Model Output Discussion - Autumn arrives

[Captain Shortwave]

44 minutes ago, MattStoke said:

GFS is normally spot on at short range and you can normally add a few degrees to most of the others but I’m surprised the Arpege isn’t higher.

Difficult to tell on the low resolution version of the UKMO with the large jump between frames but I think it this morning keeps the heat in for longer on Tuesday.

One thing yet again I am noticing is that the models are not predicting clear skies for pretty much the entire period to Wednesday. I do wonder whether the models are over estimating the effects of high level cloud. For example the models this morning from the likes of Arpege show quite a lot of cloud cover, but in reality the cloud layer is so thin that it will have no effect on the temperatures. At this point the GFS seems to be the closest to the forecasts we have seen on the BBC, Metoffice, so perhaps cloud amounts are being overplayed in modelling temperatures.

[Paul33]

6 hours ago, Polar Maritime said:

Yep that's why there is a once in a lifetime red meto warning out  covering a wide area for extreme heat..

Am I not correct in thinking that these official warnings only started in 2021 ?

[MattStoke]

UKV 3z. 40’C Monday. 42’C Tuesday  

[Gordon Webb]

33 minutes ago, Paul33 said:

Am I not correct in thinking that these official warnings only started in 2021 ?

Yes that's right and a year later the first red warning

5 minutes ago, MattStoke said:

UKV 3z. 40’C Monday. 42’C Tuesday  

yep especially in Lincolnshire up to Yorkshire for Tuesday , down to a mere 37'C for me at that time LOL

Edited July 16, 2022 by Gordon Webb

[sheikhy]

By the way 18z ecm pulled things slightly further west!!

[sheikhy]

24 minutes ago, MattStoke said:

UKV 3z. 40’C Monday. 42’C Tuesday  

And again bang in line with the red warning✌!

[Captain Shortwave]

The period after this spell looks quite messy,  a lot of shallow lows slowly moving through weak and quite amplified ridges. Probably mostly dry still for most.

It might be quite cool in the east with the wind off the north east, though how much of this there will be is still up in the air, but reasonable agreement that high pressure will move in once that low clears away.

[Weather-history]

ECM 0z, potential for a noisy end to the heat

[mb018538]

14 minutes ago, Weather-history said:

ECM 0z, potential for a noisy end to the heat

Probably ticks more boxes for more people. Big heat and then  

[Paul]

That is some hot, dry air on Monday.

And the thicknesses still blow my mind every time I look at them. It's hard to get out of the mindset that 'surely the models will change' despite the fact we're only a couple of days out now. But no, this is actually going to happen and 40c is a real possibility.

 

 

[BlueHedgehog074]

The latest UKV also bringing some bangers about heading throughout Tuesday afternoon and night with some stronger more organised thunderstorms heading North-East through Wednesday morning into the afternoon ️

 

After all the hot hot hot temperatures late this weekend into early next week, would be cracking to have it all go off with a bang!

[mb018538]

Interesting that ARPEGE ‘only’ shows 37c for Monday and 38c for Tuesday. Much lower than others like gfs/UKV etc which keep churning out 40c plus. 

[MattStoke]

Oz MOGREPS keeps the heat over London until much later Tuesday night. Even has a strong uptick Tuesday afternoon that could boost temperatures further.

[Captain Shortwave]

ECM has a raw 35c and 37c for Monday and Tuesday, so translating to around 37c and 39c in reality. Still need to firm up on the precise details but the eastward corrections have appeared to have stopped or even back west a little.

I am not expecting much rain Tuesday night, but maybe we may see some impressive lightshows if elevated thunderstorms do develop.

[Nick F]

2 minutes ago, mb018538 said:

Interesting that ARPEGE ‘only’ shows 37c for Monday and 38c for Tuesday. Much lower than others like gfs/UKV etc which keep churning out 40c plus. 

00z EC only going for 36C max just to the north of London during peak heating (15z) on Monday. 37C max inland E England / E Mids on Tuesday at 15z

 

[sheikhy]

Ecm 00z stays further west like the 18z!!!i think that will be that and a guaranteed 2 days of record breaking temps more widely!!

4 minutes ago, Nick F said:

00z EC only going for 36C max just to the north of London during peak heating (15z) on Monday. 37C max inland E England / E Mids on Tuesday at 15z

 

Add 2 or 3 degrees easy to those nick!!!!ecm way too low at times!!!

[clark3r]

Gfs has been consistent on last few runs for temps around 40 on Monday and Tuesday, it is looking like Tuesday will be the hotter of the 2 days, plume 3 is on the way next week onwards and looks like mid 30s for days interesting to see how this develops in next few days 

[KTtom]

Stunning chart for mid-week... brisk north westerly, A massive relief for most i would have thought....

 

 

[Nick F]

1 minute ago, sheikhy said:

Ecm 00z stays further west like the 18z!!!i think that will be that and a guaranteed 2 days of record breaking temps more widely!!

Add 2 or 3 degrees easy to those nick!!!!ecm way too low at times!!!

00z ICON and ARPEGE similar values to EC, GFS and UKV 2-4C higher, be interesting to see which models are more out on the day. 

Be worth checking the 00z radiosonde ascents (Hertsmonceux, Nottingham/Watnall, Camborne, Larkhill) on Monday and Tuesday, because if 1000-850 hPa thickness is 144.0 dam+ then a good chance of 40C.

[bluearmy]

Mogreps 00z

Mon: 11 runs are 35+ (a little down on yesterdays 12z run)

tues: 3 runs out of 17 don’t make 38c. One of these three doesn’t make 37c. All runs are 35+ 

[kold weather]

17 minutes ago, Nick F said:

00z EC only going for 36C max just to the north of London during peak heating (15z) on Monday. 37C max inland E England / E Mids on Tuesday at 15z

 

ECM feels too low on its surface temps with 22-23c at 850hpa, for reference that is about the same levels as we saw in July 2019 so I suspect we will be looking at maxes somewhere roughly in the same ballpark.

I suspect the ECM again is understating max temps, it certainly has been too low in the last two hot spells we've had this year.

ARPEGE is a harder one to tell as its normally closer to the mark. However upon looking at the 18z ensembles, it becomes clear that the 00z run would be right at the bottom end of the ensemble range.

EDIT - ICON IMO looks a decent middle ground mind you.

 

Edited July 16, 2022 by kold weather

[bluearmy]

 

Tues noon fax 

that CF is surely going to set it all off !

If there is a  gusty wind Tues pm over eastern England its going to be crazy with those temps 

[sheikhy]

By the way just compared the temps for tuesday on wetterzentrale for ecm and the temps are a degree or 2 higher and further west across england for tuesday!!!defo shifted things west overnight!!

[MattStoke]

Worth noting that the publicly available ECM charts show the mean temperature for each 3 hourly period rather than the maximum temperature. That at least partly explains why they are always lower than most other models. 

Edited July 16, 2022 by MattStoke

[kold weather]

1 minute ago, MattStoke said:

Worth noting that the publicly available ECM charts show the mean temperature for each 3 hourly period rather than the maximum temperature. That at least partly explains why they are always lower than most other models. 

The site weather.us (and probably othersw)_ have a T-max function that looks at the highest temperature within that time period. The temps are exactly as Nick said.

It just is lower than most of the models, who knows at this point whether its right or wrong. 

I'm struggling a little though with 850hpa being decently over 20c with sunshine on Monday and the ECM struggling to get above 35c, seems a bit low IMO. Equally I suspect the GFS/UKV are a little high as well, the profile is kinda similar to July 2019 so a 37-38c seems realistic on Monday IMO.