Jump to content
Cold?
Local
Radar
Snow?

Storm and Convective Discussion 10th June Onwards


Recommended Posts

Well yesterday was the most successful day for storms this year. It was a lovely sunny morning, but things started to happen at around 14:00 as a small thundery shower past to the South-east giving a few good rumbles and some slight rain. Then, the sun came out again and increased surface heating, and showers began to move up from Wales. At 15:50 it began to rain torrentially. This cell seemd to have lost all its electrical activity over the bay, but as it moved inland over Crosby, it gave a IC strike right overhead. It began to rain insanely heavy, although the heaviest of the rain passed to the south-east. Five minutes past, with me standing there going "give us a CG, come on, a CG now". The cell duly obliged and shot a positive CG about 100 m away. As you can imagine, the thunder was extremely explosive, with that classic sound of a positive CG with explosive bangs after the initial crack. After a load more strikes, but no more positive ones, the cell began to move away to the north east and the sun came out again. More cells past from south-east to north-east during the evening, and I could hear the great Warrington storm far away in the distance with its deep booming thunder. So only 1 overhead storm yesterday, but what a storm!

It was great wasn't it, it made up for the one I missed the other week on the Monday night :)

Link to post
Share on other sites
  • Replies 959
  • Created
  • Last Reply

Top Posters In This Topic

[email protected]

 

Nice to hear that so many left the NSC in the last couple of days, thanks for uploading photos and vids, keep it going :good:

 

Re: the electrical nature of strikes, just wanted to add that the most dangerous pos CGs are the ones coming out of the clear sky underneath the anvil. They can strike many miles away from the actual centre of the storm lightning activity, the "bolt out of the blue" as its called. Anyone of the chasers ever noted that when a storm has just passed, the last strike is normally a loud booming pos CG after which the storm moves on. That one usually is the final strike out of the anvil and is the sign to pack your cameras and equipment and get going..

 

In Europe, Stuttgart is getting pasted for the second time in 24 hrs :help:

see here         http://www.metradar.ch/2009/pc/index.php

 

The right mover with the hail in its baggage is moving in the direction of the airport there..

 

Ralph

Link to post
Share on other sites

[email protected]

 

Nice to hear that so many left the NSC in the last couple of days, thanks for uploading photos and vids, keep it going :good:

 

Re: the electrical nature of strikes, just wanted to add that the most dangerous pos CGs are the ones coming out of the clear sky underneath the anvil. They can strike many miles away from the actual centre of the storm lightning activity, the "bolt out of the blue" as its called. Anyone of the chasers ever noted that when a storm has just passed, the last strike is normally a loud booming pos CG after which the storm moves on. That one usually is the final strike out of the anvil and is the sign to pack your cameras and equipment and get going..

 

 

I have witnessed it numerous times, you will have a thunderstorm move over with lots of cloud flashes then a last bolt as it moves away. Infact it is so common that although I do enjoy the filming a storm approach, core punching and being under a storm, I will often aim to get behind the storm at some point in order to try and get that CG shot. 

  • Like 1
Link to post
Share on other sites

Didn't get anything direct from this set up , I think I'll bide my time till aug when I go to usa !!......

Think we have a whole week of boredom coming up stormwise from saturday onwards! Sun, sun and more sun!

  • Like 2
Link to post
Share on other sites

A couple of nice little storms yesterday evening, we planted some hedge plants in one of them while doggie delighted in baying at the sky - he loves his storms too! Off to Limousin tomorrow to enjoy more or less, it looks like, what you'll be enjoying over here...

Link to post
Share on other sites

Hi, not aware of anything that close, i've lived here since 1993.. Do all lightning strikes hit something? Or can they just flash without any earthing, not Inc cloud to cloud?

 

 

I remember reading an article by the late Tim Samaras, it mentioned that positive CG strikes were possible precursors to tornadic development.Just found this on NOAAPositive CG - A CG flash that delivers positive charge to the ground, as opposed to the more common negative charge. Positive CGs have been found to occur more frequently in some severe thunderstorms. Their occurrence is detectable by most lightning detection networks, but visually it is not considered possible to distinguish between a positive CG and a negative CG. (Some claim to have observed a relationship between staccato lightning and positive CGs, but this relationship is as yet unproven.)

