Model Output Discussion 18z 28/07/13

[ANYWEATHER]

Haa, Im just getting tired and fed up with some who keep posting summer like weather charts, now we are in Autumn.I feel sorry for the newbies on here who read this stuff, and think we are  going to have an indian summer, by reading those charts t+96 is the most reliable time frame and even that is not reliable!  Anyway, judging by tonights output, a Fleece or a Coat will be worth taking out, A very big change in our weather!  

[bluearmy]

the models seem to be working as a team at the moment. The GFS's cut off low scenario was corrected by the Euros and now the GFS appears to have helped out by suggesting that it might be an idea to keep pressure a bit lower to the east rather than just let high pressure calvary ride back in.

 

I'd be amazed if the UKMO doesn't make more of the low to our east this evening.

 

It might just be a delay, they may have made too much of it.....or it might prove to be enough stalling to prevent high pressure in at all.

 

i think you were away PC but the cut off low was originally an ecm theme which gfs finally took on before the other models then corrected it northwards. gfs left looking silly but its original idea wasnt so far off the mark. the nwp a real dogs dinner re next week.  maybe time to trust the ens day 4/6  i/o the ops

[Frosty.]

I think the trough to the east next week is being over egged by the models today, especially when you read how much better overall the met office update sounded today, becoming dry from midweek with warm sunny spells, lighter winds and a risk of overnight fog, sounds nice to me, apart from the fog of course and the chaos it created in kent this morning, thank god no lives were lost, it really was a miracle.

[Skeggy Winter Storm]

Haa, Im just getting tired and fed up with some who keep posting summer like weather charts, now we are in Autumn.I feel sorry for the newbies on here who read this stuff, and think we are going to have an indian summer, by reading those charts t+96 is the most reliable time frame and even that is not reliable! Anyway, judging by tonights output, a Fleece or a Coat will be worth taking out, A very big change in our weather!

yes a big change in weather and def the feel in temps from tomoro i like high pressure and summer weather but im looking forward to autumnal weather now its been a great summer here in skeg

[Frosty.]

All things considered, tonight's Ecm 12z operational run is not so bad, most of next week would be sunshine and scattered showers and although it would be cooler, it's nothing unusual for early autumn, it then trends warmer from midweek with drier and sunnier weather for the south & east of the uk, this run plays out similar to today's latest met office update in my opinion, although the end of the run shows a low moving in from the northwest, it would soon be followed by another spell of high pressure, the azores/atlantic high still has a significant role to play during the coming weeks.

[Summer Sun]

Here is the latest on the models from Gibby I'm not so sure he has saw tonight's UKMO mind as its not updated anywhere that I can find so It may well be the 00z he's viewed

 

Good evening. Here is tonight's look at the output from GFS, UKMO, GEM, NAVGEM and ECM from the midday runs for today Thursday September 5th 2013.

 

All models show a cold front across the UK reinvigorating itself in the next 12 hours as it moves across Eastern Britain. A Low pressure area is shown to form near SE England and move itself NW across the UK over the weekend with a cocktail of troughs and areas of cloud and showers affecting many places. By early next week the Low has moved up to the NW and become a trough which is shown to swing East on Monday with a band of heavy showers for all and followed on Tuesday with a period of cool NW winds and rising pressure as showers decay away from the West.

 

GFS then shows winds backing Westerly through next week with some troughs making there way across Britain at times. Some rain is possible at times as a result but with a fair amount of dry and bright weather in the South. Through the following week the weather settles down for a time as High pressure crosses East over the UK and on into Europe giving several days of warm and sunny weather. The weather slides downhill again later with some showery rain making it's way in from the SW at times in a light SE wind.

 

The GFS Ensembles show a sharp cool off in uppers in the upcoming hours with these values maintained well into next week before a gradual return to average values return later in the run. The operational was a warm outlier at times later in Scotland. rain is projected at times throughout the output but with no big quantities overall.

 

The Jet Stream shows an off shoot from the Jet flow to the NW circulating the newly formed Low over SE England. in the next few days. The main core of the Jet to the NW absorbs this feature early next week with a more direct West to East flow across the North of the UK later in the output.

 

UKMO tonight shows a cool NW flow around a High pressure close to the SW next Wednesday. the North sees winds backing Westerly with moister Atlantic air moving in later with increasing cloud.

 

GEM shows a ridge of High pressure building in from the SW early next week with a fine and bright spell for a time. Later in the run the weather deteriorates steadily from the North with outbreaks of rain and showers moving in from the NW with very much cooler air for all and strong NW winds. It may even be cold enough for the first wintry showers over the top of Scottish mountains should it verify.

