Convective / Storm Risk Discussion - 22nd July 2013 onwards

[nitro_deluxe]

Omg..Crewe's been side swiped, all action to the East of there, even a small blob of nothingness! Poor CC

Macclesfield to Buxton on the other hand..direct hit!

[Cheshire Freeze]

Not the closest or most lively storm but just heard thunder

[P-M]

All I can say Come to pappa up here in the NE - 

[LadyEv06]

Easing here now

[Weather-history]

Doesn't look like this batch will keep its act together by the time it reaches here (quelle surprise), but looks like Manchester will get battered.

The really heavy echoes looks like got hit the Manchester area, the east of me.

[Ben_Cambs]

Torrential rain and lightning about every 30 seconds here at the moment.

[nitro_deluxe]

Not the closest or most lively storm but just heard thunder

Looks worse Congleton, Cheadle way - much better than nowt! M6 acted like a storm shield lol.

[Cheshire Freeze]

Omg..Crewe's been side swiped, all action to the East of there, even a small blob of nothingness! Poor CC :)Macclesfield to Buxton on the other hand..direct hit!

Ahh bugger- just checked radar. Every bloody time looks like a beast too. Stoke stole my storm!

[The PIT]

The weak thundery shower is limping along. The shield has done it's job splitting the storm in two leaving distant thunder and lightning as we once again sit in the gap.

[nitro_deluxe]

Still time for more shows perhaps later C! bit more of that diurnal heating.Peaked here about 05.20ish then approx 30 mins of mayhem somewhere nearby got a direct hit, probably a tree or roof top?

Ahh bugger- just checked radar. Every bloody time looks like a beast too. Stoke stole my storm!

[P-M]

Synopsis:

Moisture plume will continue to destabilise as a sharp upper trough migrates northeastwards, accompanied by cooling aloft. This will result in a large area of potential thunderstorm activity, with greater than normal uncertainty in the forecast evolution given the notorious difficulties in modelling plume breakdowns.

 

Discussion:

** Map updated at 05:46BST **

Models have struggled to simulate convection over parts of the country already this evening, so no great confidence is given to any NWP output during this forecast period. A shortwave trough drifting slowly NNEwards has already developed a mixture of elevated and surface-based thunderstorms, particularly over the north Midlands at the time of writing. This zone will continue to track northeastwards across Yorkshire and Lincolnshire, with continued development possible in places, albeit increasingly elevated as a low-level nocturnal inversion develops. Given some uncertainty and poor modelling of this shortwave, isolated development further west across NW England and S/SW Scotland through the remainder of the night cannot be ruled out, but is deemed less likely.


... ENGLAND, SCOTLAND, WALES ...

The next bout of thunderstorms is expected to arrive along southern coastal counties, particularly Dorset, Isle of Wight and Hampshire (possibly also East Devon) from 00-03z onwards, transferring and expanding northeastwards towards London, the Home Counties and south Midlands during the remainder of the early hours of Tuesday morning as a second shortwave trough destabilises the moisture plume. This area of primarily elevated thunderstorms is expected to continue to track NNEwards across western portions of East Anglia and the East Midlands during Tuesday morning, although probably weakening/fragmenting with time later in the morning.

Thereafter it becomes a very messy setup, with a mixture of elevated and surface-based thunderstorms expected. It is possible a second round of initially scattered thunderstorms will develop during the early to mid afternoon hours in response to forcing aloft and diurnal heating, particularly in a zone from SE England northwards through the Home Counties, western East Anglia and the East Midlands. DLS is marginally better, so if cells can remain fairly discrete then they have the opportunity to become reasonably well-organised. Most models simulate a gradual merging of initially scattered thunderstorms into a more defined QLCS towards the end of the afternoon and into the evening, as this line continues to slowly drift eastwards. This QLCS is likely to extend from S/SE Scotland down the Pennines/E England towards the Home Counties, capable of producing strong, gusty winds and perhaps an isolated tornado given slightly backed surface winds ahead of this line. 

The slow motion of these thunderstorms and subsequent QLCS coupled with PWAT values of 30-40mm suggests local flash flooding may occur, especially given how dry and hard the ground is currently. Hail between 2.0-3.0cm in diameter is possible from any stronger cells, particularly in the afternoon where any cells can remain discrete.

Please note given the complex and (to a certain extent) unpredictable nature of his setup, a few isolated thunderstorms cannot be ruled out elsewhere across the British Isles.


... IRELAND, NORTHERN IRELAND ...

Cooling mid-levels, falling heights and the approach of an upper low will steepen lapse rates through the day, as diurnal heating raises CAPE values to 600-700 J/kg. Scattered showers and a few thunderstorms are therefore expected during the daytime, although may tend to merge into a larger area of showery rain across western parts for a time during the afternoon and evening. Here, hail between 1.5-2.0cm in diameter and a funnel or weak tornado cannot be ruled out.

