https://modeles16.meteociel.fr/modeles/gfs/runs/2026072412/gfs-0-294.png?12 

To be honest, this is actually probably the most dangerously extreme ensemble we have ever seen in terms of heat. No 45Cs but it combines record breaking extremes with longevity.

P23 is a warmer run with 28C T850s and 43C 2m temps but it doesn't last long.

That will be 40-42C for a week long of one of the member  For here 15-16C so likely surface temps 33-34C with the very dry ground factor in place.  

Any idea Q if the heatwave feed back loop can be calculated in this instance correctly I ask because it’s extreme I would expect a gradual increase T2 and not a static line like that with that extreme conditions and more to the point models have never had this sort of extreme loops to calculate before.

I think this summer has been a good example in how heat waves are difficult to remove once established, especially over such a vast area of Europe.

Thoughts of the old saying get the cold in first seems also to apply to heatwaves.

Maybe simplify the colours? 

GFS Op 0z - the pressure set-up described under FAX  continues for a week or so, to Tue 4th, with some of the extreme heat over France leaking across the Channel to south of the M4. Then a shallow LP drifts northeastwards from Brittany to Scandinavia with somewhat fresher and marginally cooler winds affecting most of Britain away from the SW until Sun 9th.

ECM to T+240 - after the 29th, first places HP near Switzerland, then LP near Azores, which in turn create a window for continental heat to move further north, say to the Scottish border, first on a southerly, then more of an easterly

AIFS - London, maxima reach 29C Wed 29th before dropping back to 25C for a few days; but from Mon 3rd 18-20C with rain then and on Fri 7th. Edinburgh, maxima declining from 20C now to 15C Mon 3rd before rising a couple of degrees, rain from time to time, heaviest Mon 29th, Wed 3rd and Sat 8th.

GEFS - for England, mean temps rise to a peak  Thu 30th (7C above norm in SE, more like 4C above in N), slowly dropping back to norm and staying there to Mon 10th (yesterday's excesses have been written out), Quite good chances of rain from Mon 3rd but only very small amounts in SE,  rather more in N & W plus a few splashes there before that. For Scotland, brief  -er - heat wave of 2 or 3C above norm Wed 29th, then mean and ens consistently a little below norm to Mon 10th, rain persistent throughout with some ens members showing big totals around Mon 3rd

There’s definitely a pattern change going on in early August. Remains to be seen whether it’s one of those transitional periods between renewed heatwaves, or a traditional August “that’s your lot” situation as we’ve got used to in recent front loaded summers. Or something else entirely. 

All the different ensembles after the 4th August have similar characteristics, and are if anything more aligned than the nearer term:

- Average seasonal 850hpa temperatures (I’m talking London here)

- Less volatility or range, not many spikes, either up or down (eg GFS this morning nothing below 2, nothing much above 15; AIFS has a few hotter spikes but not as many as next week and also nothing below 2-3C)

- Not much rain. Yes there are rain spikes but look at the mean

- SLP settling into a mid to high teens average (with the usual oscillation around this) in all the ENS that show pressure. That’s higher than next week

I’ve not looked at all the postage stamps. But that’s saying something a bit August 1976 to me. Cooler, less extreme than what went before but still pretty decent.

ECM & MetO do show a brief hot spell in the south-east mid-week but after that Low Pressure dominates with rain or showers and normal temperatures for many

GFS shows unsettled Low Pressure dominated charts out to 10th August

This is all normal stuff up here

GFS Op 0z - After heat arriving Tuesday and reaching a maximum Wed/Thu 29th/30th, LP 990mb Faeroes brings cooler weather into the north, probably not getting to the south coast. This LP keeps trying to feed cooler weather southwards, and has some success when it links to LP from the southwest 1000mb Irish Sea Tue 4th but still hot for the far SE. A more comprehensive breakdown comes Fri 7th when  new LP dives southwards to 1000mb central England. Nevertheless HP is shown as returning from the Atlantic Mon 10th.

ECM to T +240 - the LP which GFS places near the Faeroes fills without influencing the weather further south. The next LP from the SW Tue 4th is in this model. but combines with LP over France so there is not much cooling anywhere. In a different year this would imply thundery conditions but the Continent may be too dry to provide the necessary moisture. 

