Model output discussion - into July 2020

[Fourty Point Three Degrees]

Gfs 18z is dusting down the old blowtorch as early as Thursday now and is showing 31c for London on Thursday. As for Friday here is the chart is for 09.00 and you just know its going to be a hot day when charts at 9am are looking like these....

Edited August 1, 2020 by 38.7°C

[DaveL]

There's a lot of rain around next weekend on the 18Z GFS Op run, especially but not only in the west. High temperatures in the SE aren't much use for those who won't be there especially if the HP turns out to be too far north and where it's rainy.

Let's wait a few days before we get too excited.

 

Edited August 1, 2020 by DaveL

[Cheshire Freeze]

Just now, DaveL said:

There's a lot of rain around next weekend on the 18Z GFS Op run, especially but not only in the west. High temperatures in the SE aren't much use for those of us who won't be there especially if the HP turns out to be too far north and where it's rainy.

Let's wait a few days before we get too excited.

 

With a bit of luck the SE heat brigade can have their 35c and here in the west we can have the storms. 

Would leave me a happy man.

[Djdazzle]

10 minutes ago, DaveL said:

There's a lot of rain around next weekend on the 18Z GFS Op run, especially but not only in the west. High temperatures in the SE aren't much use for those who won't be there especially if the HP turns out to be too far north and where it's rainy.

Let's wait a few days before we get too excited.

 

Possibly a little misleading. GFS precip charts are pretty hopeless at that range, and it may well be showing the possibility of convective rainfall, which is no guarantee of rain in any given location.

[sheikhy]

2 minutes ago, Djdazzle said:

Possibly a little misleading. GFS precip charts are pretty hopeless at that range, and it may well be showing the possibility of convective rainfall, which is no guarantee of rain in any given location.

hows the 18z mate?better than gfs 12z?

[Djdazzle]

5 minutes ago, sheikhy said:

hows the 18z mate?better than gfs 12z?

Hot out to day 10 in the south and east. Looks hotter than the 12z, although less so for more western / northern areas.

[summer blizzard]

Euro tonight is pretty horrific for cool lovers however thankfully not likely to come to fruition with some very hot but unstable Synoptics that would be difficult to actually achieve.

GFS18z is also hot but looks wet at times. Actually very similar to late June in setup.

Also interesting around day 9-12 is the signal to build pressure in the mid-Atlantic albeit it could collapse back to the UK.

[Man With Beard]

There might be a mixture of disappointment and relief at the GFS 00Z refusing to go full blowtorch - now joined by half of the GEFS - but actually the GEFS is starting to follow the route which would bring a more extended heatwave, with a fresh wave of the Azores High ridging in by Sunday - this will keep it very warm after perhaps a transition day, and it might keep the SE above 30C for the foreseeable future anyway apart from on one day. 

The UKMO, however, remains full blowtorch, with 100F in its sights by Saturday I would imagine. 

[Captain Shortwave]

I must admit despite some impressive heat being pushed northwards on some models, there is part of me feeling a little dubious as to how long and intense this spell will be.

Day 5 (UKMO/GFS/GEM)

      

Friday still looks hot across the board, but the depth of the trough on the UKMO/GEM has diminished somewhat compared to previous outputs whilst the GFS frankly has remained similar and now there is clearly great interaction between the Atlantic trough and the deep low heights close to Greenland.

Day 6

      

UKMO and GEM develop a cut off circulation to the west/south west of the UK that draws the heat northwards significantly. The GFS has a heat low to the south but the trough has fully lifted out by Saturday. Still hot/very hot on Saturday though. Sunday onward, the high to the north east still dominates but surface conditions will depend on how all the parts play out, the GFS for example sees temperatures fall and a north east wind set in across the country, that could bring a lot of cloud into eastern areas. The GEM keeps the hot conditions going for longer, as would the UKMO. But of course neither of these models appear to have handled conditions well upstream even at quite short range, which casts some doubt on the very hot solutions.

Edited August 2, 2020 by Captain Shortwave

[East_England_Stormchaser91]

8 minutes ago, Man With Beard said:

There might be a mixture of disappointment and relief at the GFS 00Z refusing to go full blowtorch - now joined by half of the GEFS - but actually the GEFS is starting to follow the route which would bring a more extended heatwave, with a fresh wave of the Azores High ridging in by Sunday - this will keep it very warm after perhaps a transition day, and it might keep the SE above 30C for the foreseeable future anyway apart from on one day. 

The UKMO, however, remains full blowtorch, with 100F in its sights by Saturday I would imagine. 

A halfway house would even be brilliant in a long overdue August heatwave. I’d be more worried if the UKMO wasn’t having any of it, as that’s usually the party pooper model. 

