Convective Storm/Discussion thread - 11/06/16 onwards

[Bolt from the Blue]

Underneath the convergence zone here,  a few heavy downpours but no thunder, great to see some active weather again!

[jtay]

1 hour ago, AIRMET said:

Underneath the convergence zone here,  a few heavy downpours but no thunder, great to see some active weather again!

Thunder here Airmet. Rumbling it's way towards Romsey now, I reckon.

[matt111]

No thunder but a great rainbow just now from the latest shower. 

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Tue 12 Jul 2016 - 05:59 UTC Wed 13 Jul 2016

ISSUED 18:55 UTC Mon 11 Jul 2016

ISSUED BY: Dan

Large upper trough will sit across the British Isles on Tuesday, accompanied by cool mid-levels. Diurnal heating will generate 300-500 Jkg-1 MLCAPE, with scattered showers and a few thunderstorms likely, especially within the SLGT. Areas of low-level wind convergence will provide the main focus for deep convection, in the absence of any notable DLS. Here a couple of brief funnel clouds will be possible. Some small hail is possible from any stronger cells.

Later on Tuesday night, a cold mid/upper level pocket approaches from the NW towards NW Ireland / NW Northern Ireland. An uptick in shower coverage is expected through the early hours of Wednesday, and with steepening lapse rates a low chance exists of some lightning with this convection.

http://www.convectiveweather.co.uk/forecast.php?date=2016-07-12

[Supacell]

For me it has turned very quiet since the end of May and first half of June's remarkable thundery spell. Luckily this spell was so good that even with no more storms for the entire season I will have still beaten such years as 2007, 2009, 2010 and 2011 for the amount of storms I have seen.

A freeze frame from the amazing storm on the 7th June just outside Bedford.

Lets hope for another remarkable thunderstorm spell before the end of summer. Although to be honest a couple of weeks of dry, hot, sunny weather wouldn't go amiss too.

[NO LONGER POSTING]

Showers already sparking in the midlands

[Windblade]

So yesterday about 2.30pm london had a massive downpour which resulted in some minor flooding. Couldn't grab pics as I was driving at the time. No thunder although the radar did show one stirke just to the south west of london. I saw northern east anglia also got in on the action with what looked like a fairly decent storm. 

 

Today, in brixton we have some dark cumulous and towers trying to go up already so I would expect some more heavy showers later (and hopefully some thunder mixed in!).

[Nick F]

Back from being away with a storm forecast for today, given light winds aloft main threat will be flash-flooding from slow-moving storms training along wind shift zone shifting SE across SE England and E Anglia.

Storm & Convective Forecast

Issued 2016-07-12 09:28:53

Valid: 12/07/2016 06z 13/07/2016 06z

CONVECTIVE / STORM FORECAST - TUES 12TH-JULY-2016

Synopsis

Upper trough extends south to Iberia from upper low centred south of Iceland, with deeply cyclonic westerly flow across the UK. Coldest mid-level temperatures and thus steepest lapse rates will be towards SE Britain on Tuesday, so central and eastern counties of England will see the greatest risk of thunderstorms today.

... MIDLANDS, SE ENGLAND and EAST ANGLIA ...

A combination of highest moisture (dew points of 12-13C), highest temperatures (18-20C) and coldest mid-level temperatures will produce greatest instability across the above areas - with 300-600 j/kg forecast to develop this afternoon with surface heating. As a result, heavy showers and thunderstorms will likely develop. Despite lack of vertical wind shear, a wind shift/convergence zone shifting southeast across Thames Valley/E Anglia will organise bands of storms which will be slow-moving given light winds aloft ... so there is risk of prolonged torrential downpours leading to flash-flooding in some places. Therefore have issued a MARGINAL risk for SE England and E Anglia.

A few storms and more heavy showers will continue across the SE and E Anglia into the night, perhaps merging into a longer spell of heavy rain, bringing a continued risk of localised flooding, before rain clears away eastward first thing on Wednesday morning

Issued by: Nick Finnis

Edited July 12, 2016 by Nick F

[Windblade]

1 minute ago, Nick F said:

Back from being away with a storm forecast for today, given light winds aloft main threat will be flash-flooding from slow-moving storms training along wind shift zone shifting SE across SE England and E Anglia.

Storm & Convective Forecast

Issued 2016-07-12 09:28:53

Valid: 12/07/2016 06z 13/07/2016 06z

CONVECTIVE / STORM FORECAST - TUES 12TH-JULY-2016

Synopsis

Upper trough extends south to Iberia from upper low centred south of Iceland, with deeply cyclonic westerly flow across the UK. Coldest mid-level temperatures and thus steepest lapse rates will be towards SE Britain on Tuesday, so central and eastern counties of England will see the greatest risk of thunderstorms today.