 

http://ukasf.co.uk/storm-forecasts/257

 

 

Eastern parts updated to Moderate.

[Terminal Moraine]

Thunder and lightning here since around 0400 g.m.t though not overhead. Some short spells of torrential rain among longer periods of moderate rain.

[Weather-history]

Thunder and getting darker

[Cheshire Freeze]

Still time for more shows perhaps later C! bit more of that diurnal heating.Peaked here about 05.20ish then approx 30 mins of mayhem somewhere nearby got a direct hit, probably a tree or roof top?

Well had 3 hours sleep. Don't know whether to stay up for a bit incase something else develops, or go back to sleep.

[Darren Bown]

Just had our first deep rumble of thunder here.

Actually quite frequent!

And to the west

[Supacell]

Not had time to read through all last nights posts but all I can say is OMFG!

 

I have just got back from spending the night chasing storms. I headed towards Melton Mowbray as it looked to be in a prime spot from storms moving up from the south. I need to check radar images and read through posts because after witnessing about 2 hours of amazing elevated lightning displays from storms to the south and east I was greeted to the most violent storm I have ever witnessed. 

 

There were many bolts, forks, crawlers and bright flashes along with gun shot thunder. Just before the storm arrived the bolts were so intense and so bright that you could see there shape when you blinked and the thunder actually shook the ground! When it came over it produced some very powerful winds, I would guess at 50mph+, enough to blow twigs, leaves and small branches off the trees and intense rainfall. It hit around 4am.

 

I can safely say I have never witnessed anything like it in my years of chasing storms, even bettered the 28th June storm I saw last year!

 

Now I am back in Belper and can hear distant rumbles, so still more on the agenda. I have over 3 hours of footage from the last 12 hours - absolutely amazing night. 

 

Tired as hell now though 

[The PIT]

Well had 3 hours sleep. Don't know whether to stay up for a bit incase something else develops, or go back to sleep.

Go to sleep and let it wake you up. If it doesn't nothing has happened and you've had a good rest.

[nitro_deluxe]

Well had 3 hours sleep. Don't know whether to stay up for a bit incase something else develops, or go back to sleep.

Set the alarm for another hours slumber, yet more to our South - track, intensity and final positioning all as ever pretty crucial.Enough energy up there for several days worth!

[P-M]

Not had time to read through all last nights posts but all I can say is OMFG!

 

I have just got back from spending the night chasing storms. I headed towards Melton Mowbray as it looked to be in a prime spot from storms moving up from the south. I need to check radar images and read through posts because after witnessing about 2 hours of amazing elevated lightning displays from storms to the south and east I was greeted to the most violent storm I have ever witnessed. 

 

There were many bolts, forks, crawlers and bright flashes along with gun shot thunder. Just before the storm arrived the bolts were so intense and so bright that you could see there shape when you blinked and the thunder actually shook the ground! When it came over it produced some very powerful winds, I would guess at 50mph+, enough to blow twigs, leaves and small branches off the trees and intense rainfall. It hit around 4am.

 

I can safely say I have never witnessed anything like it in my years of chasing storms, even bettered the 28th June storm I saw last year!

 

Now I am back in Belper and can hear distant rumbles, so still more on the agenda. I have over 3 hours of footage from the last 12 hours - absolutely amazing night. 

 

Tired as hell now though 

 

 

Great account thanks for sharing mate - looks like its all headed towards the NE here (fingers crossed)!

[Weather-history]

Dark but I'm not expecting much. The main part of the storm is to the east of me.

[The PIT]

OH dear shield doing a good job keeping the thundery shower very weak and shredding any stronger areas before they reach here. Main part of the storm deflected west around us a smaller deflected east. Fully expect it to rebuild once past us and give places to the north of us a reasonable storm.

[March Blizzard]

Dark but I'm not expecting much. The main part of the storm is to the east of me.

It may even be east of me, had/have a decent thunderstorm here but It's not overhead.

[TheToastPeople]

Just done a all nighter.. watching lightning!!  To the north of Bedford all night was one of the best lightning displays i have seen in the uk for 10 years! I was on top of Kempston Wood which has a 360 degree view of Bedfordshire. Dear god i watched till the sun came up! just got home and im kicking myself for forgetting the camera thinking it would be a non event haha. Just got home still rumbling. I suspect some very powerful storms in the area this afternoon :D:D I hope everyone got what they wanted, thing looks BEAST on the radar!

[Cheshire Freeze]

Hmm that stuff to the S looks like it's going to go east of here again so gona go sleep I think! Looks good in a bit for Derbyshire folk. That damned eastward drift- just want a proper storm!

[Jimmyh]

Anyone think wincanton will catch anything