model discussion Model output discussion 11th July onwards

[mb018538]

Interesting look to the UKMO day 7 chart today:



Warm upper air is advected up to the west of the UK early to midweek, before by Thursday it starts to advect back down from the north.

[Frosty.]

Just looking a bit further ahead, I’ve taken a day 8 snapshot from the GEFS 0z and as you can see, the odds favour high pressure / ridging in the vicinity of the u k rather than a trough!..to me this suggests there is potential for a  predominantly summery pattern during the end of summer / start of autumn and the Gfs 0z op certainly shows that!!  

Edited August 19, 2021 by jon snow

[mb018538]

A quiet looking ECM today. No heat on offer, but a lot of dry weather. Temps will depend on cloud/high orientation.  

[mb018538]

Ok - Saturday is now looking like could very well be a write off!



Front looks much more aggressive, and moving through a lot quicker than previously forecast - even eastern areas that were promised 25/26c and a decent day in the last few days now look like seeing 22/23c at best, with cloud and rain moving in. This is also the case on ARPEGE and UKV. 

[Frosty.]

The ECM 0z op shows high pressure / ridging which translates to fine and warm weather   dominating next week and the uppers (850’s) are very satisfactory, although there is some cooling later but I’m pretty sure surface conditions would be generally warm and besides, the sun is still very strong at this time of year!  ...charts a bit messed up..do I look bothered?!

 

Edited August 19, 2021 by jon snow

[Guest]

7 minutes ago, mb018538 said:

Ok - Saturday is now looking like could very well be a write off!



Front looks much more aggressive, and moving through a lot quicker than previously forecast - even eastern areas that were promised 25/26c and a decent day in the last few days now look like seeing 22/23c at best, with cloud and rain moving in. This is also the case on ARPEGE and UKV. 

Has 25C been recorded yet this month? Might not happen at all. Probably won’t if not on Saturday. 

[mb018538]

On 19/08/2021 at 08:15, Alderc said:

Has 25C been recorded yet this month? Might not happen at all. Probably won’t if not on Saturday. 

25c at Bridlington yesterday, 26.4c at Cavendish (Suffolk) on the 15th, 25.6c Cavendish on the 14th, 25.8c Cavendish on the 12th, 25.3c Wellesbourne on the 11th

Still desperately poor. 26.4c for a UK wide max in August is dreadful. 

This morning's ECM is boring and just full of cloud. So despite looking quite reasonable on the pressure charts, in reality it'll just be a clagfest for many, which is thick enough for drizzle or light showers in places. Highest temps on the 00z data are 22c - wowwwwwwwwwweeeeeee! How amazing! It'll feel great under all the cloud!




Easterly feed not helping things at all. Makes you laugh though - we get an easterly in May or June, and the greyness is due to the sea still being cold, Well - it's late August now, SSTs are getting close to their peak and are widely 17c as opposed to the 11-13c in May/June....but we still get plagued by cloud. Lose lose. 

Edited August 19, 2021 by mb018538

[Methuselah]

While not exactly earthshattering, this morning's GEFS ensembles are, for the more most part, okay:

    

[Uncertainty]

Lots of negativity this morning ( @jon snowaside!) and there needn’t be:

The weekend low which was always going to be a wet one now looks to clear through by early Monday, HP builds in more strongly than advertised over the last few days and potentially the northern blocking at day 8+ has been toned down to allow more mid lat ridging near our local.

GEM

GFS

ECM

Notice the blues and greens appearing over N Greenland indicating lower heights and leaving room for the block to Set up south rather than north of Iceland.

MJO phase 2 August Nina composite

 

NOAA

The NOAA charts, the mjo composite and most professional mets have never advertised big heat from this spell. Dry and settled was always best case scenario here and that’s what we’re looking like getting. 

Some perspective... This time last year

 

We live on a cloudy island but beyond Sunday there is no washout ahead and a nationwide settled and dry spell beckons with perhaps more sun in the NW. 

[Methuselah]

Well, I can't see too much in this morning's GFS 00Z that justifies the mind-numbing negativity some folks persist in showing. Yes, it's quite possible that something 'less than perfect' may come down the eastern flank of the high-pressure area from time to time, but it's true that the boffins in Exeter know more than I do -- and they don't seem overly concerned?

    

    

    

Edited August 19, 2021 by Ed Stone

[Kentspur]

2 hours ago, mb018538 said:

A quiet looking ECM today. No heat on offer, but a lot of dry weather. Temps will depend on cloud/high orientation.  

Best conditions relative to average according to latest 0z ECM are going to be in Scotland Northern Ireland/Ireland and the NW according to the temperature anomalies. Weve gone from unwelcome NWly winds off the Atlantic to now what looks like NEly winds off the North sea atleast for the southeastern quadrant, particularly in Kent

Edited August 19, 2021 by Kentspur

[JayAlmeida]

1 hour ago, Uncertainy said:

Lots of negativity this morning ( @jon snowaside!) and there needn’t be:

The weekend low which was always going to be a wet one now looks to clear through by early Monday, HP builds in more strongly than advertised over the last few days and potentially the northern blocking at day 8+ has been toned down to allow more mid lat ridging near our local.

GEM

GFS

ECM

Notice the blues and greens appearing over N Greenland indicating lower heights and leaving room for the block to Set up south rather than north of Iceland.

MJO phase 2 August Nina composite

 

NOAA

The NOAA charts, the mjo composite and most professional mets have never advertised big heat from this spell. Dry and settled was always best case scenario here and that’s what we’re looking like getting. 

Some perspective... This time last year

 

We live on a cloudy island but beyond Sunday there is no washout ahead and a nationwide settled and dry spell beckons with perhaps more sun in the NW. 

