Storms and Convective discussion - 1st August 2022 onwards

[Allseasons-Si]

3 minutes ago, Azazel said:

Sorry not sorry 

FullSizeRender.MOV

Wow,where is that?

 

[Azazel]

3 minutes ago, Allseasons-si said:

Wow,where is that?

 

South of France near Frejus:) 

[Mapantz]

Wednesday's chart is very similar to one last year.. cannot remember the date, but LP swirled fronts around and precip moved E to W, then swung NW to SE, before pulling away. It looked odds on for thunderstorms, but it all missed much of the south coast.

May have been June 28th last year?

Wednesday:

Lightning ended up in an ark north of here.

Edited August 14, 2022 by Mapantz

[Scuba steve]

14 minutes ago, Azazel said:

South of France near Frejus:) 

We have an apartment in pegomas not to far away it’s a  lovely part of the world 

[Eagle Eye]

Let's talk Supercells because they rarely happen in the UK so when there is the potential that one has happened its quite a big event, normally the whole of twitter is onto it in a flash to disprove or prove it.

So let's talk facts (that I have just learnt so may not be facts).

First of all

For idealised mesocylone strength, a rare event here, then the Storm-Relative Wind coupled with stream wise vorticity would be equal with the change in distance along the direction of the increase of speed from outside the updraft core to the core itself which theoretically means that with a small SRW it could be counteracted and still become a Supercell if the updraft remained relatively stationary.

If the max updraft speed is equal to or bigger than the SRW then that is a big component in deciding whether tilting happens as well. So a strong updraft does help streamline vorticity tilting which in turn hands itself to helping to create perfect conditions for Supercells.

Earlier in Scotland, the possibility that one of the Storms was a Supercell was mentioned,I had a brief look at it but never really went in depth.

Upshear is the change of shear upwards and so would be associated with inflowing updraft which is what we want here so from the cloud layer 150:211 is decent enough for a slight right turn in terms of when the Storm is strengthening as usually happens but more importantly,it suggests the net vorticity tilting was very close to 1:1. So a persistent mesocylone was quite likely and based off pictures of the event I would suggest this was probably a mesocylone but to confirm it we would need a time-lapse to know that he distance between the outside and the core of the updraft and the streamwise vorticity also worked together well.

 

[Scuba steve]

10 minutes ago, Eagle Eye said:

Let's talk Supercells because they rarely happen in the UK so when there is the potential that one has happened its quite a big event, normally the whole of twitter is onto it in a flash to disprove or prove it.

So let's talk facts (that I have just learnt so may not be facts).

First of all

For idealised mesocylone strength, a rare event here, then the Storm-Relative Wind coupled with stream wise vorticity would be equal with the change in distance along the direction of the increase of speed from outside the updraft core to the core itself which theoretically means that with a small SRW it could be counteracted and still become a Supercell if the updraft remained relatively stationary.

If the max updraft speed is equal to or bigger than the SRW then that is a big component in deciding whether tilting happens as well. So a strong updraft does help streamline vorticity tilting which in turn hands itself to helping to create perfect conditions for Supercells.

Earlier in Scotland, the possibility that one of the Storms was a Supercell was mentioned,I had a brief look at it but never really went in depth.

Upshear is the change of shear upwards and so would be associated with inflowing updraft which is what we want here so from the cloud layer 150:211 is decent enough for a slight right turn in terms of when the Storm is strengthening as usually happens but more importantly,it suggests the net vorticity tilting was very close to 1:1. So a persistent mesocylone was quite likely and based off pictures of the event I would suggest this was probably a mesocylone but to confirm it we would need a time-lapse to know that he distance between the outside and the core of the updraft and the streamwise vorticity also worked together well.

 

Interesting fact I read some time ago that supercells where invented in England,re the Wokingham storm in the early sixties  

 

 

[Allseasons-Si]

Sferics SW Lancaster,NW England.

 

[Ben Sainsbury]

19 minutes ago, Eagle Eye said:

Let's talk Supercells because they rarely happen in the UK so when there is the potential that one has happened its quite a big event, normally the whole of twitter is onto it in a flash to disprove or prove it.

So let's talk facts (that I have just learnt so may not be facts).

First of all

For idealised mesocylone strength, a rare event here, then the Storm-Relative Wind coupled with stream wise vorticity would be equal with the change in distance along the direction of the increase of speed from outside the updraft core to the core itself which theoretically means that with a small SRW it could be counteracted and still become a Supercell if the updraft remained relatively stationary.