AIFS - London, reaches a maximum 31C Wed 29th before dropping back to 25C through to Mon 3rd, and dry. From Tue 4th maxima fall away to 19C and there is rain on most days. Edinburgh, reaches maximum 21C Wed 29th (some rain, too), then in upper teens to Tue 4th before cooling further to 14/15C with heavy rain on Fri 7th.

GEFS - in the south, mean temp peaks 10C above norm Thu 30th and again 5C above norm Mon 3rd, otherwise near norm in a bunch of ens members but some hot outliers. Rain, heavy in some runs Tue 4th, and occasionally thereafter. In Scotland, and to some extent in N England, only the first peak shows up and that at 5C above norm, else mean and ens slightly below norm to Tue 11th, rain frequent and often heavy throughout. 

An unsettled picture unfolding, maybe and cooler with time after another burst of warmth??

Of course the pattern will change, but when??

1. 500hPa ridges and troughs for longitudes 210°W to 90°E, averaged over 40°N to 60°N

2. Blues are troughs; oranges are ridges

3. The vertical axis represents time, from 26 July to 9 August

4. A bigger tilt means a more mobile pattern, while a more vertical feature indicates a more static or slow-moving pattern

I've simplified the colours. I've not yet decided where to surface these charts on the site, as there'll be GFS and GEFS too. 

That’s definitely easier on the eye 

GFS on the other hand has decided it’s going to keep on with the Sunday/Monday second plume and then set things up for a mid-August heatwave. 

Remains to be seen what ECM and AIFS are up to. 

So if I’m understanding that right, the UK is likely to be on the western edge of a high pressure for the next 10 days or so, and then low pressure is more likely to be sitting over our longitude?

To be fair though the latitude covers from Spain/Italy/Greece up to Shetland and Scandinavia. It is a useful piece of the picture but in isolation it can hide a lot of specific detail.

That's right. As usual, though, it's worth remembering that this is showing the output from just one deterministic model run. When I add the GEFS, it will probably be the ensemble mean, which should also provide some value.

GFS  Op 0z - ... not that it cools down a lot, as pressure rises across Britain for the weekend. The next development is a shallow LP moving up from the SW to1010mb S England Wed 5th,  looking less settled and bringing in some cooler though still warmish weather from the north or northeast by Sun 9th. The Azores high doesn't give up and by Tue 11th has pushed out a ridge across N England.

ECM to T +240 - a warmer/hotter outlook than FAX/GFS; on Fri 31st the cooler N-lies get no further south than Scotland, and that briefly; the LP on Wed 5th stands back and brings hotter easterlies rather than northerlies Wed 5th.

AIFS - London, about 25C to Wed 5th with extra peaks to 30C Wed 29th and Mon 3rd, and dry; then down to 20C to Mon 10th with heavy rain Fri 7th and spots at other times. Edinburgh, generally 16-17C with warmer interludes to 20C Tue 28th, Tue 4th and Mon 10th. Rain on various dates, most likely (unusually?) in the warmer interludes.

GEFS - In England, two-day peak Wed/Thu 29th/30th to 10C above norm in S, 5C in N,, then mean temp and most ens members close to norm through to Wed 12th (however several hot outliers incl op run Tue 4th), probability of rain from Tue 4th but in the SE not a lot and not in every run. In Scotland, just above norm this midweek, then 3 or 4 C below norm for the first week of August, slowly recovering, rain possible on any date, likely to be heavy around Thu 30th and Fri 7th. 

Continuing contrast between England and Scotland.

No chart review tomorrow,  I have an all-day hospital 'procedure' (their word);  maybe no review Wednesday, either.

https://www.wetterzentrale.de/en/ens_image.php?geoid=50902&var=201&run=0&date=2026-07-27&model=gfs&member=ENS&bw=1 

A bit cynical myself, but we shall see.

The CFS for August shows high pressure to the West with a shallow trough to our East, if it's to be believed, indicating a cool and showery month ahead.

Definitely seeing signs that August will be a more unsettled month although the Met long ranger continues to go for a largely warm and settler picture. 

I am getting a bit more concerned about the potential for some major troughing hitting Europe around week 2 of August as it could scupper the eclipse viewing chances. 

Hope it goes well David.

Yes, summer is loosening its grip and that is clear to see.  This weeks mini heatwave could well be the curtain call.  At least the grass will finally get a drink hopefully

You said that two weeks ago as well, yet here we are