 

NAVGEM maintains its theme of holding Low pressure close to Southern Britain next week with showers or outbreaks of rain across the UK at times with some drier and brighter spells most likely in the North.

 

ECM tonight has taken a more unsettled turn tonight with Low pressure holding close to the UK for the next week with showers or outbreaks of rain at times with the earlier ridge of High pressure holding further out into the Atlantic for longer eventually reaching the UK next Thursday with drier and brighter weather for all then. The end of the run shows hints of a GEM type conclusion of very cool North Atlantic winds moving down from the NW in the days that follow with rain and showers in abundance. 

 

In Summary we keep the trend of High pressure building in from the SW early next week. However, there is some disagreement between the models with ECM and NAVGEM bucking the trend with continued showery and cool weather lasting rather longer into next week and GFS looking a little half hearted in this theme tonight too. It looks we may have seen the last day of temperatures breaching 26C (80F) for this season with the expected North or NW component to the winds shown tonight making sure such figures won't be reached in the coming week or so.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

 

[Cloud 10]

The UKMO 12z is out on wetterzentrale,the +144 hrs chart has the same idea as the ECM with LP in the north sea.

 

[ANYWEATHER]

Its fairly easy for the models to follow a cold or warm front, but when  there is a developing low  such as now, models will disagree. Even now there is disagreement on this...  

[damianslaw]

Interesting to see the pattern we endured between summer last year and June reoccuring in the coming days i.e. the troublesome trough squeezing its way on a SE path across the country slicing heights to our west and east in two.

 

As we head further into autumn the propensity for the azores high to come under the influence of the atlantic trough will naturally increase, take charts suggesting any link up of the azores high with heights to our NE with increasing caution.. for this reason the output shown by GEM for instance is very plausible.

[Downpour]

Haa, Im just getting tired and fed up with some who keep posting summer like weather charts, now we are in Autumn.I feel sorry for the newbies on here who read this stuff, and think we are going to have an indian summer, by reading those charts t+96 is the most reliable time frame and even that is not reliable! Anyway, judging by tonights output, a Fleece or a Coat will be worth taking out, A very big change in our weather!

Still summer until 21 Sep, according to the laws of astrophysics. That all said, I have had enough of boiling hot nights and have work to do - London was exhausting today in 80 degree heat. Roll on autumn.

[Gaz1985]

 

Pressure building in once again from the SW, should feel alright 

[Scorcher]

Haa, Im just getting tired and fed up with some who keep posting summer like weather charts, now we are in Autumn.I feel sorry for the newbies on here who read this stuff, and think we are  going to have an indian summer, by reading those charts t+96 is the most reliable time frame and even that is not reliable!  Anyway, judging by tonights output, a Fleece or a Coat will be worth taking out, A very big change in our weather!  

 

So just because we've crossed into September it's not okay to post 'summer-like' charts? Seriously, I don't remember cold fans refraining from posting cold charts in late March this year! And today was far more summery than autumnal for many. The warmest September day since 2006 in fact in the SE. Sometimes I do wonder about your posts given your position as a Regional Forum Host. I dread to think how you'll react if we get a repeat of 2011!

Edited September 5, 2013 by Scorcher

[draztik]

One must use this chart with caution being in FI, but the cold air mass is rather close to the UK, if GEM has its way this morning

[mushymanrob]

Haa, Im just getting tired and fed up with some who keep posting summer like weather charts, now we are in Autumn.I feel sorry for the newbies on here who read this stuff, and think we are  going to have an indian summer, by reading those charts t+96 is the most reliable time frame and even that is not reliable!  Anyway, judging by tonights output, a Fleece or a Coat will be worth taking out, A very big change in our weather!  

 

sir, i think you are being unfair there. yes the charts have shifted away from the return of the azores high ridging in. but posting charts that were showing summery weather was perfectly correct, because thats what the models were showing. the pattern has been the same since june, the azores high trying to ridge in, so when yesterdays runs consistently showed this it wasnt 'wrong' to assume it had a good chance of happening.

 

Still summer until 21 Sep, according to the laws of astrophysics. That all said, I have had enough of boiling hot nights and have work to do - London was exhausting today in 80 degree heat. Roll on autumn.

 

eh? the laws of astrophysics determines the seasons?... nope, we (man) put the label on the seasons, we decide when the dates occur. leaves are starting to turn on some trees/shrubs, everythings dying back, its misty in the mornings, fruits are ripe, the harvests are in, and now the warm sunshine has gone... its definately early autumn.

