Gravity Waves Make Tornadoes

Now that's funny. I have *NEVER* considered Gravity Waves with anything to do with tornadogenesis. Wow, that puts a whole new *spin* on it!

I'll have to really read that and study into it......
 
I'd like to see more than a NASA press release before completely buying in...

If I read it correctly - the only thing different between a tornadic storm and non-tornadic is speed of the spin and height of the storm. Smaller / faster storms = Tornado. Not onboard with that conclusion.

Also...

[FONT=Verdana, Arial, Helvetica, sans-serif]
[FONT=Verdana, Arial, Helvetica, sans-serif]"There is also wind shear in a gravity wave, and the storm can take that wind shear and tilt it and make even more spin. All of these factors may increase storm rotation, making it more powerful and more likely to produce a tornado."[/FONT]
[FONT=Verdana, Arial, Helvetica, sans-serif]"We've also seen at least one case of a tornado already on the ground (in Birmingham, Alabama, on April 8, 1998) which may have become more intense as it interacted with a gravity wave."[/FONT]​
Click to expand...
[/FONT]

How did they determine time of gravity wave impact vs increase in tornado intensity?​

Lots of "mays" and "more likely" which I could agree with. That's not the same as saying "waves MAKE tornadoes"​
 
I recall reading some assessments re: the role a gravity wave was suspected to have played in the deadly Jarrell, TX F-5 tornado. As I understand, it was believed to have a role (as a boundary) in convective initiation of the storm complex and also perhaps was a factor in the unusual southwesterly storm motion.

Must admit, though, this new hypothesis of a gravity wave enhancing shear and contributing to tornado strength is intriguing. Perhaps the researchers will take another look at Jarrell, as the gravity wave was well documented in that event.
 
We had a gravity wave driven gust front that went thru here on Jan 8th...The forward speed of the front was 65-75 mph...It produced EF-0, EF-1 tornadoes and several non-tornadic vortices...
Picture1.jpg
 
rdale said:
I'd like to see more than a NASA press release before completely buying in...
Lots of "mays" and "more likely" which I could agree with. That's not the same as saying "waves MAKE tornadoes"​
Click to expand...

Yeah I agree with that. I think we tend to just give the seal of approval to anything NASA puts out and while they probably aren't completely wrong I would say they are more wrong than right with their assertion that "gravity waves make tornadoes". I think gravity waves play more of a role in initiation (and even the frequency of that is probably low and very debatable) than the actual mechanics of tornado formation. It doesn't really matter I suppose though since we will never be able to verify or deny assertions like that anyway.
 
I remember seeing a presentation about this at SLS a little over a year ago. The hypothesis is this: gravity waves are associated with larger environmental horizontal vorticity (wind shear). As a storm encounters this gravity wave, the updraft tilts the larger ambient vorticity and stretches it, resulting in a supposedly stronger mesocyclone-> tornado?

This isn't necessarily far fetched... we see supercells go bonkers near boundaries where you have enhanced shear AND better thermodynamics.

What I question is whether you can directly relate an individual gravity wave to tornado occurrence. Perhaps the mesocyclone is strengthened slightly, but proving the storm is actually encountering a gravity wave AND attributing this to the cause for tornadogenesis is extremely difficult.
 
Aaron, I agree with what you have said, however the article specifically mentions
[FONT=Verdana, Arial, Helvetica, sans-serif]When a gravity wave bears down on a rotating thunderstorm, it compresses the storm. This, in turn, causes the storm to spin faster. [/FONT]
Click to expand...
This is almost completely contradictory to what you just said about about stretching (which is true). I don't know how to rectify the discrepancy. LoL.
 
I just skimmed the article so I missed that tidbit. Sounds like a bad PR interpretation to me. Gravity waves travel through a fluid... actual "compression" would have to be negligible given the viscosity of air and the pressure perturbations involved (if I can still trust the fluid mechanics knowledge in my head) . With gravity waves, however, you will see oscillations of air rising/falling which will be associated with max/mins of vorticity, much like horizontal convective rolls.
 
I've searched and can't find a web presence for the Grits tool or anything related other than this story...
 
Tim Coleman of UAH is also working on this. We have had several damaging gravity wave events here in Alabama over the last several weeks including some tornadic activity. I believe that most of the action was low topped and shallow based in a weak instability environment if I am not mistaken. I'll be interested to see what conclusions are drawn.
 
Holy smokes. I was just reading up on Gravity Wave detection. That's LIGO setup is nothing short of amazing!

http://www.lightandmatter.com/html_books/0sn/ch10/ch10.html

After watching that gravity wave video from a year or so ago from Tama, Iowa. I could see how it could affect a storm system. You all have seen that video right? Anyways that LIGO is a few years old now. Is there any way besides visually to easily detect these gravity waves?
 
You're confusing two things.... the gravity field (whatever that link was you posted) and gravity waves in the atmosphere. In atmospheric gravity waves, buoyancy and gravity act as opposing forces.

While different in some ways to their atmospheric counterparts consider this wave scenario: Consider letting a water droplet impact the surface of water. You cause a perturbation in the water surface that forces it down. This in turn causes a pressure pertubation in the water that forces the water back up. What happens is this overshoots the mean water height, and then gravity acts as a restoring force to push the water back to its original height. Over time, you'll see the waves decay as the fluid eventually comes to balance. In the atmosphere, gravity is also the restoring force. The perturbation is typically caused by bouyancy... cold pools from thunderstorms for example. In many cases, we can use clouds as an indicator for gravity waves. Either as a constant field like the Iowa video, or as rows when you are near saturation and the gravity wave is strong enough to cause condensation.
http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2008/03/080315_modis_truecolor_waves.jpg
 
Question: when one sees mammatus formations that seem to line up in rows instead of the usual random clustering, is this visual evidence of the presence of gravity waves?
 
Ok, here's an kinda side topical question that I have been wondering, although it's not related to gravity wave interaction of supercells, but on the question of a supercell's rotation itself :)

Has there ever been a study of a supercell's rotation speed, between those that are tornadic and others that are non-tornadic? :)

I have been wondering for the past 8 - 10 years about the likelihood of being the supercell's rotation speed, being an indicatior of which supercells are more likely to be tornadic, than those that are non-tornatic?

I imagine that there has already been a study on this os some form, but I can't help but feel that it is something that could be looked into a bit more, if it hasn't already.

Now back to the topic itself.....

I agree with rdale on this, purely because I haven't been aware of gravity waves and so, I don't know much about them, but at the same time, I think that there wouldn't be too high a likeihood of a gravity wave influencing a storm, after all, if you look at how many stroms there are in the US every year, and thinmk about the number of gravity waves there are each year, then I imagine that the number of potentially gravity wave influenced storms would be quite low, but in saying that, I don't know of there being any evidence to prove that gravity waves do influence storms in one way or another.

Now I'm saying this as a personal view because I haven't read the report about it, but I will do at a later time :)

I remain totally open minded on the possibilities of gravity wave interaction of supercells, as like anyone else, I'm here to learn :)

Willie
 
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