Article about Moore, OK tornadoes and statistics from 538 website

[NancyM]

Fun read:

http://fivethirtyeight.com/features/tornadoes/

 

[Brian G]

Interesting read. More words than real data, but still interesting. I read The Drunkards Walk: How Randomness Rules Our Lives some time ago and it's stuck with me ever since. The thesis is that people go looking for patterns in data and almost always find something even though the data is truly random. I can't help but think this applies to the mini tornado alley theory. I'm not saying the mini tornado alley theory is without merit...far from it. But, we do need to be careful not to let our natural human tendency to find patterns everywhere influence our conclusions especially when the datasets we're working with are small.

 

[John Olexa]

Good read. Thanks for posting.

 

[Paul Knightley]

Interesting - overall, I do think that it's quite possible that there's not much in it, overall, when you look more generally at the distribution. However, the study of the stronger tornadoes is still interesting. I've been wondering for some time if topography and its ability to initiate storms has at least a part to play.

Let me elaborate - here in the UK we are often looking at areas with preferred chances of convection developing when forecasting, and certainly areas of elevated terrain - even quite modest (~300-400 feet above surrounding areas) do help with low-level convergence/forcing for ascent, and can overcome a capping inversion under certain circumstances. We then have areas, in certain situations, we know will get showers/thunderstorms. In central OK there are the Wichita Mountains, west of Lawton. In the relative flatness of the central Plains, I'm sure that areas of elevated ground like this can, under certain circumstances, favour convective initiation over other areas. With a capping inversion (typically of a fairly active set-up) perhaps the Wichita Mountains have a higher chance of setting off convection than areas to the north and south. With a typical SW upper flow in such a situation, the ensuing development would move NE towards southern OKC. Of course, this wouldn't 'favour' Moore per se - but it might make S OKC more prone than N OKC. Just a thought, anyway!

 

[Jeff Duda]

Interesting - overall, I do think that it's quite possible that there's not much in it, overall, when you look more generally at the distribution. However, the study of the stronger tornadoes is still interesting. I've been wondering for some time if topography and its ability to initiate storms has at least a part to play.

Let me elaborate - here in the UK we are often looking at areas with preferred chances of convection developing when forecasting, and certainly areas of elevated terrain - even quite modest (~300-400 feet above surrounding areas) do help with low-level convergence/forcing for ascent, and can overcome a capping inversion under certain circumstances. We then have areas, in certain situations, we know will get showers/thunderstorms. In central OK there are the Wichita Mountains, west of Lawton. In the relative flatness of the central Plains, I'm sure that areas of elevated ground like this can, under certain circumstances, favour convective initiation over other areas. With a capping inversion (typically of a fairly active set-up) perhaps the Wichita Mountains have a higher chance of setting off convection than areas to the north and south. With a typical SW upper flow in such a situation, the ensuing development would move NE towards southern OKC. Of course, this wouldn't 'favour' Moore per se - but it might make S OKC more prone than N OKC. Just a thought, anyway!

I've heard people claim the Canadian River valley (that runs NW-SE across Canadian and separates Cleveland and McClain Counties in Oklahoma) as a possible cause of strong tornadoes in central Oklahoma. The river valley really isn't that deep, maybe 200 feet at most. While that kind of topographical gradient could be enough to stir up something on small scales, it still requires the larger-scale entities to be in place. In other words, a topographical feature may enhance horizontal vorticity locally, but that enhanced horizontal vorticity isn't going to matter if there's no supercell to tilt and stretch that vorticity, and even a supercell may not be good enough if it's putting out a strong/cold RFD, which means the synoptic-scale conditions also have to be there. The synoptic scale conditions also govern the mesoscale setup, such as having a cold front or dryline present to initiate the storms.

I tend to agree that the signal is likely very small compared to the noise, but I wouldn't go as far as to say there's absolutely nothing there. There may be something to this, but it's likely heavily masked by larger-scale forces.