Uk Convective General Discussion & Forecasts, 16th August 2012>

[Lynxus]

Question...

How come all the warnings from ukasf/estofex etc are for areas where the rain isnt...?

Whats the plan today

[chionomaniac]

Well going by visuals here, well done to Boar Wrinklestorm. Something is happening above!!!

[gottolovethisweather]

In Newbury, just a few moments back, it was 20c with 100% humidity providing a 20c Dewpoint, now dropped back to 98% with the temperature rise. There is plenty of rain out West, which is heading largely due northwards. It has a sferic or two thrown in it and the mass is slowly progressing eastwards as I understand it.

For those, wanting to know whether it will Thunder or rain over their heads should go back through some of the informative posts and check the movement of the Radars (e.g. NW free radar) and Satellite images. As always, in situations like these, they may well be one or two surprises.

Some great input on these forums as always.

Eyes to the skies.

gottolovethisweather

[Coast]

I guess theres near to zero chance (even though Estofex reckons there maybe) for S-East this evening ?

No, but it is another knife edge situation that could change this afternoon. Just been washing the car and there is now a huge layer of cloud moving in from the West and I can just see a cell off the coast giving a lot of local rain in The Channel:

We are just going to have to keep an eye on the detectors and radar now!

[Kent Snow]

Mid level cloud quite rapidly moving northwards here. Watching the light showers in the channel closely.

[Robbie Garrett]

Well going by visuals here, well done to Boar Wrinklestorm. Something is happening above!!!

Mid level cloud quite rapidly moving northwards here. Watching the light showers in the channel closely.

Looks good towards the South, long may it continue it's only 11am

[Harry]

Some very interesting skies now cross my part of the world too...Ac screaming in from th S...some lumps in there as well suggesting mid level instability building.

Did anyone mention it's HOT!

[Biggin]

Can confirm 80 % clouded over here.

[gottolovethisweather]

No, but it is another knife edge situation that could change this afternoon. Just been washing the car and there is now a huge layer of cloud moving in from the West and I can just see a cell off the coast giving a lot of local rain in The Channel:

We are just going to have to keep an eye on the detectors and radar now!

So, where does Newbury in Berkshire stand in these situations, NO MANS LAND. Bah humbug and all that.

Sing along guys n gals in the Central parts , "Rain and Thunder to West of me, Accas to the East of me and I'm stuck in the middle with just High........................................................ dewpoints"

Having said that, the chaotic skies do look interesting even here with more insolation to come, so one can hope.

Edited August 19, 2012 by gottolovethisweather

[AWD]

From Met Monkey

Another Hot Day in the South and East, Warm in the West with the Risk of Rain – Supercell Thunderstorms Possible for Some

Published on August 19, 2012 by Keithy Joe

Another hot day for some, especially for anybody in the South and South East which is one of the reasons why we will be watching the potential for some severe thunderstorms today – but we’ll touch on that in just a second. Generally temperatures in the South and South East ranging from 25oC -32oC perhaps a magical 33oC some-where in London, Essex or Kent. Certainly plenty of sunshine here, but watch out for bubbling cloud especially across the West Country, along the M4 corridor and into the Midlands, Home Counties and Lincolnshire.

Further West some-what cooler air is in place and here we will see a mixture of variable cloud, some sunshine at times and the risk of the odd shower – these unlikely to be thundery in nature (here). Temperature to the West of much of England and the West Country below 24oC and closer to 21 – 23oC – still pleasantly warm.

The main focus for today is without a doubt the heat and what this heat is increasingly likely to spark off. An upper level trough features is forecast by most major weather models to develop, this feature is currently sitting across Biscay and is projected to migrate ENE towards the United Kingdom. Low pressure has been anchored to the West of Ireland during the last 24 hours, but this has in turn been the driving mechanism for pushing very warm or even hot air Northwards from the near continent during the last few days.

