New Orleans to Pensacola at high risk from Katrina

By: Dr. Jeff Masters , 4:05 PM GMT on August 27, 2005

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The Hurricane Hunters measured a central pressure of 949 mb at 11:14am EDT, up from the cental pressure of 941 mb measured at 7:07am EDT. Concentric eyewalls with diameters of 13 and 40 nm were reported, satellite images show that the eye has filled in with clouds and the cloud top temperatures have warmed. These observations indicate that an eyewall replacement cycle has begun. This was expected, since the 7:07am Hurricane Huneter report indicated that the eye diameter had shrunk to 9 nm, about the smallest diameter one gets before an eyewall replacement cycle begins.

The maximum winds may fall below 115 mph while Katrina undergoes this eyewall replacement cycle, as the inner eyewall collapses and a new outer eyewall forms. This would make Katrina a strong Category 2 storm, and indeed the maximum winds seen so far by the Hurricane Hunters were only 87 knots (100 mph) at 10,000 feet. This is a temporary affliction, since Katrina is in nearly ideal conditions for strengthening, and is expected to reach Category 4 status by Sunday. The convection and outflow are starting to look better on the north side of the hurricane, and Katrina should have a more symmetrical shape typical of Category 4 hurricanes by Sunday. As seen in the cumulative wind image below, Katrina has increased markedly in size the past 12 hours, and will deliver a widespread damaging blow wherever she comes ashore.



The favorable intensification conditions for Katrina are expected to last up until landfall, when some increase in shear may occur. Intensification forecasts are highly unreliable, though, and it would be no surprise if Katrina were a Category 2, 3, or 4 landfall. The track forecast is getting more believable, as Katrina's westerly motion shows that it has begun it recurvature, pretty much where NHC and the models were predicting. A landfall between New Orleans and Pensacola is on track for Monday morning or afternoon. I expect a Category 3 storm at landfall.

I'd hate to be an Emergency Management official in New Orleans right now. Katrina is pretty much following the NHC forecast, and appears likely to pass VERY close to New Orleans. I'm surprised they haven't ordered an evacuation of the city yet. While the odds of a catastrophic hit that would completely flood the city of New Orleans are probably 10%, that is way too high in my opinion to justify leaving the people in the city. If I lived in the city, I would evacuate NOW! There is a very good reason that the Coroner's office in New Orleans keeps 10,000 body bags on hand. The risks are too great from this storm, and a weekend away from the city would be nice anyway, right? GO! New Orleans needs a full 72 hours to evacuate, and landfall is already less than 72 hours away. Get out now and beat the rush. You're not going to have to go to work or school on Monday anyway. If an evacuation is ordered, not everyone who wants to get out may be able to do so--particularly the 60,000 poor people with no cars.

Dr. Jeff Masters

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81. leftyy420
4:54 PM GMT on August 27, 2005
yeah i just ignore 27 windows. i doubt he has kids and he has no idea what kind of child my duaghter is. my 4 yr old can read radr images and can locate her location on a map of the state so to me she is as asmart as a 10 year old. i have always pushhed her to her limits. she will be a great adult because of this
Member Since: August 24, 2005 Posts: 35 Comments: 1987
80. boiredfish
4:54 PM GMT on August 27, 2005
Increase in forward speed prior to a significant turn to the nw/n means points further west need to pay heed to this system.
Member Since: July 8, 2005 Posts: 0 Comments: 442
79. weatherboyfsu
4:52 PM GMT on August 27, 2005
IM not here to argue....just look the verification models on here and tell that they have a good handle on this....lol........yesterday they had it hitting the panhandle...the day before that apalachicola.....the NHC models have never taken it this far south.....period....
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78. GetReal
4:49 PM GMT on August 27, 2005
Last few visible satelite photos indicate DUE WEST movement has resumed. Every hour Katrina continues due west the higher the risk for Se La when, and she will, Katrina turns NW.
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77. StormJunkie
4:53 PM GMT on August 27, 2005
You would be very smart Tampa. Would have been even smarter if you had gotten out yesterday.
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76. mobilegirl
4:53 PM GMT on August 27, 2005
Lefty - explain doughnut
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75. TybeeIslandGA
4:53 PM GMT on August 27, 2005
HA!! Looks like it my friend!!
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74. StormJunkie
4:51 PM GMT on August 27, 2005
Looks like your nuke will rest safely for a while Tybee!LOL.
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73. TampaSteve
4:49 PM GMT on August 27, 2005
If I were in NO, I would be leaving NOW!!!
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72. Selu
11:45 AM CDT on August 27, 2005
Plaqumines Parish President Benny Rousselle has issued a Phase I mandatory evacuation for all of Plaquemines Parish.

