just seen and fits in with seasonal models tbh. If that run came off we would start having serious issues. 

GFS Op 0z - the LP from Spain continues northwards and by Sun 28th has combined with Atlantic LP to bring in some gentle westerlies, though the far SE may hang on to continental heat. A ridge of HP from the Azores then comes and goes; Wed 1st across the South (fresh in Scotland, warm on the south coast), Sun 5th across Scotland (fine there, easterlies for the Channel). Finally Tue 5th Britain lies in a col between 1030mb Azores and 1020mb Baltic.

ECM - much like GFS

AIFS - London, peak maxima Wed/Thu 24th/25th at 37C dropping to 25C or therabouts with a little rain Sun 28th and staying there for the following week. Edinburgh, peaks at 25C Tue 23rd and Fri 26th, then down to high teens from Sun 28th. Some rain Thu 25th, rather more Wed 1st.

GEFS - In the south, mean and ens temps 13C above norm this week, dropping sharply to *only* 4 or 5C above norm Sun 28th with several runs showing heavy rain at that time (which wasn't there in that quantity yesterday). Mean continues at that level but with big ens spread, also some chance of rain at times. In the north, the hot spell is less extreme, and end-loaded (more of a peak on 26th, not as much of a plateau as in the south). Greater chance of rain into week 2 but not in all runs.

I hope we get some rain here in SE Devon but I suspect we wont see any for the foreseeable. However I've not delved deeply into the outputs so I can hope one of the runs is right.

The heat is just something to endure.

After the heat, it seems to be a gradual cooldown and maybe a little rain around, if the EMS are correct??

Some hints of some thundery showers over SW Britian tomorrow in the Beeb- though so hit & miss.

I don’t understand how the Met Office is getting these details incorrect when tomorrow London has  a top temperature of 29 down from the projected 34 previously and still a warning tomorrow  of extreme heat . Possibly southern England may luckily get away in the end with these really high temperatures ?

Interestingly, as with the 1976 Southampton record, a wind from ENE may come into play. That means London/SE won't do quite as well as further WSW.

The station in that 1976 record was in Mayflower Park, slightly SW of the town centre and its slightly raised land. The upcoming heatwave would produce I believe staggering temperatures should the station still be operative. They pulled it apart in 2000 and the Weather Centre further in-town no longer exists either which, frankly, astonishes me as sources (including TWO) still quote 'Southampton/ Weather Centre' in daily extremes.

The initial amber warning for Mon/Tues is for medium impacts from extreme heat and the Wed/Thursday one for HIGH impacts....check out the matrix. I suspect they're positioning themselves to 'GO RED' if necessary.  Even if tomorrow's maximum are a tad lower than previously expected, it's a good warning strategy to highlight the build up. This strategy will also be heavily influenced by UKHSA input. The Met Office don't operate in isolation when it comes to heat warnings. 

GFS Op 0z - that LP moves on to N Scotland 1005mb with a spell of light westerlies though the SE never free of continental heat. Then a ridge of HP from the SW spreads across Scotland Tue 30th and the heat comes back for England from the east (but NW Scotland has an Atlantic influence). New LP develops off W Ireland Fri 3rd and brings some Atlantic air in its circulation, moving to Scotland Wed 8th, cool for Scotland, heat never far from the south coast

ECM - like GFS to Tue 30th but the ridge never really gets established, and on Wed 1st pressure falls 1005mb N England with a light northerly in its wake - much cooler.

AIFS - London, maxima reaching peak of 36C Thu 25th before falling back to low 20s for most of the w/b Sun 28th before rising to 31C from Sat 4th. A little rain now and then. Edinburgh, peak maximum is Tue/Wed 23rd/24th at 25C falling away to upper teens and rising to 26C to match London's timescale. Rain Fri 26th and Wed 1st, a little at other times.

GEFS - in the S, hot (14C above norm) to Fri 26th, then mean falls to 2 or 3C above norm Wed 1st (earlier in W), staying there, with support from the majority of ens members but a tracery of hot outliers (up to 12C above norm) persisting, Small amounts of rain in some runs, most likely Mon 29th. In the N, heat rises to a peak Fri 26th (12C above norm) and drops quickly, back to norm and staying there from Sat 27th with very few hot outliers. Rain in most runs on many days after Fri 26th

Edit to add I should have said unprecedented in June, July 18/19 2022 had over 24hrs of 20°C+ air at 850 hPa here but a less favourable westerly orientation to the approaching air mass with it maybe being less humid then? 

Yes this spell is starting to look like a bust in terms of super high temperatures but the duration is increasing. Seems we will have four or five days of 34-35 instead of two or three of 38-39. Today’s rain seems to have altered the whole dynamic. 

And on the 18Z GFS low pressure doesn’t seem to get much of a look in, even Saturday is well into the 30s. 

An extension at less intensity is welcome from my perspective (and for my free roaming outdoor rabbit).

Further attenuation in the extremes from the 18z Arpege.  I wonder if we'll see a removal/shrinking of the red zone tomorrow if this continues into the morning?

34c, 28c, 28c, 29c, 30c, 30c, 

GFS Op 0z - as FAX, then the weather settles into a more familiar westerly pattern, LP north of Scotland while the Azores high nudges in from the southwest. There's still some rather warm weather for the south until Tue 7th when the LP to the north peps up 1005mb Orkney bringing in northerlies behind it. Back to the westerly pattern later that week.

ECM (to T+240) - like GFS at first, but the ridge from the Azores develops further north and narrowly, lying across N England Wed 1st, with brisk SW-lies for the north of Scotland and easterlies (quite hot?) along the Channel.

AIFS - London, peak maximum Wed 24th at 35C, sliding increasingly quickly over the weekend to about 23C, holding there through to Tue 7th (briefly warmer Sat 4th). Rain today, Sun 28th and Mon 6th. Edinburgh, maximum is 25C today, then a more prolonged but irregular decline to around 15C from Thu 2nd. Small amounts of rain at any time but rather more Fri 26th, Wed 1st and Sat 4th.

GEFS - In the S, a slide from 13C above norm Fri 26th to a degree or two above through to Thu 9th, only a few hot outliers. Small chance of small amounts of rain at any time, perhaps a little more than this in the east later. In the N, brief peak 9C above norm Fri 26th, then back down to norm to the 9th, good ens agreement. Rain likely Sat 27th, smaller amounts from time to time in some runs thereafter.

It did... but it seems the models got this one very wrong indeed. having 5C downward corrections just 48 hours out and totally missing thunderstorm development is pretty poor.

Agree re the thunderstorms in the SE. The storms we had here were well forecast. The best three days have yet to happen, so I won’t pre-empt our actual temps yet

I appreciate forecasting can be difficult but a 5 degree drop to 35 I thought would qualify for an amber warning, not red? Or are they still unsure?

I think is because the UKV 03z still has 39/40c in the West Midlands on it.  

Arpege 06z has been resolute on the temperature downgrades with 33-35 more typical.  Still hot, there will likely be a localised 36/37C as a minimum so the June record should still fall.

If UKV downgrades Thursday to 33-035, then that *ought* to see the red warning downgraded, but they may not due to how late in the day it is & how much the red warning message has been publicised already. 

It's won't be just the absolute max temperature that they will be including for that red. Other things will be considered such as overnight lows and crucially dew points. 

37C with a dew point of 14C will feel drastically cooler then 37C with a dew point of 22C. One being more detrimental to health then the other.

Better for running in.🏃‍♂️