Uk Convective General Discussion & Forecasts, 4th August 2012>

[jessandjon]

i would like to go to the car rally at mount edgcumbe today do you think it will thunder in plymouth today? i have no idea what to look for

[Coast]

Morning all, glad to see yesterday came good for a few people!

What about today then?

Storm Forecast

Valid: Sun 05 Aug 2012 06:00 to Mon 06 Aug 2012 06:00 UTC

Issued: Sat 04 Aug 2012 22:23

Forecaster: SCHLENCZEK

SYNOPSIS

A rather complex situation has evolved over the western and central parts of Europe. High pressure over the E-central Mediterranean and low pressure over the SW UK provide a southwesterly flow at upper levels with several embedded shortwaves along an ill defined cold front. There is a transitional regime between cold air convection in weakly sheared environment over W Europe, strong shear and low CAPE in between and warm air convection in moderately sheared environment over S-central Europe. Severe thunderstorms are most likely in the transition region of moderate instability and strong shear.

DISCUSSION

... UK and N France...

Diurnal heating will create some hundred J/kg of CAPE in a weakly sheared environment. Most of the convection will develop during the afternoon and some storms might produce an isolated large hail event or a weak tornado but overall risk is too low for a LVL1.

Storm Forecast Moderate

Forecaster: Chris

Last Updated: 2012-08-05 09:20:00

Valid: 2012-08-05 00:00:00 - 2012-08-05 23:59:00

Areas Affected:

Most of Britain and Ireland (excluding northern Scotland)

Synopsis:

A slow-moving area of low pressure will drift across southern Britain during the day with various upper troughs circulating the flow bringing the risk for widespread showers and thunderstorms.

Discussion:

Numerous showers and thunderstorms are expected across much of Britain through the day, particularly this afternoon. CAPE values will range between 600 - 1000j/kg with the highest CAPE being situated across the Midlands and later in the day Eastern England. Like yesterday there will be little to no wind-shear, thus storm organisation will be relatively poor, however with proximity to the vertically stacked low over Britain and no cap, showers and thunderstorms will be plentiful in coverage.

There will be many outflow boundaries and surface wind convergence zones as the low migrates slowly from west to east across southern Britain, and at times this convergence could provide the opportunity for a brief funnel or weak tornado.

Mid-level temperatures are cold for the time of year, thus hail is a possiblity, however with lack of shear, hail saize should be relatively small.

No updates yet from SkyWarn or TORRO.

21st OWS have it over the UK at midday, then gone in the afternoon?

GFS from lightning wizard shows a lot of CAPE throughout the UK this afternoon:

Intense areas of possible activity in the West of the country, North to South:

Could this be even better and more widespread than yesterday?

Well there will be a lot of rain in the West!

Lapse rates good again:

Here's the area I would expect to see the bulk of the action in:

But shear and a slight tornado risk out in EA:

Seems like round 2 is on it's way!

Lets go for gold again!!!!

[Weather-history]

Can see what looks like 3 cells to my NW, towards Blackpool region.

Clearly can be seen on the radar now, near Southport and Blackpool

[bennewsman]

Storm approaching South London from the South, maybe heading to Olympic Park later? Can hear plenty of rumbles in the distance.

[Darren Bown]

Surprised there are a lot o rumblings already this

Morning, could be very exciting. I hope I get something before work at 2pm!

[IanR]

sun trying to break through the stratus murk now here , little more promising ,but still to murky to see any distant cells, ah they wont be coming here anyways, sod it am off to the gym

[jessandjon]

loads of rain here now but just looks like heavy rain clouds to me!!! dont think i will be going car rally after all

[Jane Louise]

Thanks Coast. It really is looking better then yesterday for me... I hope to be out my club today yay!!

[AWD]

According to Ian Fergusson, UKMO high res modelling puts risk especially around North Somerset and Bristol Channel areas again, so Clevedon it is for me today.

In terms of the UK, think Wales and Northern England could have a decent day today. Potential for most of the country though.

[DeepSnow]

I hope today I will have better luck than yesterday, it looks better for here so fingers crossed! Just need the storm shield to give in!

[Chris.R]

great, Southport is just 10 miles

North

of me. Not fair!

