Glimmer of Good, Mostly Bad

By: Bryan Norcross , 11:49 AM GMT on August 27, 2012

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The only glimmer of good news this morning is that Isaac is still strengthening very slowly. Although an eye is evident on the satellite - and in the radar aboard the NOAA research aircraft - the winds are not increasing dramatically in the huge sprawling circulation. Still, steady strengthening is likely as the center heads toward the Louisiana or Mississippi coast. The NHC is now forecasting Isaac to be a Cat. 1 at landfall, though a Cat 2 certainly can't be ruled out. (The NHC gives it a 5% probability of reaching Cat 3.) Huge circulations take longer to spin up, and this one doesn't have a lot of time.

The nightmare scenario of a long-duration landfall I wrote about last night continues. The forecast consensus is that the storm will slow to a crawl near southeastern Louisiana keeping southeast to east winds into the corner between Louisiana and Mississippi, and southerly winds against southern Alabama and the western Florida Panhandle, for an EXTENDED period of time. This will continue to push Gulf water over the coast and into Mobile Bay and other inlets for longer than normal in a landfalling hurricane.

New Orleans has decided NOT to order an evacuation, trusting the new levees. It's important to remember, however, this storm could well put much worse weather over New Orleans than Katrina. If you recall, dry air was filtering into the left side of Katrina when it made landfall. There was very little damage from wind in the city. Top readings were mostly of tropical storm strength, except on the far east side. Issac may put higher winds over the city proper meaning people will have to take precautions in their homes that were not required in Katrina.

Other areas outside the massive new levee system WILL require evacuations, however. It's extremely important that people take action today to get to a safe, comfortable place with plans and supplies to ride out a relentless attack of wind, rain, and high water from Isaac.

See you on The Weather Channel.

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27. redagainPatti
5:44 PM GMT on August 28, 2012
Isaac is Now a cat 1 hurricane .... yall be safe and careful if you are in the pathway of this storm..
Member Since: July 10, 2005 Posts: 122 Comments: 1503
26. ChrisinSLC
5:21 PM GMT on August 28, 2012
not to keep harping on this, but I found a good paper that talks about the short- and long-term impacts of the oil spill on the Mississippi Delta marshes:

http://www.pnas.org/content/early/2012/06/20/1204 922109.full.pdf
Member Since: August 27, 2012 Posts: 0 Comments: 3
25. ChrisinSLC
4:18 PM GMT on August 28, 2012
In reply to Dakster:
There is a pretty good knowledge of the existence, and in a lot of cases, the locations of submerged "tar mats" in the shallow off-shore areas of the Gulf Coast. For example, NPR did have a piece this morning where they were talking with the mayor of Orange Beach, AL about this. One of the characteristics of the Deepwater Horizon oil, was that it barely floated-- often the oil was found just below the surface of the water. This was one of the things that made it difficult to collect on the water. This was possibly because of the oil itself, because of its mechanism of entry into the water (it was basically injected into cold water at very high pressure at the wellhead, which was 4-5,000 feet below surface), and/or because of the use of dispersants, both at depth and at the surface. All these conditions and actions prevented the occurrence of the dreaded giant oil slick, but it complicated recovery considerably.

However, the oil that did make it to the surface broke down (and continues to break down) pretty readily. In the GOM, this is aided by warm water, the presence of both fresh and salt water, and very high biological productivity rates (lots of bacteria that literally eat oil for lunch). But when the oil sinks, the breakdown slows down considerably. It is still breaking down, but at much slower rates-- this is because the breakdown primarily occurs on the surface of the oil mat, so the volume "inside the sandwich" takes a while to become exposed to breakdown. Also, as breakdown occurs, even in optimal conditions, it slows down as the microorganisms consume the most "digestible" (i.e., non-toxic) compounds in the oil. Therefore, the oil becomes more toxic over time as this process (called "weathering") occurs.

