Storms and Convective discussion - August 2023

[ChannelThunder]

2 minutes ago, alexisj9 said:

They don't religiously stick to their own model, the Mets forecast is based on a blend, I very much doubt this frame would have made it into the actual ten day forecast they put out, if it was on its own. Just realized this was the forecast. Probably supported at the time by other det models they use.

Forgive me if I'm wrong, but my understanding from their various output (10 Day Trends, Deep Dives etc) is that the on-screen forecast graphics are generated directly from their models (UKMO for the bigger picture, UKV for the national picture). Whereas when independently discussing the mid-longer term in those videos not using the graphics, they'll then reference the blend of models and how many times they are run etc, showing things like spaghetti graphs for frontal positions. 

The BBC seem to have a similar thing these days in which the graphics you see on TV are generated from ECM alone, which must be MeteoGroup's preferred forecast model. 

[Metwatch]

Super close CG from Brighton pier back on Thursday. 

[Andy Bown]

23 minutes ago, Metwatch said:

Super close CG from Brighton pier back on Thursday. 

Lol those people on the beach scurrying away.

[alexisj9]

11 hours ago, ChannelThunder said:

Forgive me if I'm wrong, but my understanding from their various output (10 Day Trends, Deep Dives etc) is that the on-screen forecast graphics are generated directly from their models (UKMO for the bigger picture, UKV for the national picture). Whereas when independently discussing the mid-longer term in those videos not using the graphics, they'll then reference the blend of models and how many times they are run etc, showing things like spaghetti graphs for frontal positions. 

The BBC seem to have a similar thing these days in which the graphics you see on TV are generated from ECM alone, which must be MeteoGroup's preferred forecast model. 

Yep you are correct, I just thought you were slaving the model off.

36 minutes ago, Metwatch said:

Super close CG from Brighton pier back on Thursday. 

Lol seriously I like storms but wouldn't be standing out in the open like that ever. Tbh I don't go out in them at all, although a car is ok.

[matty40s]

10 minutes ago, alexisj9 said:

 

Lol seriously I like storms but wouldn't be standing out in the open like that ever. Tbh I don't go out in them at all, although a car is ok.

Pretty sure he is well protected on the east pier walkway.

[alexisj9]

5 minutes ago, matty40s said:

Pretty sure he is well protected on the east pier walkway.

Was talking about those on the beach.

[offerman]

Is the lower pressure coming up from the south at the weekend likely to generate storms?  Warmer humid air coming in with it. 

[mike5900]

Sundays forecast. 

[carinthian]

How about this for a convective cell. Picture taken on approach to Majorca Airport yesterday.

C

[Arnie Pie]

Angry,squally line just about to slice through Brum

[*Stormforce~beka*]

2 hours ago, carinthian said:

How about this for a convective cell. Picture taken on approach to Majorca Airport yesterday.

C

That's a winner!!

[Tobsterstorm 7469]

Just had a beautiful little storm with some loud thunder and nice lightning

 

Some beautiful stormy cloudscapes as well! 

Edited August 30, 2023 by Tobsterstorm 7469

[Neilsouth]

BBC/MET mentioning the chance of thunder and lightning tonight, any truth in that? :)

[ChannelThunder]

50 minutes ago, Neilsouth said:

BBC/MET mentioning the chance of thunder and lightning tonight, any truth in that?

There's a puny amount of CAPE along a frontal boundary that skirts the south coast tonight, so I would say there's a small chance of a few strikes, but higher chance it's just rain. UKV keeps it out in the channel but Arome has it coming quite far inland. With it being an Atlantic front I'd be surprised if there was any/much thunder on it.

[Eagle Eye]

Convective Outlook ️ 

 

A front will track East bringing heavy rain & the odd risk of an isolated lightning strike.

 

Intense showers will develop in Ireland with a risk of sporadic lightning.

 

A warm front will allow elevated showers to develop in the channel tracking E/NE.