 

 

[email protected]

 

Nice to hear that so many left the NSC in the last couple of days, thanks for uploading photos and vids, keep it going :good:

 

Re: the electrical nature of strikes, just wanted to add that the most dangerous pos CGs are the ones coming out of the clear sky underneath the anvil. They can strike many miles away from the actual centre of the storm lightning activity, the "bolt out of the blue" as its called. Anyone of the chasers ever noted that when a storm has just passed, the last strike is normally a loud booming pos CG after which the storm moves on. That one usually is the final strike out of the anvil and is the sign to pack your cameras and equipment and get going..

 

In Europe, Stuttgart is getting pasted for the second time in 24 hrs :help:

see here         http://www.metradar.ch/2009/pc/index.php

 

The right mover with the hail in its baggage is moving in the direction of the airport there..

 

Ralph

 

 

I have witnessed it numerous times, you will have a thunderstorm move over with lots of cloud flashes then a last bolt as it moves away. Infact it is so common that although I do enjoy the filming a storm approach, core punching and being under a storm, I will often aim to get behind the storm at some point in order to try and get that CG shot. 

So, let me try and get this right, this final strike from the anvil, is usually the final strike from that storm? Sort of the last shell in a repeater air bomb, and its usually the loudest!! Perhaps it's what ever electrical charge left in the clould (battery) and has to recharge to a certain level before it can start discharging again, say 30/40 miles away or the cloud disintegrates.....

I am sure I watched a prog on national geographical where a person was struck out of the blue from a storm 10 miles away, how would this strike be actuated?

I was under the impression that their were leaders rising up from the ground that a stepped leader from the cloud would latch onto for the return power stroke, how/why would a strike decide to choose a leader so far from the cloud, unless it is the clouds last charge and it sends it out until it can't go any further and runs out of charge and connects with the ground almost where it falls....?

If that made any sense, I know exactly what I was trying to say... (Normal lightning is the cloud dropping balls downwards out the cloud, the big one it throws it as far as it can sideways and falls, where it falls)

Link to post
Share on other sites

That's mainly the reason the US weather body recommends waiting at least 30 minutes before going out after a storm to prevent bolts from the blue. Apparently this is the reason why the England match was delayed for 30 minutes at the least.

Link to post
Share on other sites

yesterdays storm here was one of those one in every three year storms,   it equalled some of the storms I saw on holiday in Italy several years ago during a thundery spell they were having,  one of many they get over the summer there

 

I know some places have missed out, but I feel this year is already better than last year,  and I feel its thanks to the mild winter for keeping sea surface temps above average

 

I got two distant flashes with two distant rumbles in march, and this spell gave me two faint rumbles on saturday morning, one closer flash and one rumble during the evening,   monday morning gave three distant rumbles at work in st helens,  tues gave a couple of distant rumbles and one flash in the afternoon, then  tues evening was the biggie, must jhave seen 100 plus flashes with continual thunder at one point,

 

and we still have rest of june, july, august, september, october for potential,   then hopefully another mild stormy winter, has the nineties style weather returned

Link to post
Share on other sites

@Speedway Slider: well, yes, youre basically summing it up, its normally towards the end of the Thundercells life cycle that the positive charge in the anvil takes over. There has been much speculation as to how and why but basically it is so that normally the base of a thundercloud is negatively charged and thus the ground directly beneath it automatically takes on the opposite, positive charge as well as the upper part of the Cb, also positive. The strength of the positive charge of the ground decreases the further away the storm is, basically like isobars around a low pressure centre for example. 

 

When the storm is mature the ground underneath it and the surrounding areas in close proximity are strongly positive charged, so a pos bolt out of the upper cloud would have an immense distance to travel to a less charged area away from the storm and the difference in potential normally doesnt allow for a breakdown. (Very rarely it does, EXTREMELY DANGEROUS, experienced it only once about 30 years ago.)

 

Now when the storm is weakening, the negative charge on the base of the storm decreases and with it the positive charge of the ground underneath decreases in proportion, i.e. the neutrally or even negatively charged areas of ground surrounding the storm shift closer to it. (remember the isobars)

 

Now the distance (or voltage) required for a strike to take place is much reduced, hence the occurrence of positive CGs then. Im not good at explaining, hope this helps a bit.

 

To what happened 30 years ago: I had just moved to South Africa on a few year work stint and had bought myself a seconhand stereo receiver, a Sansui unit, the last one with valves I think (Budget was tight then) To gain access to uncensored news you had to tune into an AM station located in the then independant Transkei, it was called Capital Radio 604 and was funded by Capital in UK. To improve reception I climbed 2 trees in front of the apartment and crossed them with a length of scooby wire with the end leading through the window to the stereo. I did notice a thunderhead in the distance (30 miles maybe) flashing away in the dusk, went back inside, connected up the aerial, pushed the ON button, uncorked a beer while the valves warm up, stood by the window looking outside and then WHAM!!

