Storm & Convective Discussion 12z 21/7/14 ------>

[BrickFielder]

  Plenty to look forward to tomorrow maybe. Still way too early for any detail but sometimes it is fun to look at possibilities in the models.

 

Overnight

We have the potential for a Kent Clipper , which NMM thinks will be a near miss.

Plenty of rain there for Wales as well although I cannot see much instabillity (CAPE) at that time.

 

Tomorrow

What I am curious about is the twin cold fronts showing on the fax charts for mid day tomorrow. 300hpa humidity charts suggest a marked area of cooler drier air moving up from the south between the fronts.

This for me might suggest an area of enhanced convection tomoroow perhaps between 11am and 12am. Most likely directly over Peterborough or maybe it just skirts Peterborough and and makes a direct beeline for Doncaster.

Just joking at this range its bound to change. Other things to note are the jet aloft to the east of east anglia and some low level wind which is at a different angle to the prevalent flow.

Most of this wind turn is in the lowest level, which suggest some low level vorticity available. Winds aloft are straight line but moderately increasing with height. This should give some updraft downdraft seperation, helped by that little bit of veer in the low level wind. So some possibilites for severe weather but not really supercell characteristics (a little speed shear from one side of a storm to another is about it). If the cloud cover was a litle more broken and temperatures somewhat higher

You might fancy local conditions to develop an isolated severe storm.

Some post frontal instability remains and with perhaps a convergence zone over the south west we could see some isolated storms in the south later in tha afternoon whilst thundery weather from the front continues to trundle north.

 

 

Still way to early for any of this kind of detail, but sometimes it is fun to see how models develop and change. Just take it all with a pinch of salt at this point.

 

 

(Definately Doncaster) (Tongue in cheek of course)

Edited August 1, 2014 by BrickFielder

[TonyH]

Sferic near Bridgnorth

[Raidan]

Oops seems ive unintentionally started a debate.

Maybe I should of said the East of England and not just South East.

What I'm trying to say is that overall when it comes to storms the East does very well where as the South West does poorly.

I don't know how else to put this or explain what I'm getting at but lets say we take the last 10 years and look at how many storms there have been in the East compared to the South West.

The East would win hands down but I'm not looking at it as a competition more at stats.

that's what I meant by the hogging of storms.

Sorry to of offended people didn't mean to I apologise.

[Lauren]

You didn't offend anyone at all No worries.

 

I think it's us in the SE, got tired of hearing that we had all the storms (as it's been a misconception over the last few years), when we have been storm starved. That's all.

[lassie23]

Oops seems ive unintentionally started a debate.Maybe I should of said the East of England and not just South East.What I'm trying to say is that overall when it comes to storms the East does very well where as the South West does poorly.I don't know how else to put this or explain what I'm getting at but lets say we take the last 10 years and look at how many storms there have been in the East compared to the South West.The East would win hands down but I'm not looking at it as a competition more at stats.that's what I meant by the hogging of storms.Sorry to of offended people didn't mean to I apologise.

I thought the SW did well with storms!

[Weather-history]

Can see cumulus development in the brighter patches.

[Harry]

Oops seems ive unintentionally started a debate.Maybe I should of said the East of England and not just South East.What I'm trying to say is that overall when it comes to storms the East does very well where as the South West does poorly.I don't know how else to put this or explain what I'm getting at but lets say we take the last 10 years and look at how many storms there have been in the East compared to the South West.The East would win hands down but I'm not looking at it as a competition more at stats.that's what I meant by the hogging of storms.Sorry to of offended people didn't mean to I apologise.

 

Oh good grief no apology required at all (and there is certainly no competition implied by your post)...I was just pointing out that yes historically the SE has faired well with thunderstorms, though in recent years that really has not been the case at all...in fact I would say from 2007 through to 2012 storm coverage was very poor indeed (certainly compared to the 90s and early 00s).

 

Geographically the SW is not ideally located for storms and that will always be the case - the two principle times the SW will bag storms are either southerly imports or a CZ. Given the limited land mass available for energy to build into decent thunderheads its no surprise thunder coverage tends to be disappointing. That said, in my experience some of the most enjoyable storms are CZ storms as they can often hang about for hours, be very intense, bring frequent lightning and funnels/weak tornados - flip side of that is of course they can lead to significant flooding, I'm sure Boscastle still fresh in the minds of many, not least the affected residents and tourists.

