Model output discussion - into July 2020

[Djdazzle]

I had little faith in the GEFS even before the fiasco when the entire suite was wrong at T96!

Edited August 3, 2020 by Djdazzle

[Captain Shortwave]

5 minutes ago, kold weather said:

ARPEGE is quite a bit cooler for Thursday on this 12z run, more in line with the other models.

About 3-4c cooler than the 06z/00z run. I'm guessing Friday will be similarly cooler than it would have been, though still very much on the hot side of things.

Had a look, this run has a fair amount of high cloud around on Thursday, even across the areas that were expected to see the highest temperatures. This would be the reason for the drop on this run.

 

It is strange to see the Arpege and GFS giving the same maximum temperatures (Around 29c). Friday temperatures generally in the 32-35c range across the usual spots and no cloud issues.

The mid range looks really difficult and many models are perilously close to getting the extreme heat across the south and essentially trapping it in situ with the possibility of adverting this further north as the next trough approaches from the west. A hard, hard call because of the ramifications of the heat is retained across the south (Potential record breaker).

[Zak M]

As a convective/storm lover I really like the GEM, a nearby Atlantic/Bay of Biscay low wafts up multiple storms from the continent for 4 days straight starting @126. 18c isotherm in the SE too so I would suspect temperatures within that 4 day period to be around 30c.

No other model has been showing widespread storms though.

[MattStoke]

I look at it this way; I’d rather the GFS was on board, and it’s different output cannot be dismissed completely, however, if any model were to disagree with the general consensus, I’d rather it was the GFS. It’s so often wrong in these setups.

Edited August 3, 2020 by MattStoke

[kold weather]

1 minute ago, CreweCold said:

There is a definite shift in the ensemble mean around day 5. Doesn't mean it's correct though. I find the GEFS really quite useless.

What I find with the GFS is its very prone to following its operational run, there isn't usually too much variance with it. Sometimes that pays off, but other times it can make the ensembles almost as useless as the operational in certain situations where the models biases are tapped into. Hard to know whether this will be such an occasion, though for sure it ticks the box of being overly progressive compared to other models at the same time, which is a well known problem for the GFS in blocking situations like this because it usually underestimates the extent of upper highs which in battleground type situations (which this effectively is) makes a large difference on the surface conditions.

 

[Guest]

As others are saying there's a huge shift in the GFS ensembles, previously its only been the Ops run with this pattern but on the 12Z suite three-quarters of the ensembles suddenly follow the Ops run.....Maybe its over progressiveness is catching through the ensemble pack, maybe the scenario just has better support through newer data? 

[Captain Shortwave]

Yep a lot of the GEFs members push that trough through during Saturday. However on the flip side many are much hotter for that day too (low/mid thirties potentially before the trough moves through with the usual thunderstorm risk).

Control run for instance.

 

 

of course this is all academic if the handling of the trough is wrong earlier on.

Edited August 3, 2020 by Captain Shortwave

[Singularity]

There was an ECM rub a couple of days ago that moved a low through similarly to the GFS 12z, albeit about one day more slowly.

That gives me cause to be wary of what GFS is up to, despite all it’s typical shortcomings.

Not that it should harm the outlook for next week much - a strong signal for a lot of summery weather regardless, as Tamara pointed out earlier. Incidentally... Portugal’s really going to be showing it’s hotter side Fri-Sun+!

[Methuselah]

I'll take the GFS as the worst case scenario... But even then it's hardly the end-of-the-world -- even though the six-day run of 35C temps wouldn't happen, things still look reasonable, to me:

    

    

    

    

Aaaaand... the 12Z op is on the cool side of the temp ens. Quelle surprise!

    

    

Jesus! (apologies to Pep Guardiola!) Those 2m temp are always nonsense, anywho!

[Guest]

Hard to tell at T96 on the ECM which way its going, could be a fence sitter and decent middle ground between the Hot of GEM / ICON and the cool GFS. 

[Guest]

ECM almost identical to GEM and UKMO @120hrs, also the vast majority of GEM ensembles look very hot right through the weekend and into next week. GFS pretty much on its own despite the swing in its ensembles.

You ain't going down an unsettled route anytime soon with a chart like this at 5 days.

 

Edited August 3, 2020 by Guest

[MATTWOLVES 3]

Hi guys, your doing a great job with this next upcoming Hot spell, having a difficult time of it right now, but this place is at least relieving some of the stress.. ECM not following GFS at 120hrs..its on its own as per usual... Still looking good for sure..

[Guest]

Still very hot in the south at T144 on ECM, will need to be careful of the undercut but its a million times better than GFS and I'll have my extra small swimming shorts on all weekend - oh yeeeahhh!

[Zak M]

12z ECM @144

This looks like it's heading in the right direction. 

Perhaps that Atlantic low could pep up the plume a bit?

Edited August 3, 2020 by Zak M

[Guest]

1 minute ago, Zak M said:

12z ECM @144

Thats 0Z run my friend

[Zak M]

Just now, Alderc said:

Thats 0Z run my friend

I know, just changed it 

[northwestsnow]

Beautiful ECM this evening chaps. .

Looks warm to hot widely with HP in charge.

[Man With Beard]

UKMO and ECM in virtual tandem through T96, T120, T144. Also, the ECM has been very consistent through 3 runs now. Usually a winning combination.

With Saturday at just T120 now, we might well be looking at two days in a row in the region 35C, or even a touch higher.

If the undercut from the north sea doesn't reach the south coast on Sunday, you could make that three days in a row.

Edit: just seen Monday's chart, make that four days. Could become five.

Edited August 3, 2020 by Man With Beard

[Guest]

That is a very hot T168 chart from ECM.....

 

[Guest]

Just now, Man With Beard said:

UKMO and ECM in virtual tandem through T96, T120, T144. Also, the ECM has been very consistent through 3 runs now. Usually a winning combination.

With Saturday at just T120 now, we might well be looking at two days in a row in the region 35C, or even a touch higher.

If the undercut from the north sea doesn't reach the south coast on Sunday, you could make that three days in a row.

Even 4days looking at the T168 output.....

[Scorcher]

The ECM is much better than the GFS but unfortunately the heat still only remains south of the Midlands on Saturday. Thankfully though it looks like there's a good chance it will quickly build back northwards from Sunday onwards. A really hot outlook for the South East and hopefully the rest of us further north will also join the party.

[Zak M]

This is a HOT run.

   

@192

Edited August 3, 2020 by Zak M

[Singularity]

Ah. That’s a hot one from ECM for the southern third of England. Four days with mid-30s potential is no joke, indeed it’s seriously concerning for those vulnerable to heat exhaustion or worse.

The hotter trend from ECM means alarm bells are ringing for me. Will be a fascinating  spell of weather if it happens though. Conflicted emotions - I must separate them from model analysis, Tamara-style!

[Cheshire Freeze]

Looks like we'll start to see a storm risk day 7 onwards- there on GEM also. Does look like the heat will start to turn more humid after the weekend.

[Man With Beard]

What the ECM is doing with Monday/Tuesday next week is slightly terrifying. It's trapped the plume over the low countries over the weekend and now it's being sucked back into the England. The temperature record would probably go on this run.