[littlemissy]

Very heavy rain here atm,need the sun to pop out for anything really exciting to happen.

[tornadomanuk]

Just sitting here in the coach park at Gatwick watching an amazing "whales mouth" just going over the south terminal. No thunder/ lightning though and the rain is just a little further away from me. Amazing cloud formations and movement. Noticed one plane abort a land when the storm was over the runway but came for a second attempt with better success!

Can't tell if I can hear thunder or not, damn you Boeing!

Edited August 5, 2012 by tornadomanuk

[Stuart]

Good Luck all today and i missing all the storms in Galashiels at the mo

[Cloudwatcher]

View from the garden five mins ago

Seems to be a lot more early convection happening today compared with yesterday. Hope we can maintain the heat!

Wonder what our chances are....!

[Nick F]

Here's my forecast for today, pretty similar to yesterday, though note that a wind convergence zone is indicated from SW England up through Wales, perhaps W Midlands and in across N England this afternoon - so some funnels or even weak nadoes possible near/under this confluence of winds.

Valid: 05/08/2012 10:00 - 06/08/2012 00:00

Headline: ... THERE IS A RISK OF THUNDERSTORMS FORECAST...

Synopsis

Slow-moving upper trough across W/SW UK and slack low pressure at the surface will create an unstable airmass to surface heating again today.

... E IRELAND, MUCH OF THE UK ...

Another day of diurnal heating of cool rPm airmass across the UK, characterised by steep low to mid-level lapse rates beneath upper trough, will favour development of scattered heavy showers and thunderstorms. Like recent days of convection, weakly sheared environment and lack of great warmth does not favour organised severe weather from any storms. Surface heating should create several 100 j/kg CAPE by this afternoon across a wide area inland across the UK and E Ireland, so widespread scattered thundestorms are likely, bringing hail (some isolated hail to 2-3cm) and torrental rain that may lead to localised flooding. GFS indicates wind convergence zone shifting slowly east this afternoon across SW England, Wales, W Midlands and up into N England ... so here there is the chance of one or two weak tornadoes possible where there are more buoyant/strong updrafts into storms. Storms should fade after sunset as diurnal cooling takes over.

Issued by: Nick F - Forecaster for Netweather

As usual, forecast can be found on the site here: http://www.netweathe...89f2e21d76deeb7

[Biggin]

Very dark to my SW something formed out of nothing last 30 mins.

[AWD]

Lots of cells already forming over the SW, making their way up the M5 corridor. Taunton looks like its getting hit currently.

Also a large mass of PPN off the Cornish coast, near Penzance.

[Nick F]

Got thunder rumbling away here near Croydon, gone v. dark, looks tasty on radar too. Strong core south of London.

[Stormraider]

Plenty of cells developing around here already! Watching 2 that have developed very quickly to the North and NW of here and moving in a Northerly direction. Slate grey skies to my West. Wonder if I'll spot another funnel today?

[gottolovethisweather]

Some explosive growth around today for sure. How high will these cloud tops and to think it's only just gone 10.30am.

Not really in the favoured zone today but I think we could squeeze out a few rumbles down in CSE, especially considering the action already taking place elsewhere.

Currently 16c AT, 14.7c DP and a steady barometer @ 1006.3hpa

Game on.

gottolovethisweather

[Biggin]

Getting a few rumbles of Thunder out of it too

[NUT]

I see whites starting to develop in that band to the east of scotland (and seems to be moving in a east to west direction) I wonder if I might get more funnels later (and maybe even this time rain)

[Supacell]

Lots of convection going up in all directions here.

The best storms so far around Northumberland and SE Scotland as a result of a defined wind convergence. Another convergence zone looks to be setting up along the west coast of Lancashire.

Nearer me there looks to be a line of very narrow echos from Barnsley to East Leeds which may be worth my attention.

Edited August 5, 2012 by Supacell

[gottolovethisweather]

Some sferics recently coming out of that band of precipitation out west, the NW radar appears to indicate the strikes are due NorthWest of Glastonbury. The eastern edge of the cells over London is still going strong too.

Edited August 5, 2012 by gottolovethisweather