A bolt of lightning exited the anvil, travelling a large distance horizontally to eventually hit a tree close by, which in turn literally exploded, spewing bark everywhere. Incredible sharp crack of thunder, neighbours ran outside to look. My "aerial trees" had not gotten hit but out of the corner of my eye inside the room I saw a flash from inside the stereo and it went silent. The thin scooby wire had vaporized at the aerial connector of the stereo and when I opened it up three capacitors in the tuner were popped. After replacement the unit worked fine for many years, and I think if it had been a more modern transistorized stereo it would have been destroyed beyond repair. The scary thing about this is how much potential must have been in the air at the point where this bolt out of the blue hit to where the makeshift aerial was, the distance being at least 300 yards. Never seen something like that in Europe.....

 

Ralph 

  • Like 3
Link to post
Share on other sites

I do wonder about Friday. GFS keen on some precipitation, and CAPE levels reaching 1500j per kg in some central areas! Certainly enough to trigger some nasty storms if the cap gives way. A close watch should be kept on this build up! :)

 

I pretty much expect when Friday arrives this really wont be much of a concern but you never know

Link to post
Share on other sites

I do wonder about Friday. GFS keen on some precipitation, and CAPE levels reaching 1500j per kg in some central areas! Certainly enough to trigger some nasty storms if the cap gives way. A close watch should be kept on this build up! :)

Shh! Lets forget about it so the storms don't find out we're on to them!  :spiteful:

  • Like 1
Link to post
Share on other sites

Could there be a little bit of action on friday in places I wonder............... http://www.wetterzentrale.de/pics/Rtavn5411.gif

I saw this yesterday and thought ooh could it be the next potential risk. Then I remembered the high pressure being upon us and thought theres no point in pointing it out so I didn't. MetO slp chart still indicated high pressure on Friday. It was a non event last time hp was around with cape. I prob won't be getting involved that day unless I can see something visually.
Link to post
Share on other sites

A couple of pics took from yesterday that i thought a storm was evolving before i had a visual on that derby storm

 

post-16960-0-72857900-1402520022_thumb.j

post-16960-0-30828700-1402520049_thumb.j

 

then shortly after,the derby storm which run NE to the SE of me

 

post-16960-0-77566300-1402520181_thumb.j

post-16960-0-26428600-1402520208_thumb.j

 

as for friday,the potential is there,but i think there is no trigger there,maybe a convergance may spark a few isolated storms,we shall see.

 

  • Like 1
Link to post
Share on other sites

10 June 2014 The Flixborough chase. Pictures are in order from getting into position at Flixborough to the South bank of the Humber.

 

Got a raging abscess so excuse me for not going into more detail.

 

post-12197-0-94404000-1402520160_thumb.j

 

post-12197-0-10569100-1402520182_thumb.j

 

post-12197-0-02058400-1402520196_thumb.j

 

post-12197-0-81905000-1402520262_thumb.j

 

post-12197-0-15385700-1402520218_thumb.j

 

post-12197-0-74868400-1402520292_thumb.j

 

post-12197-0-40121800-1402520313_thumb.j

 

post-12197-0-70731000-1402520337_thumb.j

 

 

 

 

  • Like 8
Link to post
Share on other sites

My last close brush with lightning was 2005/6, summer - I was working at a garden centre in shepperton, a storm was brewing and I was standing in the carpark, when I felt the hairs on the back of my neck go up - I ran for the shop and turned to see a big pink flash hit a tree across the road - since then that's me hooked - not scared at all, more in awe.

 

Sounds like you had a step heading skywards from your head!

 

I watched a program a few years ago about lightning and how it determines where it strikes. Basically there are positive or negative charged strands both rising up from the ground and descending from the cloud called steps. There maybe steps coming from a tree, a car and a lamppost. The steps coming from the cloud head towards the steps rising from the objects and the ground. The step that is ahead of the rest is called the step leader. When both step leaders meet the lightning strikes (maybe the step from the tree wins) the tree is struck.

 

When you feel the hairs on your neck and head stand up then it's time to become as little as possible if there is no solid structure to hide in. A step is rising from you trying to meet the step from the cb.

 

There was a picture that a lightning photographer caught on this program and he was nearly struck however it was a rare shot actually showing the step that would have harmed him if it became the leader.

