Storms and Convective discussion - June 2023

[Harry]

I’ve had a shocker of a thunder year so far. Yes there’s been a few storms around and I’ve heard a couple of distant rumbles, every storm has otherwise completely missed. Not even a distant flash of lightning.

It’s looking increasingly less likely I’ll be in the money for the up coming event although in my experience I’ll never say never with some decent cape values, heat and humidity all present at times in the next 48-72 hours.

Desperately need things to change soon (or at the very least, my garden does!). 

[Allseasons-Si]

Gfs going for a Sunday evening bang now maybe for large parts of the UK...

 

[cheese]

1 minute ago, Harry said:

I’ve had a shocker of a thunder year so far. Yes there’s been a few storms around and I’ve heard a couple of distant rumbles, every storm has otherwise completely missed. Not even a distant flash of lightning.

It’s looking increasingly less likely I’ll be in the money for the up coming event although in my experience I’ll never say never with some decent cape values, heat and humidity all present at times in the next 48-72 hours.

Desperately need things to change soon (or at the very least, my garden does!). 

Just one day with thunder here, and some distant lightning. 

[Azazel]

I’m ready for another thunderless summer. Would be the third in a row. 

[Turquoise]

5 minutes ago, Harry said:

I’ve had a shocker of a thunder year so far. Yes there’s been a few storms around and I’ve heard a couple of distant rumbles, every storm has otherwise completely missed. Not even a distant flash of lightning.

It’s looking increasingly less likely I’ll be in the money for the up coming event although in my experience I’ll never say never with some decent cape values, heat and humidity all present at times in the next 48-72 hours.

Desperately need things to change soon (or at the very least, my garden does!). 

we havent had any thunder at all since August 2020.

[Harry]

4 minutes ago, Azuremoon2 said:

we havent had any thunder at all since August 2020.

[Zak M]

15 minutes ago, Azuremoon2 said:

we havent had any thunder at all since August 2020.

?

[Cheshire Freeze]

1 minute ago, Zak M said:

?

I presume he means overhead. Storms aren’t the same if you miss the cores.

[Turquoise]

7 minutes ago, CreweCold said:

I presume he means overhead. Storms aren’t the same if you miss the cores.

yes, I meant overhead. A distant rumble or two isnt really what I would call a storm. If we are splitting hairs then yes the last time we actually had a proper storm close enough to enjoy was in August 2020.

[Ravendane]

So depressed. Desperate for rain and earlier forecasts showed storms and rain heading towards the Chilterns over the next few days. Now changed to hot, humid weather. Not another drought

[Tobsterstorm 7469]

I've already had my fair share of storms in May getting 4 in a row and one of them had frequent lightning and booming, loud thunder that went on for an hour so I'm happy and the west deserve some storms! 

Although we do need some rain as it will be good for the gardens 

Edited June 9, 2023 by Tobsterstorm 7469

[Flash bang flash bang etc]

Read an article earlier about the Canada wildfires that storms with more frequent lightning are (and will be) more likely as the planet warms.

 

however, I’ve also read that as ALL LAYERS warm there will be less of a dynamic temperature difference within isolated storm systems and this will reduce the potential for the more noteworthy storms you would otherwise expect.

 

I mean is there any actually support for this theory. I agree it will be hotter, but i don’t think we will end up like Kansas anytime soon

[Turquoise]

a very decent storm on this webcam on the west coast of France, the same storm system that is going to push into our vicinity this weekend....

Webcam Royan Port de Royan - Royan Atlantique

WWW.ROYANATLANTIQUE.FR

---

Bienvenue sur la page de la webcam de Royan port de Royan. Profitez de cette vue exceptionnelle sur le territoire.

 

[Tamsin]

1 hour ago, Flash bang flash bang etc said:

Read an article earlier about the Canada wildfires that storms with more frequent lightning are (and will be) more likely as the planet warms.

 

however, I’ve also read that as ALL LAYERS warm there will be less of a dynamic temperature difference within isolated storm systems and this will reduce the potential for the more noteworthy storms you would otherwise expect.

 

I mean is there any actually support for this theory. I agree it will be hotter, but i don’t think we will end up like Kansas anytime soon

I've thought about this and I think, if anything, it will just push the storm season into the colder months either side 

[Cheshire Freeze]

Monday looks a cracker on the 0z GFS run

Would be some severe weather in that I'd imagine.

[Eagle Eye]

9 hours ago, Eagle Eye said:

Day 2 forecast 

Friday 15:00 - Saturday 06:00

An advancing plume of warm moist air continues to close in on the UK. Theta-W around 16°C and MUCAPE around 500 J/KG fairly widespread and 800+ J/KG locally potentially may allow for hefty showers and thunderstorms to form from the SW of England. These look to gradually move from the SW in the day towards Ireland overnight bringing hefty rainfall with them in places.

Forcing looks to be fairly strong along a moderately strong PV lobe to allow some clusters to build in areas but low CAPE and shearing weakens that chance of clusters forming. Though the AROME shows these clusters do form and survive across the Irish sea quite well because of the strong elevated CAPE.

