Model output discussion - summer rolls on

[Djdazzle]

14 minutes ago, CreweCold said:

At just 78 hours out, the GFS 18z has shifted the core of that Atlantic low 300 miles E of its position on the 12z 

Not surprising. The model prone to wild swings.

[Guest]

18 minutes ago, CreweCold said:

At just 78 hours out, the GFS 18z has shifted the core of that Atlantic low 300 miles E of its position on the 12z 

and deepened it significantly, too. Wonder what else the pub run has in store  

[SLEETY]

gfs stil going for another heat up by end of next week.Maybe the all time record will go then,if it doesn't tomorrow.Little sign of any significant rain again,after the weekend..And next heatwave looks more widespread too..

[Sky Full]

What are the big four showing for the 2nd August (+144hrs):

                                             500s                                                      850s

UKMO            

ECM               

GFS               

GEM              

Not all that much difference between them at this distance - all have a North Atlantic low pressure more or less centred over Iceland while the Azores high continues to doggedly reassert itself over Western Europe.  However, only the GEM has the warmest Mediterranean sourced uppers being drawn towards the UK at this stage.  Cooler conditions than of late prevail on the other three models but the picture is poised for further high pressure dominated dry and warm weather to continue well into August if the blocking across Scandinavia refuses to give way.  This has been the most exciting year for weather for a long time in my memory, and this summer has already provided enough extremes to jump straight into the top three summers of recent decades.  And it's not even August yet......    I imagine there will be many references to the 'long hot summer of 2018' on this forum for many years to come.

(Have not been able to delete these two surplus charts - just ignore them.   Doh!)

Edited July 27, 2018 by Sky Full
Surplus charts?

[Guest]

Well well, almost all the models now against the idea of major reload of the heat. After almost complete agreement from the gfs ensembles yesterday the mean is pretty much average (although a huge scattergun after the 3rd) now and a good 5c cooler. Quite a few cooler ensemble members in there suggesting high way out west is now the form horse - still I’m sure I’m reading this wrong and it’ll still be 30c+ by the middle of next week......

 

 

[shaky]

1 minute ago, Alderc said:

Well well, almost all the models now against the idea of major reload of the heat. After almost complete agreement from the gfs ensembles yesterday the mean is pretty much average (although a huge scattergun after the 3rd) now and a good 5c cooler. Quite a few cooler ensemble members in there suggesting high way out west is now the form horse - still I’m sure I’m reading this wrong and it’ll still be 30c+ by the middle of next week......

 

 

Yup i mentioned it yesterday aswell!we might have just had the hottest part of our summer yesterday and now today!!not to say we aint gona get any more hot weather cos it looks like we will but more mid to high twenties and a 30 degree max compared to the 35s and the 37s the models were showing few days ago!!rain defo still looks an issue for the rest of the summer cos apart from sunday there is not much rainfall!!

[Gordon Webb]

Well I'm back and the first thing I'm going to do is issue an apology for remarks I made in my last post about hysteria taking over common sense been lost as it turns out they were correct about the temps so sorry to all those who might have taken offense if any

[Djdazzle]

This is all very interesting. Models trending more towards HP out west (although usual caveat of it being in Fi).

NOAA still plumping for Atlantic trough and Scandi high.

Some other knowledgeable posters saying that models haven’t yet come to grips with the signals.

Anyone ruling out a return to very high temps is seriously jumping the gun at this stage. It would only take a few tweaks here and there.

[Snowyowl9]

Big changes coming then get use to very windy and wet conditions by sunday,not often I welcome this but it this summers case it will be really refreshing.

Saturday looks really cool and showery too now,breezy spell continues until midweek with showers or spells of rain.

I`ll leave sunday fax as the wind will be gusting upto 50mph plus.

http://wetterzentrale.de/pics/brack1a.gif

[seb]

15 minutes ago, Djdazzle said:

This is all very interesting. Models trending more towards HP out west (although usual caveat of it being in Fi).

NOAA still plumping for Atlantic trough and Scandi high.

Some other knowledgeable posters saying that models haven’t yet come to grips with the signals.

Anyone ruling out a return to very high temps is seriously jumping the gun at this stage. It would only take a few tweaks here and there.

