Storms and Convective discussion - June 2023

[Scuba steve]

In Lincolnshire for a wedding at the weekend  might be interesting 

[CoventryWeather]

Got some interesting weather again popping up at 120 hours on the UKV, with the risk of SB showers across the Midlands on Saturday, and a few elevated ones in the south early Saturday. 

One question I need to ask: what are the key features that allow severe storms to develop - I know DLS (in excess of 30knots) and high levels of Cape (+1000J), but what else impacts development of storms? Thanks in advance for any answers!

[Tamsin]

1 minute ago, CoventryWeather said:

Got some interesting weather again popping up at 120 hours on the UKV, with the risk of SB showers across the Midlands on Saturday, and a few elevated ones in the south early Saturday. 

One question I need to ask: what are the key features that allow severe storms to develop - I know DLS (in excess of 30knots) and high levels of Cape (+1000J), but what else impacts development of storms? Thanks in advance for any answers!

I don't know but I reckon cold air aloft seems to make a difference.  I would look into that storm on 23rd October last year in the southeast.  Daytime temperatures in the mid teens yet still severe gusts and very very frequent lightning.  Can't imagine the CAPE values were very high

[Guest]

19 minutes ago, LightningLover said:

15z UKV showing the very first tentative hints of elevated thunderstorm potential early hours of Saturday...

This is not a good setup! Would be perfectly timed to leave a bunch of decaying mid level cloud during Saturday wrecking the warmth and convective potential. 

[LightningLover]

29 minutes ago, Alderc said:

This is not a good setup! Would be perfectly timed to leave a bunch of decaying mid level cloud during Saturday wrecking the warmth and convective potential. 

Haha, I didn't say it was and you're certainly right! Just scrounging for crumbs after a remarkably quiet start to the season for these parts! Anything that's at the back end of a 15z UKV run is subject to lots of change anyway, I was just interested in the signal.

[Eagle Eye]

 

1 hour ago, CoventryWeather said:

Got some interesting weather again popping up at 120 hours on the UKV, with the risk of SB showers across the Midlands on Saturday, and a few elevated ones in the south early Saturday. 

One question I need to ask: what are the key features that allow severe storms to develop - I know DLS (in excess of 30knots) and high levels of Cape (+1000J), but what else impacts development of storms? Thanks in advance for any answers!

Dewpoint being high with good moisture levels is a good start for severe storms. Specifically talking severe hail then you would want a Supercell normally, which has the straight DLS on a hodograph. Weak LLS and strong DLS with inflow straight and in a C shape with the storm relative inflow and the LLS. Also requires significant below 0 CAPE and typically long parcel time length spent in favourable conditions. Also need cold air aloft and strong lapse-rates. Similar to non-Supercellular severe hail except the conditions need to be even more favourable. For severe squall lines, significant forcing is typically needed and large entrainment CAPE. Large values of 3CAPE also contribute to severe storm producers.

Typical Supercell hodograph.

Vs typical severe hail Supercellular mode.

  

Edited June 5, 2023 by Eagle Eye

[Flash bang flash bang etc]

4 minutes ago, Eagle Eye said:

1.  

Dewpoint being high with good moisture levels is a good start for severe storms. Specifically talking severe hail then you would want a Supercell normally, which has the straight DLS on a hodograph. Weak LLS and strong DLS with inflow straight and in a C shape with the storm relative inflow and the LLS. Also requires significant below 0 CAPE and typically long parcel time length spent in favourable conditions. Also need cold air aloft and strong lapse-rates. Similar to non-Supercellular severe hail except the conditions need to be even more favourable. For severe squall lines, significant forcing is typically needed and large entrainment CAPE. Large values of 3CAPE also contribute to severe storm producers.

Typical Supercell hodograph.

Vs typical severe hail Supercellular mode.

  

I put this into Google translate and it said “”

Can you explain 3CAPE for me? Figured I had a a lot of it figured out but posts like this always throw new terms at me and there’s always a lot more to learn

[Allseasons-Si]

Just put next Monday's Holiday in just in case i have to pull an all nighter on Sunday evening/night as i would of been up at 5:am

glad to see some potential next weekend and to be firmed up over the coming days.

