Storm & Convective Discussion - 16/07/15 onwards

[Andy Bown]

The radar accumulation is staggering. Are there any confirmed rainfall totals for the Cambridge area? I may have missed them as haven't got the time to read 20 pages lol.

 

I heard something very very strange last night in the intense rain we had 3 huge flashes of lightning followed by some deep thunder but then a huge roar, im guessing it could have been in flow winds?? The wind was seriously strong during the last storm 

There is a chance you could have heard what is called 'hail roar' from within the storm cloud.

[Luke Best]

I have definitely heard thunder from way more than 12 miles so it is believable IMO, once I heard it from a storm just west of Okehampton (about 30 miles), and a few other times from storms out in the channel, up to 40/50 miles away from here. Mostly evening or night (except one morning last July), and always from elevated storms (though storms here often are elevated). 

 

I don't know if it was positive CG's or atmospheric conditions conductive to 'bouncing' the sound waves to further distances (have heard of this before), or even bolts extend closer than the radar showed the storms or the lightning detectors plotted them? However it always corresponded to the direction and the timing which lightning was detected (with a delay of a few minutes..), and there isn't much else between me and the sea to cause the sound instead. 

I have also only heard the same sound with distant and/or approaching storms.

 

I do live in the countryside though where it is pretty quiet, wouldn't think I'd be able to do hear or discern it up in Egham.

Also on a different note, when playing back the radar (NW Extra) you can see the last cell rotating as it crosses and exits East Anglia! Also the cell and its corresponding lightning strikes on lightning maps appear to take a slightly more easterly course than the rest (possible supercell?)

Thanks for the reply, interesting stuff. Now that you mention it, I have also heard thunder from way out in the Channel - as you say, always late in the evening when there is little background noise.

Makes sense that the audible thunder may have been generated by powerful positive CG strikes.

[Luke Best]

The tanks were firing at Lulworth - I could hear it from my house pretty clearly. I live on a hill and the sound carries straight across the harbour from over on the purbecks. B-BOOOOMMM

Hmm, maybe. I did hear some simple 'booms' early on but these were followed by classic rumbles and I'd be very surprised if these were anything other than thunder. I guess maybe that could have been tank fire echoing though? Do the army tanks fire as late as 11.30pm?

[big_treacle]

Hmm, maybe. I did hear some simple 'booms' early on but these were followed by classic rumbles and I'd be very surprised if these were anything other than thunder. I guess maybe that could have been tank fire echoing though? Do the army tanks fire as late as 11.30pm?

 

They do fire late. They were definitely firing - it was far too regular to be thunder. If the conditions are right it can be pretty loud & you can almost feel it, even from Poole

Maybe you could hear something from one of the channel storms as well.

Edited July 17, 2015 by big_treacle

[NO LONGER POSTING]

The radar accumulation is staggering. Are there any confirmed rainfall totals for the Cambridge area? I may have missed them as haven't got the time to read 20 pages lol.

 

There is a chance you could have heard what is called 'hail roar' from within the storm cloud.

 YES!!! Thank you!!!! This is it!!

 

 

Sounds almost the same!! 

 

EDIT: 30-36 seconds in is a mimic to what I heard last night!!

Edited July 17, 2015 by Surrey

[mb018538]

I think totals here in cambridge were 120mm widely, with some places locally between 150-200mm....it's taken me 8 hours to get the school I work at in some sort of state to be open. I'll post some pics up later and a video of that massive hail.

[East_England_Stormchaser91]

YES!!! Thank you!!!! This is it!!

 

 

Sounds almost the same!! 

 

EDIT: 30-36 seconds in is a mimic to what I heard last night!!

Remember a number of reports of hail roar on the day of June 28th 2012 too around the Coventry and Hinckley area.

I've never heard it myself, so would be interesting!

[Harry]

I'm still perplexed by this. There is absolutely no question that it was thunder I could hear late yesterday evening. I am 100% certain of that.

I've since checked the infra-red satellite imagery for the time and there was no cloud anywhere near us that could have produced lightning (in fact we were enjoying an exceptionally clear sky). I'm very aware that thunder 'shouldn't' be able to travel more than approx. 12 miles, but I have no other explanation.

