Saturday, August 30, 2008

Gonzo Gustav Gets Going

Gustav has been getting lots of coverage across the web, and from what I can tell, in major newspapers. I'm sure (though I haven't been watching) the Weather Channel is doing a good job; their coverage of tropical storms is second to none, and they've got the expertise on board to get it right.

Nevertheless, perhaps I can point you at some info and sources that are new and interesting. Make no mistake: like Camille, Andrew and Katrina, this is going to be a storm that we remember by name for years.

According to Reuters, New Orleans Mayor Nagin may order an evacuation of that city starting Sunday morning. Even without the official order, Nagin and others have already been encouraging everyone, particularly non-residents, to leave immediately. Train and bus stations are crowded, though I haven't seen any suggestion that those using public transportation have been unable to find space.

Bush declared Louisiana an emergency area (meaning that federal monies and materiel can be used to prepare and assist ahead of the storm) first, and later added Texas and Mississippi. Then he took a nice long bike ride (seriously).

Despite assurances that petroleum infrastructure is much safer and more resistant to damage from such storms due to technological and engineering advances in recent years, drilling and pumping platforms in the Gulf are being shut down and evacuated in front of the storm. According to the AP article linked,

As of midday Saturday, slightly more than three-fourths of the Gulf's oil production and nearly 40 percent of its natural gas output had been shut down,according to the U.S. Minerals Management Service, which oversees offshore activity. Shell said it was on schedule to complete the evacuation of more than 1,300 workers from 20 production platforms and other facilities by Saturday afternoon. The task took four days and involved 17 helicopters. BP said it also planned to have its workers evacuated Saturday.

Some spills are more or less inevitable. Crude oil prices have been creeping up over the last few days as traders get jittery over the prospect of Gustav, and it looks as if prices at the pump have also risen a few cents per gallon as a result of increased crude prices (See the above article). Serious damage to pumping and drilling facilities at sea, or to refining facilities on shore (or both), would almost certainly result in a serious spike in consumer prices, drastically reducing or eliminating the drop in prices we've seen over the summer.

For the weather wonks out there, first, I found a good page on MSNBC that appears to be an updated hurricane tracking site. This is the home page (which right now defaults to Gustav), and this is the (specifically) Gustav page. Note that by clicking on the "more" button to the right of the name on the upper left, you can select other active storms, and it looks as if going to the home site over the next few months will take you directly to whatever storm is of current interest (though that remains to be seen).

Next there's an article that has a nice clear explanation of the Gulf loop current, a deep warm vortex that, because it holds a large volume of warm water, can provide an energizing kick to any tropical storm passing over it. Normally the warm water layer is relatively thin, and as a hurricane passes over it, turbulence and mixing bring cooler water to the surface. This in turn removes much of the energy source (evaporation) that drives a hurricane. So the storm, in a sense, sows the seeds of it's own weakening. But with the Gulf loop current, the warm water extends to greater depths, so mixing in that deeper water still leaves plenty of warm, evaporating moisture to power the storm. This is what happened with Katrina, and it looks like it will happen with Gustav as well.

As I was writing this up, a WaPo piece came in saying New Orleans has ordered a mandatory evacuation.

The evacuation of New Orleans becomes mandatory at 8 a.m. Sunday along the
vulnerable west bank of the Mississippi River, and at noon on the east bank.
Nagin called Gustav the storm of the century and told residents to "get
your butts out of New Orleans now
." "This is the real deal, not a
test," Nagin said as he issued the order, warning residents that staying would
be "one of the biggest mistakes of your life." He emphasized that the
city will not offer emergency services to anyone who chooses to stay
behind
. [bold added]

So unlike the Katrina episode, the Super dome (nor any other facility) will not be open for those who choose to remain behind.

Another site I've been paying pretty close attention to is Dr. Jeff Master's Wunderblog, a part of the Weather Underground site. This site is moderately technical, and if you don't have any background in meteorology, it might be more than you're interested in dealing with. On the other hand, if you're a weather channel junkie, and feel pretty comfortable with the terminology and ideas that get kicked around there in the more detailed discussions, you'll probably really like this site too: maybe a little more than you're used to, but not out of reach. Right now, he's got a great image of surface temps that really bring out the loop current mentioned above.


As you can see, Gustav should cross over the loop during the midday tomorrow; at that time it is anticipated it will kick up to category 5, the strongest and most dangerous level a hurricane can reach. Note that when I first wrote on Gustav, it was not really expected to reach Cat 5. It will then pass over cooler water, and probably diminish to Cat 3 or 4. Do Not take comfort in this prediction of weakening. This was exactly what Katrina did. When it hit New Orleans, it was in the upper-level Cat 3, where Gustav is expected to be. But Gustav (as of now) is anticipated to pass a little off to the SW of New Orleans- which is actually worse than a direct hit. To the NE of the eye, the wind speed adds onto the overall speed, so the highest winds, worst waves, and worst surges are off to the NE of the eye. More precisely, and perhaps a clearer explanation, imagine you are the hurricane; you are walking forward and swinging a rope so that it passes forward on your right side, across your field of vision from right to left, backward on your left side, and behind you from left to right. Since you are moving forward, and the rope is moving forward as it passes your right side, the fastest speed relative to the ground will be as it passes by your right side. Its slowest speed relative to the ground will be as it passes by your left. So looking at the predicted eye path of a hurricane, imagine yourself standing in the eye and traveling with it. The area off to your right is going to get the worst of the storm. This is where New Orleans sits. I am not trying to make a prediction here- I am nowhere near qualified for that- but based on simple physics and basic meteorology, and current predictions, it's beginning to look like this might be even worse than Katrina. To the folks on the Central Gulf Coast: my hopes and prayers are with you. Get your butts in gear.

1 comment:

Distributorcap said...

and there is no climate change?

i cannot believe how much you taught me about hurricanes....

thanks