Storms and Convective discussion - June 2023

[Eagle Eye]

57 minutes ago, CoventryWeather said:

I'm not brilliant at reading these, but would that show cloud heights near to 35k feet? 

Also, do you have a link to these as well? Thanks. 

Yes it would but that's assuming the air parcels remain in that space long enough for that to happen. They're on Pivotal Weather you've just got to tap on the map in the place you want to look at, only available for free with the GFS though.

[Dangerous55019]

Morning Everyone

I see that the U.K. Meto have issued their first weather warning with regards to Saturday’s storm potential.

As always, with us being this far out, please take this with a gritter load of salt, as is probably gonna change as the time approaches… But it is nice to see something else being forecast other than just high pressure. 

[ChannelThunder]

5 hours ago, Alderc said:

Arome at 18Z tomorrow evening pretty aggressive in breaking out showers and thunderstorms along the south coast. 
 

Already correcting southwestwards on the following run, although not quite to the extent of the other models. A very marginal event for the south coast I think, with a greater chance the further west you are.

Edited June 8, 2023 by ResonantChannelThunder

[ChannelThunder]

An early CW outlook for Sat:

http://convectiveweather.co.uk/forecast.php?date=2023-06-10&fbclid=IwAR3IJTzS1hKkh4U2fw8E6TciuX8YcEhYfN09uCak-RPB7m7f87I129xd3uo

[Supacell]

As we get to within the 48-72 hour time frame I am now starting to get quite excited about the prospect of getting out storm chasing again over this coming weekend.

[ChannelThunder]

UKV 12z still looks poor for tomorrow night and we're well within 48 hours now. I guess it could be picking up on the storms being very high based and very little precip. reaching the ground? Although, saying that, it's shown very high reflectivity for many past elevated events. Awaiting Dan's Friday outlook for concrete info!

[Eagle Eye]

Convective Outlook ️
Thursday 16:00 - Friday 08:00

The start of a fairly significant plume of energy Thursday evening into Friday morning with a line of elevated showers likely in the channel and southern parts of the Irish Sea. Inside an area of a fairly high Theta-W airmass (14-16°C 850's) and MUCAPE potentially up to 500 J/KG right on the coast may allow for some occasionally active but mainly sparodic lightning over the channel/extreme far coasts.

This is ahead of a lifting occluded front with fairly large scale WAA bringing warmer air into the UK and Ireland ready for the potential couple rounds of thunderstorms for areas though mainly from Friday night through to Tuesday. Tonight is just early the setup for that but a few elevated thunderstorms in the far SW of England and the extreme far south of Ireland overnight may occur as stated before.

These occur along a PV lobe just SW of the SW but a few showers wih sparodic lightning may ride a secondary PV lobe that attempts to setup in the early morning more inland for a bit. The ones that ride along that secondary one are likely to be much weaker with 1 or 2 strikes at best unless the mid-levels are more bouyant than currently forecast.

MLCIN forecasts show that the ones riding that secondary lobe are along an area of fairly strong convective inhibition weakening them yet again but I wanted to point it out as a possibility and hence why it's in the low risk. There's less in the main lobe where the area of interest is and generally there's also more available CAPE with taller equilibrium levels suggesting they'll make better use of that CAPE as well.

Generally these won't come with any severe risks. Despite the high PWAT, they won't make a lot of use of all that moisture and their elevated nature shows that a lot of that just might not hit the ground anyway. There's no real support for hail except maybe some very small hail and lightning will generally be very sparodic.

[Eagle Eye]

Thanks to Meteociel for adding the SHARPpy soundings for the ARGEGE, AROME and WRF. Here's a select few soundings for the weekend. Most of them are for me except the last one which is for the Welsh border ish on Saturday.

[Tamsin]

http://www.convectiveweather.co.uk/forecast.php?date=2023-06-10

The words "Nodrog" and "nighttime lightning display video" spring to mind here:

...evening/night, substantial CAPE will persist given the now mixed layer in the low/mid-levels, and with strengthening 600-850hPa flow through the evening this will advect more rapidly northwestwards across the Irish Sea and perhaps NW England,...

