Storm & Convective Discussion - 20th August 2015 onwards

[Thunder Snow]

Wow wasn't really expecting this tonight, very very heavy rain for the last 3 hours at least thunder and lightning a bit of wind. Wasn't expecting this tonight, stopped for awhile and starting up again. Hopefully not as much as before :/

[Chris K]

Thankyou AJ â˜ºï¸ I think I'll stay up and watch a scarey film then, get all in the mood ha

Sharknado 2?

[Eye to the sky]

Plenty of thunder around here this afternoon mostly to my west.Nothing directly overhead though.We had a few beefy showers around 3-4pm.Still feeling very muggy outside though.

[NUT]

Looking back on the NW Extra radar there was nothing really about at 10 to 3 this afternoon then from then on it seemed to erupt really quickly in places. Must have really been that humid that a trigger point was there and all of a sudden boom

[East_England_Stormchaser91]

Crikey, that is a monster over SW France! Hoping it holds out and reaches our shores!

[A.J]

ah, I see Staplehurst is on the board...Nice to see you on Dan.....for folks that don't know, Dan's the man for convective forecasts....What's your thoughts on tonight?

[Rain123]

Would you experts, looking at all the charts and that, say that the Bordeaux storm may sustain itself, or die out?

[James 'Jamie C' Croucher]

Would you experts, looking at all the charts and that, say that the Bordeaux storm may sustain itself, or die out?

 

it looks pretty intense doesnt it! also to the left now in the bay of biscay another one kicking off. i think next year im just going to move to bordoux for the summer.......

[Convective]

More importantly, that Biscay storm shows that there is real energy and potential for some big storms. Even if that one doesn't reach the UK, which is likely, there's nothing to stop more firing up near it

[pookie1989]

what about the northern france storms? Will they reach midlands or is everything now going westwards? I really hate them! 

[Mokidugway]

Flying to the U.S. tomorrow morning , could be interesting ..

[Darren Bown]

Had quite an intense shower with lightning every few minutes and incredibly loud thunder around 7:45 this evening to about 9pm. Nothing to write home about, but it was pretty strong!

[NL]

Wow what can I say.. One of the best long lived (still going on) thunderstorm, wave after wave pushing through. The lightning was fantastic, almost strobe like at times. After one particular lightning strike the clouds lit up a dull green and stayed illuminated for about a couple of seconds, never seen owt like that before..

[Dean E]

This MCS over France is huge and in the last half hour is rapidly expanding to the North. 

 

[P-M]

haha just when I thought I might get to go to sleep tonight, its now looking like round 2 might rumble north then????   

 

 

Round 2 from where?

[Winter Cold]

Round 2 from where?

 

Im not so sure myself, just a few posts earlier saying the cap towards the south might break overnight and so of anything kicks off down there they should move NW overnight. The storms Yorkshire had this afternoon are still going further north now so was just musing the possibility of something coming up again later in the night

[Dean E]

Also, development to the North once again. Its been a breeding ground all evening I've noticed, however they have been shot lived. From that latest satellite, they seem to be getting their act together now

 

[P-M]

Im not so sure myself, just a few posts earlier saying the cap towards the south might break overnight and so of anything kicks off down there they should move NW overnight. The storms Yorkshire had this afternoon are still going further north now so was just musing the possibility of something coming up again later in the night

 

 

Ah cool mate was thinking there has something else popped up your way lol Aye it's looking that way from what people are saying but we have had a decent evening here so can't complain.  Wish we had of had more but then being storm greedy I am always like that!

[Thunder Snow]

Wow the rain has finally stopped never seen rain like that for awhile

[Rain123]

Is there a chart to look at whether or not storms will sustain themselves?

[Nick F]

Severe risk on Sunday not quite so extensive as today, with only a narrow corridor of instability indicated along/just ahead of cold front.

 

CONVECTIVE / STORM OUTLOOK SUNDAY 23RD AUGUST

 

Synopsis

Negatively tilted (NW to SE aligned) upper trough will lie close to western UK and extend down towards Iberia and SW France. Shortwave trough rounding the base of this upper trough will pivot NE towards UK. Shallow surface low just ahead of this shortwave will move N across Wales Sat night before moving NW across Irish Sea and over N. Ireland before becoming slow-moving. Attendant cold front will move N and NE across England and Wales on Sunday , with warm, humid and unstable airmass ahead of the front. The front reaches the Scottish Borders by 00z Mon.

 

... S SCOTLAND, N ENGLAND, WALES, MIDLANDS and SW ENGLAND UNTIL SUN 0600HRS ...

 

 

Storms, perhaps locally severe, will continue to spread N and NW across northern and western mainland UK Saturday night, as large-scale destabilisation continues of the western edge of hot and humid continental plume to east of frontal boundary lying from eastern Scotland SW into Irish Sea. 40-50 knots of deep layer shear will overlay the above areas, which will support muticell storm structures and perhaps  weak supercell structures capable of producing isolated damaging wind gusts, isolated large hail and intense downpours leading to flash-flooding. Deep layer shear will be weaker with southern and eastern extent, so severe weather will be most likely across S Scotland, N England and Wales overnight into Sunday. Maintain a SLIGHT risk over these areas for the overnight period.

 

... ENGLAND and WALES SUN 0600HRS-MON 0600HRS ...

 

 

Models suggest overnight storm activity across northern and western areas will gradually wane through Sunday morning. As forcing subsides and instability falls.

 

However, a narrow corridor of instability is modelled to develop along/just ahead of active cold front which will move N and NE across England and Wales during the day, as shallow low across Wales in the morning moves NW towards N. Ireland  early afternoon. Despite modest CAPE values indicated by GFS in the narrow zone of instability, strong ascent along front and 40-50 knts of DL shear may create a squall line or bowing line segments capable of producing isolated damaging wind gusts and marginally large hail ... also a brief tornado cannot be ruled out across NW England and perhaps N Wales – where a combination of sufficiently low LCLs, strong low-level instability and strong low-level shear just ahead of the front will create ideal conditions for brief rotating updrafts with any broken line segments.  A broad MARGINAL RISK has been given, with a SLIGHT RISK over NW England/ NE Wales.

[East_England_Stormchaser91]

Is there a chart to look at whether or not storms will sustain themselves?

Where the upper winds are strong (jet stream) this will enable a storm to keep on being fuelled as the shear tilts the storm, therefore enabling the updraughts to be more sustained.

Little shear will mean little tilt and resulting in the downdraughts in the form of rain cutting off the updraught which is the main fuel. This will cause the storm to fizzle out quickly. These are known as pulse storms.

[carl1980]

Few random strikes to the south of me things picking up again??

[conor123]

Two rumbles here in the past 5 minutes again but nothing around on radar hmm.

[Hathers]

Lightning and thunder here. Round 2 maybe.