... MIDLANDS, SE ENGLAND and EAST ANGLIA ...

A combination of highest moisture (dew points of 12-13C), highest temperatures (18-20C) and coldest mid-level temperatures will produce greastest instability across the above areas - with 300-600 j/kg forecast to develop this afternoon with surface heating. As a result, heavy showers and thunderstorms will likely develop. Despite lack of vertical wind shear, a wind shift/convergence zone shifting southeast across Thames Valley/E Anglia will organise bands of storms which will be slow-moving given light winds aloft ... so there is risk of prolonged torrential downpours leading to flash-flooding in some places. Therefore have issued a MARGINAL risk for SE England and E Anglia.

A few storms and more heavy showers will continue across the SE and E Anglia into the night, perhaps merging into a longer spell of heavy rain, bringing a continued risk of localised flooding, before rain clears away eastward first thing on Wednesday morning

Issued by: Nick Finnis

That's looking good to me! Fingers crossed.

Edited July 12, 2016 by Windblade

[Windblade]

Things bubbling up very nicely here.

[Dami]

Cloud and lots of it from the word go, sun was out for a bit and it felt very warm even if it's only to reach 20c ish today. Had a couple of showers, one just wet the ground, the other left a pool in one our garden chairs. Thankfully they missed bubs sports day today.

Some thunder would be lovely. Not heard a clap for a few weeks now.

 

[Windblade]

Very heavy rain just started now. This is the line of cells that produced the lone strike about an hour ago.

 

Edit - and its stopped raining just as quick as it started.

Edited July 12, 2016 by Windblade

[Windblade]

Very dark and angry looking to my west and huge cb to my east...

 

Also very quiet in here, but no matter, I will post anyway!

[Frosty hollows]

Bands of hefty showers this morning. One at approx 10am causing some minor flooding. Not  sure how much surface heating we'll get. Tho it's warm in between showers we've a lot of cloud cover

[Windblade]

Yes, its very humid here. Under cloud cover now but feels very oppressive. No thunder heard yet, although we have had some very heavy downpours.

Edited July 12, 2016 by Windblade

[Greeny]

Getting rumbles in the distance, the cell west of Norwich has been right moving the last 15 minutes.

[Frosty hollows]

Very quiet in here tonight!

[Godders]

Thunder and lightning here, accompanied by very heavy rain, within the Uckfield, Heathfield, Crowborough triangle in East Sussex.

[Mapantz]

27 minutes ago, Frosty hollows said:

Very quiet in here tonight!

I thought that when I popped in earlier this afternoon. The radar looked pretty good, a fair smattering of sferics etc..

[weather09]

Despite the fairly active period during parts of May/June, for me, has been somewhat underwhelming this year, so far, for storms.  We've yet to see a period of proper heat, with setups favourable for the big storms lacking. Being the UK, always best to keep expectations low, but still..  

Short term: shortwave upper low looks to slide SE during tomorrow bringing renewed push of cool mid-levels at 500mb from the NW, steepening mid-level lapse rates and generating marginal instability with surface heating from mid-late afternoon. Discrepancy between Euro4 and other models, though, on how far SE the upper low gets during hours of max daytime heating. Decrease in moisture on previous days - NW flow pegging dewpoints down to low 10s, upper singles figures - and light shear prohibits anything significant.  Sea-breeze CZ setting up near eastern coasts with daytime heating, so one area of focus for showers/storms. Activity will be moving SE with NW'erly mid-level flow.

Further out, ridge building over much of the country end of the week, but not really going on to set up in a decent location to get the real heat and potential to come to our shores.

[Eye to the sky]

I took this photo around 2.30 over Derby as very dark clouds passed overhead.It rained heavily for around 5 mins.After looking closely I saw what thought could possibly the start of a funnel cloud.If you tilt your phones at certain angles see what you think.Then again it could be my eyes just playing games.

[alexisj9]

Had some lovely cloudscapes and lot's of convective showers, but they were all very light, no coat or umbrella needed at all type light. Big drops occasionally not really wetting anything. 

[Dami]

11 hours ago, alexisj9 said:

Had some lovely cloudscapes and lot's of convective showers, but they were all very light, no coat or umbrella needed at all type light. Big drops occasionally not really wetting anything. 

same, although there was a heavier burst when i was waiting for bubs to come out of school and i was under the cover. 

But quite boring really.

[MP-R]

Torrential downpour just moved through here in north Bristol, it kept losing and gaining intensity throughout, perhaps indicating the cell forming overhead. Very dark skies around too.

[alexisj9]

17 hours ago, alexisj9 said:

Had some lovely cloudscapes and lot's of convective showers, but they were all very light, no coat or umbrella needed at all type light. Big drops occasionally not really wetting anything. 

Had this again today so far.