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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68. SFLborn
5:01 AM GMT on August 29, 2005
Sorry not typing what I was thinking.. When I said "it" in my post I meant Andrew not Katrina in Miami.

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67. Orleans77
5:01 AM GMT on August 29, 2005
Ben the report was on the local feed...did anyone else heer hear it??
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66. Orleans77
4:59 AM GMT on August 29, 2005
still calling it 160mph..and 908 was Estimated not actual!!
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65. crawdaddy031
12:54 AM EDT on August 29, 2005
Burl1 bouy is down last report at 10pm cdt.
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64. SFLborn
4:59 AM GMT on August 29, 2005
I'm just sick to my stomach thinking of the loss of life and property that is about to happen in NO. I'm a paramedic and just about an hour north of Miami so after it hit I did my time there and that will look like nothing compared to this. I have to be up with my girls tomorrow but I'm finding it hard to leave the computer and TV.

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63. BenRMac
4:56 AM GMT on August 29, 2005
Still nothing on local news about any traffic accident. I'm calling shennagians on it, especially being from national news. Remember all the false reports in 9/11, other major disasters.
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62. sSnack
4:59 AM GMT on August 29, 2005
There's a NEW ADVISORY (12 CDT) up!
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61. AySz88
12:58 AM EDT on August 29, 2005
Oops, sorry about that. >.<
Member Since: August 25, 2005 Posts: 0 Comments: 8
60. cajunkid
11:54 PM CDT on August 28, 2005
Nagin said NO got 80% out, that's great considering the time frame...I don't think there will be as many deaths as everyone thinks. I talked to alot of people that arrived in BR a few hours ago, and they said NO is completely empty. I hope this is true and I'm not trying to make light of the situation, just thought I would give a less pesamistic picture.
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59. Orleans77
4:58 AM GMT on August 29, 2005
thks..i think im also gonna have a good cry..i dont cry easy..but my heart is breaking...
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58. bekroweather
4:56 AM GMT on August 29, 2005
Anyone has news from Stormtop?
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57. noaactionhere
4:58 AM GMT on August 29, 2005
all our thoughts and prayers are with you
watching from GA
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56. AySz88
12:57 AM EDT on August 29, 2005
MouseClick L, 154, 81
Member Since: August 25, 2005 Posts: 0 Comments: 8
55. wpb05
4:56 AM GMT on August 29, 2005
this just tops off the strsnge weather in the world this last year......this is just sickening........this is going to really hurt.....I sure hope other countries come to our aid since we help so many with our dollars
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54. pseabury
4:55 AM GMT on August 29, 2005
I'm having trouble listening to both FOX and KHOU.....I must have had FOX on during that.

As for the traffic situation....people are industrious. If that's really the situation, I would hope that they would just ram the cars out of the way and do what they could for the injured.

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53. icebear7
4:57 AM GMT on August 29, 2005
prayin with ya Orleans
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52. Orleans77
4:56 AM GMT on August 29, 2005
i also need to go say a prayer
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51. Orleans77
4:55 AM GMT on August 29, 2005
Im gonna take a five min break..have been on now for 13 hrs straight..no break...so back in 5 guys
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50. icebear7
4:53 AM GMT on August 29, 2005
Carbo, Orleans77... The rules are different tonight... there won't be any waiting for tow trucks. The people will either shove the cars/trucks off the road or off the side of the bridge(dependeing where the accident happened) after the injured are removed.

Those 15,000 cars will be fine.


certainly hope so
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49. leftyy420
4:55 AM GMT on August 29, 2005
link to live feed

Link
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48. Orleans77
4:54 AM GMT on August 29, 2005
Link

http://www.khou.com/perl/common/video/wmPlayer.pl?title=beloint_khou&props=livenoad
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47. pseabury
4:54 AM GMT on August 29, 2005
Orleans.....which station you watching?
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46. Carbo04
4:53 AM GMT on August 29, 2005
afs, getting the injured out, and pushing the vehicals of that many piled up would wil ltake to long for them to escape. Their time with God is coming within a couple hours. Bless them.
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45. Orleans77
4:54 AM GMT on August 29, 2005
afs i pray u are right
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44. sSnack
4:52 AM GMT on August 29, 2005
Which live feed are you all watching?
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43. Orleans77
4:53 AM GMT on August 29, 2005
Mayfield just said loss of live will be great...both anchors just choked up on camera..
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42. Bamaman
4:53 AM GMT on August 29, 2005
Just to note, you can kind of see the eye from the Mobile long range. So when NO goes out, Mobile will be there to see.

