Man With Beard

70% isn't bad, but neither is it a fantastic number, though, I think? Granted, massive improvements have been made in the past 30 years, but we're not yet at the stage where we can look at an ensemble means or the NOAA and think "I've got the forecast" without any doubts? Just this morning I was going through some recent ECM ensemble archives to see how well the new upgrade is doing, and I noted that it largely missed the large troughs that developed to our west on 6th July and 13th July, one of which gave us a bonus couple of hot days, and the latter one was only a few hundred miles from achieving the same yesterday (it soaked us instead).

Certainly no cherries thrown out by the ECM in the D10 period. Very few runs give the scope for a significant turnaround. The base of any trough is often towards the UK - although I will be interested to see if this trough trends back west in the D6-D9 period, though, as this has happened a couple of times in July already (not enough to give us extended heat, of course). A sniff that the mid-Atlantic High might be moving in by D15, and the Scandi trough easing, but not a particularly strong sign, with some members persisting with the current set-up. Yes! I'm very aware that we're now deep into FI, and the latter stages of recent ECM ensemble runs have given some hope that didn't materialise. I'm just posting these as a marker to return to in a few days, to see if any of the potential developments came to anything.

I was definitely one of those hoping for an improvement by 20th - a few days ago the ensembles were dragging us back to average and I guess I was hoping the trend would topple us up to the good side of average - but looks like it might topple back below average again. However, still a few days away and we see pendulums sometimes swing one way then another, don't we! Extended ECM - the very fragile hint on the 00Z at lows retreating west by the end of July have almost disappeared tonight - in fact a fairly different ensembles set, albeit still on the less settled side. The consolation remains that the ECM isn't clear in the direction D11 to D15 will go - but the caveat is that most routes suggested at present do not look particularly summery.

Que calor! I lived in Portugal as a child and loved checking our thermometer in the afternoon during August to see if we'd reached 45C! Rain in July is almost unheard of in southern parts of Portugal. It looks pretty serious a little further east for the start of next week. I've never seen the 30C uppers line approach Italy before, but some models achieve this next Tuesday. The European temperature record no doubt will be under threat again.

Unfortunately the ECM clusters gave us one cluster only - and that was one of the worst members for heat! Looking through the individual members by 29th July, it is clear that there are a range of options, though. So, I have very unscientifically attempted to create my own set of clusters. My take on them: P6: Continuation of the existing pattern - main trough NE, main ridge W, lows likely to keep coming. I felt that between 30% and 50% of members could fall in this "cluster" P31: Low pressure appears west of the UK, encouraging heights to build on the eastern flank. About 20% of members attempted to do something similar either by shorter or greater measures (although in different ways to the member shown here) P45: A UK High emerges. Around 15% of members could fall in this camp P38: The opposite of P45 - a UK low dominates. Again around 15% of members were variations on this theme IMO The rest were various combinations of these trends, although I'd suggest trending more towards P6 than any other. The positive I take is that ECM is still undecided about the last few days of July. The betting person would put money on a continuation of the same. Those following background signals that have been mentioned on this forum over the past 48 hours (and actually during the whole of this month so far) might believe that P31 or P45 will emerge over time as front-runners. My key takeaway - don't get your hopes up too much, but don't write off the end of July just yet either

Looks to me like 30-40% of ECM ensembles have some sort of low to the west by D15. Some of them have cleared the trough from the NE. Not the majority, though (yet?) The improvement I was following a week ago for the 20th July looks fairly muted now, and unlikely to bring significant warmth - but a relaxation to a relentless run of lows.

Hi Tamara, after the discussions last night I had a look back through June/July's discussions particularly from you and Matt, and I can see why it must have been frustrating to get a one liner from me "It isn't working" after so much effort you've put into your posts - so I would like to extend an apology to you too. As I mentioned to Matt, I only have snippets of time to visit the forum, I like to make sure I contribute so I post quickly if I can but yesterday reminded me of the dangers of being too brief on social media. But we're all on the same side - we are striving to make our forecasts as good as we can, and I take my hat off to you in your efforts to achieve this The LRFs, by the way, was a slip of the tongue by me - I was referring to the seasonal forecasts that I think Mike Poole posted mid way through June showing unanimous agreement on July being a month with a ridge anomaly to the north-east. I think the worry I have is - and perhaps I'm interpreting your posts incorrectly, do tell me if I am - that maybe there is an undertone that the NWP isn't really worth following beyond a few days out, and if there is a clash between the NWP and background signals then the NWP should be the one to ignore. I would argue it just isn't that clear cut, based upon a lot of observation over the years. That's what I think I was getting at last night in my very brief post.

