Uk Convective General Discussion & Forecasts, 17th July 2012>

[gottolovethisweather]

Further to Nick F's post and one or two others on this forum, I hope you lot on the south coast haven't taken your eye of the ball. The BoB area is looking good for a MCS type cell over the couple of hours and then that lot COULD well be heading to our shores. It's on, it's off, it's on again, all this confusion once again seems to be coming down to actual observation nearer the event. Radars and Satellite image watching is the way to go.

Currently 22.4c AT, 17.3 DP and steady barometer at 1014.9hpa in Newbury, Berkshire.

Attached is the latest SAT24 image and its projected path estimation. Looking good for some lucky buggers from the early hours of Friday onwards.

Cheers

gottolovethisweather

*don't shoot the messenger if the above fails to deliver

[legritter]

we could be under starters orders ,a few odd showers breaking out to our s/sw at present .also trough developing on sat 24 is now starting to push north .some good returns coming from that on lightning d;;time will tell but by say 8am tomorrow anything that as developed will be flirting with ourfront out west .it certainly is going to be more now casting but we have mostly known that this week ,at present time its very possible that there will be some action across southern and s/eastern counties later tomorrow . if you get it enjoy if you miss it theres always next week ,off to bed ,windows open and fan on cheers

[A.J]

lightning strike detected near Jersey as thundery showers start to develop over northern France and drift into the channel...There's alot of anaprop mixed in with real radar returns in the channel, but the showers can now be seen...also heavy showers breaking out just ahead and on the CF to the west over northern wales and the cheshire plains drifting NEwards, and hints of showers forming over south wales, I say hints because again there's alot of anaprop mixed in with real rainfall radar returns

[IanR]

the light showery stuff over me just produced something more torrential for a few minutes, eased off now, not thundery though

[Robbie Garrett]

Interesting, rainfall radar has something for London and South East Tomorrow morning. Let's see how things go...

http://www.metoffice...recast/?tab=map

The area between the trough and the cold front, AREA C - ISOL 3000meters in heavy thunderstorm rain. 4000ft-8000ft Cb Clouds.

The area C would tie in with the direction that the MCS over BoB is coming from....

Edited July 26, 2012 by Robbie Garrett

[Darren Bown]

I am under that dark cloudy stuff, dont get excited its just light patchy rain, did you really expect anything else? sorry about the moan, I will be off to the nsc if any more moaning is to be done about this dire lack of thunder these days

Just had a heavy shower here in Bolton, there's a heavier shower behind it, but I'm not expecting anything thundery.

[Nick F]

Valid: 27/07/2012 00:00 - 28/07/2012 00:00

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

Synopsis

A deep upper trough close to the NW of Scotland will continue to extend SE during Friday, with a deepening surface low approaching NW Scotland by 12z, while attendant cold front continues to progress SE across England and Wales, clearing the SE of England by 00z Sat .

... CENTRAL SOUTHERN and SE ENGLAND ...

Plume of warm moist air advecting NE ahead of cold front across S England over last few days is beginning to show signs of being destabilised across the English Channel this evening, with some elevated storms erupting near the Channel Islands. Further destabilisation, as increasingly cooler upper air moves over elevated warm moist plume, may bring isolated elevated storms in across central southern and SE England in the early hours of Friday, before clearing NE by mid-morning. 20-30 knts DL shear may allow organisation into fairly electrically-active multicell storms, though not much rain may initially reach ground level through a dry boundary layer.

Before the cold front clears later in the day, there is a window for further storms to develop during Friday afternoon across SE England, as insolation allows temps into the mid-high 20s destabilising stagnant warm moist airmass, aided by falling heights and upper temps. 40-50 knt winds at 500mb and 30-40 knts of DL shear will be sufficient for multicell storms capable of hail, gusty winds and torrential rain bringing a risk of localised flash-flooding. Storms should clear late evening with cooler, fresher and more stable air arriving overnight.

Can also be found here: http://www.netweather.tv/index.cgi?action=convective;sess=

[gottolovethisweather]

From all my hopes earlier, I fear it could be.....................

Another continental teaser. Close, so damn close and that's not just the humidity.

Pretty much as per BBC forecasts and our more knowledgeable members views.

