Storms and Convective discussion - August 2023

[Supacell]

Well, what a wet month we have just had. The weather may not be changing at all for the new month but our storm discussion thread is. And so what of the chances through August?

Well, early signs are showing a return to summer but this is a long way off yet. From a storm enthusiasts point of view a return to warmer temperatures, and certainly winds from a more southerly point, are a positive sign as this is a weather pattern that can produce our best thunderstorms.

This Atlantic low pressure chain that we are under can and does produce thunderstorms in the summer months though, this will be the case within the next 24-48 hours.

Where today should stay storm free across most of the UK there is an unseasonably deep area of low pressure approaching from the west and this could bring thunderstorms across Ireland later on this evening before a band of thundery rain moves through England and Wales overnight. Tomorrow then looks like a day of heavy showers and thunderstorms, especially across Central and Southern parts of Wales and England. I will let the more experienced and knowledgeable forecasters look at the specifics but it does look like quite a turbulent day tomorrow for both thundery downpours and strong winds.

Continue discussions in here.

Old thread here:

https://community.netweather.tv/topic/99001-storms-and-convective-discussion-july-2023/

[Dangerous55019]

Morning all.

First post in this new thread, and I see that the U.K. Meto have just issued a yellow thunderstorm warning for tomorrow! 
 

I’ve been too busy to look into the full juicy details, but it’s not often you see a yellow thunderstorm warning along side a yellow wind warning!

As always, fingers crossed for all of us on this.

[Eagle Eye]

Me and Jay to issue our forecast later today . Does look to be a potentially fairly active setup coming up. Not as strong as earlier setups but still could have some good storms come out of the next few days.

[Thunders]

Hopefully later this month we get some good ones. Even a couple of plumes to make up with what a “great” summer we’ve had

[Jamie M]

Let's see how this occurs tomorrow 

[Eagle Eye]

Convective Outlook 

A triple frontal setup from a low pressure provides a few different modes of potential convection setups and lots of rain for some areas. The initial warm front has little energy associated with it as it passes from the SW through to the SE but behind it is a potentially
active cold front spanning from the SW to the NW across to the SE overnight. In Ireland an occluded front may provide some action including as it swings into the NW of England in the
early morning hours.

MUCAPE potentially in excess of 500 J/KG with the most active MUCAPE being 800 J/KG. 22-24°C potential 850's Theta-W advection along the cold front suggests that along the cold
front, elevated thunderstorms could pop up and be quite active despite the moderate CAPE plume. Significant southern Europe'esque moisture with 60+ °C 850's Theta-E shows how
strong the moisture plume of air is. Surprising then that the CAPE is that low given this would normally be a big event.

A long PV maxima from northern France up to Ireland could provide as the forcing mechanism for long lived semi-active thunderstorms and heavy rainfall along the cold front. Though, the weak CAPE weakens that activeness along the front. With strong DLS, an isolated funnel cloud may form and thunderstorms that do form could be long lived with their sparodic lightning. This is very similar to initial Bay Of Biscay troughs even though it isn't. The amount of moisture is a lot so flooding may become an issue. Strong lift and some good MLLR's may allow for some hail.

[donnerundblitzer]

Been a long (ish) lull but a promising forecast tomorrow for a corridor between Cardiff to London particularly

[Thunders]

1 hour ago, donnerundblitzer said:

Been a long (ish) lull but a promising forecast tomorrow for a corridor between Cardiff to London particularly

Looking better than last month

11 hours ago, Jamie M said:

Let's see how this occurs tomorrow 

Wishing that is was a little further to the east as then I would be in the centre of the storm area

[Flash bang flash bang etc]

Tony Gilbert / UKWW not too bullish but an upgraded zone for the afternoon hours through the central south

[Thunders]

26 minutes ago, Flash bang flash bang etc said:

Tony Gilbert / UKWW not too bullish but an upgraded zone for the afternoon hours through the central south

Ohh I’m in the black

[IanT]

43 minutes ago, Flash bang flash bang etc said:

Tony Gilbert / UKWW not too bullish but an upgraded zone for the afternoon hours through the central south

Can you post a link to the source of this please..?

[Sprites]

Not sure how much surface heating there will be today. A lot of cloud around now though. Convergence around the low could be enough to force convection despite lack of sunshine.

 

 

Edited August 2, 2023 by Sprites

[Biggin]

Torrential rain here for 5 mins with small hail.

