Convective Outlook

[Thundery wintry showers]

The setup does rather remind me of the second week of May 2006:

http://www.wetterzentrale.de/archive/ra/2006/Rrea00120060511.gif

Thunderstorms broke out quite widely on the 11th and 12th, and there were two separate thunderstorms in Leeds (where I was) on the 12th, with large hail reported towards York.

[Stuart]

seem the storm risk been upgreaded for my area

[Guest FireStorm]

http://charts.netweather.tv/gfsimages/gfs.20100518/06/177/ukcapeli.png

T177 so wont come off but imagine if that was more like T+18

[Nick F]

Downgrade further south for the weekend for convection, with the northerly shunted further NE away from the UK with England and Wales under a fairly stout ridge in place keeping it dry and very warm throughout the w/e. Though some thundery showers possible for far Nern England and Scotland.

Interesting change early next week though, with a negatively tilted upper trough and surface low swinging in from the SW, which would likely bring thundery showers or thunderstorms across southern/central England next Tuesday, but like the northerly, it maybe taken away on subsequent runs

[Stuart]

still not looking bad for the north or friday and sat but south have been downgread

[Harry]

still not looking bad for the north or friday and sat but south have been downgread

Let's have less of the smiley face after the sad news of "south have been downgraded" thank you very much lol

Yes there's some convective potential, but am a bit sceptical at the moment of how much will be realised further north also, as we are under a fairly pronounced area of High pressure. Doesn't rule the risk out entirely but I'd suspect anything which does develop would be isolated.

2010 not shaping up well at all storm wise, from the Shetlands all the way down to Lands End...lets just hope that when all this Atlantic High Pressure nonsense comes to a close we can start to get some decent plume set ups going....pleeeeeeeeeease!!

[Coast]

2010 not shaping up well at all storm wise, from the Shetlands all the way down to Lands End

It's teasing us and there will suddenly be an explosion of megastorms that will ravage us for weeks with hail, torrential lightning and thunder + tornadoes!!

But not this week eh?

[Stuart]

well that a few runs now been showing storm risk for part of scotland and northern england now if there good in the morning runs i will start to ramp becuse this could well be my 1st storms of the year

[Stormyking]

Yes it is looking interesting for northern ares over the weekend with some decent cape and LI of around -3/-4 showing I reckon some could spark off :winky:

It shows a bit more of a risk more southern areas on Monday or tuesday on latest run but I think this is too far to tell so far but fingers crossed

[Stormyking]

Yeh sunday does look the better day for northern areas and the fact that there is some quite nice cape for sunday too up north so will have to keep and eye on it.

[Mesoscale]

Late monday evening looks good for the south/south east as cape at late evening will be just under 1500 j/kg whether or not it can get tapped into is another question its a long way off and most likely going to be decreased as time goes on.

Edited May 19, 2010 by Mesodiscussion

[Thundery wintry showers]

GFS 18Z shows significant chance of thundery downpours for Friday, though with a large 1030mb high over Britain that is open to some question. Sunday/Monday do indeed look quite interesting, much depends on what happens as a northerly blast attempts to break down the current warm spell.

[Stuart]

O dear storms risk have moved south

[staplehurst]

O dear storms risk have moved south

Isn't that always the way? For the past several years that I have been observing GFS Storm charts, something will pop-up, will be persistent, but in the days running up to the event it will shift further southwards and eastwards away from the country - the same can be applied to snow at times too. Most frustrating.

[Harry]

still not looking bad for the north or friday and sat but south have been downgread

HAHA! Justice - that'll teach ya for making inflammatory posts Only joking...

I do think two things should be strongly considered before remotely getting excited at the prospect of storms -

1. Proximity and strength of the HP system

2. Whether there'll be sufficient trigger for any storm POTENTIAL to be realised...CAPE is fantastic stuff, but then so is TNT - without a spark it'll produce nothing.

IMO, we are still too far from any potential event to take GFS seriously - it chops and changes from run to run and we still at least half a dozen changes until we reach the weekend!

[Nick F]

Chance of heavy showers today across N. Ireland if skies clear of murk, and threat of isolated showers tomorrow across Scotland, N. Ireland, N England and perhaps N Wales and again in these areas on Saturday as we see sea breeze convergence develop inland from sea breezes both from west and east coasts meeting and forcing warm moist air upwards. Good spot perhaps would be Pennines to see an isolated storm over next few days.

[StormChaseUK]

Chance of heavy showers today across N. Ireland if skies clear of murk, and threat of isolated showers tomorrow across Scotland, N. Ireland, N England and perhaps N Wales and again in these areas on Saturday as we see sea breeze convergence develop inland from sea breezes both from west and east coasts meeting and forcing warm moist air upwards. Good spot perhaps would be Pennines to see an isolated storm over next few days.

Agreed, best to ignore Li/cape and look at where sea breezes will form

[Mesoscale]

Sunday also looks good for south eastern england with the cape value being upgraded with -3 li!

Lets hope theres a spark in the air on sunday for everyone to get these storms going!!!

[Nick F]

Ridging on the 06z GFS suggests subsidence may inhibit convective development over SE/S England on Sunday - despite the high CAPE and -ve LIs. Showers and storms most likely Midlands north with weaker subsidence. Of course this is just based on a model output.

[Harry]

Indeed and more than likely to change (prob downward) by the time we get there.

It is noticeably warm and muggy though, so we've know we've found some moisture

[Nick F]

Netweather storm forecast out for tomorrow, chances for isolated heavy showers inland over northern areas and N Ireland. Southern Uplands and Pennines look favourable to catch a heavy downpour with the odd rumble of thunder perhaps:

http://www.netweather.tv/index.cgi?action=convective;sess=

[Thundery wintry showers]

18Z increases the convective potential for Sunday for south-eastern areas, so I think there is still scope for some to-ing and fro-ing of the regional distribution of the highest potential. Before that, tomorrow does look interesting. I agree with the forecast assessment of isolated but potentially heavy downpours.

[SnowJoke]

Big jump in potential for thundery showers over the south and south east on sunday, whats lacking though is any significant trigger to initialize storms. My best guess would be areas of geographic height ie, the chilterns and southdowns and areas prone to sea breezes creating wind convergence and uplift.

[BlueHedgehog074]

According to the Met Office 3 to 5 day outlook, Sunday would be dry with sunny spells for the West Midlands, though I suppose the potential really is more for Eastern areas to receive some stormy/showery weather with more supportive CAPE levels and good instability being embedded as cooler winds try to penetrate further South-Eastwards. Maybe if the GFS still continue to show some reasonable CAPE and moisture levels for Western areas, the odd storm/possible convective showers could break out.

[Costa Del Fal]

Does look like the East will bag it as usual on Sunday.

Still a chance here but people only talking about the East. Will be interesting to see what happens but if the East gets the storms, were likely to get the higher temperatures still. Meto going for 27c on Sunday.