Storms and Convective discussion - 25th July 2021 onwards

[philglossop]

Best photo I’ve seen so far! 

[biddie]

11 minutes ago, philglossop said:

Best photo I’ve seen so far! 

Looks like night!!

[philglossop]

3 minutes ago, biddie said:

Looks like night!!

It was! Now it’s brightening up a bit.

[beckyonsea]

Are we likely to get any in Somerset? 

[Guest]

11 minutes ago, beckyonsea said:

Are we likely to get any in Somerset? 

Nope

[Mapantz]

Quite a few models have ditched the idea of anything tonight.

The latest forecast even shows it to be dry here.

Edited September 8, 2021 by Mapantz

[Eagle Eye]

Keeping a small eye on this. 

[philglossop]

2 hrs and I think we’re over the worst. That was a cracking storm, loads of backfilling from SE and the storm caused some amazing lightning ️ even at ground level.

It’s led to flash flooding across the City and at least 1 school has been hit we think. Took out our PCs - never heard thunder so loud even under cover I was ducking!!! 
 

Thank goodness the muggyness has gone over. 

[Eagle Eye]

On 08/09/2021 at 11:21, philglossop said:

2 hrs and I think we’re over the worst. That was a cracking storm, loads of backfilling from SE and the storm caused some amazing lightning ️ even at ground level.

It’s led to flash flooding across the City and at least 1 school has been hit we think. Took out our PCs - never heard thunder so loud even under cover I was ducking!!! 
 

Thank goodness the muggyness has gone over. 

Now I want the Storms to come later when I'm at home and safe, I'm still holding out nope because there is a lot going on already in France. 

[BrickFielder]

Wind flow Changes
For much of Wednesday the low level air flow towards the UK looks like being sourced from the Meditteranean rather than across Spain. Air from this direction tends to be very dry in contrast to the mid level elevated warmth sourced from across Spain. So we have a Spanish plume undercut by dry North African air which will limit storm development over France until later when more Atlantic maritime Air gets mixed in at the lower level. Key to what happens overnight will be the low level wind convergence zone over France or not.

 

Wednesday Day Time Storm Outlook.
Satellite imagery shows MCS developed over Northern France is being Steered towards the southwest of the UK. This is likely to affect the South West for the next 3 hours and poses a risk of localized flooding. Estofex forecast warns of excessive rain fall with forecast moisture profiles showing very moist air aloft. I think i would go along with that as a prime risk along with lightning.

Wednesday Night Thursday Early Morning Storm Outlook.
Modelling suggests that Storms will develop over Northern France and move towards the UK overnight. The exact timing and positioning is a bit mixed in the models. Lightning wizard modelling suggests SuperCells and Tornadoes might be possible across France this afternoon, yet Estofex forecasters are not convinced. Having looked at the Satellite both visible and Infra Red then I think I would side with the Estofex Forecasters.

Estofex

Quote

that will cross the U.K., France, and parts of N Spain. Along the boundary, abundant lower-tropospheric moisture will contribute to MUCAPE values ranging from 500 to 1500 J/kg, increasing towards the south. More widespread initiation is forecast during the day and the storms will spread eastward. In the environment of skinny CAPE, low LCLs, and storm motions parallel to the frontal boundary, the primary threat across France will be excessive rainfall.

 

The risk is very heavy rain and a significant lightning show over night for the southern half of the UK. Timing is key and storms could be surface based up to around midnight although I have a suspicion MCS conditions might cool things to change that. Tricky to forecast and we need to watch France this afternoon. Modelling output is likely to swap and change.

 

Thursday afternoon Storm Outlook.
Generally speaking the storm threat moves North to cover North Wales, North Midlands and Northern England. There is however some suggestion of a low level wind convergence over the south west which could spark showers which build and develop as they move North East.  At this point I don't think we can rule out Storms just about anywhere but what does catch my eye is a possible upper level feature crossing which might bring slightly drier air aloft.

Temperatures will mean that some moderately severe storms are possible but the greatest risk appears to be hail and localized flooding with a possibly a lightning show for some overnight. Confidence is pretty low on exact evolution of things but still worth pointing out possible features.

 

[OddSpot]

Some great pictures and some video on the Plymouth Herald site including the one posted earlier

 

The one titled Lightning strike from the sea is good 

 

 

Thunder and lightning hits Plymouth as Met Office weather warning in place - live updates - Plymouth Live

WWW.PLYMOUTHHERALD.CO.UK

---

The Met Office has issued a yellow weather warning for thunderstorms cover much of the South West, including Plymouth

 

Edited September 8, 2021 by OddSpot

[Harry]

2 hours ago, philglossop said:

So this is what an MCS is like! 
 

It’s horrendous frequent lightning and heavy rain. 
 

All lads off street! 

Awesome aren’t they!?!?!? Your excitement is infectious I have to say. Blistering sunshine and heat here - slim chance I might get some action later

[Super_Uwe]

Looking out to sea in Salcombe with the South Sands Ferry in view. 

Ridiculously humid. Not expecting much else now though but you never know...

[ChannelThunder]

As mentioned earlier, models are a lot less keen than they were. AROME still has some interest if you're in the Sussex area tonight

[Guest]

I think I counted 7 drops of rain from that convective waste of time.

[ChannelThunder]

You can see the heaviest radar returns propagating eastwards with time. Game over for anywhere west of Selsy Bill I'd say, not that there ever was much of a game with this disappointing late season plume.

[Ceejay]

I kinda feel for you guys but we've been storm-starved in the West Country for what seems like years, so this morning was actually moderately exciting!

[ChannelThunder]

On 08/09/2021 at 15:03, Ceejay said:

I kinda feel for you guys but we've been storm-starved in the West Country for what seems like years, so this morning was actually moderately exciting!

Happy for you guys down there. Just need to get the far tip of Cornwall some storms now! 

 

[tomp456]

The AROME model was interested in the idea of storms over Sussex late evening / overnight. 

Can't see it happening myself! 

 

 

[Eagle Eye]

Wish that lot over Central France  was going our way but still a while for storms to initiate and/or strengthen. 

[Biggin]

The stuff moving out of Le Havre makes it about halfway across the channel then dying atm.

But there is a marked movement eastward  of the  storm now.

Xtra has is making landfall to the west of Brighton aroud 6 ish

Edited September 8, 2021 by Biggin

[sheikhy]

Latest ukv now is back to the forecast from earlier on breaks out storms across central england tonight and then heading north into northern england!!!

[BrickFielder]

MCS developing over Central France with Orange (Moderately Severe) Storm warnings for that part of France. Best guess is that this trundles North through parts of England late evening and into the early hours. Likely to give a deluge of rain and lightning show in some places. Since this is an MCS (Big blob of Storms) then storm like conditions might persist for some time. Somewhere between Exeter and Kent is likely to be the landing point although I should point out some models kill the storms over the channel.

We have to wait and see.

[Allseasons-Si]

The Brest peninsular is showing some sferics now 

[Dorsetbred]

2 hours ago, Alderc said:

I think I counted 7 drops of rain from that convective waste of time.

We got more than you in Poole, we got 16!