I was heavily involved in the DWH response in 2010 (which is why/how I know this info), but I have not been tracking it as closely since. So I'm not authoritative on the rate or process of breakdown of the offshore oil mats, or their current toxicity state. Comparatively, about the only thing I have to go on is reports from the 1979 Ixtoc spill that happened in the southern GOM (Bay of Campeche). This spill occurred in shallow water, and heavily oiled (with "conventional" oil) a major shrimp producing area. What they saw there was a major toxic shut-down for about 2-4 years, but then a resurgence as the bacteria were able to process the oil, with the bacteria becoming food for zooplankton, which then became food for shrimp. But heavily hit areas there were sterilized much in the same way that a hot forest fire will sterilize areas, and some of those areas (particularly mangrove swamps) are still heavily impacted (though this could have been because the Mexican government couldn't/didn't mount the same intensity of response as the DWH response). My only concern with this event is that the mechanisms are still in place for BP (the responsible party) to respond to the "secondary oil spill" if it happens.
Member Since: August 27, 2012 Posts: 0 Comments: 3
24. Dakster
1:36 AM GMT on August 28, 2012
Unless I am mistaken, no one has done a 'core sample' of the area - so it is impossible to know what conditions and where the oil 'is'. Without this knowledge, it is impossible to say what will happen. We will have to wait and see.

Doctor Masters did talk about it on 'The Weather Channel' a couple of days ago and was worried if Isaac stalled that he could churn up oil that had settled on the bottom of the gulf.

So here is another question - how long does it take for the oil to 'breakdown', if sediment covers it, does it prevent the break down? Obviously since we are pumping it out of the ground, there is some natural mechanism in place that kept it from breaking down over thousands of years.

I agree that if Isaac churns up and spits oil all over the wetlands it will do more harm than good.

Sorry I didn't really answer your question and probably added a few to yours.
Member Since: March 10, 2006 Posts: 0 Comments: 10034
23. ChrisinSLC
11:50 PM GMT on August 27, 2012
I took a look at the storm surge height & probability maps earlier today and it looks like the area that was the hardest hit by the Deepwater Horizon oil spill in 2010 (SE-E side of the Mississipi River Delta) will be the most impacted by the storm surge from Isaac. In 2010, the nightmare scenario was that a hurricane would come in and push all that oil up, over, and on top of the wetlands. Instead, there was no hurricane (hasn't really been one in that quadrant until now), and a lot of the oil has settled down on top of or into the top strata of sediments, and has had more sediment deposited on top of it in the last couple of years.

I haven't really seen this picked up on or reported, but I think a lot of that oil is still down there, and is going to get flung all over the 'cane marshes of the Delta. I'm hoping I'm wrong-- that a lot of the oil has been broken down and metabolized in the last 2 years, and/or that what does get transported will be partially weathered and/or mixed with a lot of organic matter that will maybe (?) "buffer" it when it ends up in the marshes. But my sad prediction is that there will be oil thrown. The bit of silver lining in that cloud will be that the surge will scour the bottom on the shelf, and in the wetlands in Barataria Bay, etc. So it will be better in the long-run (a little overdue housecleaning) but it might be a bad deal for the wetlands-- oiling of the vegetation that holds the place in place down there. Hoping I'm wrong, but interested to see if anyone thinks enough of this to ask some of the people "in the know" about this..
Member Since: August 27, 2012 Posts: 0 Comments: 3
22. Dakster
10:52 PM GMT on August 27, 2012
Quoting clickBOOM:
What's that saying?

Fool me once shame on you, fool me twice...




Exactly. and those that forget the lessons history taught us are doomed to repeat them...

