Storms and Convective discussion - June 2023

[Cain]

1 minute ago, ancientsolar said:

I saw a decent hail-thunderstorm here just last month  -- hey, I'm keeping a little spark ready for a storm ,  - even overnight! 

I know I’d like to see some but I just got a feeling we won’t it’s going to far east an north of us nothing firing off south of us or they have an die off 

[ChannelThunder]

Mid-levels look fairly encouraging, but some towers are just collapsing flat.

[LeeKay/]

Current clouds, Mackerel is nice

[ancientsolar]

A distant view of what I can only assume is the thunderstorm over MidWales, good 25-35 miles away

[CoventryWeather]

Can see convection to my South.

[Ian Price]

Things developing niceley in Wales. This looking north of here on Anglesey. Seems to have delveloped very quickly.

Edited June 17, 2023 by Ian Price

[Southern Storm]

I think the Southeast will start seeing their storms starting to fire into life in the next 30 minutes or so, radar just starting to come to life around the Cherbourg peninsula

[The Tall Weatherman]

This is my first Convective risk map so would like some feedback if possible

SUNDAY 00z-23z

UK-

During the early morning thick cloud can be expected locally across the Southern Midlands but will burn away and will allow <2000 j/kg SB CAPE to build locally and slowly move north. Initiation can be expected from 12:30PM- 2PM and the initial storms may be quick to mature and might produce isolated large hail as suggested by the 12z GFS hodographs. By 15z multiple MCS’S could form and would produce prolific lightning and flooding because of the moist atmosphere. As these form and move north some new storms could form behind the system and cause extra flooding locally. By 22z the system is expected to perish with most thunderstorms getting choked although the odd thunderstorm cannot be ruled out as it moves into Scotland.

Ireland-

Widespread SB CAPE <1100 j/kg will build as the cloud cover fades and multiple discrete thunderstorms will move north as the day goes on. Isolated large hail and prolific rainfall rates are expected here.

And also good luck to everyone tomorrow and am excited to see some great forum photos ️

Edited June 17, 2023 by The Tall Weatherman

[ChannelThunder]

Walking the dog and I'm seeing plenty of activity trying to build in the channel.

[Harry]

Looking very stable in the Medway at the moment but I am seeing a mackerel sky beginning to emerge from the south which is often a good sign 

[Guest]

Small cell developed on the Welsh border west of Shrewsbury, moving north with a e'er so slight easterly waft. Like, NNNE 

[Sprites]

5 minutes ago, ChannelThunder said:

Walking the dog and I'm seeing plenty of activity trying to build in the channel.

Were you resonating earlier?

[ChannelThunder]

3 minutes ago, Sprites said:

Were you resonating earlier?

I was. Changed the name as I was starting to find it too cheesy! 

Stunning red sunset through banks of AC Cas at the mo! My phone camera wouldn't do it justice 

[Scuba steve]

Signs of instability now 

[Sprites]

Just now, ChannelThunder said:

I was. Changed the name as I was starting to find it too cheesy! 

Stunning red sunset through banks of AC Cas at the mo! My phone camera wouldn't do it justice 

I see , 

Good luck for later

The nights are too short this time of year. 

 

[Jan]

Just noticed storms developing over Wales. Think they could head my way, any input??

[Allseasons-Si]

Kent clipper is inbound looking at the latest radar returns.

[Azazel]

Very light rain falling in andover

[viking_smb]

Just now, Jan said:

Just noticed storms developing over Wales. Think they could head my way, any input??

its because of the mountains mate, I've noticed as they are developing over the brecon beacons near pen-y-fan 

[ancientsolar]

CB towers still going up in the Valleys, humidity is getting to me.

[viking_smb]

Just now, Allseasons-si said:

Kent clipper is inbound looking at the latest radar returns.

that ties in with the 18z synoptic chart as a trough is by there . 

[Metwatch]

Currently on an evening stroll at the moment, and can spot some elevated convection last half hour. I think the shear is making it tilt a bit as well. 

[Jamie M]

Let's see how these do

[JR319]

If wonder if/when are where the MO will issue an Amber Weather warning? 

[Eagle Eye]

Convective Outlook  

Saturday 21:00 - Sunday 21:00

Overnight pulses of elevated storms are likely to hit areas of the SE and a few may form towards the central south. Often, models under model the elevated storms and given the capping over northern France meaning that a lot of the available CAPE hasn't been used up by storms, this looks possible tonight. 

 

A large Theta-W advection with a PBL warm nose is typically a good scenario for strong elevated storms. Saturation at the cloud formation layer up to the EL at 10km looks to be favourable for active storms. However, the amount of CAPE varies significantly between models. MUCAPE could be in excess of 1,000 J/KG or could be as low as 300 J/KG. Either way, something should form perhaps in 2 rounds. Towards midnight and early morning but it depends on the strength of that CAPE.

 

Deep-layer shearing looks quite strong with weak low-level shearing but the amount of CAPE limits the hail potential to very weak. Though 1cm hail may be possible but unlikely.

 

A few elevated storms may persist from today's storms across Ireland. A few as well in England and Wales but very scattered. Generally the SE is the focus for tonight. They develop along a PV lobe with likely gold enough forcing for clusters to form, more akin to the AROME's evolution for the central south and the southeast than the UKV's limited far SE coast view. Though the areas may not be due to that alone and there's a lot of differences between the models still at this range. The WRF also struggles with that convection and its been very good recently but it does give a lot of energy for it. We've decided to keep the night risk to a slght for now.

 

Then as we go through the day, the general risk shifts north towards the midlands and also in Ireland. With locally 2,000 J/KG of SBCAPE and strong bouyancy, storms should form potentially exhibiting Supercellular characteristics for a time with large 3CAPE. Suggesting some 2cm hail possible with some severe hail. Along with some surface flooding possible, a severe risk has been added for parts of the UK and Ireland.

 

The southeast may also pickup on the action mainly to it's north with 1,000 J/KG of SBCAPE predicted there despite it generally being an unfavourable day for the south so some areas may get 1 storm overnight then in the day depending on how everything works out.

 

So strong thunderstorms are possible tonight for the central south and south east, especially the coasts which may be fairly scattered or become a small MCS depending on the forcing. This followed by a switch further north for the risk in the day with severe storms possible.

 

Then, there may be a risk for some areas overnight on Sunday but we have decided not to include that in our forecast.