 

Interesting you raise this - a few times last night I was convinced I could hear thunder, but the nearest a cell got to me was the other side of London. I heard deep and faint growls, distinct from the aircraft flying overhead occasionally. Perhaps something to do with wind flows? One for an aerodynamics physicist possibly

[Mercury Rising]

Someone yesterday posted the link to this fascinating site

 http://www.lightningmaps.org/realtime?lang=en 

thanks for that!

found it mesmerising  to watch the storms gradually  move across Northern Europe  -now  as these current storms shown below in the captured image 

I was wondering on the significance in the varied length and direction of the green lines ? they also seem to join onto green dots on the map

Is a there any reason for this ? 

Apologies if it's a dumb question - I'm a complete novice albeit enthralled by storms 

 

 

 

[Harry]

What a night!

 

We heard our first thunder around 11.30, from the first of the line of cells passing to our west, plus (possibly) from a rapidly-developing cell to our east.  This didn't last long, and there was a fair gap during which all was quiet.  Just as I was getting ready to settle down, another cell arrived from our south, rapidly developing and electrifying, with what seemed like mostly IC lightning and readily-audible intermittent thunder.  Around a minute after I closed my eyes, there was a terrific flash; very bright even behind closed eyelids.  My immediate response was to open my eyes, and, as I did, there was one of (if not the) loudest crack(s) of thunder I've ever heard - no rumble, just a crack and a sound like a huge explosion.  My response was to shout (I think) "Bloody hell, that was close!", in reply to which my dad (a usually unflappable man not given to hyperbole) came into the room with his eyes out on stalks.  It turned-out that, the reason it was so loud was that he had to front door open (bungalow) and was standing in the doorway calling the cat to come in.  He thinks he saw the bolt rather than just the all-encompassing flash, but the immediacy of the event left him unsure.  What he did find was that his hair stood on end with the static field, and, as the sound of the thunder arrived, he felt a push on his chest from the pressure wave which forced the air out of his lungs.  Based on what happened, we think the CG strike had to have been no more than 1/2 a mile away, possibly more like 1/3 of a mile. 

 

After a few more flashes and rumbles, that storm moved away, and, after the adrenaline had subsided, I got off to sleep.  Dad reported this morning that, around 2.15-ish, there were two elevated storms visible (on to the west, the other to the north-west), but no audible thunder.  Strangely, at 4.00 am, he was awoken by the cat wanting to be let out again, and reported faint flickering high up in the atmosphere.  On checking the radar, the final cell was around 20-25 miles to our north-west, but I doubt this was the source.  Any ideas as to what he might have seen?

 

Sounds like a candidate for a positive CG... rarer lightning strikes than standard negative CGs, but far more powerful - I've heard suggestions anything up to 10 times more powerful (in terms of current and voltage). Therefore, lightning is often brighter and the thunder much more explosive; those I've heard are usually a succession of loud bangs accompanied by ground shakes and (what sounds like) a motorbike backfiring sound,  or, a single bang like that of a cannon being fired nearby. The often occur as thunderstorms are approaching or moving away, as they tend to originate high in the cloud, eg from the anvil. Positive CGs, for this reason, often get referred to as dry lightning or bolts from the blue.

 

That would explain the insanely bright flash you observed, the earth shattering thunder and the shockwave feeling your Dad experienced.

 

As regards your point about the source of the flickers, almost certainly from the same series of storms. My house was being illuminated at times by the storms last night and I am a good 20-25 miles (or more) from the closest cell that occurred last night. One night a few years back, my room was illuminated by storms in the Channel (well over 60 miles away). Don't doubt the distances from which you can see flickering lightning, particularly where its elevated or at the top of a thunderhead. Particularly if you have murk or light clouds around, particularly haze at high altitudes, it will act like a mirror for storms many tens of miles away

Edited July 17, 2015 by Harry

[Homerr]

I think the green lines represent the path to the Lightning detector that detected it and the boldness of it determines how close?

