Model Output Discussion - heading into April

[Djdazzle]

ECM 216

[Allseasons-Si]

216

 

[Mike Poole]

T240:

+16 uppers into the SE now, not bad for May.

Edited May 13, 2020 by Mike Poole

[Allseasons-Si]

240,my word!!!

+16's into the SE

[Djdazzle]

ECM 240

Surely a hot outlier?

Edited May 13, 2020 by Djdazzle

[I remember Atlantic 252]

13 minutes ago, Djdazzle said:

ECM 216

FI, but more interesting is the number of fines to be issued for the 3 days after this day

Edited May 13, 2020 by I remember Atlantic 252

[Djdazzle]

Just for Interest this chart produced the May record of 32.8C

Edited May 13, 2020 by Djdazzle

[Guest]

ECM 12Z should come with a warning! Its complete weather porn 

It would be hard to find better model output in May in the UK, just a shame its 6-10days away. If anything like that materialised I think the May record of 32.8C would be under serious threat. A seriously hot run that also delivers some very very high minima for May, almost nationwide mins are above 16C with 18+ for many. Also looks as though you'd get some serious fireworks.....Its got to be a massive outlier. 

[Man With Beard]

23 minutes ago, Djdazzle said:

ECM 216

Raw temperatures on this chart are bonkers. 29C in Lancashire!! That usually translates to 30-32C for the actual. 

[mb018538]

ECM will undoubtedly be a big hot outlier. GFS looks far too progressive. As usual the reality will probably be somewhere in the middle. First 27c of the year?

[Djdazzle]

Just now, mb018538 said:

ECM will undoubtedly be a big hot outlier. GFS looks far too progressive. As usual the reality will probably be somewhere in the middle. First 27c of the year?

Yes probably, but even if the ECM was moderated, we’d still be pushing 30C.

[Mike Poole]

So, to compare models a bit after the 12z runs, first at T144, to include the UKMO as that is far as it goes, here UKMO, ECM, JMA, GEM, GFS:

Two things here, the degree of amplification and the east-west position of the trough.  UKMO and ECM most amplified, JMA close, GEM and GFS much less so, particularly GFS.  Trough in same position in all though.  Move on to T192:

I agree with the comment made earlier by @Alderc that the GFS and GEM runs are starting to look a bit odd by this point.  ECM and JMA look like clean evolutions still, and I'd favour them at the moment.  

But by now the position of the trough is not the same in all runs.  If we accept that SSTs have a role in this, here they are currently:

But given the uncertainty over the position of this trough, we could have totally warm UK high, less likely now, potential plumes, more likely now, or the thing progressing more to the east, as per some earlier GFS runs, which I know some people think will happen, but I don't.  Interesting model watching whichever way it pans out!

All the best, and stay safe.

Mike

 

Edited May 13, 2020 by Mike Poole

[Frosty.]

That’s some hot stuff from the ECM 12z operational...especially with the chili peppers!

 

 

Edited May 13, 2020 by JON SNOW

[Mike Poole]

ECM ensemble mean at T168, T240:

Supportive of the op run, at T168, and fairly so at T240 although obviously more uncertain by this point.  I don't see much of the GFS solution in that mean to be honest.

Edited May 13, 2020 by Mike Poole

[mb018538]

Heres the Z500 and T850 ensembles for the 12z ECM. Outliers as expected, but the mean is hardly terrible.

 

[Singularity]

ECM's solution may be a bit on the extreme side in terms of how much trough disruption and then suppression occurs - but I can see in CFSv2's AAM projection why it doesn't steamroll the ridge with Atlantic troughs.

There's a rising AAM tendency this week in response to a large N. America positive mountain torque (+MT) event that's just taken place. This outweighing some negative frictional torques (-FTs) being generated by anomalously strong trade winds in the tropical Pacific (as a La Nina SST pattern begins to emerge). In this, comes the potential (not a guarantee) for high pressure to hold on across the UK until at least next weekend.

 

We've seen a lot of large +MTs in recent weeks and months, working to keep GLAAM higher than it could have been considering the tropical setup with little eastward-propagating MJO activity in the Pacific Ocean. It's interesting seeing so much 'fight' against entering a La Nina style regime of negative AAM orbits.

