Storms and Convective discussion - September 2023

[Sprites]

2 hours ago, Zak M said:

Some fantastic lightning to my SE a few hours ago. Really happy with these shots considering how far the storms were

   

Was this about 20.00 ? 

[Eagle Eye]

Stuff from yesterday evening. 

Timelapses

     

 

 

 

Photos

Edited September 23, 2023 by Eagle Eye

[Zak M]

11 hours ago, Sprites said:

Was this about 20.00 ? 

Around that yes

[Flash bang flash bang etc]

Well looks like the U.K. storm season started and ended last week for the south  

[sunnijim]

Warnings issued for Wednesday SW England,Wales and Ireland together with Northern England and Scotland.

Likely to be named soon I would imagine

[CoventryWeather]

Most of the talk recently has been about the likely named storm for midweek. However, the UKV and other models show the risk of thundery showers early Tuesday, not too sure if the atmosphere is unstable or not, but seems like perhaps there is still a chance of a small 'plume', if that is what you call it. Mainly East Anglia and the SE, but models have it much further west (Arpege has it in Cornwall and NEwards). Charts below. 

[matty40s]

4 hours ago, sunnijim said:

Warnings issued for Wednesday SW England,Wales and Ireland together with Northern England and Scotland.

Likely to be named soon I would imagine

Next in the list is a Gaelic name,  Morebleedinrain I think.

[NL]

I'm surprised nobody has mentioned ESTOFEX as they have issued a level1 threat of severe wind gusts and Tornado threat across Ireland, Northern England and Scotland for this evening/overnight.

DISCUSSION

... Ireland to N England and S Scotland ...

A sharp short-wave trough is forecast to cross the area in the evening to night hours. Strong synoptic-scale lift and drop in the 500 hPa temperature will result in a pocket of steeper mid-tropospheric lapse rates and marginal CAPE. At first, CAPE will be elevated with some embedded showers or weak thunderstorms embedded in the main stratiform rain shield. At and behind the cold front, strongly forced linear segments may form with surface-based CAPE. Strongly sheared environment with 0-1 km bulk shear reaching 15 m/s will yield isolated severe wind gust and tornado threat.

European Storm Forecast Experiment - ESTOFEX

WWW.ESTOFEX.ORG

 

Edited September 24, 2023 by NL
spelling

[Allseasons-Si]

47 minutes ago, NL said:

I'm surprised nobody has mentioned ESTOFEX as they have issued a level1 threat of severe wind gusts and Tornado threat across Ireland, Northern England and Scotland for this evening/overnight.

DISCUSSION

... Ireland to N England and S Scotland ...

A sharp short-wave trough is forecast to cross the area in the evening to night hours. Strong synoptic-scale lift and drop in the 500 hPa temperature will result in a pocket of steeper mid-tropospheric lapse rates and marginal CAPE. At first, CAPE will be elevated with some embedded showers or weak thunderstorms embedded in the main stratiform rain shield. At and behind the cold front, strongly forced linear segments may form with surface-based CAPE. Strongly sheared environment with 0-1 km bulk shear reaching 15 m/s will yield isolated severe wind gust and tornado threat.

European Storm Forecast Experiment - ESTOFEX

WWW.ESTOFEX.ORG

 

And Torro are on the same page...

The Tornado and Storm Research Organisation (TORRO)

WWW.TORRO.ORG.UK

---

TORRO is a privately-supported research body specialising in severe convective weather in Britain and Ireland

 

[matty40s]

4 hours ago, NL said:

I'm surprised nobody has mentioned ESTOFEX as they have

Actually, I did first thing this morning, but not on here!!

I sent my brother in Western Bulgaria a warning for their level 2 storms and large hail.

[Flash bang flash bang etc]

Tomo looking to have potential in the south

[Metwatch]

Amazing timing with the lightning there, a dream of mine to do something similar.

Popped on my feed a few days ago, looks to have been somewhere in Mongolia, during July this year. 

[Flash bang flash bang etc]

5 hours ago, Metwatch said:

Amazing timing with the lightning there, a dream of mine to do something similar.

Popped on my feed a few days ago, looks to have been somewhere in Mongolia, during July this year. 

I tried something like this, fell over

[Flash bang flash bang etc]

Nick F storm forecast for tomo:

 

Longwave upper trough extends south over the N Atlantic from Greenland and Iceland to the west of UK and Ireland on Tuesday. A surface low will be slow-moving to the south of Iceland, a cold front will move eastward across Ireland and UK through the day, lying across W Scotland, Wales and SW England at noon then N Sea and Low Countries at midnight.

