7:45 AM Snapshot of Katrina - looks like the eyewall will miss NO...

[Junkdrawer]

[Christa]

1. Katrina's weakening rapidly--worst missing New Orleans

Katrina is due south of the Mississippi-Louisiana border, and moving northward at 15 mph. On this course, the western edge of the eyewall will pass some 20 miles to the east of New Orleans, sparing that city a catastrophic hit. As the eye passes east of the city later this morning, north winds of about 100 mph will push waters from Lake Pontchartrain up to the top of the levee protecting the city, and possibly breach the levee and flood the city. This flooding is will not cause the kind of catastrophe that a direct hit by the right (east) eyewall would have, with its 140 mph winds and 15-20 foot storm surge. New Orleans will not suffer large loss of life from Katrina.

Biloxi and Gulfport Mississippi will take the full force of Katrina's right eyewall, and a storm surge of 15-20 feet is likely along the central Mississippi coast. Katrina is a strong but rapidly weakening Category 4 hurricane, and will probably come ashore about noon CDT near Gulfport as a weak Category 4 hurricane with 135 mph winds. The latest pressure measured by the Hurricane Hunters was 925 mb, and this pressure is 7 mb higher than an hour ago. The cloud pattern in satellite imagery has decreased on the west side due to dry air entrainment, and the eyewall has opened up to the south and southwest in radar imagery. With the center passing over mixed swamplands and water, much of the energy that sustains the hurricane will be cut off, making any further intensification unlikely. Katrina is not hitting at maximum intensity and is sparing New Orleans a direct hit, and although the damage will be incredible, it could have been much, much worse.

http://www.wunderground.com/blog/JeffMasters/show.html

[Massacure]

3. 20 miles east is probably the worst thing in terms of flooding.

The winds rotate to the counter clockwise. Katrina's winds coming from the northeast are going to take Lake Ponchartrain and dump it into the city.

[regnaD kciN]

14. Actually, it would have been a lot worse...

...had the eye passed to the west. You would have had the entire 28-foot high storm surge come from the Gulf right up the Mississippi River into town.

The winds off the lake will cause some problems, but there's a world of difference between Ponchartrain and the flippin' ocean in terms of the extent of storm surge.

[spinbaby]

2. 20 miles to the east, is what I heard

Bad, but it could have been much worse.

[benburch]

4. Excellent news!

Had it continued on its forecast track and at its worst intensity, we would have had major loss of life in NOLA.

[soothsayer]

5. Thank you, Marie Laveuax! And the whole pantheon of gods

who protected that beloved city---Yemaya, Oya, Oshun, Elegba. (sorry for whomever's going to take the brunt now, but....)

[Junkdrawer]

6. 9:15 AM EDT - Eyewall passing over east edge of Lake Pontchartrain...

This is the most dangerous moment of this storm...

[geomon666]

7. TWC has already reported that a levee has been compromised.

They don't know where though.

[Junkdrawer]

8. I'm guessing they're reinforced concrete, so one compromise...

won't necessarily cause others to fail. :shrug:

[geomon666]

9. Levee Breach at Tennessee St.

TWC just reported.

[bvar22]

10. Most of the levees are dirt and riprap.

They are dirt mounds reinforced with concrete riprap. They are compartmentalized, though some of the areas are pretty large
I haven't heard reports ot levee breaching in New Orleans.
Eastern New Orleans (eastern Lake Pontchatrain) is low lying and swampy (and in most places uninhabitated beyond fishing camps), and does not have the best levee protection.

[Junkdrawer]

12. That doesn't sound good...Rushing water is extremely erosive...

Is this a "levee break" or a "dam burst"? :shrug:

[geomon666]

13. A levee break n/t

[bvar22]

15. Tennessee St

is in Eastern New Orleans. The same area that flooded in Betsy.
I haven't seen any reports from that area.
If that levee completely failed, there would be some serious flooding, but it would be local. That area is populated, but along a "corridor" that is bordered by swampland.

[JHB]

11. Storm total rainfall link

http://radar.weather.gov/radar/latest/DS.80stp/si.klix.shtml
This is for the storm total rainfall. Click the sidebar for other views.