Harry

MetO seem to edging away from heatwave Friday, suggesting temps of 21-22C in London with "thundery showers" in the SE. Let's hope for a shift in models tomorrow and Wednesday to something a bit better than that!

Im working from home Friday, planning to start early JUST in case I need to witness something. I'm hoping that even if it all does slither East there might be merit in me dashing to Dymchurch hopefully to catch something. Time will tell!! Here's a couple of pics/stills from the last couple of years to inspire hopefully some luck

Don't say that will be gutted if all goes East...despite the fact I know it's very possible and always has been! I'm sick of this crap, chilly, NW weather bring cloudy skies and cruddy torrential drizzle...I want to feel some heat and humidity and witness just one poxy AcCas turret I'm buying a camcorder tomorrow night just on the off chance - the past couple of years we've had some awesome storms - July 2013 in particular had 4-5 hours of storms, which during the early peak of the storms was shooting out bolts every 2-3 seconds (think it was an active multi-cell setup)...blitzortung however did not depict this and I was slightly disbelieved last years double night time banker of 17th/18th July again came was but the vid on my eye phone isn't great quality - there any way I can upload it onto here do we know?

Interesting that the BBC aren't sure what to make of it all either - they are plumping for 24-25C which to me is a bit of (sensible) cop out. In reality it looks like it'll either be 20C or 27-29C on Friday depending on which side of the fence you sit.

Towering Cauliflower and Pea sized hail, with potato Peeling thunder, mEso soup with a layer of lasagne sheet lightning.... How tragically bad

Oh yes indeed - the point I was making was that the projected presence of ludicrous SBCAPE (at 00z and 03z) in addition to MLCAPE suggests a highly unstable atmospheric profile from top to bottom, leading to an expectation that any storms have a good chance of persisting rather than pffffting out overseas. Interestingly, and this is a query rather questioning you, why if high SBCAPE is progged would we only look for mid-level instability? Admittedly, during plumes we look towards mid-levels for our 'juice' given the channel presence (and because often SBCAPE often vanishes overnight) , but it's not unheard for I mports (again, not that we appear to be needing these in this instance) to remain surface based if conditions are conducive - based on what the charts are 'currently' indicating this is possible (amplifying severe risk I would suggest)?? Overjoyed by the 12z reverting to earlier predictions...waiting to see if the 18z follows suit and loses its storm killing tendencies

To be fair, history tells us that overnight crud can be problematic. It does seem likely that numerous storms will fire over France on Thursday and drift northwards. I'm not in fact inclined at this stage to believe any storms that are likely to fire will readily die, given that SBCAPE (that's before MUCAPE is considered) is pretty impressive throughout night hours up towards the SW approaches. Where I am inclined to agree with Mapantz however is that given the yo-yo modelling at the moment, it might well be over analysis given we still aren't sure whether the heat and humidity will reach us in the first place. Assuming it does, as I briefly referred to earlier, given the signfiicant instability present and in all likelihood fairly weak capping, I don't think crud will be as much of an issue as it often is. All that said...let's just see if we get the Spanish Plume juice first 12z rolling out...will be interesting to compare it to the 12z of yesterday.

Sausage roll cloud

Super Celery

Worth noting also GFS has eradicated potential next week, so all or nothing in the near future.

Indeed...always a concern. However, I suspect there will not be a huge amount of CIN and the air will be unstable with or without extensive heating. I'm not hugely concerned with this set up if there is a bit more crud. Models arrive heat/instability Thursday night initially across the SW, so here is where any low cloud/murk associated with storms should resides. Any storms moving north Thursday night should follow the instability westwards.

This isn't always the case. It is true in my experience particularly if we've had a sustained period of warmth/humidity - it is as if the entire profile of the atmosphere warm/moist and therefore instability reduces. However, where plumes are relatively short lived AND the contrast between pre and post frontal airmass is significant enough then significant, widespread thunderstorms can arise. 28th July 2011 springs to mind, with a huge swathe of the SE portion of the UK received very electrified and torrential downpours, all (if memory serves well) thanks the CF. I think on that occasion it may have caused a pre-frontal trough (which is not at all that uncommon). In any event the timing of the CF will be crucial...if it holds back just long enough to allow the plume to spread across then I think widespread thunderstorm activity is highly like. If however it progresses too quickly it may rule all out. In any event, on this occasion I would be surprised if the CF was not a catalyst for thunderstorm activity. No, the colder/drier air will be behind the CF. Pre frontal troughs like that are our often our best friends in these setups

