weather09

I don't think some understand how reasoning should be played out. If all models indicate and actually show storms affecting SE and EA but one still wants to conclude that storms will not affect those regions, then you need to back that up. Otherwise we could say just about anything in here. I could say 'nah, Scotland looks more at risk of severe storms'. 'Potential for tornadoes over the Midlands' Just complete nonsense. Optimism or pessimism shouldn't come into if you're actually trying to gauge the likelihood of storms occurring. And it also doesn't matter whether you're an amateur or a professional. If you say something is more or less likely, explain why that is so.

Ah right, didn't know there was a risk for tomorrow. Only been mentioning for the last few days. Appears my posts have gone into the void again And it's not about patterns, it's about looking at the period at hand and not have your thinking influenced by what has happened in the past. Just because there have been occasions when storms have missed the UK, doesn't mean storms will keep missing the UK.

So we've gone from confident of storms only clipping the SE, to squall line over east Anglia. Lets cover all bases so one can't be wrong. And since when did what happened several years ago have any bearing whatsoever on what's going to happen this evening and into tomorrow? BS.

Ah, well there you have it. Forget your reasoning and forecasting, everyone. It appears mother nature is discriminating against certain nations to bring exciting weather. No-one has said that any activity is going be widespread. Your personal opinion has no reasoning to back it up. ".a large band of rain moves over the SE with occasional lightning". Really?

No, was more in reference to recent comments that likelihood is storms will miss our shores. Anywhere along and E of the cold front in with a shout, and it doesn't look like moving east at any real rate, forming a wave along the boundary and holding EA/SE in the warm, moist air mass for Thurs.

Thing is, storms may very well stay over the continent come the time, but the fact is all current outputs are showing storms tracking across SE/EA during Weds evening/early Thurs, then further sfc based risk during Thursday afternoon. So you can say that the UK will end up getting no storms, but either then provide actual reasoning as to why you think that is more likely, or let me know where you purchased your crystal ball.

Latest Met synoptic output has cold front oriented SW-NE from IOW to the Wash 12z Thurs. Along and to the E of the boundary potential for severe thunderstorms, initially potential elevated storm clusters/MCS surging NE over SE/EA Weds evening and into early Thurs: ...then more heightened risk of severe convective weather during daytime with heating of very moist boundary layer air mass - 12z Euro4 modeling a 18C dewpoint for midday Thurs around London. Might be potential for squall line/line segments in association with CF given strong deep layer shear, heightening large hail and strong downdraft wind risk. Supercell risk dependent on discrete storm development, but a bit more uncertain. If the positioning/timing of cold front remains unchanged between now and period in question, anyone who thinks there's no risk at all would be wise to provide reasoning. Sure enough, might be last minute alterations which sees main push of WAA barely clip our shores... but ain't seeing that on current outputs.

Be good to know the names of these 'knowledgeable' posters. They seem to crop up each year. Names would be handy, then I can ask them why they are ruling out storms affecting the UK at all.

06z Euro4 modeling 18-19C DPs for early Thursday across far E/SE. Strong June sunshine heating such a moist air mass will likely generate low-end moderate instability. Wise to be cautious of the risk in terms of likelihood given uncertainty in positioning of frontal boundary... things could still shift onto the mainland. However, I don't there's much open to question regarding potential storm severity if all comes together.

Is a fine line between severe risk and no risk at all. Models have initial NE'wrd advection of fairly high low-level moisture during Weds, but it's really post 00z Thursday that moisture increases further. Euro4 has sfc dewpoints to 17C already on Weds, so be interesting if it follows the GFS for 18-20C dewpoints for Thurs afternoon. Certainly can see potential for some severe storms. Whether frontal boundary shifts further east though...

Met on board this morning with early warnings. Things look like they've nudge a little east on this morning's outputs, but regardless of relatively narrow region at risk, conditions look favourable for low-end severe convective weather for far E/SE slice of the country during period of interest. Shame a more wider area wasn't at risk.