Member Since: March 10, 2006 Posts: 0 Comments: 10034
21. Dmkk1996
8:56 PM GMT on August 27, 2012
Hi Brian. Appreciate all your hard work on keeping up with these storm. But just an FYI. The piece of land that you circled on the tropical update at 3:30 pm central time referencing the European model was Mississippi not Mobile Bay. In fact the cone wasnt even over Alabama. This has been happening A LOT with the national media lately. Not sure why. Mississippi has already experienced this when Katrina came through Mississippi and devastated all six Mississippi gulf coast counties. But we understood when the week faulty levees failed in New Orleans and the focus was changed to the unprepared people and city officials there. But please I would hope that a person as educated as you are would know that Mississippi is between Louisiana and Alabama. keep up the good work! DeAnna
Member Since: August 27, 2012 Posts: 0 Comments: 0
20. stratcat
8:03 PM GMT on August 27, 2012
For all intents and purposes, latest vis. sat. shows it is stationary. It is getting better organized, and I don't think the air from the Yucatan is very dry. I think storm may take a move toward the N or NNW later today or this eve.

Continental short wave heading toward NE and Mid-Atlantic with weak cold front may pull storm more northward as storm ducks under wave.

Once it gets its dynamics together, storm is likely to jump cats very quickly. Can't say for sure where it will go, but pay attention to the European model.

Anyone know where pressure tendencies are at their lowest along Gulf coast?
Member Since: May 1, 2008 Posts: 0 Comments: 15
18. Neapolitan
6:57 PM GMT on August 27, 2012
Quoting gyutee:
thanks twc, you destroyed the one good thing on the internet.
What do you believe TWC destroyed? And how do you believe they destroyed it?
Member Since: November 8, 2009 Posts: 4 Comments: 13473
16. stratcat
6:24 PM GMT on August 27, 2012
Visible imagery still shows no eye, though the pressures have fallen slightly. It appears to be moving more to 270-275 degrees and is slowing down. May be getting ready for a course change, possibly northward, following the track of the lone European model. If it misses this course change, will end up bashing into Texas or stalling.

After landfall, this model, so far dependable, moves the storm to the mid-Atlantic with heavy rain.

Why won't it develop higher winds? I know it is large, but still, cannot find a logical reason. Warm SST's, plenty of moisture and light shear. No more land interaction, so what gives? I think it will reveal quite a jump in next 24-36 hrs. Eastern semicircle is building good CDO and outflow, with developing feeder bands. This region is ripe for a big storm!
Member Since: May 1, 2008 Posts: 0 Comments: 15
15. gyutee
5:21 PM GMT on August 27, 2012
thanks twc, you destroyed the one good thing on the internet.
Member Since: June 4, 2012 Posts: 0 Comments: 1
14. FelineTexan
4:59 PM GMT on August 27, 2012
Better be safe than sorry is also my recommendation to the city of New Orleans. If the $16 billion new levee can withstand the storm surge, it may not prevent flooding to the low-lying grounds due to lasting heavy rains. Best of luck to NOLA!!!
Member Since: August 27, 2012 Posts: 0 Comments: 0
13. glfinman
4:51 PM GMT on August 27, 2012
Drought of 88 ended with the Hurricane Gilbert almost on the same dates. Ended in midwest Sept 19
At the time one of strongest hurricanes ever.
Issac isn't as strong but if it moves inland
like Gilbert it could end the Midwest drought.
Member Since: February 7, 2007 Posts: 0 Comments: 3
12. J0hnD03
4:09 PM GMT on August 27, 2012
Wow. I'm quite surprised LA decided not to order an evacuation. Sure it's a small storm, but why wouldn't they want to be safe than sorry(given the past)?

