Well jel. They'll be sleeping well at night too! 👍

Down here the Mon/Tue rain has receded and faded out, instead replaced by more 30s... more desertification. It's the irony of the UK climate that those places which don't need rain get loads, whereas the millions down here who do - go without. The 6z op GFS shows next to nothing for 2 weeks for much of the southern half of England...

https://images.meteociel.fr/im/96/7674/384_777UKjjg3.GIF 

Incidentally 32 rainless days on clay soil in the hottest July really isn't fun. I'll refrain from posting pictures of my big crack in the garden, but it's an inch and a half wide now! 

https://xcweather.co.uk/forecast/heathrow 

Note the low dewpoints now, see a burst of more humid/typical summer air on Tuesday into Wednesday, then see more low dewpoints as pressure builds again. Until that upper support moves away we're stuck with it down here. It's the summer version of classic Scandinavian High setups, where a cold high dominates, dewpoints fall but now and again moister Atlantic air tries to move in, only to be repelled as the block builds again.

I continue to suspect it'll take an Atlantic hurricane heading our way to break us out of this. And once the block finally collapses - that's our autumn started!

Glad to hear it 🙂 

Doesn't surprise me Darren.  I mentioned to my neighbour that I didn't think it would start raining till September. He looked horrified.  Some forecast models bear me out on this. 🙂🙂🙂🙂🙂

On the subject of September, it looks like autumn may start right on cue in this first full week of August in much of Scotland. Cool and unsettled looks like the theme, especially in northwestern parts but to an extent more generally.

Subject: Personal Model Verification: ECMWF vs GEFS vs GFS (Summer Track Record)

Having tracked the model runs closely over the past few months against actual UK synoptic behavior, I’ve put together a quick post-mortem on how the main global models have performed.

1. THE WINNER: ECMWF / AIFS

• Synoptic Accuracy: Hands down the most grounded of the group. Whenever GFS attempted to introduce phantom Atlantic troughing or severe thermal spikes at T+240, the Euro was far quicker to lock onto the persistent European High-Pressure block (1016mb–1030mb).

• AIFS Performance: The AI-driven AIFS run performed remarkably well at nailing the core temperature envelope for southern England (maintaining the 22°C–25°C baseline with brief 29°C spikes) without getting spooked by operational noise.

2. THE TRUTH FILTER: GEFS (ENSEMBLES)

• Outlier Filtering: Essential for cutting through the operational hysteria. When social media started hyping up "40°C heatwaves," the GEFS mean consistently held ground in the manageable high-20s.

• North-South Split: Correctly identified weeks in advance that the Atlantic storm track would be deflected northward—properly keeping high rain totals over Scotland while keeping the South locked in dry conditions.

3. THE WILDCARD: GFS OPERATIONAL

• High Volatility: Continuously struggled at long lead times (T+180h+).

• Phantom Fronts: Kept teasing Channel breakdowns that completely evaporated within 48 hours as the continental ridge squeezed them out.

• Low-Pressure Phantom Spikes: Just recently spun up a deep 960mb ex-hurricane off Newfoundland heading straight for the UK, only to completely drop it from the charts on the very next 0z run.

SUMMARY / KEY TAKEAWAYS

1. ECMWF / AIFS: Best for determining real synoptic positioning (whether Highs will actually hold or break).

2. GEFS Ensembles: Best for realistic temperature bounds and filtering out phantom heat spikes.

3. GFS Op: Useful for catching early hints of trend changes, but unreliable for medium- to long-range details until supported by ECM.

Yup we had some great nights with Younger Dryas as gfs was really good at sniffing those polar outbreaks from the North years ago it just didn’t know what to do the pattern change.

She done some really daft things over the years always very reluctant to undercut one event was sub T76

A Little daft with wind speeds but having said that sometimes it is better that way than ukm always underestimates then goes into overdrive.

I think as a hobbyist over the years looking at these charts imo  we are actually in more uncharted water than we ever was with model predictions this warmer worlds feed back loop we have seen is much sooner than predicted hence the data for all is hard to calculate.

btw thanks for your conclusions.

A great summary, not dissimilar to what I've noticed doing the regular chart review, though any conclusion from the latter tends to get lost in the daily detail.

A useful reminder to our heat seekers not to go overboard when the GFS Op produces more extremely hot days.

Whilst the sentiment may be true, not sure I totally agree to be honest when it comes up with this part. I know some places in southern England may have had a day below 25c in the last month, but I doubt they had more than a few, and brief 29c spikes, I wish.

