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mushymanrob

a question about lightning

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ok... was in ibiza on monday when i experienced a fantastic storm, classic old style that we used to get here but dont seem to anymore (not like this anyway)...

it build slowly from the west, in an slight arc, and came over us... however the lightning was 'odd', and its not something ive ever seen before.

quite a few strikes (about 10%) were 'u' shaped. they left the cloud heading down towards the ground but for no apparent reason doubled back on itself forming a 'u' shaped strike.

is this common? what causes it?

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Hi Rob, that sounds great! Could it have been CC lightning that you thought was going to be CGs?

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yeah i know what cc and cg are, its just that ive never seen such cc , the scale was very small, ive seen 'usual' cc but nothing before on this small scale. the 'usual' cc is pretty horizontal isnt it? what i saw was certainly heading down before making an abrupt change back up. i cant quite understand why this would happen when its shorter to go more or less straight instead of a 'u' or 'v' shape.

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yeah i know what cc and cg are, its just that ive never seen such cc , the scale was very small, ive seen 'usual' cc but nothing before on this small scale. the 'usual' cc is pretty horizontal isnt it? what i saw was certainly heading down before making an abrupt change back up. i cant quite understand why this would happen when its shorter to go more or less straight instead of a 'u' or 'v' shape.

Could it have been a normal run-of-the-mill CC strike whose low-altitude channel just happened to pass outwith the cloudbase?

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Strikes me (haha!) that it could have been a CC/CG strike combined, or alternatively a low arcing CC.

 

There was an awesome video circulating on facebook of a storm in Belgium or possibly the Netherlands from over the weekend and that was exactly as you describe - appearing to drop from the cloud then connect with another forming a horse shape bolt.

 

Scientists are still learning about what lightning is and how it forms, so I doubt there is going to be a conclusive answer for you. Most likely in my opinion is that an adjacent cloud offered better electrical discharge than the ground and so, for whatever reason it followed that path to the adjacent cloud rather than through the ground. I would imagine it would be more evident on thunderstorms with bases closer to the ground than those which are more elevated - this would in all likelihood accentuate the visual effect.

 

I have noticed though that all storms behave differently; some have a tendancy to be predominately IC/CC, while others a higher proportion of CGs; some have a higher proportion of +ve CGs than others; some deliver fatter or thinner bolts; the most notable and obvious 'behavioural' aspect of storms is the thunder, sometimes lengthy explosive peels, other times light crackles and no more (regardless of whether the bolts are within a few hundred metres or a few miles away).

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The strangest lightning I ever saw was almost perfectly straight CG lightning, no forks coming off, no bends. Just looked like a straight pillar of lightning. That was in Bulgaria many years back. I did wonder if it was some sort of trick of the light through rain or something.

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Strikes me (haha!) that it could have been a CC/CG strike combined, or alternatively a low arcing CC.

 

There was an awesome video circulating on facebook of a storm in Belgium or possibly the Netherlands from over the weekend and that was exactly as you describe - appearing to drop from the cloud then connect with another forming a horse shape bolt.

 

Scientists are still learning about what lightning is and how it forms, so I doubt there is going to be a conclusive answer for you. Most likely in my opinion is that an adjacent cloud offered better electrical discharge than the ground and so, for whatever reason it followed that path to the adjacent cloud rather than through the ground. I would imagine it would be more evident on thunderstorms with bases closer to the ground than those which are more elevated - this would in all likelihood accentuate the visual effect.

 

I have noticed though that all storms behave differently; some have a tendancy to be predominately IC/CC, while others a higher proportion of CGs; some have a higher proportion of +ve CGs than others; some deliver fatter or thinner bolts; the most notable and obvious 'behavioural' aspect of storms is the thunder, sometimes lengthy explosive peels, other times light crackles and no more (regardless of whether the bolts are within a few hundred metres or a few miles away).

 

interesting... cheers..

thats another thing about this storm, not much thunder, it wasnt until the storm was overhead that we heard thunder and that was quite faint. huge wind whipped up too as it approached. this for me was a quite unusual storm.

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yeah i know what cc and cg are, its just that ive never seen such cc , the scale was very small, ive seen 'usual' cc but nothing before on this small scale. the 'usual' cc is pretty horizontal isnt it? what i saw was certainly heading down before making an abrupt change back up. i cant quite understand why this would happen when its shorter to go more or less straight instead of a 'u' or 'v' shape.

but not everyone reading this thread may.

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The year before last, we had a cracker of a storm, which, for my neck of the woods was unusual.  The lunch-time BEEB forecast storms developing over the Bristol area, then moving west along the M4 corridor.  Around 1500 I heard the first thunder and I shouted on my next door neighbour as I knew he loved storms.  More thunder, then the first lightning appeared. Closer-closer-closer, now down to 2 seconds. A beautiful green flash over the railway bridge just up the road, and we were all systems go.  I happened to be looking toward the chapel in front of my house, when to my amazement, there was a large line of very black cloud that seemed to be rolling, just like a wave on the beach, but not going anywhere.  I said to my neighbour---'look at that',  and as I spoke,  there came totally blinding flash of light, and in the same second, a cataclysmic ear shattering bang, followed by a even louder one, and then a second or so after, a wave of hot air hit the two of us.  Half blinde, and almost deaf, I turned to Alan to say something, but he was already running for  his front door.  I made a dash for my porch, and on entering the living room, there was my 'er' indoors', sitting on the settee with her hands over her ears, her mouth wide open , her eyes shut, and a look of horror on her face. Before I could say anything, there came another blinding flas of light, followed almost immediately by 2 bone crunching bangs, and followed up by tremendous bangs and crashes of thunder than went on fot several seconds. Once my eyes had cleared I went to the back door, and watched the storm moving away over the fields and away to the west.   Later that evening I was talking to Alan, and we both agreed that, quite possibly we had both had a very lucky escape as that first flash was no more than a few yards away, and that the rolling cloud above us meant that we were on the edge of a vortex, and our lives were probably in a dangerous position.  In all my years at sea I had never witnessed anything of that magnitude before, but, as idiotic as I am, I look forward to the next one!!

p.s. nice to meet you all.

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Although I couldn't see the cloud formations because it was dark and because of the rain, that sounds similar but not completely the same as our Aire Valley supercell in July. The lightning was constant, I mean stroboscope stuff but elevated so unlike you we had little loud thunder, just constant low rumbling. I was sitting out in the garden watching the lightning but came inside because there were CGs over the hills and it got to feel unsafe to be out on a metal garden seat(!). Inside, I watched toward the other side of the valley, countless CGs and all the time this constant flickering aloft. The noise that followed was on the verge of indescribable - some say it was "hail roar" others that it was some sort of vortex, but it was incredible. The trees were swooping left then right then left again almost round in circles. Then...everyone knows this bit...we got the golf ball hail. It's the sound that was so bizarre though - how nature with no mechanical devices can make a sound like something enormously mechanical. It was an amazing experience but one which instilled a deeply routed respect for the power of nature-and, yes, I admit to being pretty scared at the time. And...the pepper-pot dents are still in both cars. Only today I was showing the ones in my Fiesta to one of my French neighbours, they were amazed. They've had a small tornado a few villages away, but here never anything like we had. There have been supercells in the region but not here. Awe inspiring...

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