AIFS 12z mean above 20c now. Crazy times.

https://wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=aifs&var=2&run=12&lid=ENS&bw=1 

Not only that but t2m values here reach above average for a day or two!

Yes easterlies not helping you even with way above average 850s. Hopefully you can get a hot spell at some point this summer.

GFS Op 0z - following on from FAX, HP revives over Scotland and slack LP moves up from Spain; these two dance around each other with a direct SE-ly flow established by Thu 25th. From Sun 28th LP moves from mid-Atlantic to N Scotland (1000mb Tue 30th) with eventually cooler westerlies for all. For the rest of the period to Sun 5th there is a nondescript W or NW-ly drift for Britain.

ECM - very much like GFS

AIFS - London, maxima in upper 20s through to Tue 30th with as couple of spikes through to 30+C Tue 23rd and Sat 27th. Then back to 25C with significant rain Wed 1st. Edinburgh, warming to 20C with only Sun 28th breaking 25C.Dry-ish for the beginning of next week but otherwise rain at times.

GEFS - mean 8-10C above norm in the S until Sun 28th when mean slowly drops back to norm, the 'slowly' being the average of ens members which drop off one by one (control quickly, op slowly). Little rain, perhaps a bit as July starts esp in N England. In Scotland , less etreme heat and slower to start (not until Tue 23rd) which marks the start of a few dry days, otherwise smal amounts of rain on many days.

Manky Monday, Terrible Tuesday, Woeful Wednesday... I won't go as far as Friday! 😂

You can see why the Met Office issued that amber weather warning, and why they did it unusually far in advance. The output is coalescing around a truly remarkable spell, and I wouldn't be at all surprised to see the 1976 record fall. (And if it does, at least it'll dent the "it's just summer", "1976 was hotter" type stuff you see online). 

(ICON, FWIW, has "only" 34C on Tuesday, but even that is a good 13C or so above average for the time of year. Truly remarkable output all round, really.)

https://images.meteociel.fr/im/22/27893/iconeu_uk1_31_102_0rih9.png 

Irish sea coasts around here looking to have a few tropical nights coming by the 20c definition, with temps around 25c at 9pm and 9am bedrooms will be sticky in the towns.

Bought the last available portable aircon unit from the local screw fix earlier.. Blyss 9000 BTU. 

Met office have 4 consecutive ones for this location. And the nights either side of the run are both 19 so we could actually end up with 5 or 6 consecutive tropical nights 🥵

GFS Op 0z; That HP sticks around the N Sea/Baltic and with shallow LP drifting north from Spain up to the west of Ireland, the hot southerly flow is maintained across Britain to Sat 27th. That LP then exerts a bit more influence with weak westerlies for the north but the hot air never leaves the south, through to Fri 3rd. Then a heat low from Spain moves north to the Channel and brings in something a little cooler (and more disturbed?) for Britain over the weekend 4th/5th. But the heat is not far away and could still affect the SE .

ECM - agrees with GFS (to T+240 = Mon 29th at time of posting)

AIFS - London, heat builds to a peak of 36C on Wed 24th and then slides back down to maximum of 23C Mon 29th, continuing to decline to 20C by Sat 4th. Some rain Sat 27th, spits and spots at other times. Edinburgh, reaches a peak of 25C Tue 23rd and a secondary peak 23C 23C Fri 26th, then slides to 16/17C Mon 29th onwards. Some rain on most days after Fri 26th, just a little before that.

GEFS - In the S, a heat bulge (rather than a peak) Mon 22nd to Sat 27th, up to 13C above norm, then mean temp drifts down surrounded by a cluster of ens members to a couple of degrees above norm from Wed 1st (op is a hotter outlier at the end). Chance of rain from time to time but not shown in every run. Somewhat similar in the north, but only 9 or 10C above norm and end-loaded, more runs showing rain from time to time but no definite pattern.

https://services.meteored.com/img/models/ecmwf/ECMWF_114_GB_SFC_fr-FR_fr.png 

https://services.meteored.com/img/models/ecmwf/ECMWF_150_GB_SFC_fr-FR_fr.png 

https://services.meteored.com/img/models/ecmwf/ECMWF_162_GB_SFC_fr-FR_fr.png 

https://services.meteored.com/img/models/ecmwf/ECMWF_168_GB_SFC_fr-FR_fr.png 

That is going to feel so oppressive! Being in the city I imagine those nights will take a long time to fall to those values if they even drop that low. 

The fat modus darts players are going to struggle.

Arpege showing 35°C at 10am Tuesday, Hampshire/Berkshire border.

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