 

Hopefully the info is still accurate :D

Edited by Greenday
  • Like 1
Link to post
Share on other sites

@Speedway Slider: well, yes, youre basically summing it up, its normally towards the end of the Thundercells life cycle that the positive charge in the anvil takes over. There has been much speculation as to how and why but basically it is so that normally the base of a thundercloud is negatively charged and thus the ground directly beneath it automatically takes on the opposite, positive charge as well as the upper part of the Cb, also positive. The strength of the positive charge of the ground decreases the further away the storm is, basically like isobars around a low pressure centre for example. 

 

When the storm is mature the ground underneath it and the surrounding areas in close proximity are strongly positive charged, so a pos bolt out of the upper cloud would have an immense distance to travel to a less charged area away from the storm and the difference in potential normally doesnt allow for a breakdown. (Very rarely it does, EXTREMELY DANGEROUS, experienced it only once about 30 years ago.)

 

Now when the storm is weakening, the negative charge on the base of the storm decreases and with it the positive charge of the ground underneath decreases in proportion, i.e. the neutrally or even negatively charged areas of ground surrounding the storm shift closer to it. (remember the isobars)

 

Now the distance (or voltage) required for a strike to take place is much reduced, hence the occurrence of positive CGs then. Im not good at explaining, hope this helps a bit.

 

To what happened 30 years ago: I had just moved to South Africa on a few year work stint and had bought myself a seconhand stereo receiver, a Sansui unit, the last one with valves I think (Budget was tight then) To gain access to uncensored news you had to tune into an AM station located in the then independant Transkei, it was called Capital Radio 604 and was funded by Capital in UK. To improve reception I climbed 2 trees in front of the apartment and crossed them with a length of scooby wire with the end leading through the window to the stereo. I did notice a thunderhead in the distance (30 miles maybe) flashing away in the dusk, went back inside, connected up the aerial, pushed the ON button, uncorked a beer while the valves warm up, stood by the window looking outside and then WHAM!!

A bolt of lightning exited the anvil, travelling a large distance horizontally to eventually hit a tree close by, which in turn literally exploded, spewing bark everywhere. Incredible sharp crack of thunder, neighbours ran outside to look. My "aerial trees" had not gotten hit but out of the corner of my eye inside the room I saw a flash from inside the stereo and it went silent. The thin scooby wire had vaporized at the aerial connector of the stereo and when I opened it up three capacitors in the tuner were popped. After replacement the unit worked fine for many years, and I think if it had been a more modern transistorized stereo it would have been destroyed beyond repair. The scary thing about this is how much potential must have been in the air at the point where this bolt out of the blue hit to where the makeshift aerial was, the distance being at least 300 yards. Never seen something like that in Europe.....

 

Ralph 

Thanks, very informative.....

Now, does that mean that anyone under the length of that bolt, ie from where it left the anvil/cloud to the point if strike, lets say 7 miles away would here the thunder instantly as it would be directly over people for 7 miles, everyone underneath the bolt would not count past 1 second before they heard the thunder produced from the section of bolt above them, if so, that would be the thunderclap from hell, yes?

Link to post
Share on other sites

Sounds like you had a step heading skywards from your head!

 

I watched a program a few years ago about lightning and how it determines where it strikes. Basically there are positive or negative charged strands both rising up from the ground and descending from the cloud called steps. There maybe steps coming from a tree, a car and a lamppost. The steps coming from the cloud head towards the steps rising from the objects and the ground. The step that is ahead of the rest is called the step leader. When both step leaders meet the lightning strikes (maybe the step from the tree wins) the tree is struck.

 

When you feel the hairs on your neck and head stand up then it's time to become as little as possible if there is no solid structure to hide in. A step is rising from you trying to meet the step from the cb.

 

There was a picture that a lightning photographer caught on this program and he was nearly struck however it was a rare shot actually showing the step that would have harmed him if it became the leader.

 

Hopefully the info is still accurate :D

 

Maybe not as accurate as I thought but the right idea, best probably reading this :)

 

http://en.wikipedia.org/wiki/Lightning

Link to post
Share on other sites

l thought the weather was supposed to be settling? according to the met office text forecast theres a risk of an isolated thunderstorm on friday.

According to Chris Fawkes on the regional forecast, humidity building 'with the risk of a late storm' on FridayCertainly caught me by surprise!
  • Like 1
Link to post
Share on other sites
Guest
This topic is now closed to further replies.
×
×
  • Create New...