P21 delivers. To see 40C being shown on these charts so late in the season is crazy. 

Lets hope not, that's god awful 😢. And FI looks at least as awful.

We desperately need rain. We'll need relief from the heat too soon. You can't drink if it doesn't fall out of the sky first and our environment just isn't adapted for 30-35C plus for days/weeks on end.

Still, the school holidays eh? The 'its always rains' nonsense will still take some shifting 😂

Insanely hot UKMO 12z. The 20 degree isotherm in overnight Tue/Wed and then back again on Saturday...

Notice this year those western side of England and Welsh border seem to cop all the heat than London area even London itself 3C cooler than outside the city.  Won’t happen but if does new national record of 40c in extreme SE Wales.

I see the MetO raw is up to its usual tricks down here - each day the forecast gets that bit hotter. It's now showing 26/32/30/28/28/26 for the next six days, and the GFS is following suit - it now shows 28/32/32/30/29/23, which would be a remarkable heatwave for my coastal location.

Intriguingly both MetO and GFS show the hot weather on Tuesday will be accompanied by easterly winds, from the North Sea, so it shows just how hot the upper air is expected to be. The 0z MetO had the 20C 850 isotherm across southern England, while the 12z has it over the SE (including here):

https://images.meteociel.fr/im/97/4418/ukmo_1_72ksk0.png 

GFS also has it brushing the south:

https://images.meteociel.fr/im/18/23916/gfs_1_54bvu1.png 

That would imply a very humid / oppressive feel and a couple of horribly warm and sticky nights as well. Expect zombies on the roads on Wednesday and Thursday mornings in the SE if that comes off!

Let’s hope so. It’s summer, and the longer it continues the better. September feels like a summer month nowadays too

Would like to know myself as to what a 'man made front' is. What does that even mean? 

High pressure, with perhaps a random summer shower, a clear signal now for the next 10 days with no clear signal after that on the en means. 

And look where the heat is - what an extraordinary event that would be if it were to come off. 40c in Wales would be beyond exceptional. 

These days i reckon 40C is possible up to the first week of September.   🙂🙂

Remember we have the MO breakout thread here for OT:

https://www.theweatheroutlook.com/twocommunity/Posts/t24393-Model-output-breakout-thread 

I've just moved posts to it.

GFS Op 00z; HP just east of Britain and LP to the west bringing up warm/hot air, even reaching N Scotland, and perhaps with some embedded thundery activity. The pressure blocks shift around on Fri 16th with HP near or to the north of Scotland and LP over France generating light E-lies through the Channel, though still warm for S England. Pressure drops generally over Britain Wed 20th 1015mb but the HP Scotland/LP France setup soon returns, until Tue 26th when the LP over France becomes more dominant.

ECM; similar to start with, though from Fri 15th, the HP slips E-wards and by Tue 19th the synoptics are very much the same as they are today, implying a fifth(!) heat wave.

AIFS; London, peak temps 32C Tue 12th, then maxima close to 25C and dry until Wed 20th, by Fri 22nd dropping to 20C with significant rain. Edinburgh, peak temps 25C Wed 13th/Thu 14th, followed by a fairly steady decline to 15C Fri 22nd and staying there, small amounts of rain in the first week, drier later. The change from one pattern to the other appears to be near the Scottish border.

GEFS; in the S, peaking for a day or two 10C above norm Tue/Wed; after a slight dip, mean again rises, to about 8C above norm Tue 19th for a few days, then down to norm with probable rain from Fri 22nd. In the N, similar temp profile but flattened out and not so extreme (6 or 7C above norm, not 10C)rain possible at any time except for a few days around Mon 17th

I've just moved some more posts to the breakout thread where the discussion can be continued if you wish.

https://www.theweatheroutlook.com/twocommunity/Posts/t24393-Model-output-breakout-thread 

Please use this thread to discuss the model output itself. 😊

The most prolonged heatwave of the summer if this mornings output is on the money.

The 6z doesn't argue with that either- in fact, implies that this fourth and any possible 5th heatwave actually could merge into a single longer hot spell.

Not sure about it as it been delayed and cutting short than what models predicted.  Lot of cloud and rain to the SW which was totally wrong forecast.  Very worried about tomorrow near mid 30s and sunny won’t happen as it haze overcast and not very warm today. 

Agree poor forecast especially for the SW rain.  But it has reached 30c in the SE. 

Some quite general rain at the moment, resolving later in the evening into the classic line of showers down the mid-line of the SW peninsula.

https://weather.metoffice.gov.uk/maps-and-charts/rainfall-radar-forecast-map 

My rain gauge hasn't tipped once today thought it's been 'raining' on and off since late morning. It has though, kind of, been modeled for several days tbh.

Wrong thread I guess, but it’s really odd. We are right under the rain and have been for a couple of hours yet not a drop has hit the ground. I can only assume it’s evaporating before it reaches the ground?

That'll be it. 850 temps are rising* and marginal ppn can't keep form. I love to see 'virga' curtains draped windward when the rain can't reach the ground. 

*The MOD bit.

All the talks about heatwaves, full sunshine and high temps i don't see it at all just continuing unsettled and overcast all against what the models predicted, can't see temps of low 30's tomorrow here with the clouds being a issue.  I wonder why we getting so many fronts this year that kept interferring all last 3 heatwaves that being cut short like this one no exception so that another 3 days lost.  Gave up this one and the ensembles show another warm/hot spell this weekend onward so hope to be sunny and hotter one than this fail one.

Plus most models are predicting mid 30's in the West/SW/and Welsh border so how it can be reached with this current rain and extensive overcast skies now.  Well i will read what the comments for 12z runs and focus the next batch of warm/hot weather this weekend ownard.

This evening's update looks warmer towards the end, at least in the south. The signal for wetter conditions during the last third of the month is still present, but weaker.

GFS Op 00z; HP over N Sea and LP to the west directing hot air over Britain, and even though the pressure gradient declines and cuts off new supplies, the hot air remains in place and if anything gets anchored over Britain as HP develops over Scotland 1030mb Sat 16th. This HP finally transfers to mid-Atlantic Sat 23rd with cooler N-lies. At this time there's an ex-hurricane near the States which fills and tracks round the 'top' of the HP introducing W/NW regime from Tue 26th.

ECM; the HP transfers to Iceland rather than mid-Atlantic Wed 20th with LP approaching England from the S. The hurricane just creeps into the SW corner of the last chart in this model, Fri 22nd.

GEM; doubles up and on Sat 16th has Hp over Iceland AND mid-Atlantic; and then doubles up again with TWO hurricanes heading NW-wards towards Britain Fri 22nd, the leading one having arisen only a day or two earlier over the Gulf Stream, the following one having taken the usual route from the Caribbean

AIFS; London, temps dropping from tomorrow's peak of 31C to about 25C and dry to Fri 22nd when a further drop to 20C with some rain. Edinburgh, starts at 25C then a more gradual decline to 15C Wed 20th, staying thereabouts with rain Fri 22nd and Wed 27th.

GEFS; In the S, peak heat tomorrow soon dropping off but back again around Mon 18th 8C above norm, then a gradual decrease in temps to a little above norm Sat 23rd, staying there as a balance between increasing spread of ens members. A little rain from Fri 22nd onwards. In the N, same trends in temp though not as extreme; some rain Thu 14th and from Thu 21st onwards.

Heat lovers make the most of the next 8 days or so; but gardeners should continue to worry beyond that

First Autumn chill later next week on the cards. Will come as quite a shock. 

in the short term,  UKMO still showing the hottest scenario with a better shaped high.