Fully agree. As it stands merged GFS data is giving temps of 28-32 from Wed onwards all the way to the middle of August. Some outliers taking temps up to mid thirties. With the worst ones showing 22-25. Barely any rain. 

So so whatever happens the amazing summer continues.

All other models pretty much the same.

[Guest]

 

18 minutes ago, Djdazzle said:

This is all very interesting. Models trending more towards HP out west (although usual caveat of it being in Fi).

NOAA still plumping for Atlantic trough and Scandi high.

Some other knowledgeable posters saying that models haven’t yet come to grips with the signals.

Anyone ruling out a return to very high temps is seriously jumping the gun at this stage. It would only take a few tweaks here and there.

Yes next week has got to happen before anyone can be proven right or wrong! A fascinating spell of model watching to come

[danm]

It shows how good this summer has been that we are talking of possible temperatures in the mid to high 20s being a downgrade. 

I think most of the heat lovers will gladly settle for further sunny, dry weather with temperatures between 24c and 29c if we can’t get record breaking heat.

Edited July 27, 2018 by danm

[mb018538]

Bit of a modelling bomb by the looks of it - after a few days of really showing a plume around the 3rd, it’s all but gone now. Shame really, could have definitely had a crack at the UK all time or 40c

[tight isobar]

In an-average summer (not that this is!) Some would likely be raving about set ens-set up-.

Especialy as we migrate a little further into the new month of august!

They remain firm and notable to pressure rises going forwards...and with the 'already' mass in place iberian/southeastern euro warm/hot pool firmly in-place the possibilities of aligned placements for a uk tap in remain firmly on the table.

Surface cond's also stark in there note of remaing above/well above going forwards.

Its a the moment as if the models(bar gem) are desperate to resort to default..and with the slight expance of atlantic cooling thats is going to happen as complexities are deciphered!.

Im still of the opinion that august will have at least blasts of hot iberian/continental surge.

And again with some eye catching temps.

And it will certainly be an, interesting watch...seeing how cross model suites unfold ...especialy once the weekend closes.

Edit; taking all onboard id expect the mods to slowly begin to make less of the atlantic influence-and more of dominance via a southerly traction of weather into NWeuro as a whole...including the uk.

Edited July 27, 2018 by tight isobar

[Leo97t]

Look guys the Gfs is complete bs at the most moment I can't trust it when in changed its mind about Friday at +24 hours. Even if we don't any more extreme temps, a huge anticyclone essentially over us is still excellent

[Singularity]

I agree with tight isobar's sentiments. 

The main issue with the 00z ECM and GFS runs is that they take the Atlantic trough out west and break it down, with a small cut-off low dropping down west of the Azores while the rest moves off to the ENE or NE. This leaves an area west of the UK into which high pressure can build quite strongly.

This type of trough breakdown with cut-off low formation requires a flat upstream jet pattern. Those two 00z runs feature that, but the Nino-driven forcing should bring about a more meridional (N-S, S-N) jet movement instead. That would maintain a curve of the jet down toward the Azores, with a cut-off low dropped in favour of a broader-scale trough that prevents ridging from becoming focused west of the UK.

 

Handily, the 18z GFS of yesterday (right) had this going on, albeit not very strongly so, and you can see the stark difference to the 00z (left) in the ridge pattern south of the main jet.

 

That GFS keeps producing some runs with this feature suggests that the modelling isn't far away from resolving the Nino-derived forcing's domination over the MJO-derived forcing. I see the 00z ECM as having come closer to that than the 12z of yesterday so there's some progress there too.
 

It's a strange position that I find myself in really; I know that imports from S or SE of the UK could be very dangerous to health, but I also know that it's strongly supported by teleconnections to be a feature of our weather patterns during at least half of August. A conflict of desires!

[Tamara]

1 hour ago, mb018538 said:

Bit of a modelling bomb by the looks of it - after a few days of really showing a plume around the 3rd, it’s all but gone now. Shame really, could have definitely had a crack at the UK all time or 40c

Unsurprisingly I very much share the sentiments of both @tight isobar and @Singularity

Why is it a modelling bomb?  That exaggerates and masks the reality

Its not necessary to repeat the whole extracts of yesterday but best to look at ensemble means and then integrate them into the bigger diagnostic picture as described and not take each and every operational output at face value. Its a big pity that the focus of continuing to make temperature records is detracting from the fact that the outlook continues to be very much an above average summer one with conditions that many would jump for joy about in an average summer.