St. Bernard Parish has issued a "recommended" evacuation for its residents while St. Charles Parish, like Plaquemines has called for a mandatory pullout.

As of yet, no decision has come from parish officials in St. Tammany, Jefferson or Orleans, though announcements are expected around noon.

http://www.nola.com/newslogs/weather/

We should hear more about NOLA evacuation in about ten minutes.
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71. leftyy420
4:51 PM GMT on August 27, 2005
yeah thats my feeling but its still a huge possibility that she could doughnut and there would not be any more cycles, just a period of stregthening until landfall. we have to watch this storm closely for many reasons
Member Since: August 24, 2005 Posts: 35 Comments: 1987
70. weatherboyfsu
4:49 PM GMT on August 27, 2005
Lefty i will be here as always.....until I see a definitive motion to the north, jury is still out.....I want everyone to go look at the model verifications on here....look for yourself.....
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69. hookedontropics
4:41 PM GMT on August 27, 2005
Link

This is what everyone should prepare for. Go northwest from NO go ne from alabama points east
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68. leftyy420
4:49 PM GMT on August 27, 2005
weatherboy this will be my last post on the subject, she had divergent models on the landfall at fl. she took the southern model route, belive it or not the nhc was only off 15 miles on the landfall. they have a good handle on this and u will see. the model concnesus is astounding. that alone with out the nhc track and my knowledge lead me to m,y prediction. this will be my last post to you on this
Member Since: August 24, 2005 Posts: 35 Comments: 1987
67. Dragoon
4:48 PM GMT on August 27, 2005
I would not consider an increase in forward speed a good thing. Note in the NHC discussion the increased chance of shear around the time of landfall.. if Katrina is moving faster than expected.. this shearing environment may have less of a chance of materializing..and she could well hit as a stronger storm.

Yes lefty that would be the worst case scenario. However I that it will probably shrink a bit before taking over as the main eyewall.
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66. leftyy420
4:48 PM GMT on August 27, 2005
yeah she will be a bigger storm after this. quite dangerouse
Member Since: August 24, 2005 Posts: 35 Comments: 1987
65. TybeeIslandGA
4:48 PM GMT on August 27, 2005
Boy this 27windows is a "piece of work" huh!?!
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64. weatherboyfsu
4:43 PM GMT on August 27, 2005
Im thinking that there is way to much uncertainty on what particular area is going to be hit.....heck if it keeps on it might hit the Yucatan penisula.....I remember one storm that did just that......if you guys look at the NHC projections and where katrina has actually went.....when she made landfall north of miami....no one predicted that she would be where she is now or this strong, period......and im not saying thats all bad, we are dealing with alot of unknowns, and IM sure that the NHC is doing the best that they can......at this moment the eye is almost at the same latitude of key west....look at the radar....and I do believe people see what they want to see.....
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63. leftyy420
4:46 PM GMT on August 27, 2005
dragoon worst case would be for her to donought like isabele did and have one gian 40 milw wide eye for days. i could see that happening but still unlikley
Member Since: August 24, 2005 Posts: 35 Comments: 1987
62. wxfan
4:46 PM GMT on August 27, 2005
Increased convection over the last 90 mins around the new eye.

She's getting big.

