Is Ike changing course, or just wobbling?

9/7, 4:44 PM EDT: That’s the question Alan Sullivan is asking, as he watches the satellite loop and sees a distinct northerly component to Hurricane Ike’s motion over the last several hours. I see it, too.

It’s too early to say, however, whether this is a mere “trochoidal wobble” or an actual change in course. The consensus at the Eastern U.S. WX Forums is that it’s probably just a “wobble” — unsurprising, given that the storm is currently going through an eyewall replacement cycle. Likewise, Dr. Jeff Masters, commenting on his own blog, wrote at 3:09 PM EDT:

Yes, there has been some WNW motion the past hour, as pointed out. This is probably a wobble, and the storm will resume a W motion within the next two hours. The models are pretty firm that the WNW turn is not due yet. Still, every wobble north increases the chances of a Cat 3+ in the Florida Straits.

I suspect the 5pm NHC advisory will say something similar. The forecasters tend to be very conservative about wobbles, as they know from experience how often such events prove transitory.

On the other hand, Sullivan — who, remember, is (like me) not a meteorologist, just a weather buff with a strong layperson’s knowledge of hurricanes — thinks this “wobble” is the real deal:

Leaving the tip of Grand Inagua Island, the eye of Ike was heading straight west, but in the last couple of hours its course shows a shift to the right. This could be just a wobble, but on the larger-scale vapor-loop, I am seeing subtle changes in the steering pattern over the Atlantic, Caribbean, and Gulf — changes that also hint at a rightward shift. If this trend bears out in the next hours, it will increase the likelihood of a swipe at the lower Keys.

We shall see.

Even if this apparent course change is “just” a wobble, it could be significant nonetheless, as one poster on the Eastern WX forums pointed out: “Every WNW wobble that is not countered by a WSW wobble will shave [time from the storm’s passage] over Cuba . . .  given the trajectory from which it will be moving and the anticipated turn. Every single wobble is potentially very significant.”

You can watch the progress of the “wobble” for yourself on the visible, infrared and water vapor satellite loops, and on Cuban radar.

UPDATE, 5:24 PM EDT: It looks to me like the wobble is over, and Ike is moving due west again.

UPDATE, 6:21 PM EDT: Sullivan writes in comments, “Yes, but previously it was moving WSW. I still think we could be seeing a course change.” Meanwhile, on his blog, he posts an update:

I see the wobbles, but I think they overlie a course-change that has in fact begun. For that reason, let me propose a best case scenario. Everyone loves worst cases. There is still a chance that Ike won’t cause a major disaster. Imagine that the hurricane wobbles along the north coast of Cuba, but never quite drives ashore, and weakens as it interacts with land. Next, it passes a bit south of Key West, battering the town only moderately. Ike moves into the Gulf and scares the bejezus out of everyone, then encounters shear and dry air. Eventually it heads ashore in Texas at category one, and drops rain on droughty areas inland. Best case. And it could happen.

Sounds good, though to truly be “best case,” it would have avoid “scaring the bejezus” out of New Orleans, in particular, to the point of evacuation. If New Orleanians are forced to evacuate their city twice in two weeks, for two “false alarms,” I fear it will set back disaster preparedness in that city for a generation. Don’t get me wrong: another evacuation order would be necessary if the risk once again gets high enough. No doubt about that. But the fact remains, there are only so many times you can tell people to flee the next potential “mother of all storms” before they stop listening — and twice is two weeks is too often. So, as I said earlier, I hope New Orleans gets not just a near-miss, but a far-miss.