Katrina weakening--but still of catastrophic intensity

By: Dr. Jeff Masters , 4:31 AM GMT on August 29, 2005

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The 10:36pm EDT Hurricane Hunter mission found a central pressure of 908 mb, up 6 mb since this afternoon's minimum of 902 mb. The maximum flight level winds in the northwest quadrant were 122 knots, which translates to a Category 3 intensity at the surface (130 mph). However, Katrina's strongest winds are in the northeast quadrant, and the Hurricane Hunters have not sampled that quadrant yet. Winds of 160 knots were found there by the previous mission at 8pm EDT. The rising pressure implies that we should see some diminishing of the winds in the next few hours, making Katrina a strong Category 4 hurricane. Hurricanes rarely maintain Category 5 intensity for more than 12 hours, and that is how long Katrina has been at Category 5.

I have been expecting Katrina to undergo a shrinking of the eye and an eyewall replacement cycle tonight, but instead the eye diameter has increased to 30 nm (35 miles). This is an incredibly large eye for a storm with a pressure this low, and makes me very uncertain about what intensity fluctuations Katrina may undergo in the next few hours before landfall. I see nothing to change the label of "catastrophic" for Katrina at landfall.

The eye is now clearly visible on long-range New Orleans radar. This view may not be around too much longer, I expect Katrina will destroy the radar site. This happened to the Miami radar during Hurricane Andrew, when a 160 mph wind gust ripped the radar ball from its rooftop mooring. When one looks at this radar image animate, considers the forecast track, and sees the huge size of the eye, it is very difficult to imagine that New Orleans will not get a portion of the eyewall. New Orleans will likely flood, causing immense destruction and heavy loss of life.

I just received this email from user Adam Henderson: "My friend is stuck on I-10 and has just called me saying there is a 12 car pile up. His CB is buzzing with news that a 18 wheeler is involved." At this stage, it might be best not to try to evacuate. Being stuck in a traffic jam on I-10 when the winds start blowing 130 mph is probably more dangerous than riding out the storm in the Superdome.

Tropical Depression 13
A new tropical depression formed in the mid-Atlantic today, and is headed northwest over open ocean. This is one we definitely do not need to worry about for now. The storm may even dissipate due to hostile wind shear within the next few days.

See you in the morning. My prayers to all in the path of Katrina.

Dr. Jeff Masters

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618. leftyy420
8:42 AM GMT on August 29, 2005
i dunno. isee a north motion till after landfall but we willsee
Member Since: August 24, 2005 Posts: 35 Comments: 1987
617. cajunkid
3:41 AM CDT on August 29, 2005
she is gonna turn ne shortly
Member Since: July 10, 2005 Posts: 3 Comments: 1279
616. 53rdWeatherRECON
8:40 AM GMT on August 29, 2005
oops jumped the gun a little when it gets going for real we will know it.
Member Since: August 5, 2005 Posts: 2 Comments: 80
615. cajunkid
3:39 AM CDT on August 29, 2005
We are the champions my friend!!! She aint gonna do it!!!
Member Since: July 10, 2005 Posts: 3 Comments: 1279
614. leftyy420
8:38 AM GMT on August 29, 2005
pressure is upto 017 but the flight level winds are still 132kts recoreded in the se quadrant in the last hour. i think thye might lower the intensity to 150 if at all. we will see full adv in 20mins
Member Since: August 24, 2005 Posts: 35 Comments: 1987
613. deadmandancing
8:37 AM GMT on August 29, 2005
Valence, a couple of hours ago, everyone was talking about some guy in shorts walking his dog on the bead cam. Perhaps they were messing with my head, 'cause I never could find him.
612. WeatherSpotter
8:37 AM GMT on August 29, 2005
Link for French Quarter Cam?
611. iyou
8:36 AM GMT on August 29, 2005
SirV - truth? - i'm kinda gullible - going to check the GOES IR
Member Since: July 25, 2005 Posts: 0 Comments: 5219
610. leftyy420
8:37 AM GMT on August 29, 2005
yeah its hitting the fan on streetcar cam
Member Since: August 24, 2005 Posts: 35 Comments: 1987
609. cajunkid
3:35 AM CDT on August 29, 2005
I think NO has done it again...I'll take the Saints over Katrina any day
Member Since: July 10, 2005 Posts: 3 Comments: 1279
608. Valence
8:36 AM GMT on August 29, 2005
guy with the dog?