Ahead of the cold front, the nose of 14-16C theta-w plume will push in across SE England / E Anglia through the morning. An area of elevated instability looks to develop on the northern extent of the plume across S England and E Anglia during the morning, as a shortwave trough moving in from the Atlantic moves NE creating lift of the northern edge of the plume and steepening lapse rates. This will support the development of heavy showers and perhaps some elevated thunderstorms moving NE over these areas through the morning and into the early afternoon.

Cold front across the west of mainland Britain at noon before moving east across the UK through the afternoon will also produce some convection, thanks to forced ascent of warm moist conveyor ahead of front, with a risk of isolated thunderstorms embedded in band of showery rain along front. Heavy showers and a few thunderstorms may also develop across Ireland, Irish Sea coastal areas and SW Scotland in post-frontal airmass characterised by colder upper air / steep lapse rates.

[Eagle Eye]

Convective Outlook  (meant to say brief, isolated tornadoes on map)

Along a cold front, a squall line looks fairly likely to set up Approaching Ireland and Scotland by around mid morning with widespread 90 KM/H+ winds along the cold front bringing squally winds and rain. Strong winds and heavy rainfall look to be the main severe threats.

As the morning gets on, the lift will increase along the south of England and along the squall line. So showers form and move through the central south and southeast of England in areas with 75+ J/KG of 3CAPE for some sunrise showers to form and move north east into the early afternoon potentially. This occurring along a shortwave trough, may bring the risk of some weak flooding with it.

The Irish risk continues on into S/SW Scotland with 150+ J/KG of 3CAPE along the squall line and 35+ knots of LLS. Large amounts of that momentum is shifted downwards and that may transfer into stretching the surface streeamwise vorticity. This may transfer into a local increase of the LLJ in certain areas, for some rotation along spots of increased vorticity. So some brief spin up tornadoes are possible.

Most energy looks to be transferred downward so the spin up tornadoes and strong wind gusts are fairly potential risks along the squall line. Mainly in the slight risk areas where squall line intensity and potentially lightning frequency looks to be increased. Eventually, the cold front weakens as it moves through Northern England and Scotland mid afternoon and lifts north, significantly weakening to essentially nothing by the evening.

[WeatherArc]

Just come across this good vid from the severe thunderstorm outbreak we had 2 weeks ago, i believe this was the storm near Holbeach, absolute insane shelf on that thing 

Sounds like continuous thunder as well, quite rare for the uk and indicative of a very powerful storm. 

Edited September 25, 2023 by WeatherArc

[WeatherArc]

 

[StormLoser]

55 minutes ago, WeatherArc said:

Just come across this good vid from the severe thunderstorm outbreak we had 2 weeks ago, i believe this was the storm near Holbeach, absolute insane shelf on that thing 

Sounds like continuous thunder as well, quite rare for the uk and indicative of a very powerful storm. 

That is just awesome!!

Estofex looking good for parts of the UK tomorrow! A Level 1 for some of us.

[Rufus Butterfield]

57 minutes ago, WeatherArc said:

Just come across this good vid from the severe thunderstorm outbreak we had 2 weeks ago, i believe this was the storm near Holbeach, absolute insane shelf on that thing 

Sounds like continuous thunder as well, quite rare for the uk and indicative of a very powerful storm. 

That does not look out of place in the Great Plains 

[Flash bang flash bang etc]

53 minutes ago, WeatherArc said:

 

I like this - but it did make me go on Twitter which I’m trying to avoid. But thanks for posting

[ChannelThunder]

Little pockets of mid-level instability around this morning as the 'mini-plume' makes its way in. Also notably warm as I left for an office day earlier!

[WeatherArc]

Didn't expect this today, just had two massive CCs directly over me!

[LiamC]

1 hour ago, WeatherArc said:

Didn't expect this today, just had two massive CCs directly over me!

Same here in Long Eaton. Had some really intense heavy rain here, still going, and just had a big flash of lightning and thunder to my east.

[Flash bang flash bang etc]

1 hour ago, LiamC said:

Same here in Long Eaton. Had some really intense heavy rain here, still going, and just had a big flash of lightning and thunder to my east.

Squall line setting up

[Windblade]

11 hours ago, WeatherArc said:

Just come across this good vid from the severe thunderstorm outbreak we had 2 weeks ago, i believe this was the storm near Holbeach, absolute insane shelf on that thing 

Sounds like continuous thunder as well, quite rare for the uk and indicative of a very powerful storm. 

Incredible. I would've loved to have been there to see that. 

Usual bright and sunny here. However, forecast was for potential late morning/early afternoon so will see if anything develops.