Convective/Storm Discussion Thread - 19th May 2018 onwards

[LightningLover]

Just now, Windblade said:

Well, my newly adopted pessimistic approach to storm forecasts seems to be working, so I'll keep it up in the hope of more storms!

Still no storms this year here in Hastings 

[Tom dewey likes thunder]

There couple lighting dots near a24 east England on real lighting maps

[Hodgheg]

Still some great convection behind the main lot 

[Hodgheg]

A final photo to end off the day

[Biggin]

over 2 hours ago  one of the loudest thunderclaps I have heard. Was miles away over London but crazily loud.

[Mokidugway]

Distant thunder heard possibly over north Lancashire or a plane , not shure 

 

[Hodgheg]

Looks like that last tower in my pic is producing lightning now. 

[Nick F]

12 minutes ago, Biggin said:

over 2 hours ago  one of the loudest thunderclaps I have heard. Was miles away over London but crazily loud.

Probably the CG that hit something very close to where I live near Addiscombe (Croydon) was watering plants about 6pm and saw it out the corner of my eye, followed by a huge bang that set car alarms off. Was almost continuous thunder at one point, mostly from IC lightning, with occasional CGs, was an unexpectedly active cell thunder wise, though high based with a crap structure.

[East_England_Stormchaser91]

Not a bad day for some! Could see some of the towers that gave southern areas the storms today. They looked pretty impressive from 80 miles north. 

Eyes are now shifting to the Belgian coast, quite a decent storm passing near Brugge heading WNW about to exit into the North Sea! 

[convector]

Didn't see much today besides cloudscapes this evening. Looks like they'll be plenty of opportunities however, the 12z gfs keeps instability around for the entire rest of the month. 

[East_England_Stormchaser91]

11 minutes ago, convector said:

Didn't see much today besides cloudscapes this evening. Looks like they'll be plenty of opportunities however, the 12z gfs keeps instability around for the entire rest of the month. 

I honestly can’t remember seeing such a sustained convective window. It’s not like it’s skinny typical UK CAPE either that’s the thing! But proper continental stuff, some of the values in these outputs are up there with the US Midwest. -9 to -10 LI and even some -14’s the other side of the channel, going on for up to 5 days on the bounce or more, and all being steered this way going by the upper 500hpa flow! 

Very exciting times ahead. Could be a wild bank holiday weekend! 

[Harry]

As has been said above the charts for this weekend (bit far out at the moment though) are insane!!! Decent enough potential across S-UK this week for similar kinds of storms has we saw today - small, discreet but very potent! From Friday onwards though the potential skyrockets. Let’s go hope he conditions come to fruition. 5-7 days out not ideal.

Cant resist sharing - terms and conditions apply! All chart grabs are 18z each day starting Friday

Edited May 21, 2018 by Harry

[SarahWxm]

View from my back garden in Wrexham from west to east. Sky is black ink dark to the east and gone noticeably cooler and windier the last couple of hours. Nothing showing on radar though! 

[poseidon]

Some sferics getting closer to the East Anglia coast. Will it survive the crossing though?

[Summer Sun]

http://www.convectiveweather.co.uk/forecast.php?date=2018-05-22Day 2 Convective Outlook

VALID 06:00 UTC Tue 22 May 2018 - 05:59 UTC Wed 23 May 2018

ISSUED 20:22 UTC Mon 21 May 2018

ISSUED BY: Dan

Upper forcing will be weaker on Tuesday compared with Monday, with forecast profiles generally warmer and drier as a result. This will largely limit any deep convection to those areas where pronounced sea breeze convergence can develop, or orographic forcing can play a role, hence LOW threat levels issued generally for coastal counties. A few isolated heavy showers / weak thunderstorms may develop during the afternoon and early evening hours in response to diurnal heating and low-level convergence, the mean upper flow then steering these showers to the S or SW.

A low-end SLGT has been issued to better highlight the area with the best multi-model consensus - though some uncertainty as to how electrically-active such cells will be (assuming they do develop) given very little shear and weaker instability than on Monday. Dorset is another area where there is some limited multi-model support.

