New Orleans is in Trouble

We’ve got a situation developing that has the potential to dwarf 9/11, or anything else in the memory of living persons, in terms of impact on an American city.

Several hours ago I shared the following with a private discussion group regarding my own personal suppositions about what would happen with Hurricane Katrina, based on my experience and readings as a tropical meteorologist. Again these were personal and do not represent anything official whatsoever! [For the official forecast, which is the one you should always use for real, go here.] As of about 0700 GMT, my thoughts were…

“As I type this, that [rapid deepening] is precisely what is happening and a trend which should continue through the remainder of the forenoon hours. Its first eyewall replacement cycle (which occurred surprisingly early in its reorganizational phase) is done, the surface pressure is dropping like a rock through the 930s of millibars, and objective Dvorak T numbers have climbed into the 6’s using a ragged-eye pattern on IR imagery.


“This “ah,” already much better defined in low levels based on RECON reports, has drilled its way up through the CDO (more properly, evaporated the CDO above it through subsidence), and should get deeper, warmer, smaller and sharper through at least 15Z, if not beyond. By the time many of you wake up and read this, the raggedness will be smoothed away; the storm will look absolutely ferocious in satellite imagery, and deservedly so.

“After this rapid deepening phase I expect the intensity to level off in the 915-925 mb range…”

Holy crap! It appears that unofficial prediction (which seemed uncomfortably aggressive but quite probable to me at the time) has vastly understated the ferocity of Katrina. The last publicly available measurement I’ve seen (as of 1230Z) was a sea level pressure of 908 mb.

No, that is not a typo. 908 mb! That’s 2 mb deeper than the landfall pressure of Camille in 1969 (though Cami was a little deeper still, over open water). It’s a solid Category 5 on the Saffir-Simpson scale, as of this writing.

The satellite presentation looks ferocious, and yet, still not as much so as that airplane reading. I won’t even bother to make another prediction of how much *lower* the pressure could go before leveling off. This sucker has passed Opal standing still, and along the way, also has waved adios to Anita (1977), Carla (1961), Indianola (1886) and Galveston (1900) for minimum known MSLP, and now heads into almost uncharted territory for the open Gulf basin — a rarefied level exceeded only by Camille and Allen (not including Labor Day 1935, which was deepest around the Keys).

To put into perspective, Katrina will need to *fill* by 40 mb from that RECON pressure to match Betsy at landfall. It will have to fill by 23 mb to match the strongest LA eye strike, also around New Orleans, in 1915 (this was the one Isaac Cline *successfully* warned for). Plenty of factors still could cause such filling; but Katrina still could strengthen some more first.

Of recent storms, Opal at its most intense wasn’t this deep or this large — with plenty of high oceanic heat content (OHC) to go before reaching shelf waters; and Katrina’s much closer to prospective landfall than Opal was when she went into a rapid deepening phase that wasn’t anywhere nearly so insane as what “Katie” has done in the wee hours this morning.

As of this writing, the latest official forecast track goes generally northward across the New Orleans Metro. I believe it, and so should you. Could it weaken? Of course! Could it veer off? Sure. The closer and stronger it gets, though, the less probable it is that New Orleans will avoid serious trouble. I hope for the sake of those left in the Bayou City that these forecasts are all dead wrong and the thing veers away *and* weakens a lot. Believe me, if I know those hurricane forecasters like I think I do, they desperately hope they’re wrong!

I cannot overstate the sorrow and misery that the latest projected landfall could evoke. For those interested, please read this earlier New Orleans Times-Picayune series on the utterly horrifying situation New Orleans and points south *could* (and now, potentially *do*) face.

Scary. Of course, I was made aware of these problems way back while working as a full time tropical meteorologist 12-15 years ago; indeed this very scenario was the most frightening possible to hurricane forecasters even then. That series of newspaper articles actually does a decent job (for mass media) of translating that threat into plain language.

I don’t think most of us have considered the far reaching social and economic ramifications of the wrong type of hurricane strike there (as now is threatened by Katrina).

New Orleans never, ever should have been built there, and we may be about to find out why, at a staggering toll to humans, property and economy. Either this thing veers off the official course and weakens, or…

Get ready for sustained surprising flood-casualty totals, an inundated and largely uninhabitable New Orleans, a sucker-punched national economy, >$3-4/gal petrol, and hundreds of thousands of southeast Louisiana refugees streaming in for the long haul to all other parts of the country — if this official strike path scenario plays out, causing the dreaded easterly and northeasterly fetch into and across lake Pontchartrain.

[My paycheck comes from New Orleans too. Yikes. There had better be a good backup plan for that.]

Much more importantly: If an eyewall replacement cycle, strong shear, significant dry intrusion or another cause of substantial weakening doesn’t happen, pray for the souls of all those who couldn’t get out of that city. Their safety and welfare right now means far, far more than any controversy over chase videos, or just about anything else going on now, for that matter.

This situation is getting truly disturbing.


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