Isolated storms for parts of the south and later into late morning onwards, the threat moving through to the London area and later still, the southeastern parts. Of course, if the MCS were to make it then this place could be full of Thunder reports come the morning rush hour.

Regards

gottolovethisweather

[Convective]

It's spiced up pretty nicely in the last hour down near the Channel Islands.. The far south coast could get a little treat later on..!

Besides, what on earth is that near Newcastle?! Could turn thundery?

Edited July 26, 2012 by Convective

[gottolovethisweather]

It's spiced up pretty nicely in the last hour down near the Channel Islands.. The far south coast could get a little treat later on..!

Besides, what on earth is that near Newcastle?! Could turn thundery?

The Newcastle cell is heading out to sea I believe and talking of the sea, have you looked at the oversea situation recently, convective? MCS, please come visit our shores for a change.

[gottolovethisweather]

COME TO GREAT BRITAIN EL SPANIARDO, COME TO DADDY.

or tears or cheers?

Tired Regards

gottolovethatMCS

*assuming it is by definition, an MCS, looks like its about 300 miles wide and consists of several cells.

Edited July 27, 2012 by gottolovethisweather

[scud]

http://www.sat24.com/en/gb

Looking good

[scud]

Very good sferics on IOW detector.............Damn your all in bed lol

[scud]

No,i'm still here

I agree with the radar,you should get the weather 1st i guess

[Grazy2266]

A pleasant looking radar this morning, south and east is best I guess

[95 Degrees]

Been watching the storm attempts for the last hour or so but off to bed now because storms are dying out in their channel progression and it's the same as usual, soon as storms leave France they die and rain goes from v.heavy to heavy/moderate, maybe a couple of rumbles later and heavy rain but not worth staying up for, didn't expect much anyway.

[legritter]

certainly some action now in channel isle of wight to kent aprox .that was at 4am .some bright colours could hit london area about 6 am ish also some developement of fto s/west but direction unknown ,im typing this half asleep as just woke up with a start about 4am ,so its back to bed ,but will check thread later just in case this is just a dream ,i think with whats moving up from south could bring a few surprises ,going to have a quick fag and check the sky with light just breaking .cheers gang .

[Biggin]

Talk about a damp squib atm that is some dying out.

[Nick F]

Yes, storms have stayed over the Channel and across Normandy coast, a few sferics earlier this morning near IoW, so lightning was probably visible from the south coast. Pretty active mid-level storms though along Normandy coast, in last hour 566 strikes.

Still a chance of some 'home-grown' storms developing later across the SE, as temps reach the mid-20s with any sunny spells. Cold front clearing away the warmth and humidity tonight.

[Biggin]

Just started getting spits n spots here Nick

Edited July 27, 2012 by Biggin

[Coast]

Morning storm nutters!

So whose turn is it today? According to ESTOFEX it's the French, the Belgians and the Dutch:

Storm Forecast

Valid: Fri 27 Jul 2012 06:00 to Sat 28 Jul 2012 06:00 UTC

Issued: Thu 26 Jul 2012 21:59

Forecaster: TUSCHY

A level 1 was issued for N-Spain, France, Benelux and NW Italy mainly for large hail (a very large hail event is possible), strong to severe wind gusts and heavy rain.

A level 1 was issued for parts of Germany mainly for strong to severe wind gusts, an isolated large hail event and heavy rain.

SYNOPSIS

A deep trough is placed over Scotland and moves a bit to the south. A weakening upper level low over E-Europe moves slowly to the east but still assists in an area with deep convergent flow over Poland/Slovakia and Hungary. Ridging over N-Africa builds to the north and enhances the geopotential height gradient over France and also the mid/upper level wind field mainly over the W-Mediterranean.

Cool mid-levels and abundant BL moisture are present over most parts of Europe and hence an active convective day is anticipated.

DISCUSSION

... France, Benelux, Germany and NW Italy ...

