Dr. Lee, it's good to see you.
Hank. It's great to see you too. It's been a while.
Yeah, it has since our last discussion
There's been a lot of progress with your work
and with your team. High on that list is that you've grown another
superstorm in a supercomputer that drops a long track EF5 in an
environment similar to a historic environment that also did the same thing.
That's correct. So about a year ago you and I had a little conversation on your channel
Where we talked about my simulation of a 24 May 2011 storm in El Reno Oklahoma.
Now one of my research goals and research goals of my team is to not just do this for one storm but to do this
for multiple storms.
So for the last year or so
we've been searching around for different environmental conditions to initialize our model with so we can grow some new storms.
Dr. Katherine Finley at the University of North Dakota took a sounding...
This is the National Weather Service balloon launch data...
So anybody can go online right now go to the 18z Jackson, Mississippi sounding for 27 April 2011
Download that sounding and run it in a cloud model and it should produce a tornado, if you run it high enough resolution.
So we're pretty excited about this. The storm that we have produces a long track EF5 tornado on the virtual ground
for at least a half an hour.
April 27th 2011 was the big outbreak in the southeast.
There was an EF4 tornado in Tuscaloosa Alabama.
There were multiple EF4s and EF5 tornadoes in this event. From my perspective
what makes the southeast so challenging is the topography. You as a chaser of course would agree I think.
It's a difficult region to study because of all the hills and all the trees.
Yeah, you usually get a one shot at those storms.
It comes. It flies by you.
You get your 5 minutes if you're lucky of video and then you try to catch up to it
But then you have to stop because there's trees and your road. There's cars in your road.
There's people in the road. So we sought out that event because it was such a major event.
Your team has finally had some time to analyze the data. Or you've had more time.
You're developing some pretty solid theories on tornadogenesis and
Making some pretty bold statements.
Yes.
I continue to make the assertion that you do not need a rear flank downdraft
To have a tornado or at least to maintain a strong tornado.
So one of the leading theories of tornadogenesis involves a downdraft in the rear flank that triggers a tornado. And you addressed that
really well in our first talk. So far as I know that theory does not
Extend to the maintenance phase of a tornado. What our theory does not contain is a trigger.
We do not have a triggering mechanism that leads to the tornado.
What our simulations are showing and that what's sort of becoming clear is that...
The updrafts can be very strong very close to the ground.
And this is something I think that is a relatively new discovery.
The amount of stretching that the updraft can do is a lot more than we thought because the updraft is stronger than we thought
near the ground.
It's almost as if when you look at what's going on near the ground, that the storm itself is finding ways to consolidate vorticity.
It doesn't matter if it's from the environment or if it's from the cold pool the storm is generated itself.
But it's basically taking all this horizontal vorticity from different areas,
It's converging it towards the center and then it's abruptly tilting it into the vertical.
When that horizontal vorticity is tilted into the vertical it then becomes vertical vorticity which
contributes towards the mesocyclone and maybe even towards the tornadoes rotation, because that rotation has to come from somewhere.
What we've discovered is in the vicinity of the SVC the air pressure is dropping like a rock.
When you have very low pressure just above your head
It's going to create a pressure gradient that is going to make the air want to go up.
Okay, if you create a vacuum air will go into fill it.
That's like one of the fundamental forces of nature and that's the pressure gradient force. So what I'm thinking is going on is the SVC
results in the lowering of the pressure. A lowering of the pressure
results in a strengthening and a lowering of the updraft base. The strengthening and the lowering of the updraft base
results in extreme stretching and tilting of vorticity near the ground which ultimately
results in a tornado. Not only does it result in a tornado,
but it helps to maintain the tornado that forms. And again this theory is not in stone.
I would suggest that what explains
the clear slot and the big wraparound that occurs prior to tornadogenesis...
instead of it being a cause of the
tornado, I think it's an effect of the rapidly lowering pressure in the lower part of the mesocyclone.
the air is responding
to that drop in pressure such that air that would normally sort of scoot towards the rear and just continue to go
ends up getting pulled back inwards. So it gets sucked around this big low-pressure region. So perhaps
What you're seeing is the pressure drops, then you see the wrap around in the RFD then the tornado forms.
I'm not going to claim to have solved this problem.
I don't want to appear like I have. I just have an alternate theory at least
for the specific type of storm that we're studying that does not involve any
downdraft in the rear flank to trigger or to even maintain the storm.
I'm arguing that it really has to do with the forward flank, the SVC and other things.
You know, I'll also throw out that I've been underneath storms with big tornadoes on the ground and there appeared to be no RFD.
(VIDEO) I'm On the backside of this thing and oddly enough. There's no RFD. This is really weird.
See and that's more like what ours is doing.
It's funny one of the students who was looking at this work along with what my collaborator Katherine Finlay and she said
Where's the RFD?
It's like an RFU. See that would be consistent with our type of tornadogenesis regime.