[clark3r]

I know it is only one run from the gfs but still looks good to me, 35 Friday, 33 Saturday, much cooler Sunday then warming up again, ecm very hot Friday Saturday, then breakdown by Sunday. UKM very hot There is quite a difference from last nights 40 degrees lol but still quite intense heat for at least 1/2 days 

Edited August 2, 2020 by clark3r

[Captain Shortwave]

ECM

     

In all honesty a cut off system will be good enough to steer the heat northwards across many parts of the UK. Hot Friday/Saturday with thunderstorms possible Saturday night into Sunday.

However this route seems a lot more complicated beyond Friday, a simple Atlantic trough is fairly stable to model, now we have cut-off systems that may or may not exist come next weekend.  

 

Edited August 2, 2020 by Captain Shortwave

[Man With Beard]

Friday and Saturday both look like 35C plus days on this morning's ECM (and still a chance of getting to 37/38C on Saturday) 

Like many ensembles last night, the ECM then clears away the serious heat and gives us low 20s north / high 20s (possibly 30) south for the following days, which is what I would call a more "traditional" heatwave? 

Still as CS states above, the cut-off trough renders a precise forecast beyond D6 difficult. 

Edited August 2, 2020 by Man With Beard

[Djdazzle]

Looking like two fairly nailed-on very hot days on Friday and Saturday. Still hot beyond, but with varying options as to how hot. As others have mentioned, the models may be struggling to handle low pressure out west.

[Methuselah]

Good morning, folks. 

Right then, the GFS 00Z has turned down the heat a tad... but it still suggests that a stonking three-weeks' weather is on the cards, with a good number of c. 30C days:

    

    

    

    

And a cracking set of GEFS ens too!

    

    

NH profiles:

    

    

[northwestsnow]

EC 00z is beautiful.

The heat is coming,will we see any juicy storms is the question?

Looks potentially thundery next weekend..

[Man With Beard]

ECM ensembles fairly united until Saturday, but a big divergence by Sunday in southern areas with members fairly evenly spread between 22C and 35C! (raw 1pm temps) Northern areas fairly likely to see less hot conditions by Sunday. 

[Djdazzle]

2 minutes ago, Man With Beard said:

ECM ensembles fairly united until Saturday, but a big divergence by Sunday in southern areas with members fairly evenly spread between 22C and 35C! (raw 1pm temps) Northern areas fairly likely to see less hot conditions by Sunday. 

That’s some divergence. With UKMO and GEM looking to continue the very hot conditions, I would slightly favour that outcome for now. But as the cliche goes - more runs needed!

[NApplewhite]

9 hours ago, 38.7°C said:

Gfs 18z is dusting down the old blowtorch as early as Thursday now and is showing 31c for London on Thursday. As for Friday here is the chart is for 09.00 and you just know its going to be a hot day when charts at 9am are looking like these....

 Massive downgrade for the hot weather for North East Wales and Cheshire its turning into just warm weather on Friday and Saturday with temperatures falling by 10c during Saturday night and Sunday daytime - from 29 down to 19. The wind direction has shifted markedly in the GFS forecasts this morning (London hangs onto the heat). No blowtorch for Wales! 

[NApplewhite]

19 minutes ago, Man With Beard said:

ECM ensembles fairly united until Saturday, but a big divergence by Sunday in southern areas with members fairly evenly spread between 22C and 35C! (raw 1pm temps) Northern areas fairly likely to see less hot conditions by Sunday. 

I dont want cool conditions in Wales! Its not fair! The heat is only 100 miles away! 

Edited August 2, 2020 by NApplewhite

[Guest]

2 minutes ago, NApplewhite said:

I dont want cool conditions in Wales! Its not fair! The heat is only 100 miles away! 

Don't take the temperatures as gospel. They will change with every data update. The key is getting the hotter 850s in for the end of next week. Models at this range, notably GFS, will model any convective precip in a clunky way (big, low-res blobs) and will cause some unnecessarily low and incorrect temperature figures. 

It's easy to torture yourself with upgrades and downgrades. It looks very likely we're getting the heat in. Still question marks over how long for and what the peak will be  

[Scorcher]

7 minutes ago, NApplewhite said:

 Massive downgrade for the hot weather for North East Wales and Cheshire its turning into just warm weather on Friday and Saturday with temperatures falling by 10c during Saturday night and Sunday daytime - from 29 down to 19. The wind direction has shifted markedly in the GFS forecasts this morning (London hangs onto the heat). No blowtorch for Wales! 

It's only the GFS though- no point getting too disconsolate. The ECM and UKMO are much better for your area and still hot on Friday and Saturday at the very least. The GFS has been the odd one out for the past few days.

[Djdazzle]

The hot day last Friday exposed the GFS temperature predictions big time! Even at 24 hour range.

[bluearmy]

The overnight runs show why post day 6 is always up for enough change to make over analysis of it unnecessary ...... the ec op doesn’t have support in yesterday’s 12 z clusters/spreads with the upper trough swinging ne  with that depth ......

[Guest]

Bbc already flagging up 35c for friday....