Also, my heart and prayers go out to those 15,000.
41. leftyy420
4:52 AM GMT on August 29, 2005
i am waiting to hear about it on the live feed. they are not in a situation where they can properly report the news. this is just their other office. their main office was evacuated so while we have a feed we will still not know much
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40. cajunkid
11:52 PM CDT on August 28, 2005
wwl live feed?
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39. pseabury
4:50 AM GMT on August 29, 2005
Caramel - If we were just talking winds, then yes...most/all reinforced conrete would do just fine. We're talking about wind and water though. Water is orders of magnitude more dense than air. You get moderate waves (10ft) slamming into structures not designed for that, and you are exerting TONS per square foot of pressure on them. Moving water is probably the most underestimated force in the world.
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38. Orleans77
4:52 AM GMT on August 29, 2005
was reported on live feed 20 min ago
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37. afs
4:49 AM GMT on August 29, 2005
Carbo, Orleans77... The rules are different tonight... there won't be any waiting for tow trucks. The people will either shove the cars/trucks off the road or off the side of the bridge(dependeing where the accident happened) after the injured are removed.

Those 15,000 cars will be fine.
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36. fortlauderdalegirl
4:50 AM GMT on August 29, 2005
Let's hope all the way West -- far to Texas. Not East or those people are doomed. When Dennis hit, we were on our way w/my niece and nephew to Disney. We got caught in a feeder band -- just past Lake City. I really thought we were going to die. Monsoon, blinding rain and probably 50-60+ wind. I have Ford Expedition. It was blowing around. I thought we were done for -- no joking. Scared me to death.
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35. BenRMac
4:51 AM GMT on August 29, 2005
The 3 fatalities were reported on WWL, they were elderly people being evacuated to a shelter. No word on the exact cause, but implied that they were just fragile and couldn't stand the move.
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34. Orleans77
4:51 AM GMT on August 29, 2005
dunno..I-10 is supposed to get 12-15' surge with waves on top...I-10 should have Hurr winds in 3-4 hrs..so they better clear it quik
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33. leftyy420
4:51 AM GMT on August 29, 2005
blackout of sat img. now all we have is radar.i expect to lose the radar in about and hour or 2
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32. SFLborn
4:49 AM GMT on August 29, 2005
I haven't heard on the live feed about a accident on I 10 has this been confirmed. I'm in tears thinking of those people caught behind the accident. I have two little girls and I can't even imagine being there having them and myself know what was about to happen.

God bless them and keep them all safe.
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31. leftyy420
4:51 AM GMT on August 29, 2005
from the live feed
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30. cajunkid
11:46 PM CDT on August 28, 2005
I've been at Walk-On's all night, and they have 10 tv's and I haven't heard anything about 15,000 people stuck anywhere. Neither the local news nor the NO news has reported such a thing, but I'm not saying it aint true
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29. Orleans77
4:50 AM GMT on August 29, 2005
local feed...hurr force winds in grand isle by 1am...8am landfall at grand isle...8am...1pm NO..per NHC
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28. TxCandy
11:47 PM CDT on August 28, 2005
what will the people stuck on I-10 do--this is really horrible!
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27. Orleans77
4:49 AM GMT on August 29, 2005
scares me to lefty....dont know FLL..they did not say
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26. Weather89
12:47 AM EDT on August 29, 2005
where did u hear about the three fatalities?
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25. caramelnutlog
4:42 AM GMT on August 29, 2005
What is the official building code and height above sea level for the superdome?
Is it a valid alternative? Wouldnt any steel reinforced concrete building (above the flood, and away from windows) be sufficient? Its going to have to be for some.
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24. Orleans77
4:47 AM GMT on August 29, 2005
FOX NEWS just reported that very likely tomorrow there will be a large scale call up of many if not all Reserve and Guard Units in US not already committed to Iraq / Afghanistan
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23. leftyy420
4:47 AM GMT on August 29, 2005
remebr guys. this is the time we saw th 34 mb drop and 30 mph increase aftyer strugling to maintain a cat 3 status yesterday. thats what scares me about this storm right now
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22. fortlauderdalegirl
4:48 AM GMT on August 29, 2005
WHERE on 1-10 did the accident happen???
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21. bekroweather
4:47 AM GMT on August 29, 2005
So are the people stuck just west of New Orleans??? The swamp is not the best place to get hit by a hurricane. Is there any forecast for the status of I-10 tomorrow?
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20. Carbo04
4:47 AM GMT on August 29, 2005
my god, all those people are going to die. They can't get anywhere, and the storm is coming to fast to spare them. God bless them.
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19. Orleans77
4:47 AM GMT on August 29, 2005
car accident on I-10...18 wheeler..road is blocked with 15,000 cars behind them
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18. pseabury
4:44 AM GMT on August 29, 2005
I agre with Masters....as I did per our (orleans, lefty, etc) discussion earlier that the non-corellation of the eye size, and pressure (larger eye, low pressure) leaves a lot of room for extreme concern. I think it wouldn't be prudent to forecast any significant weakening until the storm shows that ground truth. The pressure leaves too much room for eyewall shrinkage and for Katrina sustaining her curren strength, or increasing her strength locally around the eye.

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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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