FWD speed is up a bit tho - is that a good thing, you think?
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61. Valence
4:44 PM GMT on August 27, 2005
For those of you who are watching water vapor or infared picutres of Katrina trying to pick up changes in motion, please have patience. She is undergoing an eyewall replacement cycle (right now there are two eyewalls), so motion and speed is very hard to detect in the short term.

After the center reorganizes, go back and connect the dots to get a much better sense of the current heading and speed.

JV
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60. pseabury
4:43 PM GMT on August 27, 2005
Like I said TampaSteve, that is absolutely bad news...but not as bad as the scenario I painted. By staying East of the City as it approaches, it doesn't push as much water into the Lake before then dumping it into the city. Either way, the W/NW/N trend of winds on the backside of the storm as it passes would make the levees look like speedbumps. Let's hope they have the pumps primed.
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59. boiredfish
4:45 PM GMT on August 27, 2005
He's actually telling people to leave Miss. and hunker down in Baton Rouge? I believe I'd go east, not west, unless I was going all the way to at least Beaumont, if not further.
Member Since: July 8, 2005 Posts: 0 Comments: 442
58. leftyy420
4:46 PM GMT on August 27, 2005
yeah dragoon. u see how her vis appearance imporved over the last 3 hrs. very impressive
Member Since: August 24, 2005 Posts: 35 Comments: 1987
57. Dragoon
4:44 PM GMT on August 27, 2005
Speaking of satellite images.. the current visible satellite shows the concentric eyewall structure perfectly. One can see the original eye and eyewall surrounded by a roughly 40 nm wide secondary structure. This will be taking over as the main eye structure in the next several hours.
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56. PascMississippi
11:45 AM CDT on August 27, 2005
How many Pascagoula people do we have in here?
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55. GetReal
4:43 PM GMT on August 27, 2005
Eyewall replacement cycle almost complete, she should start ramping up again.
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54. leftyy420
4:43 PM GMT on August 27, 2005
i said i told u earlier. come ion here on monday and tell me where she is at. she will be some where near the al,la border give or take 50 miles on each side. than we will see who was right.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
53. leftyy420
4:42 PM GMT on August 27, 2005
that sucks valence. hope u guys are safe and ur property un damaged
Member Since: August 24, 2005 Posts: 35 Comments: 1987
52. weatherboyfsu
4:40 PM GMT on August 27, 2005
Lefty I really didnt understand your last blog.......mistypes
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51. ihave27windows
4:37 PM GMT on August 27, 2005
StormJunkie,

You're entitled to your opinion, and I am as well. I stand by the comment I made to Lefty. (and I suppose a 4 yr old playing a video game for hours, so as not to bother him, is perfectly ok. I say the standard "whatever". ) I also stand by what I said about viewing sat images. We often see what we want to see.
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50. GetReal
4:36 PM GMT on August 27, 2005
Does anyone else see that it appears that Katrina maybe picking up forward motion, approx 10mph now???
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49. hookedontropics
4:39 PM GMT on August 27, 2005
weatherboyfsu, you thinking further east?
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48. StormJunkie
4:40 PM GMT on August 27, 2005
People in Knoxville will really have to hunker down too. This will be one to remeber.
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47. bigpoppapascagoula
11:36 AM CDT on August 27, 2005
I also appreciate the vigorous discussion.

Until tomorrow when I head North and will not have internet acess. :(
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46. leftyy420
4:39 PM GMT on August 27, 2005
and itold you earlier.come in here on monday and tell us hwere she will be. cause as far as i am concerned i have high confidence in her forcasted path and that rough for no and the gulf coast god bless their souls
Member Since: August 24, 2005 Posts: 35 Comments: 1987
45. Valence
4:38 PM GMT on August 27, 2005
Yeah, i bet the residents of Pensacola and nearby cities are just HOPING for a storm to hit there. Its been so long they may not remember what a hurricane looks like!
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44. Dragoon
4:38 PM GMT on August 27, 2005
Absolutely lefty. Katrina seems to be doing something similar to what Ivan did on his way to Grenada. Strengthened rapidly into a category 4 storm.. weakened rapidly to category 2 and began to come back just before hitting Grenada. The ultimate result of that cycle was the first of Ivan's three times as a Category 5.

