 29, 2005
just got back from church, people are worried, you can tell who was from NO, you can see on their faces, some of these poeple I've known for a long time and thier lives are about to be turned upsidedown, SUX
Member Since: July 10, 2005 Posts: 3 Comments: 1279
1455. WSI
12:52 AM GMT on August 29, 2005
Good luck to all of those in the path of this monster. You all and everyone down there are in my thoughts and prayers.
1454. linny
12:44 AM GMT on August 29, 2005
All you there in LA, MS and Al. You have my prayers.
1453. LALady
12:24 AM GMT on August 29, 2005
At least I have battery backup on my laptop...and a generator to recharge.
1452. LALady
12:20 AM GMT on August 29, 2005
Power out already here in Denham Springs (east of Baton Rouge) HOT, HOT, with no A/C!!!
1451. pseabury
12:04 AM GMT on August 29, 2005
Radar loop our of BR/NOLA definitely shows a N/NW (approx 330 degrees) for the last hour or so.

Radar Loop
Member Since: May 28, 2005 Posts: 0 Comments: 3
1450. pseabury
12:01 AM GMT on August 29, 2005
Easy to see the water in Lake Pontchartrain coming up rather quickly, and easily surpassing normal tidal ranges:

Mid-Lake Pontchartrain gage height
Member Since: May 28, 2005 Posts: 0 Comments: 3
1449. linny
12:00 AM GMT on August 29, 2005
North northwest now. Any thoughts?
1448. pseabury
11:57 PM GMT on August 28, 2005
Anything I miss that isn't on this first page of blog? had to grill chicken etc....feel like I was gone hours.

Member Since: May 28, 2005 Posts: 0 Comments: 3
1447. Jedkins
11:38 PM GMT on August 28, 2005
Pascmississipi I hope if you are less than 75 inland that you are in a shealter or a very strong structure....
1446. PascMississippi
11:20 PM GMT on August 28, 2005
It looks like it just took a hard turn north! What does everyone think?
1445. StormJunkie
11:12 PM GMT on August 28, 2005
30+ ft waves 64nm S of Dauphin Island.
Member Since: August 17, 2005 Posts: 26 Comments: 16348
1444. weatherguy03
11:11 PM GMT on August 28, 2005
long range loop....Link...
Member Since: July 5, 2005 Posts: 592 Comments: 29704
1443. tomjonesdaphneAL
11:08 PM GMT on August 28, 2005
This is the buoy data from the point just south of Dauphin Island, AL... that is the mouth of Mobile Bay.

Wind Direction (WDIR): E ( 100 deg true )
Wind Speed (WSPD): 31.1 kts
Wind Gust (GST): 36.9 kts
Wave Height (WVHT): 28.2 ft
Dominant Wave Period (DPD): 14 sec
Average Period (APD): 9.8 sec
Mean Wave Direction (MWDIR): ESE ( 123 deg true )
Atmospheric Pressure (PRES): 29.44 in
Pressure Tendency (PTDY): -0.09 in ( Falling )
Air Temperature (ATMP): 79.2 F
Water Temperature (WTMP): 85.5 F
Dew Point (DEWP): 76.1 F
Heat Index (HEAT): 83.5 F
1442. StormJunkie
11:08 PM GMT on August 28, 2005
How long is the long range radar blackout? We seem to have it everday so I assume it is a blackout.
Member Since: August 17, 2005 Posts: 26 Comments: 16348
1441. weatherguy03
11:07 PM GMT on August 28, 2005
wind chart....Link..for people in BR..
Member Since: July 5, 2005 Posts: 592 Comments: 29704
1440. TampaSteve
11:05 PM GMT on August 28, 2005
Cosmic...I thought Andrew went over the NHC in 1992...

Anyway...Katrina is gonna wreck New Orleans...hope everyone got out in time...good luck, people...
1439. weatherguy03
11:04 PM GMT on August 28, 2005
Just to put my two cents in...BR will see winds 75-85 sustained with possible gusts to 100. but if storm wobbles to the east alittle this will be much less. Still destructive winds but not devistating.
Member Since: July 5, 2005 Posts: 592 Comments: 29704
1438. Valence
11:03 PM GMT on August 28, 2005
Josh-

