Smooth Channel lightning - any science ?

[Michael Thompson]

Up until the Moore tornado day (20th May 2013 ) I had only seen smooth lightning on video, and near always in association with a large supercell.

I searched the internet and have found nothing to explain its properties.

It is clearly different. The lightning I caught on video around the Marlow area was smooth channel. Charateristics - not jagged, not branched, does not appear to pulse, long lazy curves. Here are some stills.

My question is it is a clearly a different type of lightning, is there any science or explanation?

 

[chrisbray]

Is it maybe just the exposures being done in the daytime cannot resolve the leaders or other smaller branches? Notice how all those are taken during the day.

 

[Dan Robinson]

These are positive cloud-to-ground flashes. Positive leaders usually don't branch. They seem to be common in the forward flank precip region of supercells.

 

[cdcollura]

Good day all,

Dan is correct about these lightning strokes ... These are POSITIVE lightning strikes, and the forward stroke is originating from the GROUND upwards TO the cloud (GC lightning, opposed to CG in a sense).

The smooth channel is in the lower section of the lightning channel, but should branch higher up (not visible as the "branching" is inside the cloud).

Large supercells generate tremendous areas of positive charged cloud material (thick Anvil) and wind shear prevents excessive negative strokes as with "normal" thunderstorms. Downdrafts, such as the FFD, bring the positively charged cloud material closer to the ground, where such lightning occurs.

Above: On May 22, 2008 - This is a positive GC (ground to cloud) stroke with a 'smooth' staccato type appearance. These bolts also sound radically different than other lightning (more like a sonic boom shock-wave / high speed jet than a "crackling" sound) because of the lightning structure (smooth channel and more powerful current discharged). Such a polarity "shift" in supercells is loosely correlated to tornado-genesis.

Above: A positive stoke in Chicago on Jan 7, 2008 off the spires of the Willis (Sears) tower. The upwards branching here is very prominent. These are common from radio towers and buildings, especially in winter storms.

 

[Jake Orosi]

Kewl stuff! I've read about positively-charged lightning and what causes it, and that it typically originates (or rather terminates) in the anvil for the stated reasons; but I don't recall seeing any photographs strictly identified as positive strokes, or anything explaining how they might be visually different from your standard negatively-charged strokes. However, that description does make logical sense and it's very interesting to see.

Positive lightning. Just looking at the photographs makes me feel better, like I can do anything!

 

[James Gustina]

I think I might have an example of this. I didn't catch it striking the ground, but I caught the terminus in the anvil.

 

[Greg Campbell]

Good thread!

Check several neat 'rope lightning' examples in the superb http://www.stormtrack.org/forum/showthread.php?24353-Your-Best-Lightning-Shot-to-date thread.

 

[Joshua Nall]

Post #339 by Jim parsons in "your best lighting shot to date" is the craziest smooth channel bolt I've seen. Then there are some awesome ones in #311. I posted a few less dramatic in 312 and the first was coming directly out of the wall cloud of an intense supercell. The second from the base of a storm that was nearly directly overhead. The ones I've seen were very near or directly under the base. Of course if you could see the whole thing they may still look like the upwards branched ones you see under anvils.

 

[dallasdeboard]

I all way's called them noodles Marlow in that area hold a lot of iron in the ground butt who knows I see them all time down here.

 

[Jeff Wright]

Maybe the camera format comes into play...

 

[Michael Thompson]

Hi, thanks for the replies, I am still not 100% there, perhaps 95%. I do however concede that cloud bases were very low on this day and branching could have been higher.

I had always assumed that these were examples of positive + bolts, am I wrong ?

The bolts that land sometimes well away from the storm.

Perhaps the + bolts that come from a forward anvil in precip are the different +?

 

[Jeff Duda]

I've never seen what you call a "smooth lightning" strike in person. It seems to me these are the result of camera processes not resolving areas of the stroke that make it appear more "jagged" to the human eye. I'm not up on my research on positive lightning strikes, but I get the sense that, despite being much faster, they still form more or less as discretely-propagating segments.

 

[Michael Thompson]

I've never seen what you call a "smooth lightning" strike in person. It seems to me these are the result of camera processes not resolving areas of the stroke that make it appear more "jagged" to the human eye. I'm not up on my research on positive lightning strikes, but I get the sense that, despite being much faster, they still form more or less as discretely-propagating segments.

I was calling it smooth channel on the day well before reviewing any footage. It was visually different to the naked eye. Nothing to do with camera. if anything was surprised that the video agreed with what I was seeing, although many bolts due to the single pulse did not carry to video that well (thanks to the dreaded rolling shutter). I hope to have some footage on YD soon.

 

[Michael Thompson]

Here is the video footage. In 35 years of chasing storms, albeit 99% in Australia, I had never seen this type of lightning before, and this has included some supercells.

I must apologise about the freeze frames, on review they are distracting, I half expected Youtube to skip some of the bolts with changes in resolution and quality which I why I put them in. Note also the thunder with the bolts. No rumbles, just shot gun blasts (although that I have heard before)

Watch video >

 

[Justin Wilcox]

I was just telling my ol'lady yesterday about this back on May 31st-El Reno. Seemed to me like it was more abundant than usual. And like Michael said, it sounds just like a gun shot, or even a big firecracker. No crackle really, just "bang" and a little echo. Spooky stuff.