09L: Hurricane Ike

[Darren Addy]

Interesting to watch most recent loop of MIMIC imagery. (Long download time, requires Java).

Watch the coastlines starting at 11:15 today. From that point on - until the last image (14:30, as I write this) the image center shifted almost exactly 1/2 degree west and 1/2 degree south. That is a pretty significant "wobble" that results in a nearly straight SW vector over that time period.

 

[Mike Hollingshead]

From Darren's post above.

Anyone know how common it is to get a major hurricane to form from what looks more like a wound up non-tropical system? I mean, most strong ones seem to have more of a round disc in the middle without the large "coil" or "spiral" look to the center. Seems once it has that sort of look in there(not talking outer banding spirals at all here, strictly the center) it never is able to really become a major hurricane. Seems like it keeps appearing like it would, but reverts right back into the coiled spiral, more than the classic round disc. In a way this makes me think of a cluster of supercells merging into a squall line. It's storm mode is then stuck in the squall line till it dies. I don't know, I haven't followed canes much, but this is what I keep thinking lately once they have the dominant inner spiral look. Perhaps it's more to do with local conditions like water temps, shear or dry air, than a mode the storm has entered which it has a hard time coming out of.

 

[Tim Vasquez]

Regarding those buoy observations it gives a swell height of 23 ft and a wind wave height of 16 ft. Does the wind wave superimpose on the swell wave? If so that would give an max observed wave height of (23/2)+(16/2) * 2 = 39 ft... amirite? Of course that's just trough to crest.

Our classes didn't cover much oceanography and that was 15 years ago, so I'm out of my element with these things they call "buoys".

Tim

 

[Dustin Wilcox]

Seems once it has that sort of look in there(not talking outer banding spirals at all here, strictly the center) it never is able to really become a major hurricane.

I have also noticed the same thing, seems like the major hurricanes are just an inner circle of at least a 100+ mile radius of solid rain. Gustav was some what similar to Ike with a spiral type configuration when it came on shore, with several areas not all that far from the eye experiencing no rain and much lighter winds. I can't recall in my few years of cane watching ever seeing one go from this spiral type look, back to a major hurricane...

 

[Darren Addy]

Everything I'm reading seems to indicate that Ike is a very atypical storm. It's starting to look like you can "throw the book out" on this one, which is what makes it atypically fascinating (as if your "garden variety" hurricane wouldn't be interesting enough).

 

[Robert Dewey]

Ike definitely doesn't look all that impressive to me at the moment. The IR imagery definitely shows a very asymmetric looking storm.

 

[Tim Vasquez]

That is a pretty significant "wobble" that results in a nearly straight SW vector over that time period.

That looks to me to be an artifact from their image processing or the use of another satellite. Note the surrounding cloud fields hundreds of miles away jump too.

Tim

 

[rdale]

Note the surrounding cloud fields hundreds of miles away jump too.

You mean Ike is instantly moving cloud layers hundreds of miles away on a dime - quite a storm

 

[rdale]

18Z recon showing big jump in pressure to 953mb, and even weaker surface winds around center (60mph.)

 

[Darren Addy]

Wow. Just wow:
http://tropicalatlantic.com/recon/
a beta web-based dropsonde decoder.

 

[Darren Addy]

18Z recon showing big jump in pressure to 953mb, and even weaker surface winds around center (60mph.)

This would appear to be a brief stabilization/weakening period that accompanies the end of the EWRC. Intensification should follow and I think we'll have a much clearer picture by the 11:00 PM EDT forecast discussion tonight.

For those (like me) who are just learning, this page has a good explanation of the concentric eyewalls (the situation that Ike has recently been dealing with). I didn't realize that Katrina also had a concentric eyewall cycle:
http://www.milli-bar.com/wsoldani/Katrina/Katrina5.htm

 

[Tim Vasquez]

Not sure how accurate this image is. But perhaps we're seeing it cross the depleted cooler waters from Gustav? Whose position may have shifted a bit from last week of course.

Tim

 

[rdale]

Similar to this which also doesn't show any dramatic source for strengthening...

 

[Jeff Snyder]

Similar to this which also doesn't show any dramatic source for strengthening...

Perhaps not rapid intensification, but that certainly looks fine for some strengthening. The current MPI (Maximum Potential Intensity) data indicate that conditions support Cat 4 winds (though few cyclones reach their MPI). In addition, RECON just found 102 kt winds ~ 100 miles NE of the center of circulation. The 945-955 mb central pressure that Ike has had the past day would otherwise support stronger than the current-advisory 100 mph winds, but the structure of Ike is, for whatever reason, leading to a large area of weaker PGF, as opposed to a smaller area of strong PGF / winds that typically characterizes tropical cyclones. I don't recall too many storms that had stronger winds 100 miles from the center than it had near the center. If the double wind maxima structure can fix itself, then I foresee little reason why Ike's winds won't pick up to at least Cat 3 range. That said, I still think the surge will be the major danger with Ike. Jeff Master's made mention of some interesting things in his blog, any case anyone is interested.

 

[Greg Campbell]

First Gustav, now Ike. Both storm have suffered chronic structural disruptions that have delayed / blocked intensification. Ike is enjoying a relatively favorable environment, yet seems unable to properly organize.

Forgive the wild-eyed tangent, but I'm wondering if, just possibly, the Gov't is running some secret seeding program? If they were clever, perhaps they could design a seeding pattern that would induce the sort of core oscillations we're seeing?

Or are these sorts of fluctuations fairly common? I can't remember similar storm behavior, but I've only been following this sort of thing for a short while.