If you're off by about 50 miles (which is not large error), that puts you 30 miles from the center, and about 20 miles from the eyewall? Are you ready for that?
1437. CosmicEvents
11:02 PM GMT on August 28, 2005
To those on the blog located in Baton Rouge......base your decisions, thoughts, and actions on what you hear from the NHC.....and local meteorologists. No sense in getting into an argument with anyone on a blog. Most of us have no formal meteorological training, though many have an inflated ego. Personally, I have no training...just personal experience. I'm only hear out of an interest in tropical cyclones, and in the near term, to help in any way I can with those in the path of Katrina..
.
.Just as an insight from the NHC, and from going through Katrina in South Florida....... Realize that Baton Rouge is in the cone of uncertainty...albeit on the far left side. Talk to people in South Miami, who were also on the far left side of this cone, including ironically enough NHC headquarters. Yes, Katrina was the first storm to ever pass directly over NHC headquarters in Miami. Nobody knows exactly where the storm is going now. My advice is simply to prepare for the worst and hope for the best.
Member Since: August 3, 2005 Posts: 10 Comments: 5560
1436. Joshfsu123
11:00 PM GMT on August 28, 2005
okay leftyy... Like others have stated, we disagree. The NW side of the storm is not as strong as other parts of the Hurricane and Baton Rouge is about 50 miles to the NW of New Orleans. If the center comes in about 20 miles east of New Orleans, which I predict, then that puts the eye about 70 miles to the east of Baton Rouge. That will be Hurricane force sustained (80mph) but Nowhere near 120-130 sustained. The strongest winds of over 100mph will be about 20 miles near the center, in the eyewall.
Member Since: July 6, 2005 Posts: 5 Comments: 580
1435. Orleans77
11:00 PM GMT on August 28, 2005
U guys see the turn to the N?? its moving due N now...Lefty do u think this might turn NE and miss NO???
1434. Valence
10:59 PM GMT on August 28, 2005
Right now it looks like two possible landfalls

Grand Isle, LA

Bay St Louis, MS

And it DOESNT REALLY MATTER. This is category 5! Does anyone remember the pictures of Homestead, FL after Andrew passed by?

Or you can check out this site on Camille.

And remember, its not just the landfall point. If you are 200 miles E or W from the center, you are getting at LEAST tropical storm force winds and lots of rain. Flooding will be EVERYWHERE.

And those of you inland, while not having the storm surge, and still getting hit by a hurricane! This will still be a hurricane all the way to the N border of AL or MS. Is your home prepared?
1433. SaCaCh
10:58 PM GMT on August 28, 2005
It looks like the right side of the storm is begining to collapse. see the newest infared images.
1432. Weather89
10:58 PM GMT on August 28, 2005
The pressure is now up to 904 mb according to recon reports. What do you guys make of this??
1431. dragonflyvortex
10:58 PM GMT on August 28, 2005
new jeff masters update
1430. leftyy420
10:58 PM GMT on August 28, 2005
also the hurricane force winds extend outward from the center 105 miles on each side of the storm.


here is a link to the windfield

Link
Member Since: August 24, 2005 Posts: 35 Comments: 1987
1429. nervouspete
10:58 PM GMT on August 28, 2005
Hello, folks.

First post here. Name's Pete and I live in the UK, I didn't know about Katrina until early today and I've been following the news for the last two hours. It's 11:53 am here, no work tomorrow thanks to Bank Holiday, so I'll keep following this through tomorrow. The last big hurricane in the UK was Andrew, which killed 32 people and washed cruise liners onto the shore. I remember the power going out for that one, even though I lived up North two hundred miles from landfall!

I'm keeping my fingers crossed for Louisianna. It's hard to believe the study toll predictions of 25,000+ - I guess they were following the worst case scenario of gridlocked traffic being hit by the hurricane within the bowl. How many people do you think will be staying in New Orleans?

All a bit surreal really. My mate went down there a few weeks before Ivan and he really enjoyed it there - but he's a bit worried now as to what's happening.

Stay safe, you chaps. Hope the doomsday scenarios are on the right side of fanciful, and that Orleans is spared the worst. (Though it's becoming increasingly hard to see how, guess it all depends on the structual integrity.)

Do you think there's many left in the bowl?
Member Since: August 28, 2005 Posts: 0 Comments: 20
1428. Canenut
10:58 PM GMT on August 28, 2005
904mb/160kts
1427. EZMonster
10:56 PM GMT on August 28, 2005
Guys, that forecast page is a region page. If you look at the column to the right of it where it says PINPOINT FORECAST, you can click on that map and it gives a slightly more realistic forecast. For example, if I click just on the New Orleans waterfront, I get:

Tonight: Rain and thunderstorms likely, then occasional rain after 7pm. Low near 80. Windy, with a east wind 20 to 25 mph increasing to between 55 and 60 mph. Chance of precipitation is 100%.