Edited June 5, 2023 by Allseasons-si

[Eagle Eye]

1 hour ago, Flash bang flash bang etc said:

I put this into Google translate and it said “”

Can you explain 3CAPE for me? Figured I had a a lot of it figured out but posts like this always throw new terms at me and there’s always a lot more to learn

It's just simply the 0-3 km AGL mixed-layer CAPE, typically more than 40-50 j/kg is a sign that we're getting close to that severe category. Take the latest GFS for Saturday in the south east, marginally severe thunderstorms possible with large CAPE but that shear doesn't really suggest any hail or tornadogenesis possible but strong 3CAPE based off the forecast, shows adequate low-level instability for severe thunderstorms. This is likely the GFS being overly unstable for now but we are getting very close to Saturday and it's still showing signs of that strong instability and the background factors appear to support this strong instability fairly well for now.

Edited June 5, 2023 by Eagle Eye

[Flash bang flash bang etc]

9 hours ago, Eagle Eye said:

It's just simply the 0-3 km AGL mixed-layer CAPE, typically more than 40-50 j/kg is a sign that we're getting close to that severe category. Take the latest GFS for Saturday in the south east, marginally severe thunderstorms possible with large CAPE but that shear doesn't really suggest any hail or tornadogenesis possible but strong 3CAPE based off the forecast, shows adequate low-level instability for severe thunderstorms. This is likely the GFS being overly unstable for now but we are getting very close to Saturday and it's still showing signs of that strong instability and the background factors appear to support this strong instability fairly well for now.

This makes good sense now, thank you

[legritter]

Hi gang , good luck for all looking for Storms  this weekend .Not posted lately but I've been a lurking and yes sausage baps are still on the menu cheers gang . 

[CoventryWeather]

I'm shocked at how quiet it is, considering the ECM this morning shows 4 consecutive days and nights of storms! 

Most likely gone by tonight, but the risk of convective weather seems to be increasing. 

A couple of the ECM charts below, courtesy of Windy.com

[Guest]

I’m assuming majority of energy release is from the mid levels as current GFS has almost zero surface based CAPE until Sunday. Be honest to me it looks like decaying showery ruining the weekend and delivery more clag in places. 

[ChannelThunder]

1 hour ago, Alderc said:

I’m assuming majority of energy release is from the mid levels as current GFS has almost zero surface based CAPE until Sunday. Be honest to me it looks like decaying showery ruining the weekend and delivery more clag in places. 

Yep, all mid-level energy:

Coinciding with a nice fall in pressure and an increase in uppers:


 

[Eagle Eye]

4 hours ago, Alderc said:

I’m assuming majority of energy release is from the mid levels as current GFS has almost zero surface based CAPE until Sunday. Be honest to me it looks like decaying showery ruining the weekend and delivery more clag in places. 

Wouldn't be surprised if that happened but we'll have to keep an eye on the saturation. I think Saturday/Sunday will be the biggest storm risk as the saturated layers clear and the surface based CAPE can form and with the large bouyancy in place, any clearance will allow very quick energy release and deep pulse-type convection assuming current forecasts are correct.

[Eagle Eye]

Can I order more of the ICON-EU please?

[alexisj9]

20 minutes ago, Eagle Eye said:

Can I order more of the ICON-EU please?

As long as it stops missing Dover lol 

[ChannelThunder]

Great to finally have one of these 'Deep Dives' from the MO that goes into stormy stuff, even skew-Ts!
 

 

[Rufus Butterfield]

3 minutes ago, ResonantChannelThunder said:

Great to finally have one of these 'Deep Dives' from the MO that goes into stormy stuff, even skew-Ts!
 

 

Actually helped me understand what skew-Ts were!

[ChannelThunder]

2 minutes ago, Rufus Butterfield said:

Actually helped me understand what skew-Ts were!

I used to struggle to understand them too - I'm still far from perfect tbh! The simpler the explanation, the better!

[Eagle Eye]

17 hours ago, Eagle Eye said:

It's just simply the 0-3 km AGL mixed-layer CAPE, typically more than 40-50 j/kg is a sign that we're getting close to that severe category. 

216 J/KG? That's well into the severe category. All for fun of course at the moment but wow.

Edited June 6, 2023 by Eagle Eye

[viking_smb]

3 hours ago, ResonantChannelThunder said:

I used to struggle to understand them too - I'm still far from perfect tbh! The simpler the explanation, the better!

I'm glad aidan managed to explain them so happy now

[ChannelThunder]

My one response to the UKV for midnight Saturday night is: bank.

Shame it'll probably disappear completely from the next run!

[lassie23]

had all my thunder in april

[lassie23]

4 hours ago, ResonantChannelThunder said:

Great to finally have one of these 'Deep Dives' from the MO that goes into stormy stuff, even skew-Ts!
 

 

I'm glad they are only given 3 minutes on TV lol