Yes, the 00z is much more pleasing on the eye! Certainly gives much wider areas of the UK risk of potent storms, both day time and night time storms. It is however significantly different to the 18z GFS so certainly much further to go before the models start aligning. Will be interesting to see how the 06z, 12z and 18z evolve today. As W09 pointed out yesterday, the charts should not be relied upon until later tomorrow at the earliest (if you need an example of why, toggle between the 'current' and 'previous' runs for Friday at 18:00). I would suggest if on Wednesday we have similar signals like the 00z you can think about purchasing some balloons and bunting (by for safekeeping until just before any event!)

Hope some of the others are right and GFS is an outsider - 18z even worse than 12z seeking to cut off even any potential Thursday night/Friday morning. Not staying up to see how early next week fairs - sufficed to say it's turning into a classic boob Am going to hope that I get to work tomorrow to more favourable 00z and 06z

15% or greater chance of extremely severe weather over a 50km2 area if I remember correctly.Hail of 5cm diameter or larger, strong tornadoes (EF2+) or wind gusts exceeding 119km/h While Estofex is down had to blaspheme and rely on wikipedia

I am going to buy a video camera just in case there is action in the next week (or if not then over the summer). Looking at the Sony PJ620 - if anyone in the know could PM me whether they think it'd be a good purchase (particularly for night time storms) I'd be really grateful, or any other recommendations Back on topic, like a poorly disciplined child I can't help getting a bit excited about a potential plume...year in year out I do it myself lol

The WRF looks remarkably like the 6z GFS - though if the time mark at the bottom of the chart is GMT or c.European (today at circa 5:30pm) then it'd be more recent that 12z GFS.

When was the last WRF model output Supacell?Couldm be that it is based on similar data to GooFuS

Indeed - but to be fair, the 06z for Friday (not the depressing 12z) could well be the closest I've seen to a possible level 3, but even then there are a a few factors which lead me away even then. A level 3/'high risk' in the UK is extremely unlikely (certainly can't recall one ever in my lifetime). Conditions would have to be so so perfect which alas in a small temperate island nation are pretty hard to come by!!

Indeed, a pretty staggering and significant change between the 6z and 12z - but then the emergence of instability early next week is a sudden change so not sure what to make of it all - other than to try and avoid chart gazing until Tuesday/Wednesday to see what's what. As for -12 LI over the UK, that can be safely archived in the fantasy aisle that's not even common in the U.S.

Fair play - however I did caveat by saying I've not been following too closely the past few days

Raidan, experience suggests your pessimism is well placed. The subtlest of model changes will be the difference between heatwave/storms and keeping the status quo. GFS is suggesting a max of 20-21C Thurs, 28-29C Fri, then back down on Sat so the window is very narrow. This however should enhance storm potential if indeed that plume reaches us. 3-4 days out now is generally a more comfortable window but the detail, I'm going to suggest now, will be virtually impossible to nail down.

The 06z is unreal...3000 CAPE with LI of -9 across the SE quarter (I have not checked every single model update but that is a striking upgrade from 3-4 days ago...usually it goes the other way round) What strikes me even more is the contrast in airmass between the Spanish plume and what is diving out of Greenland behind it...whether eastward shift continues or not, somewhere across Europe are going to be some phenomenally powerful and violent thunderstorms based on those charts. It is not that common to have models indicating such contrasting air masses over the UK or the NW Europe generally, but adding the active jet into the mix we have a real possibility of supercells, or, even if not supercells in the text book sense, strong severe thunderstorms. An active cold front sweeping through could of itself introducing the potential for intense squalls, if the convection initiated action is limited. While premature, I'm inclined to maybe cheekily ask for next Friday off just in case something does materialise...the train strike may give me added excuse!!

The potential of a plume is good enough...a day over 26C would also be a welcome relief too

Certainly a lot more activity than the SPC forecast suggested. Cap appears to have broken not too far from you so here's hoping Edit - by not too far, I mean New Mexico which on Blitzortung looks a lot nearer than the several hundred miles away it actually is