Still small discrepancies on timing/positioning of low/frontal boundary between ECM/GFS and UKMO-GM, but, as things stand, ever increasing likelihood of possible severe convective episode late Weds and particularly into daytime Thurs across far E/SE, where initial storms/MCS earlier in the period would transition to surface-based risk during afternoon/evening period Thurs. 12z GFS modeling NE'wrd surge of fairly high low-level moisture over the region: Large scale ascent with upper trough/divergence with under left-exit jet, and upper disturbances all releasing moist and potentially moderately unstable air mass. Those fairly strong SW'erly mid-level winds generating a good sheared environment for storm clusters/MCS early period, then supporting more strong, organised storms when combined daytime heating. Three days out a long way in convective forecast terms, but given agreement between models, and likely severity of storms if current outputs verify, worth the detail.

Still while out and likely to be considerable change ahead, but adding to Nick's summary above, ECM/GFS still going for thunderstorms across far E/SE quarter from Weds eve and into Thurs when we see moisture-rich low-level airmass of high WBPTs advect over the region, destabilising with forcing with approach of upper trough/forcing aloft. Given likelihood of strong mid-upper winds with SW jet aloft, generating strong deep layer shear and large scale forcing, and drier mid-level air atop moist low-level airmass, creating a very unstable environment, strong thunderstorms and general MCS storm mode looks likely for aformentioned regions if current outputs verify, bringing hazards such a frequent CG lightning, potentially large hail, and strong downdraft winds. With rich moisture and large scale forcing, risk not dependent on diurnal heating, however daytime surface-based storms (which is most possible Thurs on current outputs) always bring increased risk of severe convective weather as they draw greater energy from good insolation and strong heating of boundary layer.

Indeed. While those up north have been trying to wrap up warm, down here in the urban jungle we've been subjected to extreme humidity, with doopoints generally around 12-13C. Stifling. Sounds dull and boring up north.

Yes, and UKMO-GM as well has a more easterly solution to the 500mb pattern and therefore surface low pressure, keeping main region of instability over mainland, so hard to get too interested in recent GFS modeling. More often than not a game of 'catch up' with GFS in relation to euros. Though, for fun, if something like the last couple of GFS runs were to verify, would see risk of severe thunderstorms, possibly supercells, given overlap of strong shear and moderate/large CAPE. So a Jun 28 '12.

Hi Nick. Presume the ECMWF CAPE outputs are available at a premium? Always wanted to view these ahead of storm risk days. Do you find that the ECM is more conservative with CAPE values compared with the GFS and more closer to reality? I think I tried a limited trial version out a while back, not sure which site, but vaguely remember it not being in spring or summer, so didn't really get to see any noteworthy CAPE outputs.

~76mm dumped in half an hour. Many here though their number was up..

Doesn't look too bad to be honest, CDF. Normal flash flooding you get from a storm. Was worse here last Wednesday, when whole cars were submerged, manhole covers blown open, roads cracked, homes flooded, and people running for their lives. You could have taken a canoe out and sailed quite a bit down the road it was that bad.

Agreed. This would be the norm for Brum. Though imagine it would be too hot for those up north, where they'd be more used to upper teens than upper 20s! Back to now, stifling humidity of the past week or so has been replaced by something a bit fresher today. Not feeling like a jungle.

Yeah, heard the rumbling approaching from the N and E, but activity just rained itself out, and with instability having waned significantly into the evening, no chance of proper re-invigoration. Not so lucky today in all for this locale. Got lucky Tuesday when cell(s) over Black Country built further activity east over the centre of Birmingham, with a CG dropping just down the road. Been an active week in all though across the region.

Thunder from the popcorn cell to my N, heading this way. Get in!

Can hear the Stourbridge storm grumbling loudly all the way from here. Enjoy Blizzards.

Yep, can see that too. Always interesting watching the movement of these lowerings. Tuesday evening was really good. Was watching rapid spin and rising motion at the cloud base from a small shower, and you could see it was close to organising into funnel, but it just couldn't quite get there.

Can see the tops of those storms toward the east shearing off to the south on satellite imagery. Being picked up by the modest N'erly jet winds (300hPa). Further down in the mid-level, however, winds remain light, so unlikely to increase storm longevity or severity.

Looking at radar imagery, Will, there's a defined 'hook' signature to the storm over there, so a tornado is on the ground. Get into your storm shelter! Quick!