Edited August 1, 2014 by Harry

[matt_in_dudley]

Gone very dark here and bucketing it down!

[Dami]

When I lived on the southeast coast, I can remember it was pretty much all or nothing. Sudden heavy thunderstorms out of no where, whole nights of constant lightning, days watching the massive thunderheads out at sea. I have woken up to thunder and looked out of the window to see dense fog at my location, but a storm 'close by'. The problem i had was the south downs  affecting the weather, so i expect alot of storms blew out before i even saw them. Here, by bedford, I have no idea what causes storms to break up. Only today, i watched a shower on the radar break up before it reached me. However on another note, I seem to be in a perfect area for storms to start to develop. 

[Weather-history]

There's no thunder or lightning yet, but there are some bloody dark and ominous clouds here.

Not looking good at Old Trafford cricket ground!https://mobile.twitter.com/RVISkyStatto/status/495243494508990464/photo/1Suppose to be a T20 game quarter final tonight.

[pip22]

Here some strange clouds over Chorley, Lancashire. One of the pictures looks like a Tornado.

 

 

 

 

 

[Greeny]

Thanks Brickfielder for your forecast, it's good cause I learn't something new and more If I had looked at vertical velocity then I could have been doubtful of a storm from the earlier potential that I infact posted a few hours ago. It seemed to be spot on, some capped convection earlier. Vertical velocity was only little and then disappeared during the afternoon which it did and so did much of the convection.

 

The interesting pointer about the wind at surface and 500mb is good info too. (I'm familiar with the convergences part).

Edited August 1, 2014 by Greenday

[Nick L]

Had some hefty downpours this afternoon, nothing electrical though sadly.

[Greeny]

A pure amateur here so no hopes high please but Is it me or is it that the Southwest could also see something overnight? Looked at GFS 700mb vertical velocity is high and so some relative vorticity too. Cape and -li values are also not far away either.

 

Edit: looks like the potential continues for the southwest into later Saturday morning and spreads.

Edited August 1, 2014 by Greenday

[MP-R]

Oops seems ive unintentionally started a debate.Maybe I should of said the East of England and not just South East.What I'm trying to say is that overall when it comes to storms the East does very well where as the South West does poorly.I don't know how else to put this or explain what I'm getting at but lets say we take the last 10 years and look at how many storms there have been in the East compared to the South West.The East would win hands down but I'm not looking at it as a competition more at stats.that's what I meant by the hogging of storms.Sorry to of offended people didn't mean to I apologise.

 

What you mean is 'Bristol does poorly'. Can't complain with the number of thunderstorms I've had here in North Somerset. The number of times I've either driven into a cell in North Somerset from a dry Bristol or Bristol has missed out is just unbelievable. The city just has a shield!

[Weather-history]

Showery bursts of rain, sometimes heavy today

[legritter]

Evening gang ,the radar here in north somerset as been showing rain for past two hours but only had spots apart from earlier when we had a deluge just before 3pm .but as of now 7.20pm i can see a massive cell forming even with all this murk about ,it may miss here mendip but looks like towards bristol and channel could very well get a good storm ,please keep reports coming in ,alot is happening in our atmosphere right now so lets hope for some action overnight ,best of luck gang .

[Harry]

Interesting signs in the skies here...sky is a mackerel rash with recent onset of some AcCas and undulatus.

Temperature and humidity feels as if it has waned but still a fairly healthy 21.5C.

Visually, it's quite encouraging IMO

Edited August 1, 2014 by Harry

[poseidon]

WRF 12z radar composite:

 

 

Interesting to see what if anything happens.

[IanR]

a few torrential bursts here today, but not sferical in nature

[Guest HectorTheAwesome]

What you mean is 'Bristol does poorly'. Can't complain with the number of thunderstorms I've had here in North Somerset. The number of times I've either driven into a cell in North Somerset from a dry Bristol or Bristol has missed out is just unbelievable. The city just has a shield!

 

 

Bogsdon, where I live, also seems to have a storm shield around it. Doesn't help that we're way up on a big hill, so it's colder and not as conducive to storms.

[TonyH]

Bogsdon - now why have I not heard of that aptly named place before!

[Guest HectorTheAwesome]

Well it's just a wee village on the outskirts of a bigger town. Only a couple of houses here. We only just got broadband internet installed. 

[Biggin]

Watching for somethin 4 the SE Nothing yet.

[Neilsouth]

Storms are starting to go up over france