If the max updraft speed is equal to or bigger than the SRW then that is a big component in deciding whether tilting happens as well. So a strong updraft does help streamline vorticity tilting which in turn hands itself to helping to create perfect conditions for Supercells.

Earlier in Scotland, the possibility that one of the Storms was a Supercell was mentioned,I had a brief look at it but never really went in depth.

Upshear is the change of shear upwards and so would be associated with inflowing updraft which is what we want here so from the cloud layer 150:211 is decent enough for a slight right turn in terms of when the Storm is strengthening as usually happens but more importantly,it suggests the net vorticity tilting was very close to 1:1. So a persistent mesocylone was quite likely and based off pictures of the event I would suggest this was probably a mesocylone but to confirm it we would need a time-lapse to know that he distance between the outside and the core of the updraft and the streamwise vorticity also worked together well.

 

You've lost me 

Just for the rest of the people here, it might be helpful to explain what "Storm-Relative Wind", "Streamwise Vorticity" and "Net Vorticity Tilting" is  

Edited August 14, 2022 by Ben Sainsbury

[viking_smb]

@Ben Sainsbury any update on tomorrow night please? 

[Ben Sainsbury]

6 minutes ago, viking_smb said:

@Ben Sainsbury any update on tomorrow night please? 

This is what me and @Met4Cast have issued for tomorrow: 

Long story short, convergence zones setting up across S Ireland, SW England & E/NE England during the day. Isolated to scattered thunderstorms developing here but nothing too extreme currently. Into the evening, a low approaches SW England and numerous thunderstorms are expected to develop on the leading edge of the trough/occluded front across SW/CS England and S Wales. I'd expect some fairly frequent lightning at times.

 

Edited August 14, 2022 by Ben Sainsbury

[Scuba steve]

9 minutes ago, Allseasons-si said:

Sferics SW Lancaster,NW England.

 

I’m in Morecambe I’ll keep an eye and ear open 

[harrywhiterowoutdoors]

1 hour ago, ResonantChannelThunder said:

Looking a tiny bit further ahead, ECM is still interested in some imports flirting with central south and southeastern channel coasts late on Tuesday night into Weds AM. Only posting the precip. charts since this is just  48-60 hours away now 

That looks close enough to me that I might get a little bit of action 

[Eagle Eye]

5 minutes ago, Ben Sainsbury said:

You've lost me 

Just for the rest of the people here, it might be helpful to explain what "Storm-Relative Wind", "Streamwise Vorticity" and "Net Vorticity Tilting" is  

I lost myself half way through writing that so not all of it will be correct probably haha and maths isn't my strongest suit hence why I avoided it.

Anyway 

Storm-relative Wind is best described as:

"The wind “felt” by the storm is called the storm relative wind. An analogy is driving a car 50 miles per hour into a 20 mile per hour wind. The wind sensed by the car is a 70 mile per hour wind. A storm moving into the wind field will result in an addition of the storm motion to the wind interacting with the storm. A storm can move in a different direction as compared to the low level wind when directional shear with height causes the storm to be influenced by the overall wind direction interacting with the storm. For example, winds from 700 to 300 may be strong from the west. While the wind at the surface may be strong from the southeast, the storm motion will be heavily influenced by the west winds aloft."

Streamwise Vorticity:

"

the amount of horizontal vorticity that is parallel to storm inflow. Storm inflow is the velocity of the low- evel wind moving toward a thunderstorm. Helicity is the amount of streamwise vorticity that is available to be ingested by a thunderstorm. Helicity is a great chart to use to assess horizontal vorticity and the threat for rotating thunderstorms."

Net Vorticity Tilting:

"

A vortex in a uniform flow field will not tilt, it will stay as it is aligned and move along with the flow. However, if there is a gradient in the velocity field, this can cause a vorte"

So essentially it's how far it's tilted as far as I'm aware.

 

[viking_smb]

4 minutes ago, Ben Sainsbury said:

This is what me and @Met4Cast have issued for tomorrow: 

Long story short, convergence zones setting up across S Ireland, SW England & E/NE England during the day. Isolated to scattered thunderstorms developing here but nothing too extreme currently. Into the evening, a low approaches SW England and numerous thunderstorms are expected to develop on the leading edge of the trough/occluded front across SW/CS England and S Wales. I'd expect some fairly frequent lightning at times.

 

thanks ben, hopefully the low will be a bit further south, but see what is like in the morning. just want a good nights sleep.