That elevated CAPE and the cold mid-level air may in general allow some small hail to form but there's only small support for hail.

Lightning is likely to be sparodic but frequent at times in the best areas of forcing and CAPE crossover. We've therefore decided to go for a low-mid end slight risk.

This sets the stage for Saturday where we continue to see that WAA and the unstable plume be more favourable for more widespread storms. However, I won't talk about that yet.

No changes to this forecast but its now the Day 1 forecast.

[Eagle Eye]

5 hours ago, Flash bang flash bang etc said:

Read an article earlier about the Canada wildfires that storms with more frequent lightning are (and will be) more likely as the planet warms.

 

however, I’ve also read that as ALL LAYERS warm there will be less of a dynamic temperature difference within isolated storm systems and this will reduce the potential for the more noteworthy storms you would otherwise expect.

 

I mean is there any actually support for this theory. I agree it will be hotter, but i don’t think we will end up like Kansas anytime soon

The entire point of storms forming is that the air parcel temperature is warmer than the environmental temperature around it. Also if its still warm above the surface that means more chance of that air parcel becoming the same or less temperature than the environment around it and only having low-level instability. However, that won't be a problem for us from today through to Tuesday as far as I can tell.

[East_England_Stormchaser91]

2 hours ago, Eagle Eye said:

The entire point of storms forming is that the air parcel temperature is warmer than the environmental temperature around it. Also if it’s still warm above the surface that means more chance of that air parcel becoming the same or less temperature than the environment around it and only having low-level instability. However, that won't be a problem for us from today through to Tuesday as far as I can tell.

It’s often a high risk game for the U.K. to get the real proper storms, as they often come with a strong cap (high 850’s and lack of landmass to sufficiently heat and overcome the inversion, unlike the near continent). But explosive CAPE stored below it. Getting the windshear is also a challenge too without masses of high level cloud blocking out the insolation! Cold 500hpa temps and high 850’s are usually the best result for many, which deliver the elevated storms. 

Edited June 9, 2023 by East_England_Stormchaser91

[Met4Cast]

Tomorrow is shaping up to be a very interesting day if you're in the W Mids/Wales. A plume of very warm theta-e's will push northwards across the UK tonight/tomorrow morning associated with a broad upper (albeit weak) shortwave. This will be provide the main forcing for any storm development into the afternoon.

A selection of Skew-T's show some slight capping in the lower levels during the morning but most models have this eroding by the early-mid afternoon, especially across the Mids/Wales, less so for S/SE England for example so storm risk here is likely to be somewhat muted. 

Expecting initiation in the Chilterns area 2-4pm as a rough time before rapid development expands north-westwards through the W Mids and Wales, perhaps a few storms popping off over the SW too helped by orographic lift, although less certainty there.

Discrete cells seem likely initially, CAPE in excess of 2,000J/KG seems plausible with one or two models on the extreme end close to 3,000J/KG, rather remarkable by UK standards, particularly in June! Cells may merge to form longer spells of torrential rainfall/multi-cell clusters. Main risks are localised flooding, would not be surprised to see >100mm in a few localised spots, slack steering winds suggest very slow storm movement. 

Large hail is less likely, however cannot be ruled out if we manage to see some self-sustained updrafts if cells are able to fully utilise the amount of CAPE available, cloud tops potentially punching 40,000 feet. Wind shear is weak, stronger shear would likely have resulted in a genuinely severe thunderstorm outbreak tomorrow.

Potentially the best storms of the year so far.. and then there's the next few days too. Lots to keep an eye on!

Edited June 9, 2023 by Met4Cast

[Supacell]

An interesting few days coming up from a convective standpoint, especially when in relation to the dryness and calmness of the last 3-4 weeks. The interest starts today and runs right through to probably Tuesday of next week, so potentially 5 days of storm potential! I am thinking this thread is going to get quite busy. However, showers and storms do look very hit and miss and many places will stay dry, and with a return of dry weather after the convective potential, some places could end up going into a 5th week without rain.

Overall, there looks to be daily build up of reasonable CAPE for intense thundery potential but shear is weak and the support for organised activity looks low. Even so, with the magnitude of CAPE available, any storms that do form have the potential to be briefly severe before they collapse, with a lot of lightning and gusty winds. The highest risk of impacts would appear to be from flooding where any storms occur as storms will be slow moving and, especially through Sunday and Monday, could train along convergence zones, allowing some places to pick up in excess of 50-70mm of rain. This falling onto hardened ground after the recent dry spell.

I will attempt to go through the thundery potential over each of the next few days but remember this is just a forecast based on what the models I am looking at are currently showing. Even for tomorrow it is somewhat uncertain, by Monday it is just really a guideline currently.

Today – 9th June

Light showery rain is already affecting the far southwest of Cornwall and the Scilly Isles, but I would not be surprised if people underneath it are still relatively dry as most is probably evaporating. Some slightly more robust showers to the south of the Channel Islands but these are for now devoid of thunder. Individual pockets of rain are moving north-westwards as the area moves slowly north-eastwards.