 

anyway this is a weather forum, and meterologically its autumn.

Edited September 6, 2013 by mushymanrob

[Frosty.]

The Ecm 00z operational run shows the weekend trough filling by early next week but leaving a residue of instability ( weakness) which basically means a mixture of sunshine and scattered heavy and potentially thundery showers with temperatures generally close to  average, actually, sunday looks a decent day with sunny spells for eastern parts of the uk but feeling relatively cool and fresher compared to recent times but pleasantly warm in the sunshine, the ecm then shows pressure rising and bringing a more settled and warmer spell through the second half of next week with long sunny spells & light winds, especially across southern and eastern parts of the uk with temperatures nudging into the low 20's celsuis and feeling more like summer again, however, the following weekend another trough swings southeast into the uk with the sunshine and showers mix once again, the run ends on a messy confused note with a shallow trough and the jet gradually tilting towards a nw-se alignment so a risk of upstream amplification further ahead.

[ANYWEATHER]

So just because we've crossed into September it's not okay to post 'summer-like' charts? Seriously, I don't remember cold fans refraining from posting cold charts in late March this year! And today was far more summery than autumnal for many. The warmest September day since 2006 in fact in the SE. Sometimes I do wonder about your posts given your position as a Regional Forum Host. I dread to think how you'll react if we get a repeat of 2011!

Ok ,sorry Ive upset you. Ive said nothing wrong, imho, and im just saying what the models are saying in a more reliable timeframe! There are newbies on here who get confused by folks putting up charts which suit them. Ok that's fine, but we still need some realistic approach in this thread! Anyway .little change in the output, with a typical Autumn like feel to the charts. If I look into deep FI gfs has cooked us up a real indian summer!  

[johnholmes]

If only folk would quote the time frame they are using to illustrate their view and show the charts then all of us could appreciate what was being said?

[Northern Sky]

If only folk would quote the time frame they are using to illustrate their view and show the charts then all of us could appreciate what was being said?

That would be a very good idea John. I often have a quick scan of the model thread to see a summary of what the weather might hold and see people talking with great certainty about a nice sunny warm period of weather (summer) or freezing cold and snow (winter) only to find on closer inspection that to get to this spell we have to get through 5 days of something very different - and we all know what usually happens after 5 days...

[Tamara]

If ever there was a time to be especially sceptical of operational output it is now. The trough sitting ahead of the atlantic high pressure continues the theme of recent days (and to a degree weeks) of the models making a meal over these features, in the same way as they tried to overplay the longevity of the trough that is here for today and the weekend. The current output through next week is not to be trusted at all and I suspect the weakness of pressure just sitting there for days over the nearby continent and north sea is being over played.

 

The jet streak for later next week is the one constant feature of the pattern upstream and I think that we will find that the split from NW UK to SE UK takes over our weather again rather quicker than a lot of the modelling is trying to suggest atm.

[snowking]

And to further add to Tamara's point, anyone who thinks the days 5-15 day pattern is in any way certain just needs to take a look at this:

 

 

4 models....4 completely different MJO outcomes at days 10-15.

 

I'm not sure in the shorter term the prognosis of the trough to the East of the UK is too far away from the mark, given the continued MJO phase 1 signal for at least the next 5-7 days, but beyond that it becomes unclear. I would suggest that given any lack of tropical forcing so far this year has tended to co-incide with the Azores high ridging towards the UK then this must surely be the form horse, and this is indeed the favoured approach from the GEFS this morning:

 

 

...but this is September, and we are looking at very different seasonal wavelengths beginning to come in to play now. My personal thoughts are a predominantly unsettled second half to September, but before we get there plenty of uncertainty still to come!

 

SK

Edited September 6, 2013 by snowking

[Tamara]

And to further add to Tamara's point, anyone who thinks the days 5-15 day pattern is in any way certain just needs to take a look at this:

 

 

4 models....4 completely different MJO outcomes at days 10-15.

 

I'm not sure in the shorter term the prognosis of the trough to the East of the UK is too far away from the mark, given the continued MJO phase 1 signal for at least the next 5-7 days, but beyond that it becomes unclear. I would suggest that given any lack of tropical forcing so far this year has tended to co-incide with the Azores high ridging towards the UK then this must surely be the form horse, and this is indeed the favoured approach from the GEFS this morning:

 

gefs_z500anom_nh_49.png

 

...but this is September, and we are looking at very different seasonal wavelengths beginning to come in to play now. My personal thoughts are a predominantly unsettled second half to September, but before we get there plenty of uncertainty still to come!