You essentially have a parade of vortices coming along the forward flank of the storm. At some point in the storms evolution when that
pressure drop becomes really intense,
everybody just goes towards that location. Convergence just happens and everything just gets
concentrated into one spot. Going further back in time, It's the pressure drop.
It's the pressure drop. And then the question is what leads to the pressure drop? And that's why I'm honing in on the SVC
because the SVC is definitely a region of low pressure. So if we can find out what causes the SVC
When do SVC's form? When do they not form?
Then maybe we can say well an SVC is formed in this storm.
That might be an indicator that it's going to produce a longer tornado the normal or something. We don't know yet,
okay, but I'm hypothesizing why we're focusing on these features is because they might have
diagnostic predictability qualities where we can use to maybe give people a better idea that kind of storm that's forming. And again,
That's really my ultimate goal. If the SVC is real we find them in nature. Then the question is, okay
How do we detect them and how do we use them as a new tool in our toolkit of
forecasting to give a better prediction of what that storm is going to do? Can we?
I know that some people think the SVC is just along for the ride.
Maybe something else is leading to it, and it's just getting sucked up and it's just a passive thing.
I don't think that's true. But it's up to me to prove that or to show that and that's what we're working on.
So someone like me can only publish my results if I do my due diligence on observational work as well
It's very rare that you'll publish a paper that just talks about the model simulation
and doesn't look at the real atmosphere because what's the point?
With that,
what do you say we go look at some of the matches? And I wanted to see what you thought about some of the matches
that I have picked out for us.
Sure, alright let's do this.
Let's open up comparison number one.
Yes!
So this one is one of my favorites.
I think if you don't know anything about supercells, you might see all those lines and
stratification and then you might think that doesn't look natural. But a storm chaser will say
That's kind of the ideal storm you want to see.
You want to see an updraft that has all that wind sculpting.
We just go crazy for that. One of the things that I really like about this comparison that I've done is
You've got these extensions... these appendages at two different layers
streaming in from the south into the updraft and your storm
rendered something very similar to that.
This is why I love this collaboration we have Hank.
I'm just gobsmacked by how similar these two images look.
In the Tuscaloosa storm, or the storm are calling the Tuscaloosa storm, the new one,
you get these cloud bands and when I animate the storm, you see that they sometimes they come and they go.
Look at the wall cloud. There's even a little tiny tail.
Yeah!
Let's go into the next one.
So the next one, this was the same atmosphere after that storm died
Another storm popped up to the north.
and again
I'm using this just to say look here's another storm with all of those wind sculpted striations to show people that yeah
this is actually common and we do see that weird-looking UFO shaped updraft.
This is really amazing. What you've done Hank. I want people to understand this.
You're coming up with stuff that looks really similar and again, I can even count the layers in the layer cake.
You got three of them. I mean I just have to say tremendous work.
So this says to me
that the model that we're using is
probably doing a pretty decent job when you can actually create something that looks a lot like Mother Nature.
In the simulated storm you have a very clear tail cloud.
You see the similar feature in Hanks image there and you see striations in the barrel like
mesocyclone and you can certainly tell that there's rain falling in the Ford flank.
So, very nice comparison.
Awesome. Thank you.Let's move on to number three.
Number three. Oh boy. It's all about that Tail cloud, isn't it?
So on your other storm, we had all different kinds of tail clouds.
We had the long streaming tail cloud. And on this one, you just kind of have a nub.
You have a nub. Exactly. But that happens all the time.
Happens all the time.
And here's a storm that I got this year in Colorado
I was like, wow, this tail cloud is very similar to the one that I witnessed
So I just want to show that this little nubby wall cloud is actually a very common feature that we see in these storms.
Exactly. Another thing I would say is look at the rain foot in my image the black thing.
Yeah oh wow! I didn't even notice that. How it's
bending into the updraft. Right! You can sort of point your way to the updraft
By the way, that that rain foot is oriented Wow. Good call. Yeah you see it in your image, you see it in mine.
So there's another similarity between those two so excellent. Excellent
Awesome! Sweet! And then number four.
Oh yeah ! haha!
There you go, so this is one of my favorite storms.
This was the first tornado of the day and again you got kind of a little tail cloud.
You've got these tiers in the updraft and the mesocyclone, you know that little vault-ish area and then perspective the tornado
Relative is pretty similar spatially.
Man, I gotta tell you that is just so cool. As a modeler when I see stuff like this
I just go wow! Because
I spend a lot of time looking at the stuff on the right which is like, okay, it looks good
But it's a model
but when I see this stuff you've got it just...
It warms my heart because it means that we're on the right track and I as a scientist you might think I'm crazy to be
so conservative about my opinion
but I'm very very aware of how it's easy to have your own sort of
confirmation bias where you're seeing things and you're focusing on the thing that you think is there already. That happens inside
So when you've got a dude doin git for you it's always comforting right?
It helps! That just means it just says look chances are we're getting this stuff right because Mother Nature is Mother Nature.
She's doing what she's doing. The model is essentially the laws of physics as well as we do understand them.