Katrina may be well on its way.
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43. weatherboyfsu
4:38 PM GMT on August 27, 2005
Im still not convinced on the projected path....look at all the model archives.....look at the key west radar.....
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42. leftyy420
4:37 PM GMT on August 27, 2005
its all good, hey dragoon one thing i think we can agree on is she will defen be getting alot stronger in the next 6 hrs or so. lol she will be amonster
Member Since: August 24, 2005 Posts: 35 Comments: 1987
41. pcolaFL
11:32 AM CDT on August 27, 2005
27 windows quote " get the feeling those of you, and not everyone of course, who reside in Mis and Ala, are hoping it hits you. Same thing with those in Fla. "

Not so for anyone I know! The farther away --west-- the better--when I say I have a feeling this is going more east than predicted--it's not with a sense of glee but a sick feeling in the pit of my stomach. If Katrina goes where the models say, my town will just have a rainstorm. Sounds good to me! I am afraid we will be lulled into that sense of safety and she is going to come just to our west and wallop with her eastern edge. I sure hope I'm wrong.
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40. PascMississippi
11:35 AM CDT on August 27, 2005
Thank you to everyone else too. This is a great place to learn.
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39. weatherboyfsu
4:35 PM GMT on August 27, 2005
whats up lefty????
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38. StormJunkie
4:30 PM GMT on August 27, 2005
27windows. First you tear up Lefty for letting his kid play video games and now you want to try and make the people who enjoy these storms feel bad. I want this one to hit anywhere but NO. I do enjoy seeing the powers these storms hold, some are scared and that is fine also. I would never jump out of a plane, but I would sit and have through a CAT 4 storm. None of us in here want anyone to be injured, but if a storm is coming then some of us want to see it. The final point on this matter is that you act as if somehow some one wanting a storm can make it happen. That is silly.

PLEASE READ IF YOU LIVE IN OR AROUND NEW ORLEANS.
Link


flooding map of NO
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37. Dragoon
4:34 PM GMT on August 27, 2005
Judging by the flight level winds that they're finding, Katrina may very well be downgraded to a Category 2 hurricane at the 2 PM advisory. However this doesn't really matter, because as lefty said.. Katrina is going to get stronger when this cycle is over.
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36. leftyy420
4:35 PM GMT on August 27, 2005
thanks man i appreciate that.one thing i know there are alot of us in here who know whats going on. we will be here to do wehat ever we can to help forcast whats happening between updates from the nhc
Member Since: August 24, 2005 Posts: 35 Comments: 1987
35. GetReal
4:30 PM GMT on August 27, 2005
Latest high resolution satelite loops indicate that Katrina is now movingslightly north of due west; not a true wnw yet. NOLA could still yet be sparred a direct hit if nw movement was to start earlier than predicted.
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34. Valence
4:32 PM GMT on August 27, 2005
Jim Cantonre is doing a live report, advising people of the Voluntary Evacuation for MS. Telling them to go to Baton Rouge! Huh?

Not to mention, they'll be clogging up traffic on I-10 if they do evac NO, and make it one way.

JV
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33. leftyy420
4:34 PM GMT on August 27, 2005
i do belive she will have a bigger eye wall when this is all said and done. it correlates with her larger sixe
Member Since: August 24, 2005 Posts: 35 Comments: 1987
32. TampaSteve
4:26 PM GMT on August 27, 2005
Even if the eye passes just East of NO, it would be catastrophic...the storm will push Lake Ponchartrain over the levees and inundate the city...bad, bad news...
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31. weatherboyfsu
4:28 PM GMT on August 27, 2005
With all due respect Mr.Jeff Masters Katrina has for the most part went her own direction. If you look at the model verifications on here.....the NHC has been completely off...and dont get me wrong....Im a big fan of the NHC.....But by far, they have been way off on their projected path, and I do understand how hard it is.....Im still not convinced on its path projection......the key west radar still has the eye movement in range...it still is moving around 265/6, or just south of west........
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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.