Let's hope so @Addicks Fan 1981

Well I was rather surprised that a couple of lines I wrote last night, based purely upon observation of this thread and the models, in a very non confrontational manner, got a pretty stinging attack last night!!! @MattH, I offer an apology, yes I was too broad-brushed in mentioning LRFs without context - I was referring to many long range predictions that had been shared on this forum in June (not including yours), which mostly went for trough west/ridge east anomalies for July. I'm afraid I don't have much time to write so I'm sometimes overly brief, too brief this time. However, my response to Tamara yesterday was down to a bit of twitchiness at the insistence by some that a turnaround is coming soon. Anyone who has seen my tweets over the past decade know how much I want this to be true! But I simply and honestly don't think that claim can be made at the moment with excessive confidence, and I don't think such voices should be shouted down. The NWP isn't perfect but the ECM ensembles up to D15 is doing a good job IMO. I present this morning's ECM clusters D11-D15 - they would suggest a write off for a heatwave in July. I'd be both shocked and delighted if these clusters are completely wrong!

As much as I enjoy reading Tamara's posts, I cannot ignore the fact that the LRFs have and will be wrong for the first 20 days of July, and that ECM ensembles D6-D15 have been a good guide since their upgrade.

ECM clusters D11-D15 provide no clear way forward (a relief it isn't worse!) Cluster 1 seems to follow the op after D10, with average to slightly above average heights - which at this time of the year should lead to something fairly warm. 40% of members in this cluster. Cluster 2 is the non-summer cluster, with trough after trough over the UK Cluster 3 is slightly smaller in number but interesting as it hints at leaving part of the trough to the SW, with weak heights building to the south - which maybe just maybe would result in us flirting with a plume? Given such a range of options, best wait for the next run

Nice to see but I'd prefer to see the same movement towards this pattern on the ECM ensembles - a couple of days ago this kind of outcome looked promising, but over the last 36 hours this has been a 30% option in the ECM ensembles at best.

The Scandi block will need to get its skates on now, or there's going to be a bit of an inquest into these LRFs!

Going by the latest ensemble trends, I'm starting to think we may get through the whole of July without a notable heatwave, which has been pretty rare recently. The signal for a slight improvement around the 20th has not developed, yet, into anything more than "slight" - the general picture of westerly or even north-westerly influence remains, with the trough to the north reluctant to progress far enough away to allow neither a longer settled period nor a southerly draw for more than the briefest period. The clusters look pretty clear this morning in that regard: So whilst comparisons with 2012 are inaccurate, it does look like July 2023 will come in underneath the average July by 21st century standards, unless a dramatic change occurs soon.

A slight step backwards on the ECM ensembles for D10-D15 today. The trough is a little slower to clear east on most members, meaning the Azores High penetrates a little less. However, still a good few members that successfully push heights through, so still a work in progress by the models.

However, ECM ensembles D6-D15, performance has been pretty good for a while, hence my growing confidence for the last third of July.

ECM mean D12 The trend has been going on for days, less unsettled conditions pushing up slowly from the south at around 20th July - with westerlies, I always look for the yellowest line (the first yellow line after the greens) as an indicator of where the most mobile weather will be, and you can see it's just cleared the north coast. No certainly of an improvement for the north, but I'd wager that southern parts of the UK won't do too badly around this period 19th-24th, perhaps changeable, perhaps an extra push of pressure for a day or two upping the heat, less settled moments still possible but more "in passing". Not the insane summery weather we've become accustomed too in the last 5 years, but summery all the same - well that's my punt

and the anomaly at D10 shows a return to average for the south - slightly at odds with NOAA, actually... I guess this would mean improved conditions but probably still changeable on a westerly flow.

Models not a good resemblance for the radar right now!

So that's a few ECM ensembles on the bounce that try to push pressure upwards after 18th, at least for SE regions. However, nothing clear cut yet.

Another interesting table - the ECM 00Z ensembles sea level pressure for London. The green waves indicate lower pressure passing through around 11/12th and then again around 15/16/17th. Do I detect an uptick in pressure on the majority of runs towards the 20/21st...

I hope it is ok to link this - I just saw Alex Deakin's 10 day summary and thought it was a brilliant technical overview with reference to model output from ECM and I think MOGREPS. I think it's well worth a watch to understand what the modelled conditions for the next 10 days will actually mean in reality:

Odds of any kind heatwave before 20th July no better than 10% on the ECM ensembles (which now run at the same resolution at the op run)

With the ECM ensembles now at such a high resolution, the clusters become even more relevant for mid-term analysis. The clusters for D5-D7 reveal an almost 50/50 split between scenarios where the low either goes through the country, or the other where the low is centered much more to the north with the south-east on the edge of something less unsettled. Compare the 576mb lines on each chart (the thicker line):

An interesting subtle variance of the morning runs. The trough for the weekend tends to stay further west, and slightly further north into next week. This doesn't save anywhere from wet weather but does put a different spin on the wind direction, with early next week slightly warmer than anticipated especially for the south and east. The ECM this morning suggests temperatures into the low 20s widely and maybe even the mid 20s if we assume the raw values are underdone. I guess the maximums will depend upon where the breaks between rainy periods fall. Overall, there might be more periods next week where it feels very warm in the sun than we might have expected 24 hours ago.