Monday: Occasional rain. High around 80. Windy, with a north wind 105 to 110 mph decreasing to between 60 and 65 mph. Chance of precipitation is 100%.
1426. leftyy420
10:56 PM GMT on August 28, 2005
ur wrong josh. theres a reason they are in a hurricane warnning. did u not know they were in a hurricane warning the are expecting winds of 90+ sustained and higher gusts. its more likley to be 120-130 sustained with gusts to 150-160
Member Since: August 24, 2005 Posts: 35 Comments: 1987
1425. Canenut
10:56 PM GMT on August 28, 2005
moving about 355 degrees now, yes?
1424. K8tina
10:55 PM GMT on August 28, 2005
pcolanative said "Repeatedly, people described it as the 'most terrifying night of their lives.' I am not talking about things I read, saw, or heard second hand. I am speaking of friends who stayed..."

I am one of those who stayed for Ivan. Me, my hubby, my 6-month old triplets and 2 neurotic cats! It was not something I would want to repeat any time soon. That is why I cannot fathom why these people are staying in NO and partying on Bourbon Street... or anyone who refuses to evacuate from the path of this storm. It is not going to be all fun and games! This storm is going to bring mass destruction and sadly, many lives will be lost. Why don't some ppl get it???

(Sorry for venting!!!)
1423. leftyy420
10:54 PM GMT on August 28, 2005
its not the nws fault. they leave the forcasting at that point to the nhc who issues advisories. they are in a hurricane warning and its there for a reason.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
1422. StormJunkie
10:53 PM GMT on August 28, 2005
Just hunker down good Cane.
Member Since: August 17, 2005 Posts: 26 Comments: 16348
1421. Joshfsu123
10:53 PM GMT on August 28, 2005
Baton Rouge will not be in the eyewall unless it goes further west. Baton Rouge is off to the North and West of New Orleans.... They will get winds between 50/80mph sustained and higher gusts. That is bad enough. But I don't see it getting over 100mph in the area.


BTW, this storm is big.... they have updated the forecast in Tallahassee to a 90% chance of rain and now forecast winds between 35 to 50mph with higher gusts in the rain bands.

Also, Steve Lyons from the Weather Channel just stated it looks like it may hit the very southern tip of Louisiana and push into Mississippi (Not New Orleans) if the turn to the North continues without any wobbles.
Member Since: July 6, 2005 Posts: 5 Comments: 580
1420. MexicoMark
10:53 PM GMT on August 28, 2005
Lefty,

Have been (mostly) lurking and I appreciate your efforts to educate people and get them to safety. I looked at your link

click this link and tell me where it says a cat 5 is comming

and found the same drivel as weather.com puts on their site. Someday someone will take them to task (legally) for understating the gravity of the situation.

1419. StormJunkie
10:52 PM GMT on August 28, 2005
NOLA LIVE FEED
Member Since: August 17, 2005 Posts: 26 Comments: 16348
1418. Orleans77
10:52 PM GMT on August 28, 2005
http://www.wwltv.com/perl/common/video/wmPlayer.pl?title=beloint_wwltv&props=livenoadLink
1417. SFLborn
10:52 PM GMT on August 28, 2005
http://www.wwltv.com/perl/common/video/wmPlayer.pl?title=beloint_wwltv&props=livenoad

live feed for Ch. 4

Though I wish I could get a Fox live feed.

1416. leftyy420
10:51 PM GMT on August 28, 2005
u know what guys i am done trying to convince them. when all hell breaks lose they will than know. please have a safe night
Member Since: August 24, 2005 Posts: 35 Comments: 1987
1415. BostonGeologist
10:51 PM GMT on August 28, 2005
Meant to say national spike in gasoline to $3.25, of course, not oil.
1414. CaneJunkie
10:51 PM GMT on August 28, 2005
I'm stickin' to my guns. 75 mph here in B.R. I do appreciate the concern though. I won't push the debate any further. We're prepared and will be safe.
1413. sallyb
10:51 PM GMT on August 28, 2005
Does anyone have a live feed site from NO?
1412. leftyy420
10:50 PM GMT on August 28, 2005
and hugo was not as big as this storm. this si the strongest storm since cammile and she is almost at camilee strength and twice as big
Member Since: August 24, 2005 Posts: 35 Comments: 1987
1411. StormJunkie
10:50 PM GMT on August 28, 2005
avlos- It has been that way since Florida weakend the N side but not the S. It is very intresting though.
Member Since: August 17, 2005 Posts: 26 Comments: 16348
1410. Valence
10:49 PM GMT on August 28, 2005
One thing i've noticed:

Because there is still a lot we do not know about hurricanes, specificially with regards to intensity forecasts, most TV weather men are always pretty cautious when they give their reports. "This storm could wobble East, you roof might come off, you may not have power for x days", etc.

Some people hear that and immediately take the attitude that "It wont happen to me". Its not so much complacency as it is arrogance or ignorance. IT NOT ONLY CAN HAPPEN, ITS HAPPENING. LOOK OUT YOUR WINDOW!

1409. Orleans77
10:49 PM GMT on August 28, 2005
i agree 100% boston

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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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