 

There is also potential for elements of elevated convection from mid-level instability over East Anglia and SE England, both early Tuesday and again on Tuesday night into early Wednesday.

 

http://www.convectiveweather.co.uk/forecast.php?date=2018-05-22

[Flash bang flash bang etc]

Schoolboy error - went to the hills near farncombe and got a lovely timelpse of the CBS rolling past then realised i’d basically missed the storm that was sliding across the east of Surrey.

jumped in the van but only managed to see the two last bolts over cranleigh and the whole thing shut off after that.

if I’d have got there moments earlier might have caught something...

At least plenty more chances to come - need to free up space on my phone anyway!

[Biggin]

25 minutes ago, Harry said:

As has been said above the charts for this weekend (bit far out at the moment though) are insane!!! Decent enough potential across S-UK this week for similar kinds of storms has we saw today - small, discreet but very potent! From Friday onwards though the potential skyrockets. Let’s go hope he conditions come to fruition. 5-7 days out not ideal.

Cant resist sharing - terms and conditions apply! All chart grabs are 18z each day starting Friday

Nice one H 

[Nick F]

Time lapse of the cells that went up and produced a thunderstorm over SE London early evening, quite high-based.

 

[Wilxy]

Elevated convection moving across kent currently with strikes detected!

[Thunderstruck]

Small storm appeared just across the Thames from me. Eyes and ears peeled but nothing so far...

Edited May 21, 2018 by Thunderstruck

[Flash bang flash bang etc]

the London cell (closer than it looked!)

[Thunderstruck]

Looks like that Kent Cell is dying. Hasn’t put out anything for a little while. That’s two storms in about 3 weeks that have come close but not close enough. Hopefully I’ll get my first rumble in 2018 soon, we’re already two days behind last year! 

[Flash bang flash bang etc]

Is this elevated convection safe from nocturnal cooling? Or is it likely to peter out completely by midnight?

[Nick F]

Storm & Convective Forecast

Issued 2018-05-21 21:54:04
Valid: 21/05/2018 00z - 22/05/2018 00z

THUNDERSTORM OUTLOOK - DAY 1 TUES 21 MAY 2018

Synopsis

Upper level high over Scandinavia will retreat east across western Russia on Tuesday, meanwhile an upper ridge will build NE across the far west of British Isles and NE Atlantic. Weakness in the geopoential height field across S England and subtly lower surface pressure towards near continent combined with surface convergence will support the development of scattered thundery showers on Tuesday across southern Britain.

... S and SE ENGLAND, W MIDLANDS and SE WALES ...

Elevated instability drifting out of Belgium Monday night may support scattered heavy and perhaps thundery showers, with some lightning, pushing over the south N Sea in across parts of SE England and E Anglia early on Tuesday, before activity wanes as by mid-morning.

Then, with heights rising as upper level ridge builds NE across N and W Britain on Tuesday, thunderstorms will be less widespread than Monday with the risk generally confined to S England - where subtly cooler air aloft, higher temperatures and more abundant moisture will produce steeper lapse rates and most unstable airmass. Models indicate modest CAPE values during peak heating in the afternoon of around 400-800 j/kg - which will support isolated thunderstorms which will likely be triggered by surface breeze convergence and some orographic influence. With weak flow aloft - no severe weather is anticipated, any storms will be slow-moving and will drift towards the S or SW, with the main risk being locally high rainfall totals leading to surface water flooding. Some hail is also possible. 

Issued by Netweather here: https://www.netweather.tv/weather-forecasts/uk/convective

 

[NO LONGER POSTING]

We got very lucky yesterday in my part of Surrey, we never got a direct hit but 2 thunderstorms pass near enough to see the lightning and one strike that was Cloud to ground apparently has blown the power out in a car wash in Chertsey. 

Fantastic day yesterday all in all 

This is first much further away but still watched it grow from nothing to a mature thunderstorm 

The second one was much harder to photo because we were almost right under it but the lightning and thunder was absolutely epic!