That way they can't be blamed for the people who stay put etc. Yikes. Oh well, best of luck to everyone riding out this luckily small storm.
Member Since: September 25, 2011 Posts: 0 Comments: 0
11. wlittle1686
4:00 PM GMT on August 27, 2012
As a Red Cross Disaster Action Team (DAT) volunteer AND SBC Disaster Clean-up & Recovery volunteer, I appreciate these updates Bryan. You make it a little easier to prepare - as in getting ready to mobilize - with your explanation of where Issac appears to be heading and what kind of strength he has. Keep up the good work.
Member Since: May 28, 2008 Posts: 0 Comments: 0
10. miajrz
3:17 PM GMT on August 27, 2012
Thank you, Brian. It's good to see you here.
I've been trying to educate myself about the New Orleans levees and have learned that the post-2005 ones are designed to a 100-year standard. What this means in real life is unclear due to a larger problem with the Saffir-Simpson scale as shown in the Nola.com/Times-Picayune article
http://www.nola.com/news/index.ssf/2008/08/100yea r_storm_moniker_misleadi.html
Apparently the NHC and others are working on a new rating system. One commenter on Dr. Jeff's blog (credit where it's due) suggested a two-part system, one for wind strength, one for storm surge. This would address storms like Katrina which made landfall with Category 3 winds and a Category 5 storm surge.
Someday, when things calm down (October?), I'd love to hear your thoughts on this.
Thanks again and welcome.
Member Since: June 27, 2009 Posts: 0 Comments: 195
9. Pirate999
2:41 PM GMT on August 27, 2012
Great update...
Member Since: August 30, 2008 Posts: 0 Comments: 173
8. clickBOOM
2:20 PM GMT on August 27, 2012
What's that saying?

Fool me once shame on you, fool me twice...


Quoting Dakster:
Apparently, local officials think that rebuilding of the levees is strong enought to handle whatever Isaac can throw at it. I am not sure sure that it is a wise decision to trust it during its first real test. But the future will tell us.

Also, what ahppens is Isaac all of a sudden deepens and becomes a Major Hurricane and brings an 18 ft storm sruge with it? Can the levees handle that type of storm surge?
Member Since: August 24, 2012 Posts: 0 Comments: 19
7. NOLALawyer
2:09 PM GMT on August 27, 2012
I think there may be a good deal of people caught off guard down here, Bryan. This could be quite bad.
Member Since: September 3, 2009 Posts: 0 Comments: 520
6. thebandman
1:42 PM GMT on August 27, 2012
I am concerned about the amount of rainfall they will get. Here in South Florida I am seeing more standing water in my neighborhood than we had yesterday.
Member Since: July 29, 2006 Posts: 0 Comments: 39
5. NWflier
1:28 PM GMT on August 27, 2012
Thanks for the concise, through update Brian. I hope the folks along the Gulf Coast are listening!
Member Since: July 9, 2005 Posts: 0 Comments: 2
4. Dakster
1:12 PM GMT on August 27, 2012
Apparently, local officials think that rebuilding of the levees is strong enought to handle whatever Isaac can throw at it. I am not sure sure that it is a wise decision to trust it during its first real test. But the future will tell us.

Also, what ahppens is Isaac all of a sudden deepens and becomes a Major Hurricane and brings an 18 ft storm sruge with it? Can the levees handle that type of storm surge?
Member Since: March 10, 2006 Posts: 0 Comments: 10034
3. redagainPatti
1:09 PM GMT on August 27, 2012
I am over 200 miles INLAND - northern part of Mississippi ... but back in 2005 - that darling storm blew in with winds of around 78 miles per hour, took down trees all over the place.. I had mess in the front yard and the back. Lost 60 feet of fence, and three trees... I have blogs of that time in here..

I have learned, you can not get too far inland away from those darn winds. And I do not want any member of my family south of I10 or anywhere, 100 miles of NO... where my daddy's family is from. They all moved away from NO back in the 60's because it was too hard to get out with the lack of roads and the amount of people living down there.

I hope folks get the heck away from the coast, the water and the cotton picking winds..
Member Since: July 10, 2005 Posts: 122 Comments: 1503
2. Beachfoxx
12:16 PM GMT on August 27, 2012
Thank you!
On the Florida panhandle, watching & waiting....
Member Since: July 10, 2005 Posts: 157 Comments: 29383
1. GeorgiaStormz
12:02 PM GMT on August 27, 2012
Thanks for this blog..
Yes the winds could become a problem.
We shalls see what happens.
Member Since: February 11, 2012 Posts: 0 Comments: 9721

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