Isolatd to scattered convective initiation (CI) is forecast during the day with scattered to widespread coverage after sunset. Despite lowering mid-level geopotential heights, strong thermal ridge is still placed over most of France/Germany. However, strong diabatic heating is likely, so convective temperatures will exceed the required threshold during the day. At upper levels, weak waves traverse the area from SW to NE (becoming stronger betimes due to stronger cyclonic curvature of the flow) and numerous PV streamers also affect those areas, so CI can occur everywhere. The most likely CI during the daytime hours probably exists along the fringe of the thermal ridge, namely NW/N France and Benelux into NW Germany. Further to the south over C/S-France and S-Germany, CI will be bound to topography (at least until sunset).

During the evening hours onwards, a pronounced short wave crosses France and parts of Germany and provides adequate lift for numerous overnight thunderstorm clusters, which then also affect C-France/Germany.

Shear will be on the moderate side with DLS in the order of 10-15 m/s, increasing to 20 m/s over far N-France and Benelux and far S-France. Shear in the lowest 3 km remains marginal during the day but increases to 15 m/s as the short wave approaches during the night. A rather pronounced MLCAPE axis of 1500 J/kg evolves from W-France all the way towards Benelux. This amount of CAPE and aforementioned shear magnitude assist in organized multicell thunderstorms and isolated supercells during the day, the latter risk mainly over Benelux and far NW Germany, where the passage of a weak 'wave' increases SRH. Large hail, heavy rain and a few strong downburst events are forecast although we do not want to rule out an isolated very large hail event with any longer-lived storm. Thunderstorms may already grow upscale into a first MCS event mainly over Benelux during the afternoon hours. In that case, a concentrated swath of strong to severe wind gusts would be a distinct possibility. However, weak forcing and marginal wind field beneath 3 km next to mixed model signals preclude a level 2 upgrade for now. As a side note, in the 18Z model runs, there are more signs of an environment, conducive for enhanced supercell probabilities over Benelux (stronger 3km shear, enhanced SRH-3). If this trend continues, an upgrade may be needed tomorrow during the day. Isolated storms over Germany will be slow moving with good mid-tropospheric moisture present, so heavy rain accompanies that activity, next to isolated large hail.

During the evening hours and the night, numerous storm clusters (probably organized into numerous MCS events) bring strong to severe wind gusts, isolated large hail and heavy rain to France/parts of Germany and Benelux. Again, weakening CAPE and moderate wind field next to the magnitude of the expected forcing do not inidcate any area with a risk of a concentrated swath of severe wind gusts for now and hence a broad level 1 remains in place.

Now if some of those meteorological events could take place 40 miles further North........ Of course looking at the radar and comments here for the early hours those imports have struggled, but maybe if we get a bit of heat into the day, South coast areas will be favoured this afternoon???

UKASF, SkyWarn and TORRO are having none of it for today and hopefully, seeing Nick's comments above, NW will put out something later on for a possible hit this afternoon down here?

21st OWS has Sussex and Kent still on for it!!

Aviation forecast says too far East:

GFS was good yesterday and this morning goes with:

All a bit more towards Hampshire?

It certainly looks like NE France and Benelux will get something, lucky buggers!

HiRLAM has Hants covered too, but plays it all right down:

Going to be touch and go this afternoon and we really need a bit of sunshine and heat to kick it up a bit here along the South coast. Simple GFS says no, but I reckon it's worth a sneaky peak at the radar and lightning detectors this afternoon to see if some stray sferics come our way!

[legritter]

must admit i was half expecting one or two storms to track n/east further west ,still time but looks at the moment like our european neighbours will catch the best of any action today ,sun out here now so with main front coming through later something may pop up . plenty of potential next week but time will tell whether any action is coming our way ,although plenty of areas of intense rain fall crossing the uk .half expecting MICHAEL FISH to be in opening olympic ceremony tonight , they say the british are obsessed with the weather , and it would be a tribute to him as hes done alot in promoting the understanding of the weather . regards legritter

[Robbie Garrett]

Always under the impression that an Azores ridged high is not good for storms..... today has proved that once again. Really we need a euro high and a iberian low pushing up a disturbance... then it has no choice but to wipe out the UK.

[chionomaniac]

Looks like another perfect miss.

[Kain]

Well this makes a change im down south for once visiting mates in Fareham for a few weeks! So i come down south from the west to see stuff missing from down here too lol damn it! Its muggy here and quite overcast but there is a chance for later and with the GFS showing a little cape could help kick it off. Damn would i like to be in france lol