[Biggin]

2 minutes ago, Biggin said:

Torrential rain here for 5 mins with small hail.

[alexisj9]

37 minutes ago, Sprites said:

Not sure how much surface heating there will be today. A lot of cloud around now though. Convergence around the low could be enough to force convection despite lack of sunshine.

 

 

Where's it cloudy, we have some, but not enough to stop surface heating.

[Eagle Eye]

Convective Outlook 

A low pressure moves through the south bringing strong wind gusts and behind it a few thunderstorms are likely to form in areas of 1,000+ J/KG of SBCAPE. 3CAPE in excess of 100 J/KG suggests some fairly strong storms are possible.

Fairly strong SB buoyancy along slightly increased areas of weak DLS. This suggesting pulse storms but quite tall and therefore some fairly frequent lightning for a time. Near 30,000 feet cloud height is quite good compared to recent weeks but in general terms it's not particularly special.

Inside a deep rooted moisture tongue from previous moisture advection, there lies tall moisture convergence especially in a line along the slight risk. With the strongest PV maxima in that area as well(when thinking height wise rather than just at the PBL depth).

Fairly strong LLLR's mixing with alright buoyancy suggest some small hail possible. This is confirmed with the <0°C CAPE. So small hail, some surface flooding given moisture and strong wind gusts are possible.

Saturation is strong which weakens lightning risk. So we have kept it to a slight risk.

[CoventryWeather]

Bit surprised by how few of the forecasts are showing little in the Midlands. Convergence here could develop a few strong storms I feel, especially later in the afternoon. 

Not having a go, but seemed a little surprised. 

[Flash bang flash bang etc]

1 hour ago, IanT said:

Can you post a link to the source of this please..?

Sorry, you do not have permission for that!

WWW.UKWEATHERWORLD.CO.UK

apologies I figured most ppl already had a link to it.

Along with this site it’s a pretty essential one for U.K. chasers

Sorry, you do not have permission for that!

WWW.UKWEATHERWORLD.CO.UK

WWW.UKWEATHERWORLD.CO.UK

 

something going on with the links

[Flash bang flash bang etc]

May need to go via Google if that doesn’t work - but UKWW usually takes you to the right place. You may need to sign in/ sign up to get to the juicy bits where he posts convective forecasts

1 hour ago, Eagle Eye said:

Convective Outlook 

A low pressure moves through the south bringing strong wind gusts and behind it a few thunderstorms are likely to form in areas of 1,000+ J/KG of SBCAPE. 3CAPE in excess of 100 J/KG suggests some fairly strong storms are possible.

Fairly strong SB buoyancy along slightly increased areas of weak DLS. This suggesting pulse storms but quite tall and therefore some fairly frequent lightning for a time. Near 30,000 feet cloud height is quite good compared to recent weeks but in general terms it's not particularly special.

Inside a deep rooted moisture tongue from previous moisture advection, there lies tall moisture convergence especially in a line along the slight risk. With the strongest PV maxima in that area as well(when thinking height wise rather than just at the PBL depth).

Fairly strong LLLR's mixing with alright buoyancy suggest some small hail possible. This is confirmed with the <0°C CAPE. So small hail, some surface flooding given moisture and strong wind gusts are possible.

Saturation is strong which weakens lightning risk. So we have kept it to a slight risk.

So I’m hopefully done for the day soon … have work to do at home but if need be I can get out locally to see any passing activity

[StormLoser]

Plenty of showers to come, but I'm not holding up much chance of anything unusual here (Reigate - I'm back).  If anything turns up, I'll post!

[Jamie M]

ESTOFEX has the SE in a Level 1 although no particular mention for England in the actual outlook itself as such 

European Storm Forecast Experiment - ESTOFEX

WWW.ESTOFEX.ORG

[alexisj9]

10 minutes ago, Jamie M said:

ESTOFEX has the SE in a Level 1 although no particular mention for England in the actual outlook itself as such 

European Storm Forecast Experiment - ESTOFEX

WWW.ESTOFEX.ORG

I'm not sure I want to be in this specific level one.

[WeatherWatchmanG]

Just a total washout, heavy rain no lightning on the maps. Metoffice has removed that from the forecasting at least for London and only now shows hail at 3pm.

[Mitch the motorbike storm]

I can't see any storms happening tonight unless it's supposed to strengthen 

[Jo-anne]

Still showing a risk here on BBC weather just wondering what that round yellow thing is on the 20th