WTF?
607. 53rdWeatherRECON
8:34 AM GMT on August 29, 2005
Wow that web cam is really getting hit now...
Member Since: August 5, 2005 Posts: 2 Comments: 80
606. iyou
8:34 AM GMT on August 29, 2005
SirV - i think that's lightning...
Member Since: July 25, 2005 Posts: 0 Comments: 5219
605. SirVivor
8:32 AM GMT on August 29, 2005
FYI, for you trivia freaks out there, the first web cam was invented by a computer professor at a university because he got tired of going to get a cup of coffee and finding the pot empty. SOP he rigged a web cam so he could look at the coffee pot at any time and see if there was enough coffee in the pot to make it worth his while to walk down stairs to get a cup. Alas the coffe pot cam was finally taken down after about 15-20 years. It was an icon for geeks everywhere
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604. xkcd
8:30 AM GMT on August 29, 2005
I haven't seen anyone mention Lili -- I recall that it was looking like a pretty serious hit, cat-4 at least, and then just as it made landfall (overnight, I believe) it weakened dramatically and caused far less damage than expected, and no one was entirely sure why it had happened.

Anyone have more info on that? I remember someone saying that probably some Ph. D theses were going to be written on the reasons for Lili's disintegration.

Could that be happening to Katrina now? The weakening, not the theses.
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603. 53rdWeatherRECON
8:31 AM GMT on August 29, 2005
Almost about to get daylight back. All those who made it through the night all I can say is wow. Now lets hope she makes landfall before this convection starts just blowing up and wraping around again.
Member Since: August 5, 2005 Posts: 2 Comments: 80
602. cajunkid
3:33 AM CDT on August 29, 2005
anyone have the new advisory?
Member Since: July 10, 2005 Posts: 3 Comments: 1279
601. iyou
8:31 AM GMT on August 29, 2005
yeah, he's gorging on those kremes-sugar-coated air
Member Since: July 25, 2005 Posts: 0 Comments: 5219
600. Valence
8:33 AM GMT on August 29, 2005
Sir, sounds about right.
599. deadmandancing
8:32 AM GMT on August 29, 2005
hey, Lefty, got any time frame on that cop? I was strangly crushed that I missed the guy with the dog on the beadcam earlier. I must be in stage five of sleep deprivation
598. Remek
8:30 AM GMT on August 29, 2005
Check out the French Quarter cam - visibility's gone way down now.
Member Since: August 29, 2005 Posts: 0 Comments: 118
597. SirVivor
8:30 AM GMT on August 29, 2005
I think it is both a traffic light and a cop. I"ve seent he cop...but I've also seent he green light reflected. So I think it is an itnersection but when you see the light strobing, it is the cop driving by. I've seen the cop drive by and I've seen the green light that doesn't strobe and I've seen a red light that doesnt' strobe...and then I've seen blue nad red lights strobe just before the cop drives by...so everybody is right on this one...I think..
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596. AySz88
4:32 AM EDT on August 29, 2005
Some helpful links (auto-posting every 20 minutes):

Projected Flooding from Katrina

WWLTV/KHOU webcast (switched operations to Baton Rouge) (Open in Windows Media Player)
CBS affiliate; guest had claimed WWL was the only remaining news feed out of NO
Alternate: KHOU Server

New Orleans Long-Range Radar Loop (Alternate Presentation)
NO Radar Analyzed on Wunderground (for tornadoes, etc.)

VORTEX Recon Decoder (Raw)

GOES Ch.4 IR Loop (Updates every 30 min)
GOES-12 Interactive Map (Updates every 15ish min; set options then click hurricane in picture to animate)

Lake Pontchartrain & Area Water Levels (1, 2, 3)
Near-Katrina Buoy Measurements

New Orleans Winds (click a site, then "Real-Time")
(Direct link to real-time winds at WWL-TV)
Member Since: August 25, 2005 Posts: 0 Comments: 8
595. cajunkid
3:29 AM CDT on August 29, 2005
mn
Member Since: July 10, 2005 Posts: 3 Comments: 1279
594. iyou
8:29 AM GMT on August 29, 2005
whoever patents the wiper will be a billionaire - have you ever checked out the mount st.helen's webcam?? half the time it's blurred out from rain...
Member Since: July 25, 2005 Posts: 0 Comments: 5219
593. leftyy420
8:29 AM GMT on August 29, 2005
though i haven't seen him in about 15-20 mins so he might not be back. he might be hunkered down now waiting for the worse
Member Since: August 24, 2005 Posts: 35 Comments: 1987
592. SirVivor
8:26 AM GMT on August 29, 2005
Well, it is a parade cam...it doesn't normally rain during parades, so they don't usually need wipers, right? At least taht is what I'm guessing since they call them parade cams....I don't think the cam was designed for watching killer 'canes hit the city. However, I could be worng...I was once...I think it was back in '64...but I could be wrong.
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591. leftyy420
8:28 AM GMT on August 29, 2005
no, i have been watching this cam for a long time now. he will drive by the cam with his lights on fromtime to time. i meane right up to the cam.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
590. iyou
8:26 AM GMT on August 29, 2005
i've been up since Emily..................
Member Since: July 25, 2005 Posts: 0 Comments: 5219
589. Valence
8:24 AM GMT on August 29, 2005
Lefty-