AIFS Performance: The AI-driven AIFS run performed remarkably well at nailing the core temperature envelope for southern England (maintaining the 22°C–25°C baseline with brief 29°C spikes) without getting spooked by operational noise.

Not sure what the point is here? No different to the non-mammals chasing the snow-dragon in winter 

Not great at all IMO, and a reminder that "AI" is trained on... forums like these! It's just a mushed-up regurgitation of threads on here, including your model summaries, APS' praising of AIFS, and all the stuff on NW with, of course, the usual lack of context leading to errors. The baseline and spikes bit is an example of those errors - the "baseline" it mentions of course the 91-20 mean, with a degree or so exaggeration, not the "baseline" temperature so far this past month! The CET max for July was 25.6, for example, and in southern areas it'll have been even higher). 

We don't need an "AI" summary to pull out posts that tell us that T+180 charts are unreliable, and we don't need "AI" to tell us that ECM tends to be the most accurate model either.

Same with the apps not only at day 10 but nowcaasting wrong constantly.  00z ensembles show uppers as high as 17C here for 5-6hours on the prime hot time tomorrrow so widely expecting 33C here and mid 30's in London.

https://wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=aifs&var=2&run=0&lid=ENS&bw=1 

It was useless over winter - as was the AIGFS - both of them showed endless easterlies and none of them happened. And through the summer it's consistently tried to break things down, either through climatological bias or because that's what normally happens. 

The premise is good, but pattern-matching falls down when the climate's warming so rapidly (Scandinavian Highs are all but extinct now, so just because situation x led to one in 1985 doesn't mean a similar situation will effect a Scandinavian High now), and when there's nothing else in the record to go on then you can't pattern-match (as we've never had such a dry July down here). When we're in a run-of-the-mill standard Atlantic setup they'll be much better, but of course the same applies to the regular physics-based models. 

It doesn't mean the "AI" models are completely pointless, but they're definitely not anything special at the moment. I suspect the future lies in something closer to the new GEM, a mix of pattern-matching and physics. I look forward to seeing how that model performs over winter.

https://wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=gfs&var=2&run=0&lid=ENS&bw=1 

Tbf all the models had a rubbish winter. 

You're probably right though going forward a model that blends the best physics and AI is the future. 

GFS Op 0z - the weather pattern established by FAX - HP to the west or southwest of Ireland, LP Norway or N Sea - remains substantially stuck in place through to Tue 18th, winds mostly light NW-ly. (a shallow LP briefly  crosses Scotland Sun 16th, but the pattern soon resumes)

ECM to T +240 - diverges from GFS from Sat 8th, with HP further south and LP near Iceland. That LP develops a trough southwards, bringing more heat to Britain before itself moving east to cover Britain Wed 12th.

AIFS - London, maximum 29C tomorrow (Mon) dropping to 21C Thu 6th before rising again to 27C Thu 13th,, dry; then cooler with rain (but consistently 20-21 C along the south coast). Edinburgh, generally 18-20C with a few warmer days 23C around Wed 12th,rain most days this week then dry until Fri 14th.

GEFS - In England, burst of heat Mon/Tue 3rd/4th (7C above norm in far south, 4c above further north) mean temp supported by ens members soon reverting to norm and staying there to Tue 18th, in the far south minimal chance of rain until Sat 15th and not much then; further north,. small amounts of rain at any time. In Scotland, noticeable temp feature is a drop Fri 7th to 3 or 4 C below norm, before resuming average for the rest of the period. Rain on many days but especially heavy this week.

For the southeast, the drought goes on ... and on.  BBC weather suggesting it might rain on Saturday 15th but that comes under the heading of rain tomorrow, never rain today. Whatever happened to the traditional thunderstorm when an Atlantic cold front moved in from the west, as on this coming Tuesday? Just too dry, I suppose.

Yeah, I should have said early to mid-Spring.

https://www.wetterzentrale.de/en/ens_image.php?geoid=50902&var=201&run=0&date=2026-08-02&model=gfs&member=ENS&bw=1 

GFS 00z EMS looks rather flat, and the dry theme continues, bar a few showers away from the North and far West.

A more mobile westerly flow has been showing consistently on the extended ECM second half of August.  Seems like a gradual transition.  

I've thought that heatwave No6 may occur in September. However,  we could have another in August so September could deliver heatwave  No7. 🙂🙂🙂

I’m sceptical now about 6. Very sceptical about 7

The 12s have steadied the ship a bit for heatwave 6.