(Jay wrote the discussion. I didn't even realise there was a chance) 

[Metwatch]

June 2023 convective thread - 192 pages

July 2023 convective thread - 66 pages

August 2023 convective thread - 57 pages

Just by this I can tell it's been a sort of front loaded summer for thunderstorms, and after mid July, activity waning away with a few attempts of something more widespread in August for the south.

I think I will look back at this summer quite fondly for the storms earlier on in summer and May. One of the better seasons for convective weather in recent years along with 2020 up here. Much better than 2021 and a lot of 2022 for sure. Let's see if September can bring us a few surprises, like last year.

Also have 2 storm days / events in mind from this year to post in the best storms seen in the UK thread which i'll likely do tomorrow.

[Eagle Eye]

Convective Outlook 

In southern Ireland, 400+ J/KG of SBCAPE will allow for storms to form. This will occur on the southern tip of the Theta-E loop. That's a typical area from these showers and storms to form with rapid surface based-PBL parcel-temperature difference advection from the south into moist air. That creates a localised area of lift forming showers through forced points with the best mid-level cold pool advection. These showers will form across southern Ireland late morning-early afternoon and moving SE.

In the SE of England, throughout the day there should be a pool of 800+ J/KG of SBCAPE. With large DLS, there's a small chance of a Supercell but it's unlikely. There's also a chance of a funnel cloud.

Small hail is possible in both areas. Along with some weak surface flooding. However, both should keep with non-severe strength in both areas.

[Flash bang flash bang etc]

36 minutes ago, Eagle Eye said:

Convective Outlook 

In southern Ireland, 400+ J/KG of SBCAPE will allow for storms to form. This will occur on the southern tip of the Theta-E loop. That's a typical area from these showers and storms to form with rapid surface based-PBL parcel-temperature difference advection from the south into moist air. That creates a localised area of lift forming showers through forced points with the best mid-level cold pool advection. These showers will form across southern Ireland late morning-early afternoon and moving SE.

In the SE of England, throughout the day there should be a pool of 800+ J/KG of SBCAPE. With large DLS, there's a small chance of a Supercell but it's unlikely. There's also a chance of a funnel cloud.

Small hail is possible in both areas. Along with some weak surface flooding. However, both should keep with non-severe strength in both areas.

Supercell? Tomo?

you havin a giggle or what?

[Eagle Eye]

1 hour ago, Flash bang flash bang etc said:

Supercell? Tomo?

you havin a giggle or what?

What I should've said is Supercellular characteristics.

Fairly good and well rooted lift increasing updraft, though weak SRH values due to limited inflow layer space and strength. That will weaken Supercell prospects. However, the 3CAPE is decent and with hydrolapse rates post PBL that strong, that's a Dixie Alley esque saturation setup. CAPE is not particularly limited to post PBL despite the dry surface layer setup and post PBL, the slight warm nose does decrease CAPE availability, I suspect a less warm nose here would put it more in the noticeable category. A near surface LCL also suggest large amounts of available ECAPE which increases Supercellular potential and also Supercellular characteristics potential. Hail wise and there's good ECAPE with the near surface LCL's and fairly good EL's if the AROME is correct here. That mid-level dry nose does weaken storm potential as it's a bit too much. However, with more CAPE that is a Supercell potential. More energy into the storm can actually be used as a Supercellular indicator, especially given that the DLS isn't that far away from being a straight hodograph, it's in-between that and multi-cellular esque.

Large DCAPE suggests a fairly good downward transfer of energy however, so a lot of the storms energy will be outflow dominated with the weak and shallow inflow layer meaning Supercellular potential sort of stops there. However, as you can see, it wouldn't take too much of a difference in moisture advection and where the energy is distributed to form a Supercell.

Then there's this one, very similar with better inflow but a similar layer strength. Along with increased DCAPE. It's really only where the energy is distributed that's making this a multi-cellular or longer lived pulse-type event. Some slight variations and it's Supercellular.

 

Edited September 1, 2023 by Eagle Eye

[Supacell]

Locking this thread now. Apologies to @Eagle Eye you got in early . Please feel free to copy your forecast into the new thread if you wish.

New thread here