I dont think thats a cop! I think its the stoplight at that intersection being blown around. Its not blue, its green!
588. leftyy420
8:26 AM GMT on August 29, 2005
a wiper on the cam thats to much lol
Member Since: August 24, 2005 Posts: 35 Comments: 1987
587. iyou
8:23 AM GMT on August 29, 2005
lol - you guys are a scream!! what's sleep?? you'd think someone would have thought to put an intermittent wiper on web cams-i'm sure it's not rocket science..
Member Since: July 25, 2005 Posts: 0 Comments: 5219
586. cajunkid
3:23 AM CDT on August 29, 2005
funny schwartz aint around when sh** is deep...we need that dude right now
Member Since: July 10, 2005 Posts: 3 Comments: 1279
585. Valence
8:23 AM GMT on August 29, 2005
where exactly in NO is this camera? im trying to match up with the radar
584. Remek
8:23 AM GMT on August 29, 2005
she still appears to be heading straight for NO in the latest radar loop - no more major wobbles
Member Since: August 29, 2005 Posts: 0 Comments: 118
583. SirVivor
8:23 AM GMT on August 29, 2005
Bummer of a job...riding around in circles with no Krisp[y Kreme and on the night before he is about to meet his maker when Davey Jones' locker meets the Big Easy. I think I'll keep my job...
Member Since: Posts: Comments:
582. deadmandancing
8:22 AM GMT on August 29, 2005
Parade cam looking a little punchy, as well.
581. leftyy420
8:21 AM GMT on August 29, 2005
no but really it shows the storm is trying to reprginise and the problem is she nmight run out if time
Member Since: August 24, 2005 Posts: 35 Comments: 1987
580. leftyy420
8:20 AM GMT on August 29, 2005
it means that cop aint getting no kripsy kreme lol
Member Since: August 24, 2005 Posts: 35 Comments: 1987
579. JaxAdjuster
8:20 AM GMT on August 29, 2005
u guys are definately "punch drunk" from lack of sleep. LOL
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578. Valence
8:19 AM GMT on August 29, 2005
Thanks lefty - definately need a squeegee out there!
577. cajunkid
3:19 AM CDT on August 29, 2005
must sleep
Member Since: July 10, 2005 Posts: 3 Comments: 1279
576. deadmandancing
8:17 AM GMT on August 29, 2005
As much as I've been on this blog in the past days, I should know, but I am half-crazy with no sleep. What does it mean for the storm that it is filling in with deep convection?
575. JaxAdjuster
8:17 AM GMT on August 29, 2005
are 2 hour recons running? I keep hoping it will move to 2 hours.
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574. leftyy420
8:16 AM GMT on August 29, 2005
link to cams

Link
Member Since: August 24, 2005 Posts: 35 Comments: 1987
573. Valence
8:16 AM GMT on August 29, 2005
A streetcar named Katrina?
572. cajunkid
3:13 AM CDT on August 29, 2005
yes, deep convection to the south, could be her last ride on the warm eddie
Member Since: July 10, 2005 Posts: 3 Comments: 1279
571. Valence
8:15 AM GMT on August 29, 2005
Could someone repost the link for the cams...i had to reboot and its too far down the thread.
570. SirVivor
8:13 AM GMT on August 29, 2005
Can't say I ever met a gal with deep convection filling her backside, but my hubby once dated one who 'squirted' when she made the "O" face.
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569. Valence
8:12 AM GMT on August 29, 2005
I think we're all starting to get punchy due to lack of sleep.

On that note, just brewed up some coffee - its going to be an all nighter.
568. MONJAYB
1:13 AM PDT on August 29, 2005
RiverCam is still working too. Seeing some good transformers blow on that one!
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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.