 

SK

I'm still learning the implications of the MJO links, but I did see them and the disagreement within them, and thought that it was a background factor in terms of the confusing output but probable inevitable change. Thanks for illustrating it better than I could and confirming it   I was thinking that this year with the entrenched summer pattern feedback in place it might take a little longer for the seasonal wavelengths to play their natural part - but sooner or later they will of course as you rightly say. In an ideal world I would prefer they waited a little longer till after my very late season holiday

[shedhead]

24hrs on and things look considerably different across the model suite, with little if any sign of the high pressure dominance touted by both ECM and GFS for next week.  Both the big two now suggest a fairly cool and rather mixed pattern, with winds generally predominating from between west and north.  This is not to say we won't see some decent weather at times across the south in particular, but the summery charts allued to by ANYWEATHER are now conspicuous by their absence, pretty much as expected by many.

[Summer Sun]

Here is the latest from Gibby on the models

 

Hi everyone. Here is this morning's report on the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Friday September 6th  2013.

 

All models with the exception of NAVGEM and the outer reliable limits of ECM have changed somewhat today. Gone is the extensive build of pressure for the UK next week and in it's place is the reluctance to clear this weekends Low away East early in the week maintaining cloud and showers in much cooler conditions than of late for all for much of next week.

 

The Fax Charts today illustrate a cool and unsettled period to come. With winds shown mostly from a Northerly source it will feel much cooler than of late with troughs scattered around the British Isles ensuring all areas see at least some rain at times.

 

GFS shows Low pressure stuck out in the North Sea from Tuesday until Thursday of next week with cool Northerly winds and rain or showers in the East and more scattered showers but still cool conditions in the West. By the end of the week further Low pressure slips down from the NW keeping things cool and unsettled next weekend too in NW winds. It's only from 10 days out High pressure develops a foothold over the UK with fine , dry and warmer weather developing by day with foggy nights likely.

 

The GFS Ensembles show an extended cooler phase of weather now with rain at times with some recovery in uppers to more normal levels in the South late in the run as High pressure comes back on to the scene especially in the South drying things up here.

 

The Jet Stream shows a trough developing over the UK, one that is maintained in some form or another for the next week or so before the flow returns North of Scotland at the edge of reality.

 

UKMO today shows a showery trough close to SE England next Thursday with a developing Westerly flow over the North. Showers in the SE will be joined by increasing cloud and occasional rain on a westerly breeze in more northern and NW parts late in the week.

 

GEM does show a ridge moving across the UK from the West midweek tempering down the shower risk for a time but Westerly and then SW winds strengthen markedly as the remains of an ex-tropical depression and attendant pool of warm moist air winds up a powerful depression close to NW Scotland late in the run with the first real Autumn gales battering the North and West with heavy rain to boot to in places especially across the North and West.

 

NAVGEM show no such drama as it maintains it's recent theme of holding Low pressure close to Southern Britain next week with Easterly winds and thundery showers the most likely weather for the South. High pressure ridged across the North is shown to extend further South by the end of next week with fine and settled conditions for all shown by then.

 

ECM looks quite unsettled this morning with a slow moving Low to the East of the UK next week with rain and showers spinning South at times over the UK followed by reinforcements from the NW later on ending with a complex Low pressure area or trough across the UK with further rain or showers at times for all in temperatures close to average at best.

 

In Summary the embryonic downturn hinted at last night in next weeks prospects have gathered some pace this morning. We have GFS, UKMO and ECM all looking like holding Low pressure close to the East well into the middle and end of next week with the door open for reinforcements to move down from the NW by next weekend as GFS and ECM both highlight. GEM does give a 'batten down the hatches' type scenario next weekend as the remains of an ex-tropical storm gets caught up in the flow to the NW and that would mean very autumnal conditions for many. It's only NAVGEM and GFS in FI that bring some balance to the argument with fine and bright weather on offer in 10 days time as High pressure builds back over the UK  from differing evolutions. So all in all still a lot of uncertainty in the mid to long term with some of the output beginning to look distinctly Autumnal if not always for the British Isles for the Northern hemisphere in general.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[Yarmy]

Why doesn't Gibby post his summaries himself anymore? They really are superb.

[Summer Sun]

Why doesn't Gibby post his summaries himself anymore? They really are superb.

 

I think some people were having a go at him earlier in the year for some stupid reason and he's not come back since

 

I have sent him an e-mail to see if he's coming back I shall report back when I get a reply