Quite an impressive high theta-ew plume sits across France and Benelux and combined with high heights in the upper levels this will likely lead to strong capping, too strong to overcome. However, across Southern England and especially those areas North of the M4 close to or around Reading Northwards towards Lincoln cooling upper levels, combined with a very strong jet streak will over-run the extremely warm and moist frontal boundary. This alone will increase the likelihood of surface convergence, and where there is rising air – in the upper levels air will diverge and thus pressure will lower.

Although weather models have been some-what uncertain on today, we have decided to issue a range of 20% – 60% risk for Severe Thunderstorms. In fact with the jet streak particularly strong, low level heat and moisture in place, an element of vorticty and surface convergence strengthening with strong lapse rates – all ingredients are in place for one or two supercell thunderstorms to develop.

We do expect the majority o thef storms to develop from 14.00 or 15.00 onwards, towards evening. Fairly strong capping will be in place across London, Essex, Sussex, Kent and parts of East Anglia thus a risk was not extended here. Capping should weaken significantly through the day across the M4 region as far West as perhaps Bristol. Even areas to the South of the M4. Any storm that does develop, should become strong and fairly well organised quite rapidly with the risk of frequent lightning, large hail, gusty winds and more especially to the North of the M4 from Reading into counties running into Oxfordshire, Northamptonshire and parts of the East Midlands and Lincolnshire – the threat of supercells could bring about the risk of the odd tornado – potentially a strong one.

So although we should all enjoy the heat, we do recommend that you do a bit of sky watching today. Conditions are definitely ripe for supercells, and these can bring about some especially severe weather.

[snowfluff]

Some very interesting skies now cross my part of the world too...Ac screaming in from th S...some lumps in there as well suggesting mid level instability building.

Did anyone mention it's HOT!

Yep, got some light rain from the Ac, hmmm, interesting

[AWD]

I think the Cap in the South East isn't as strong as what is forecast as it looks to be a very interesting afternoon down there with showers ( at the moment ) breaking out over North France and the Channel!

[Supacell]

Currently sat just outside Doncaster and the sky is covered in Ac clouds and been the odd spit of rain. I am now in the risk area but my plan is to head further south to reside somewhere around Grantham

[staplehurst]

I think the Cap in the South East isn't as strong as what is forecast as it looks to be a very interesting afternoon down there with showers ( at the moment ) breaking out over North France and the Channel!

These are mid level showers above the low-level cap. Furthermore, a lot of this rain will (initially) evaporate before reaching the ground, until enough has fallen to moisten the lower layers. Excessive altocu cast may inhibit rising temperatures somewhat also, further reducing the chances of breaking said cap later on...

[Joey.G]

holy crap, storm in the channel, lots of sferics v v quickly, interesting day to come!

[East_England_Stormchaser91]

From what I am seeing, things really could kick off this afternoon, more especially if them storms brewing over N France and the Channel head north and get fuelled by the mentioned jet stream, perhaps causing some supercells to develop, watch this space!

[coffee lover]

2 very deep rumbles of thunder heard here on the isle of wight.. It has come over very dark and eerie looking....

[Kent Snow]

First few spots of rain just started to hit the ground. Fairly hefty shower to the east of Canterbury from the radar though.

[Polar Maritime]

Few heavy spots of rain just starting to fall here, very still and muggy...

[chionomaniac]

Phew! I got the lawns cut since the last post!! A few heavy spots of rain fell, but the cloud building up and it is going to go boom. The mid level AC now is being joined by the first signs of lower level cumulus fractus combining. When the surface layer gets sucked in this is only going to go one way....

[nanu]

well by latest radar looks like the south east kent/london etc is in for it.. so much for the bbc this morning saying another hot sunny one for us

[Allseasons-Si]

Afternoon folks

ok what should i do,stay here in s yorkshire or head lincolnshire way

[gil]

Thunder rumbling in Chichester

[paul m]

2 very deep rumbles of thunder heard here on the isle of wight.. It has come over very dark and eerie looking....

Two tasty storms not far away from you

[Methuselah]

Fingers of Ac rushing northwards, but still quite sunny, 28C...