Storms and Convective discussion - 16th June 2021 onwards

[karyo]

Scattered towers to the west of London now. Regardless of whether they lead to a storm or not, at least they are nice to look at. I got bored of the empty skies of the last week.

[Petorious]

Plenty of cloud bubbling up all over the place today and very quickly, will the maintain or will they fold flat as quick as they went up? Guess we shall need to wait and see..

[Tn9]

38 minutes ago, Petorious said:

Plenty of cloud bubbling up all over the place today and very quickly, will the maintain or will they fold flat as quick as they went up? Guess we shall need to wait and see..

Yea this is just south of Chatham ,over the downs I guess ...

[Ciderwithrosie]

Cloud suddenly popped up here in very sunny Somerset but 30C still. 

I suspect just temporary cloud but we shall see.  

[Tn9]

11 minutes ago, TN9 said:

Yea this is just south of Chatham ,over the downs I guess ...

Proper bubbling up though ..vigorous even ,but they could fade just as quick I guess 

[Ben Sainsbury]

First shallow radar returns SE of Reigate, still further heating expected so potential is there later.

AROME 6z has timed initiation well, and forecasts isolated thunderstorms across London/SE by 4pm.

Edited July 19, 2021 by Ben Sainsbury

[Harry]

Signs of increasingly robust convection starting to get going. Third image is the area possibly towards Reigate way I believe.

[Jamie M]

1 hour ago, Chris Lea-Alex said:

I've noticed today that the convective clouds are leaning to one side. My picture doesn't show it well, but is it in any way advantageous for them to lean?

 

Indication of the strong shear present (20kt ish) which in theory should help a storm to sustain further because the updraft/downdraft can separate from each other. Although, it can just rip these developing showers apart if its too strong.

[Jamie M]

Bloody hell that was a bit quick

[Newben76]

Looking South East towards East Grinstead from Reigate. 

[Petorious]

1 minute ago, Newben76 said:

Looking South East towards East Grinstead from Reigate. 

Wow that was very quick, fingers crossed we may get something for southern midlands.

[Stormhog]

One tower has just shot up on satellite south of London. Heavy rain in a very localised area on radar, making a beeline straight for me in Hailsham :)

[Sparkiee storm]

That SE storm looks very intense already and developed in 15 - 20 mins.

Also wonder how big the potential is for the Midlands and Home counties overnight, as CW mentioned additional showers could develop here.

[Jamie M]

I suspect @Eagle Eye is a happy bunny right now!

[staplehurst]

12z Herstmonceux sounding modified for 28C air temp with a dew point of 18C. Profile suggests 28C is required for deep convection to occur from the surface, which we've now achieved across SE England (locally 30C in the London area). Aside from the moist layer between 780-850mb (probably due to continued attempts at convective cloud so far today helping to moisten the layers), the profile is very dry with evidence of the dry, sinking air aloft characteristic of high pressure.

This will mean it's a bit of a tug of war going on in the vertical - air trying to rapidly rise from the surface, while also experience sinking aloft attempting to suppress it. So we are heavily reliant on strong forcing from the surface (sea breeze convergence aided with lift over the Downs etc) to get convective cloud to grow tall enough for heavy rain/lightning etc. Impressive SBCAPE of 1,600 J/kg, however this doesn't necessarily mean much if convective cloud is unable to use the whole profile (other than fast updraft speeds, at least initially). Evidence of some directional and speed shear, with 30kts 0-6km, which will help separate updrafts from downdrafts and enable cells to potentially last sometime - subject to them not being overcome by the very dry air aloft.

Fairly slow storm motion of 12kts could result in some local flash flooding, and if cells can be sustained and utilise this magnitude of CAPE then some marginally-severe/large hail will be possible. High cloud bases due to the deep mixing of the boundary layer, with bases around 4,000ft, but the inverted-V profile beneath the cloud bases could allow some rather gusty winds to develop.

[Sparkiee storm]

Development in SE Wales too.

[Ben Sainsbury]

3 minutes ago, Sparkiee storm said:

Development in SE Wales too.

I have a cracking view from my window, unfortunately struggling to reach sufficient height atm.

[Nick F]

Looking from the north here in Caterham on the North Downs at the storm over East Sussex 

[MP-R]

8 minutes ago, Sparkiee storm said:

Development in SE Wales too.

Can see some convection that way from here.

 

[Atmogenic]

Got a thundery cell in ashford, getting rumbling thunder from time to time

Edited July 19, 2021 by Atmogenic

[dr weather]

 

This is the cell which is currently over SE Wales. 

 

[shogan83]

Yeah Down in Winchelsea beach , East Sussex, at the in laws caravan.  Can see the convection from the storm north of here 

[alr1970]

6 minutes ago, Atmogenic said:

edit: strange the video is unable to play for me

You can't drop videos into a post like you can images. Upload it to YouTube and paste the link from there, to get it automatically embedded.

[Karl83]

Photo of the cell that's fired up near Abergavenny..

[Atmogenic]

1 minute ago, alr1970 said:

You can't drop videos into a post like you can images. Upload it to YouTube and paste the link from there, to get it automatically embedded.

Yep will do, just before it would tell u if the file is too big and wouldn’t upload but this it didn’t. I’ll put on youtube later when i’m home