That's my best guess for the minute

[stainesbloke]

4 thunderstorms aint bad bud lol!!! The last one was sort of the grand finale and I got some decent overhead lightning with booming thunder..

 

Rain by far was the most impressive, you can tell this morning because all the cars and stuff around the bottom is plastered with dirt!

Yes we did well last night, sat under that narrow 'train' of developing storms as they moved up. Am SO happy we got a proper soaking at last!!! I don't have to water the allotments today Maybe summer 2015 will be notable for thunderstorms? Got a month and a half of summer to go....

[Nouska]

Someone yesterday posted the link to this fascinating site

 http://www.lightningmaps.org/realtime?lang=en 

thanks for that!

found it mesmerising  to watch the storms gradually  move across Northern Europe  -now  as these current storms shown below in the captured image 

I was wondering on the significance in the varied length and direction of the green lines ? they also seem to join onto green dots on the map

Is a there any reason for this ? 

Apologies if it's a dumb question - I'm a complete novice albeit enthralled by storms 

 

 

 

 

If you place your cursor over the 'stations on' button, it gives a full explanation of length and colour coding.

[Thunderbolt_]

Yes we did well last night, sat under that narrow 'train' of developing storms as they moved up. Am SO happy we got a proper soaking at last!!! I don't have to water the allotments today Maybe summer 2015 will be notable for thunderstorms? Got a month and a half of summer to go....

 

Yes July 2015 is currently in a three-way tie with August 2012 and July 2013 as my thunderiest month on record, with 4 days of thunder each. All I need to do now is hear one rumble of thunder in the next two weeks and I've done it. Then it's onto August, and hopefully that will be a good one!

 

It's just a shame that June was completely thunderless though...

[Thunderbolt_]

Yes July 2015 is currently in a three-way tie with August 2012 and July 2013 as my thunderiest month on record, with 4 days of thunder each. All I need to do now is hear one rumble of thunder in the next two weeks and I've done it. Then it's onto August, and hopefully that will be a good one!

 

It's just a shame that June was completely thunderless though...

 

[NO LONGER POSTING]

Remember a number of reports of hail roar on the day of June 28th 2012 too around the Coventry and Hinckley area.

I've never heard it myself, so would be interesting!

 

It was like the storm was over head no rain... then HUGE 3 flashes of lightning and thunder,and this ROARRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR just before it started to hammer down, and when I mean rain like wow

Edited July 17, 2015 by Surrey

[Andy Bown]

Just thinking about this last 2 to 3 weeks with several plumes and the unexpected elevated storms a week ago, these allied to last summer' spectacular plume storms, perhaps we are returning to a period of summers as a lot of us remember from the 80s/90s with frequent thundery outbreaks. The higher frequency therefore meaning more chance of all areas being affected at some time or other.

 YES!!! Thank you!!!! This is it!!

 

 

Sounds almost the same!! 

 

EDIT: 30-36 seconds in is a mimic to what I heard last night!!

Brilliant glad to be of help.

 

I think totals here in cambridge were 120mm widely, with some places locally between 150-200mm....it's taken me 8 hours to get the school I work at in some sort of state to be open. I'll post some pics up later and a video of that massive hail.

Goodness that is remarkable in only a few hours, look forward to the video.

[Mokidugway]

Netweather said T and L for my area at 5am I got T and L at 5 am this morning ,good call ...

[Supacell]

 YES!!! Thank you!!!! This is it!!

 

 

Sounds almost the same!! 

 

EDIT: 30-36 seconds in is a mimic to what I heard last night!!

 

This is exactly the sound I heard before a storm on the evening of 22nd July 2013! I always wondered what it was, almost sounded like constant distant thunder but it was definitely this. Thanks for sharing

[NO LONGER POSTING]

This is exactly the sound I heard before a storm on the evening of 22nd July 2013! I always wondered what it was, almost sounded like constant distant thunder but it was definitely this. Thanks for sharing

 

That is what I thought and then realised nah, this is something else.. A sound I won't forget and would like to hear again! 