Through today areas of light showery rain from Ac-Cas cloud is likely to continue in the southwest, maybe pushing into South Wales later in the afternoon. By evening there may also be some flashes of lightning in the far southwest of Cornwall. It will be feeling much more humid in these areas with temperatures pushing into the mid to high twenties, especially where any sunshine is more prolonged. Overnight showers will become a little more widespread over the southwest and the West Country with the risk of thunderstorms, the thunder risk probably more likely across the far southwest of Cornwall.

Elsewhere for today, it is a continuation of the theme we have become accustomed to, although cloud should break a little faster for eastern parts. Sunshine was already out here in Derbyshire by 8am, earlier than any of the past few days.

Saturday – 10th June

Showers, possibly with the odd flash of lightning, are likely to be affecting the Southwest of England through the morning. During the afternoon these scattered showers and thunderstorms push/expand north and west across the West Country, Wales and parts of the West Midlands/NW England, eventually into Northern Ireland and Western Scotland by evening. These storms will be slow moving and could produce a lot of rain leading to the risk of flooding. Temperatures in these regions will be around the mid to high twenties with high humidity, so it will feel very warm or hot. Storms continue across the far west of the UK into the first part of the night. Not all areas will see these showers and storms, they will be scattered in nature (and this will be the form horse across the entire 4-5 day period). I have highlighted this area in yellow on my map.

To the east of this will be a tongue of hot, humid air bathed in sunshine allowing temperatures to rise into the high twenties, maybe even reaching or exceeding 30 degrees in a zone from London across the Midlands and into Northwest England. Here there will be a stronger cap in place, and it is quite plausible that storms will not develop, leaving the area dry. This more especially the further south and east one goes. However, if temperatures can exceed 27-28 degrees (which is quite likely) then a few isolated storms could break out and where they do they have the potential to be intense with frequent lightning, gusty winds and torrential rain. The caveat to this is if cloud from the system further west or running up from the south affects sunshine amounts and reduces the forecast daytime temperatures. If this happens then the cap will remain intact and thunderstorms will not break out in these areas. I have highlighted this area as orange on my map.

There is some divergence between high resolution models with regards to activity in the orange box but good agreement on the risk of storms further west (yellow box).

Sunday – 11th June

It looks currently like storms will generally be more widespread than on Saturday. For the morning there will probably be some cloud and showers across Wales and the West Country with some pockets of rain but also some very warm and humid sunny spells. Areas further east will see sunshine and the heat building again from the word go. By early afternoon the first storms look likely to break out across Wales and the West Country and these could be intense with torrential rain, frequent lightning and gusty winds (I have highlighted this area yellow on my map).

Further east  scattered thunderstorms are likely to start breaking out through the afternoon. Currently the models are still not sure on where will be mostly affected but the central spine of the country, especially from north of London, through the Midlands and up towards the Pennines looking a good bet. These storms will be forming in an area of 1000-2000 j/kg of CAPE and so any that form could be very active with a lot of lightning. They may also form into a line along a north to south aligned convergence zone through the central part of the country and this will push slowly westwards through the West Midlands and North-west England. Storms may then rumble on into the night across Wales (this is the orange area on my map).

Monday – 12th June

By Monday is a great deal of uncertainty but it does look like Monday could possibly be the most widespread day of thunderstorms. The ECM model shows some particularly tasty storms across the entire western half of England, Wales and Northern Ireland but this zone could easily be further east or further west. The entire forecast could change with it being 3 days ahead and so I won't go into too much detail.

By Tuesday it appears that the storm risk will be transferring westwards as drier, more stable air returns with maybe only Ireland at risk by this stage.

Edited June 9, 2023 by Supacell

[Dangerous55019]

Morning everyone

I see that the U.K. Meto have now issued a yellow warning for thunderstorms on Sunday as well as Saturday!

We all know that storms can be fickle things, so good luck to everyone with this over the coming few days.

[Rufus Butterfield]

Literally on the border

[James1979]

12 hours ago, Harry said:

I’ve had a shocker of a thunder year so far. Yes there’s been a few storms around and I’ve heard a couple of distant rumbles, every storm has otherwise completely missed. Not even a distant flash of lightning.

It’s looking increasingly less likely I’ll be in the money for the up coming event although in my experience I’ll never say never with some decent cape values, heat and humidity all present at times in the next 48-72 hours.

Desperately need things to change soon (or at the very least, my garden does!). 

I've seen 1 bolt of lightning  about 5 meters long and heard 3 rumbles all within 5 mins of each other. First let down of the year is well and truly on again this weekend. Same old story zzzz

[Rufus Butterfield]

Also just wondering why the GFS is showing the highest cape values in the east on Sunday, but weather warnings are placed further west. I know it’s still a couple days away and there’s a lot of uncertainty but I’m just curious?

[alexisj9]

4 minutes ago, Rufus Butterfield said:

Also just wondering why the GFS is showing the highest cape values in the east on Sunday, but weather warnings are placed further west. I know it’s still a couple days away and there’s a lot of uncertainty but I’m just curious?

It less capped in the west.