The northern Pacific has recently warmed quite a bit in the space of a week. Suddenly, I'm less sure about there being a negative PDO to help imprint the La Nina forcing from the tropics onto the atmosphere. 

Still some semblance of a -PDO as a result of the waters away from the coast being more anomalously warm, but it's weak and unusually high temps in the western US and Alaska have in places warmed the nearshore waters to a similar degree of positive anomaly. An example of how our warmer climate can mess with the patterns of old and leave us wondering if we can really second-guess how this summer will pan out. Another is the Arctic experiencing unprecedented bouts of sunny yet anomalously warm weather.

Traditional methods strongly suggest more Greenland highs and N. European lows than usual to become a theme by July, if not sooner. Yet, my confidence in an outlook along those lines is not strong.

[damianslaw]

Short term - as I commented yesterday and day before, position/orientation of the ridge all important, we see it taking on a SW-NE axis, which allows for a positively positioned atlantic trough to move through into western and northern regionas through the weekend, bringing dull wet conditions here, whilst the south and east stays dry but fairly cloudy hence temps not quite as high as was looking a couple of days, nudging into the low 20s in one or two favoured spots, high teens for most- not bad for mid May, but nothing special.

Into next week, divergences taking place between the models, all do show the ridge reorientating itself once again build northwards through the UK which acts as a block to the atlantic, ECM then shunts heights eastwards, eventually drawing in very warm locally hot continental air to much of the UK, with lowish heights to the SW. The key difference with the GFS is the strength of the low heights to the SW, these are shown to be a much stronger feature anchoring into the UK to allow a unsettled cyclonic spell possibly thundery, under quite humid tropical maritime air. These heights then ebb away and a new ridge builds down through the UK with the atlantic still quiet.

Jetstream profile forecasts which I've been looking at past 2 days back up GFS scenario with the deep cut off low scenario to the SW, a split jet formation. Is the ECM underplaying these low heights I wonder, or is the GFS overdoing them? The past 48 hrs the jetstream profile forecasts have been very accurate with general direction of travel for the weekend, and conversely also the GFS.. not saying this will remain the case, but important to note.

My own view is there will be an interplay with lower heights to the SW, more so than being shown by the ECM which will prevent the extreme warmth being shown by ECM, something more unsettled but still warm, thereafter a return to pleasant warm dry conditions.

[Man With Beard]

57 minutes ago, Mike Poole said:

ECM ensemble mean at T168, T240:

Supportive of the op run, at T168, and fairly so at T240 although obviously more uncertain by this point.  I don't see much of the GFS solution in that mean to be honest.

Ensembles look good, but I'm keeping in mind that the hottest solutions at this time of year need an ideal set-up, and usually one that takes us close to the edge with Atlantic influence - so it will be a few days before a really hot set-up could be predicted with substantial confidence. 

[Allseasons-Si]

 Tonight's 6-10 and 8-14 day 500mb height anomaly's from cpc has the high pressure perfectly in place to pump those temps up into the UK

EPS/GEFS height/850's temp anomaly's

EPS slightly better as you would expect following a great ECM op run

but lets not get carried away just yet until we see these charts get into the reliable time frames

now come on pub run,give us a southern comfort special

Edited May 13, 2020 by Allseasons-si

[Ben Sainsbury]

ICON 18z at 120 much more amplified than its 12z run.

 

[Mike Poole]

9 minutes ago, Allseasons-si said:

 

now come on pub run,give us a southern comfort special

Does the pub run still exist now pubs don't?

[Allseasons-Si]

2 minutes ago, Mike Poole said:

Does the pub run still exist now pubs don't?

Virtual pub special

[matt111]

There's virtual pubs everywhere else at the moment so why not for the models?

[SMU]

30 minutes ago, matt111 said:

There's virtual pubs everywhere else at the moment so why not for the models?

The ECM mean & operational fairly close, at the moment you would say high 20s, but slack flow & continental flow could see 30c- as ever it depends how quick the atlantic trough pushes East..

[Allseasons-Si]

Lobe separation to the north at 114 on the gfs,it should be a better run this

18z 114 v's 12z 120.