The modelling looks to be attempting to repeat the early-mid summer pattern with a sub tropical ridge extension with the heat axis focussed around how sharp the cut-off features are to the south west to advect the greatest heat northwards and north eastwards. This in itself isn't a bad thing anyway by any means - with a lot of highly enjoyable summer weather. Many will be very happy with temps well into the twenties without need for record breaking heat (as interesting and exciting as it is to see from an enthusiast point of view) so as to live day to day comfortably

But the difference this time around, and why it was stated yesterday that the latest solutions are not necessarily end-games, is that the atmospheric circulation has started adopting a more Nino-like feedback (for all the detailed reasons and illustrations given) which doesn't support Atlantic ridging sustainably and I suspect once the upper tropics start to register the next round of tropical forcing and associated rise in angular momentum the pattern will adjust east with re-set of the Atlantic trough and ridge to the NE. This suggests that further plume conditions cannot yet be ruled out - as said yesterday its about timing of such a development

That is actually the less settled outcome as we are currently seeing. Its no coincidence that the warmth of this summer has sustained long-term from the 'home-grown' variety topped up with some tropical maritime air in the circulation of the sub tropical ridging. In other words a stable high pressure environment. Its no coincidence that the appearance of a plume has injected instability into the equation which in turn helps facilitates a breakdown. That is the risk vs reward factor of east/west patterns. These plume patterns can of course be cyclical in themselves with continual re-loads following thundery breakdowns. A summer such as 1994, just for example, featured quite a lot of this type of pattern during June and July

We should count ourselves very lucky in 2018 that we have a summer which is featuring both kinds of anomalously warm patterns. These sorts of summer do not come about very often

 

 

[Frosty.]

I can't see any downgrade from the extended Ecm 00z ensemble mean, it shows high pressure / robust azores ridge gradually building in next week with our weather becoming largely fine and warm again following this upcoming cooler / fresher atlantic blip.☺

[chrisbell-nottheweatherman]

1 hour ago, Tamara said:

Unsurprisingly I very much share the sentiments of both @tight isobar and @Singularity

Why is it a modelling bomb?  That exaggerates and masks the reality

Its not necessary to repeat the whole extracts of yesterday but best to look at ensemble means and then integrate them into the bigger diagnostic picture as described and not take each and every operational output at face value. Its a big pity that the focus of continuing to make temperature records is detracting from the fact that the outlook continues to be very much an above average summer one with conditions that many would jump for joy about in an average summer.

The modelling looks to be attempting to repeat the early-mid summer pattern with a sub tropical ridge extension with the heat axis focussed around how sharp the cut-off features are to the south west to advect the greatest heat northwards and north eastwards. This in itself isn't a bad thing anyway by any means - with a lot of highly enjoyable summer weather. Many will be very happy with temps well into the twenties without need for record breaking heat (as interesting and exciting as it is to see from an enthusiast point of view) so as to live day to day comfortably

But the difference this time around, and why it was stated yesterday that the latest solutions are not necessarily end-games, is that the atmospheric circulation has started adopting a more Nino-like feedback (for all the detailed reasons and illustrations given) which doesn't support Atlantic ridging sustainably and I suspect once the upper tropics start to register the next round of tropical forcing and associated rise in angular momentum the pattern will adjust east with re-set of the Atlantic trough and ridge to the NE. This suggests that further plume conditions cannot yet be ruled out - as said yesterday its about timing of such a development

That is actually the less settled outcome as we are currently seeing. Its no coincidence that the warmth of this summer has sustained long-term from the 'home-grown' variety topped up with some tropical maritime air in the circulation of the sub tropical ridging. In other words a stable high pressure environment. Its no coincidence that the appearance of a plume has injected instability into the equation which in turn helps facilitates a breakdown. That is the risk vs reward factor of east/west patterns. These plume patterns can of course be cyclical in themselves with continual re-loads following thundery breakdowns. A summer such as 1994, just for example, featured quite a lot of this type of pattern during June and July

We should count ourselves very lucky in 2018 that we have a summer which is featuring both kinds of anomalously warm patterns. These sorts of summer do not come about very often

 

 

In other words, high pressure over the UK with a Tm feed now and again generates more stable warm, dry weather but not the extreme heat and consequent thundery aspects of a southerly plume?