[Mesoscale]

What an insane night, first visible lightning just after 10pm (would have been earlier but it was still too light to see them at a distance) 4 different storms marched their way over head the last one exiting after 1:30am, they would give a few flashes here and there then all of a sudden they would spit multiple lightning strikes a second, very elevated though with the occasional louder thunder, the rain was torrential, no hail here that I know of but my garden flooded. Weirdest part was the CG that beaded out in front of me, it had a short sharp crack but it wasn't that loud with no residual rumble? It was close and I was expecting it to be a massive boom. I got video of some of the storms but the iphone is rubbish at shooting at night and it didn't pick up half of the flashes that occurred. The best lightning display I have ever seen in the UK, I have been to Florida a few times and that storm would not have looked out of place there. Incredible.

[East_England_Stormchaser91]

It was like the storm was over head no rain... then HUGE 3 flashes of lightning and thunder,and this ROARRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR just before it started to hammer down, and when I mean rain like wow

Looked bloody awesome mate. I never even heard any thunder or had any rain hardly lol, but just the sheer sight of the amount of lightning going on all across the Eastern skyline was unprecedented. That alone was marvellous to look at.

Hope things like this are becoming a common trend again! Feels like we have reverted back to what the good old days of the 90's were like!

Edited July 17, 2015 by East_England_Stormchaser91

[chrisbell-nottheweatherman]

Sounds like a candidate for a positive CG... rarer lightning strikes than standard negative CGs, but far more powerful - I've heard suggestions anything up to 10 times more powerful (in terms of current and voltage). Therefore, lightning is often brighter and the thunder much more explosive; those I've heard are usually a succession of loud bangs accompanied by ground shakes and (what sounds like) a motorbike backfiring sound,  or, a single bang like that of a cannon being fired nearby. The often occur as thunderstorms are approaching or moving away, as they tend to originate high in the cloud, eg from the anvil. Positive CGs, for this reason, often get referred to as dry lightning or bolts from the blue.

 

That would explain the insanely bright flash you observed, the earth shattering thunder and the shockwave feeling your Dad experienced.

 

As regards your point about the source of the flickers, almost certainly from the same series of storms. My house was being illuminated at times by the storms last night and I am a good 20-25 miles (or more) from the closest cell that occurred last night. One night a few years back, my room was illuminated by storms in the Channel (well over 60 miles away). Don't doubt the distances from which you can see flickering lightning, particularly where its elevated or at the top of a thunderhead. Particularly if you have murk or light clouds around, particularly haze at high altitudes, it will act like a mirror for storms many tens of miles away

 

 

Thanks - I did consider a +ve CG, but thought they were unlikely during summer - more of an autumn/spring phenomenon?  It certainly would fit our observations - my room isn't totally dark at night by any means, yet, even with my eyes closed, the flash was surprisingly bright.  Regarding the 4.00 am stuff, the final cell was around 20-25 miles away, and, as you suggested, light high cloud left-over from the cold front might have reflected it.

[East_England_Stormchaser91]

 

As regards your point about the source of the flickers, almost certainly from the same series of storms. My house was being illuminated at times by the storms last night and I am a good 20-25 miles (or more) from the closest cell that occurred last night. One night a few years back, my room was illuminated by storms in the Channel (well over 60 miles away). Don't doubt the distances from which you can see flickering lightning, particularly where its elevated or at the top of a thunderhead. Particularly if you have murk or light clouds around, particularly haze at high altitudes, it will act like a mirror for storms many tens of miles away

You're spot on there. Last year, I was seeing the 17th July 2014 lightning flickering as far away as Wiltshire, Hampshire and Surrey! Well over 100 miles away.

Last night was no exception either, with reports on here about seeing the Cambridge lightning all the way from Barnsley in South Yorkshire!

People wouldn't believe it if you told them that's what cracks me up!

[Spikecollie]

BBC report flooding last night in Stevenage and Royston. Also in Scotland where there have been power cuts too.

 

Accounts on here, especially Surrey's, make me understand what I heard here on July 1. As well as the wind, there was a very distinctive noise like an underground train going by, except overhead. That must have been "hail roar" too...