So this means that when I start to present results, really quantitative results from our work and I show images like this,
it's going to be hard to argue against...
My theory should at least be plausible because look at mother nature and look at the simulation. They're very similar.
So one of the things about our simulation, is that the tornado condensation funnel
Doesn't always extend at the ground and that has to do with the issue with the way we handle the micro physics. In a real
tornado if you get rain in the tornado it gets spun outwards. It get centrifuge outwards.
Our model doesn't have that physics in it yet
So sometimes our tornado gets filled with rain and that ends up sort of eating away some of the clouds. So sometimes you don't see
the condensation funnel all the way to the ground but rest assured there is a tornado on the ground. And a
tornado itself can be on the ground causing damage and there not be a condensation funnel that is certainly occurs in nature as well.
Oh, yeah, I can show you plenty of video of that.
If there wasn't any dust you wouldn't even know there was a tornado there.
Exactly! So that happens in our models sometimes.
And sometimes it happens for the right reasons and sometimes it happens because oh well
We got to find a way to get that rain to spiral out of the tornado.
Again, it's work in progress. And that's true with anything scientific.
When you see a scientist talking about their work rest assured that you know, they're not done. It's always work in progress
It's always just keeping the needle pushed towards the direction of understanding and understanding what's going on in the world.
But that's a beautiful comparison right there.
This is kind of a new storm for you. Your last storm, by the time I caught wind of it, you had been
lecturing about this storm for two, three years, and I had a plethora of
angles and it was no problem getting all these different results. Really, all that
I've gotten from you so far is this one rendering.
and with that one rendering I was still able to get a lot of close similarities
So again in my opinion, that's a supercell!
ha ha ha!
That's a supercell! I'm of the same opinion Hank and as we've talked recently
using some new software
I can change the angle and move the box around and such and we can do more of these
comparisons and at some point I wouldn't mind just getting you in front of the software where you can actually start playing with this stuff too.
I would love to do that and an opportunity might present itself
as I'm traveling through and then afterwards we'll go storm-chasing together.
So I did send you some requests because I have this one shot where I'm following a storm in, Canton, Texas
And the mesocyclone is cranking and it's got some different tiers in it and I felt like man
This might be a good match, but I don't know if it's really the same structure of the supercell
But I'd still like to see it and I'll put them side-by-side for any of our other viewers
To see what I was thinking and how they differ.
I think it'd be cool to see how they differ
One thing that I want to point out to a lot of people, there's several different kinds of super cells that can drop
Strong tornadoes. I mean, there's things called mini supercells which might not drop EF4s or EF5s.
I bet there has been one somewhere down the road, but can still draw powerful
EF2 or EF3 tornadoes. And then also you have the classic like you got of that El Reno beast.
You know these massive updrafts and you can also have supercells that are really skinny. They almost look like
tornadoes just dropping out of a cumulus tower and those are just glorious to observe.
This particular one that I'm talking about dropped it long track EF4.
So even that type of supercell looks really different. I imagine over the years of doing more and more simulations
you're gonna get all these different
kinds of supercells that look really different and that will probably help you zero in on some of the
similarities that are causing these long track tornadoes.
Absolutely. Yeah, we're gonna be doing more storms in more environments. Not just a long track EF5s.
We're gonna be looking at the tops of the clouds. Not just the bottoms, you know, we'll see what happens.
We'll just toss it in the pot and make some gumbo and see what comes out.
If you could get a cyclic supercell... and I'm talking about a subset of a subset of a subset
But something like Pilger. And I mean that's that's really a crazy
Unique scenario. You've got two long track EF4s on the ground.
But having two on the ground might double
The chances of seeing some of the features and the currents. How awesome would that be? That would be so awesome, dude
I have tried to simulate Pilger. We got a sounding that looks like a loaded gun
sounding. Looks great and we ran in the model and basically
it just dies after like a half an hour. The storm goes up and it's just poof...
Clearly we have more work to do to understand Pilger.
Now Pilger was especially odd as you say it was a subset of a subset of the subset. You had 2 cyclonic tornadoes.
That is weird! That type of storm and and let's also mention 31 May 2013, the big
2.6 mile wide... Those are fringe cases.
But sometimes the fringe cases will tell us things that we wouldn't even known to ask about.
I have simulated May 31st, but it doesn't produce a two point six mile wide EF4 or EF5 tornado.
But I'm still working on that storm. As you can imagine these things are complex, you know
The modeling world is far from ideal. And we have far from ideal initial conditions to feed the model in most cases.
So the fact that we're able to get something that looks reasonable is
really a testament itself. Science can be a whole lot of fun Hank. We don't know what we're gonna discover. That's what makes it
So much fun
As we continue to do these simulations
We're gonna have different tornadoes different situations and we're just gonna unwrap this stuff and see where it takes us.
Alright, well keep us posted on all your new developments and thank you again for sitting in with us.
Absolutely Hank. Take care, and thanks for having me on.
MUSIC: "Crossed the Line" by Southern Backtones