[SMU]

1 hour ago, Frosty. said:

I can't see any downgrade from the extended Ecm 00z ensemble mean, it shows high pressure / robust azores ridge gradually building in next week with our weather becoming largely fine and warm again following this upcoming cooler / fresher atlantic blip.☺

Agreed - not sure what all the fuss is about TBH...

Same people saying the same the same recycled posts from last week..

Thats the ones saying that this weeks heat was downgrading & almost outrage when I said we would get North of 35C

Now look today we are still talking probabilities of 38c going.

All this waffle about downgrades - dont let em fool you, the original plume was forecast Friday next week & its pretty much on track as expected...

Another 35c here we come...

Edited July 27, 2018 by Steve Murr

[ITSY]

TBH even if you take the GEFS 06z at face value (which I'd advise against), the Midlands southwards is looking at two weeks of sustained dry and variably sunny weather with temps into the mid 20s as a mininum, at least after Tuesday. (Conditions not too different even further North and West). Given how awful it has been to work and sleep this week with temps in the mid 30s (it is currently 33c in Cambridge), I would bite your hand off for this and very much see it as a continuation of the incredible summer until now. Even with Ydays thunder we've had less than 10mm of rain since the first week of June. Anyone complaining about downgrades, especially as plume scenarios still cannot be ruled out (see Tamaras usual outstanding post above, and SMs too), needs a health check from heat stroke. 

[danm]

7 minutes ago, ITSY said:

TBH even if you take the GEFS 06z at face value (which I'd advise against), the Midlands southwards is looking at two weeks of sustained dry and variably sunny weather with temps into the mid 20s as a mininum, at least after Tuesday. (Conditions not too different even further North and West). Given how awful it has been to work and sleep this week with temps in the mid 30s (it is currently 33c in Cambridge), I would bite your hand off for this and very much see it as a continuation of the incredible summer until now. Even with Ydays thunder we've had less than 10mm of rain since the first week of June. Anyone complaining about downgrades, especially as plume scenarios still cannot be ruled out (see Tamaras usual outstanding post above, and SMs too), needs a health check from heat stroke. 

Completely agree with this and @Steve Murr above. Yes, we may not be seeing the same record breaking runs in the operational's at the moment as we were a few days ago but the outlook is still predominantly sunny and dry with warm to very warm temperatures at a minimum. It's worth remembering what average temperatures are for this country. 24c is the average for London at this time of year and we will get above that with the high 20's post Wednesday next week for many areas. 

You'd think by some of the comments on here that the jet is forecast to fire up and send multiple depressions our way. 

Edited July 27, 2018 by danm

[Snowy L]

Ok I keep seeing summer's over and huge downgrade posts, so I look at the models myself, expecting low pressure systems all over the UK and instead I see a huge high pressure sat right on top of the UK from Thursday through the whole run pretty much. What is wrong with this thread lol.

[Frosty.]

Looking at the GEFS 6z mean there's plenty more very summery weather to come nationwide with high pressure / strong azores ridging, warmest further south.☺

[Derecho]

The models don't make much sense to me at the moment.... I thought the weather was supposed to turn horrible when the school holidays started??????

The GFS doesn't show the intense heat of recent runs but high pressure is firmly in charge, anchored right over the UK.

The really high uppers are mostly locked away in Iberia but we may just see a delay in the onset of the really high uppers. Temperatures by day into the upper 20s in most areas with nights perhaps more comfortable for sleeping.

Selfishly I was hoping Summer 2018 would scoop all of the following

- Hottest summer (should be on track if the 06z verifies?)
- Driest summer (the 06z is especially dry for most after Sundays autumnal blip)
- Hottest month (July 2006 may well be out of reach?)
- Hottest temperature (I presume these next 3 weeks may be the best opportunity for it).

Regardless, its still a super outlook for early August and I can see it being anticylonic like 1955, 1976 and 1984 with the risk of the odd cooler intrusion from the NW if the high anchors to the WSW.

We shall see....