Colour me excited

[kold weather]

A bit of a shift away from an outbreak on this afternoons higher resolution models it has to be said, they all look less impressive than they did on previous runs. Although most still havw some decent activity in the SW portion of the country and into Ireland

[Cheshire Freeze]

7 minutes ago, kold weather said:

A bit of a shift away from an outbreak on this afternoons higher resolution models it has to be said, they all look less impressive than they did on previous runs. Although most still havw some decent activity in the SW portion of the country and into Ireland

Yeah looks like the drought will carry on for most.

Makes you wonder when we’ll next see widespread rainfall. Looking at the UKMO/GEM etc the next 7-10 at least looks devoid of it.

Another 4 weeks or so of this pattern and I can see hosepipe bans being implemented, especially with water demand increasing with the temperatures.

Edited June 8, 2023 by CreweCold

[A Face like Thunder]

35 minutes ago, CreweCold said:

Yeah looks like the drought will carry on for most.

Makes you wonder when we’ll next see widespread rainfall. Looking at the UKMO/GEM etc the next 7-10 at least looks devoid of it.

Another 4 weeks or so of this pattern and I can see hosepipe bans being implemented, especially with water demand increasing with the temperatures.

Sunday may be interesting in our neck of the woods.

[Rufus Butterfield]

The potential for us looks best on Sunday, but they look like they’re going to be quite isolated. I’m not going to get my hopes up until I know something is coming my way.

[CoventryWeather]

1 hour ago, kold weather said:

A bit of a shift away from an outbreak on this afternoons higher resolution models it has to be said, they all look less impressive than they did on previous runs. Although most still havw some decent activity in the SW portion of the country and into Ireland

I wouldn't say they have shifted away, seems similar to those earlier. There's a significant CAP in the low levels, that requires a temperature of 26/27 to overcome. 

I believe models are struggling with the convection, as they are likely to be mid-layer showers, so it's likely that they maybe underestimating convection. 

The UKV 15z has come out - some showers in the channel Islands tomorrow night, but nothing significantly different from the previous run (maybe a risk of a downpour in the Central Southern areas tomorrow afternoon). 

[sheikhy]

Just to add ukv once again has no where near as many storms as the gfs!!could be a nice heatwave this for a lot of us!!!

[pad199207]

West is best for storms too now is it?

[Jamie M]

Lovely stuff

[TwisterGirl81]

We are a month without rain here in Exeter and as much as I am loving to warm sunny weather I was looking forward to a good few thunderstorms with torrential rain, looking at the weather forecasts it’s not looking promising currently but maybe we’ll be surprised 

25 minutes ago, pad199207 said:

West is best for storms too now is it?

I’d say wales, midlands and northeast England, we don’t get thunderstorms here in Exeter all that often 

[JR319]

1 hour ago, sheikhy said:

Just to add ukv once again has no where near as many storms as the gfs!!could be a nice heatwave this for a lot of us!!!

Boo. Could do with something to break up the ongoing high pressure saga and we need the rain as things are getting increasingly dry. 

[Paul]

Starting to look very interesting this weekend and into next week. @Nick F has written a really informative blog about what's likely to happen and why. 

Growing risk of thunderstorms this weekend and into early next week

WWW.NETWEATHER.TV

---

A plume of warm, humid but unstable air will spread north across parts of the UK this weekend and will linger into early next week, bringing an increased risk of thunderstorms breaking out in places, as temperatures...

 

[CoventryWeather]

38 minutes ago, Jamie M said:

Lovely stuff

Tad further east and it'll be better

[Coops241180]

Saturday and Sunday are certainly looking interesting. Although looks like if anythings going to happen it'll be later on. 

What i'm not looking forward to is the stifling evenings between, but there usually a good sign that storms aren't far off  

[Eagle Eye]

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.

[Peachy]

Starting to look very interesting from Saturday afternoon into late on Sunday for anyone fortunate enough to be living in the west Midlands and Shropshire and into the Welsh marshes. 

Just now, Peachy said:

Starting to look very interesting from Saturday afternoon into late on Sunday for anyone fortunate enough to be living in the west Midlands and Shropshire and into the Welsh marches

 

[damianslaw]

One thing I look out for is a sudden stirring of wind, often heralds arrival if a downpour.

Convective thunderstorms rather than frontal are notoriously diificult to predict.

We will have enough heat to trigger them, but lots of other factors.

As always a case, look at the sky and see where any large towering dark clouds are building.

In classic situations yesteryear I would look to the SW and the ominous dark grey marching its way towards me, then the heavens open, often happened around the 4-5pm mark, peak heat.