It has been a terrible August overall even if things do look markedly better next week. You make a decent point with that chart from last year but don't forget that we'd had three weeks of really good weather beforehand. It's like we've had last August in reverse.

Edited August 19, 2021 by JayAlmeida

[mushymanrob]

Id suggest the ECM 00z is a pretty good match to the 8-14 day NOAA 500mb mean anomaly chart, therefore imho is the option most likely to be most accurate.. no heat, but its not overly bad.

[MATTWOLVES 3]

1 hour ago, Ed Stone said:

Well, I can't see too much in this morning's GFS 00Z that justifies the mind-numbing negativity some folks persist in showing. Yes, it's quite possible that something 'less than perfect' may come down the eastern flank of the high-pressure area from time to time, but it's true that the boffins in Exeter know more than I do -- and they don't seem overly concerned?

    

    

    

The negativety Pete I feel is a case of having such a poor Summer....bit like having long term Health problems,when it's been going on for long enough,you can get to the stage where you feel your never gonna improve. And I think that's what's happening with some of our less optimistic posters more than anything...The output today is not bad,obviously some areas are gonna fair better...perhaps towards the E/SE could see some issues with cloud and murk,so wall to wall sunshine and very warm temps being off the menu.

I'm noticing a fair amount of scatter on the Ecm extended ensembles out to day 14...with the mean at this point coming in at around 1014mb.

So it looks better...fantastic...no! But you know me,I'm easily pleased.

 

[Methuselah]

As is often the case -- summer, autumn, spring or winter -- Day 10's GFS-prognostication looks spiffing. Very spiffing indeed! 

    

[Methuselah]

So there we have it: a better than average prediction from the GFS 06Z. Only one question remains, of course: will it be right? But alas, I suspect the answer to that question will be 'no'! 

    

    

    

[MATTWOLVES 3]

Yes Pete the 6z op run does turn out to be a very encouraging run,all be it beyond day 10 especially! Does it have support? Well the op is a little on its own for a time next week...and the early set of ens are showing support for a better spell of weather. There are even hints on that op further along the line of a more traditional type North to South split! Which as clearly been lacking so far this season.

Edit...sorry...the op pretty much in line with the mean next week..I mistaken another ensemble for it....my bad!

Edited August 19, 2021 by MATTWOLVES

[Downburst]

Saw this on the charts section of ecmwf site. Might be useful for the mad chase for Scandi blocking in the winter, - or + NOA etc. Shows the Atlantic and Euro Weather Regimes. So Atlantic Blocking, Scandi based on variance from 20 year data etc. 

You can clearly see the Atlantic Block incoming. Followed by some Scandi Blocking and then ending into, well I can't guess. The usefulness is a broad view well ahead of any strongly favoured regime in the forecast. One has to be aware of how terribly difficult forecasting is on Europe and particularly northern Europe, so an aid to those that gamble on predictions.

 

" The climatological frequencies of the Euro-Atlantic regimes, computed over 29 years of extended winter periods (October to March) of ERA-Interim , are 32% for the NAO+, 26% for the Blocking, 21% for the NAO- and 20% for the Atlantic Ridge."

 

[Frosty.]

The ECM 0z ensemble mean indicates a period of  anticyclonic dominance next week, much less diluted than a few days ago when the mean in particular had a wobble!...I currently think next week, or at least most of next week could be settled and warm?...hopefully extending into the BH weekend?..at least further s / se!!  

 

Edited August 19, 2021 by jon snow

[Mike Poole]

1 hour ago, Downburst said:

Saw this on the charts section of ecmwf site. Might be useful for the mad chase for Scandi blocking in the winter, - or + NOA etc. Shows the Atlantic and Euro Weather Regimes. So Atlantic Blocking, Scandi based on variance from 20 year data etc. 

You can clearly see the Atlantic Block incoming. Followed by some Scandi Blocking and then ending into, well I can't guess. The usefulness is a broad view well ahead of any strongly favoured regime in the forecast. One has to be aware of how terribly difficult forecasting is on Europe and particularly northern Europe, so an aid to those that gamble on predictions.

 

" The climatological frequencies of the Euro-Atlantic regimes, computed over 29 years of extended winter periods (October to March) of ERA-Interim , are 32% for the NAO+, 26% for the Blocking, 21% for the NAO- and 20% for the Atlantic Ridge."

 

Worth noting that the popular cluster charts from ECM use the coloured border (same colours) to distinguish these 4 regimes, so in this example, some are -NAO and some are Scandi Blocking.

[Kirkcaldy Weather]

18 hours ago, Kirkcaldy Weather said:

I think the most likely contributor is phase 2 of the MJO Mike, the anomaly of the chart u posted and the composite of phase 2 for August are matched really quite closely  

 

Just to add a bit to this, might be a reason for the higher pressure being modelled to be stronger thanks to the record high amplitude 

 

[Methuselah]

This is not an entirely unwelcome pair of ensembles. The only downside is that the operational run is a tad on the warm side? 

    

What better way is there of rounding-off the perfect summer? 

Edited August 19, 2021 by Ed Stone

[MATTWOLVES 3]

UKMO looking  

Edited August 19, 2021 by MATTWOLVES

[Frosty.]

The Gfs 12z op so far is looking good next week, barely a trace of rain from next Tuesday onwards as high pressure looks dominant!  

[Methuselah]

3 minutes ago, jon snow said:

The Gfs 12z op so far is looking good next week, barely a trace of rain from next Tuesday onwards as high pressure looks dominant!  

Indeed mate. It's nae bad at T+306!