[harrywhiterowoutdoors]

3 minutes ago, Ben Sainsbury said:

This is what me and @Met4Cast have issued for tomorrow: 

Long story short, convergence zones setting up across S Ireland, SW England & E/NE England during the day. Isolated to scattered thunderstorms developing here but nothing too extreme currently. Into the evening, a low approaches SW England and numerous thunderstorms are expected to develop on the leading edge of the trough/occluded front across SW/CS England and S Wales. I'd expect some fairly frequent lightning at times.

 

Interestingly I'm just in the mdt zone in the south west maybe I might get a little bit of storm action  

[Turquoise]

11 minutes ago, Ben Sainsbury said:

This is what me and @Met4Cast have issued for tomorrow: 

Long story short, convergence zones setting up across S Ireland, SW England & E/NE England during the day. Isolated to scattered thunderstorms developing here but nothing too extreme currently. Into the evening, a low approaches SW England and numerous thunderstorms are expected to develop on the leading edge of the trough/occluded front across SW/CS England and S Wales. I'd expect some fairly frequent lightning at times.

 

Fantastic. I'm in that grey patch just to the east of Central Wales. Honestly couldn't make it up.

[Peachy]

8 minutes ago, Azuremoon2 said:

Fantastic. I'm in that grey patch just to the east of Central Wales. Honestly couldn't make it up.

I wouldn't worry too much. Thunderstorms could develop just about anywhere over great Britain in the next 3 days.

[Scuba steve]

Short spell of heavy rain no thunder heard

[damianslaw]

6 minutes ago, Scuba steve said:

Short spell of heavy rain no thunder heard

I was in Morecambe just a couple if hours ago. Great to see the resort thriving on a hot summer's day.

[Ben Sainsbury]

Very interesting right-mover just approaching the Irish border. Long-lived and intense core to it, would love to see the structure on it right now.

[SnowBear]

52 minutes ago, Eagle Eye said:

I lost myself half way through writing that so not all of it will be correct probably haha and maths isn't my strongest suit hence why I avoided it.

Anyway 

Storm-relative Wind is best described as:

"The wind “felt” by the storm is called the storm relative wind. An analogy is driving a car 50 miles per hour into a 20 mile per hour wind. The wind sensed by the car is a 70 mile per hour wind. A storm moving into the wind field will result in an addition of the storm motion to the wind interacting with the storm. A storm can move in a different direction as compared to the low level wind when directional shear with height causes the storm to be influenced by the overall wind direction interacting with the storm. For example, winds from 700 to 300 may be strong from the west. While the wind at the surface may be strong from the southeast, the storm motion will be heavily influenced by the west winds aloft."

Streamwise Vorticity:

"

the amount of horizontal vorticity that is parallel to storm inflow. Storm inflow is the velocity of the low- evel wind moving toward a thunderstorm. Helicity is the amount of streamwise vorticity that is available to be ingested by a thunderstorm. Helicity is a great chart to use to assess horizontal vorticity and the threat for rotating thunderstorms."

Net Vorticity Tilting:

"

A vortex in a uniform flow field will not tilt, it will stay as it is aligned and move along with the flow. However, if there is a gradient in the velocity field, this can cause a vorte"

So essentially it's how far it's tilted as far as I'm aware.

 

THUNDERSTORMS

WWW.WEATHER.GOV

Quite a good page on info there. 

I understand what those labels you quote mean mostly, but it's difficult to explore further here without a whiteboard to draw diagrams etc to show how the air masses at various levels interact and twist both laterally and vertically in 3d space. 

Keep learning! 

Hurricanes next

Edit: added another link

Lecture 31 - Thunderstorms and tornadoes

WWW.ATMO.ARIZONA.EDU

 

Edited August 14, 2022 by SnowBear
Added link to AZ lecture

[Scuba steve]

18 minutes ago, damianslaw said:

I was in Morecambe just a couple if hours ago. Great to see the resort thriving on a hot summer's day.

Not been up the front today but traffic for the coast has been steady  all day 

[Scuba steve]

There’s a fair bit of activity around Kirby Lonsdale at the minute 

[Cheshire Freeze]

54 minutes ago, Azuremoon2 said:

Fantastic. I'm in that grey patch just to the east of Central Wales. Honestly couldn't make it up.

Not looking good for us once again I’m afraid…onshore flow from the NW pretty much stabilises the atmosphere for us.

[The Eagle]

Picking up over here last few minutes roughly from Co Clare across to Co Waterford in the southeast

Edited August 14, 2022 by The Eagle