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Model Output Discussion 18z 28/07/13


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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Here is the latest on the models from Gibby

 

Good evening. Here is a quick look at the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Friday August 30th 2013.

 

All models are in pretty sound agreement on the course of events between now and a semi breakdown midweek next week. The cold front currently crossing Southern Britain will move clear of the SE by morning with a cooler and fresher NW flow with rising pressure from the SW. the weekend will be dry and bright spare a few showers for the far North with temperatures close to average but cool Autumnal nights. As High pressure then transfers across and to the East of Southern Britain early next week warmer winds will be imported with some very warm weather possible in the SE for a time towards midweek. In the North and later the West too cloud will be thicker and rain will proceed East across the UK midweek, some possibly heavy and thundery marking the commencement of a more unsettled phase of weather.

 

GFS then shows a showery period later next week with cooler temperatures before things dry up from the west later in the weekend with a ridge of High pressure giving a couple of dry and sunny days with reasonable temperatures. Slightly more changeable weather does threaten again later in the run under slack pressure but High pressure never strays far away to the West.

 

The GFS Ensembles show a 4 day warm up starting at the beginning of next week in the South before temperatures return to more average values at the same time as more unsettled weather develops with rain at times. Things from the Ensembles look typically spaghetti like for the North from early in the run with all kind of options possible.

 

The Jet Pattern shows a flow to the North of Scotland currently before an undulating pattern develops next week as the troughs pass east. By the end of the run the pattern shifts more direct West to East close to Northern Scotland.

 

UKMO tonight shows a trough having passed East on Wednesday night with rain for all replacing the warm and humid conditions in the SE with cooler and fresher conditions with sunshine and scattered showers for all through the day.

 

GEM tonight shows a similar scenario moving forward behind the trough with a new build of pressure from the SW promising further dry conditions developing by the end of the weekend.

 

NAVGEM shows a weaker trough crossing East soon after midweek before a slack ridge builds back by the weekend with dry and bright weather with average temperatures following the showery midweek period.

 

ECM tonight shows a complex Low pressure system developing over the UK later next week revolving around Southern England and eventually being displaced in the far NW by higher pressure later but with a cool east wind. Cloud and rain could be quite heavy and thundery at times in the South in average temperatures. The Northwest would gradually turn less unsettled at the end of the weekend as the low relaxes further South over France.

 

In Summary nothing seems any clearer tonight as all models continue to serve up differing outcomes for the weather behind the agreed upon midweek trough. In the meantime there is a few more good days of weather to come for all and a bonus of a very warm interlude in the SE early next week before the trough arrives with it's attendant showery and potentially thundery rain. After that it appears to be anyone's guess at the moment.

 

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

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Posted
  • Location: Helensburgh,22 miles from Glasgow
  • Weather Preferences: Snow,snow and....a bit more snow
  • Location: Helensburgh,22 miles from Glasgow

Another really brilliant and thundery ecm 12z tonight especially if you like hot and humid weather!!where are all the guys that said we gona see autumnal weather from the north west next week!!it looks like we are gona see a breakdown from the south instead and a thundery one at that!nothings for definate yet but some real positive news from the ecm 12z for heat lovers!!

To be fair , folk are just saying what they see.iIt seems clear to me that very little is clear....and it may take a few more days before it gets clearer..i hope that makes it clear.I think there are more than a few options on the table.
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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Looking at GFS and summer will continue into next week with very warm temperatures widely in England and Wales locally hot possibly in the south

 

Posted ImagePosted ImagePosted Image

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Posted
  • Location: Live Haddenham (Bucks). Work Heathrow Airport
  • Location: Live Haddenham (Bucks). Work Heathrow Airport

ECM still shows it turning unsettled from late next week just in a different way from previous runs. Warm rain now instead of cold rain. But ultimately still er wet!!!!!

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

At least the cool, unsettled stuff is still where it's been for much of the past 3 months: a week away...Posted Image

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Posted
  • Location: Keyingham, East Yorkshire
  • Weather Preferences: Spanish plumes, hot and sunny with thunderstorms
  • Location: Keyingham, East Yorkshire

The ECM mean in FI highlighting the great uncertainty but theres no overwhelming support for low pressure, nor is there for high pressure. But it looks like warm air will not be too far away.

 

Posted Image

Posted Image

Edited by Milhouse
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Posted
  • Location: st albans
  • Location: st albans

Well you cant complain that it isnt interesting. Another 'trough' conundrum. I hope these wear themselves out by the time we get to winter or this place will be 'bi polar'.

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Posted
  • Location: Bristol
  • Location: Bristol

As an illustration of the change, the ECM ensembles for Glasgow have staged a big turn around this evening - they show a trend for above avg temperatures (apart from this wkend), rainfall levels are now, on average, below the expected norm.

all in all, autumn is on hold tonight, but what will tomorrow bring!

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Posted
  • Location: Droylsden, Manchester, 94 metres/308 feet ASL
  • Weather Preferences: Dry/mild/warm/sunny/high pressure/no snow/no rain
  • Location: Droylsden, Manchester, 94 metres/308 feet ASL

As an illustration of the change, the ECM ensembles for Glasgow have staged a big turn around this evening - they show a trend for above avg temperatures (apart from this wkend), rainfall levels are now, on average, below the expected norm.all in all, autumn is on hold tonight, but what will tomorrow bring!

 

Hopefully more of the same, the longer we can leave the heating off the better.

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Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL

Hopefully more of the same, the longer we can leave the heating off the better.

Then the GFS pub run is your friend as we are warmish and reasonably settled into deepest, darkest FI. Personally, I'm in warm mode from April to September, but come October I'm looking for something cooler and seasonal.
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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby

The ECM mean in FI highlighting the great uncertainty but theres no overwhelming support for low pressure, nor is there for high pressure. But it looks like warm air will not be too far away.

 

Posted Image

Posted Image

 

this will be interesting then, because the anomaly charts have all now shown (upper) low pressure dominance for several runs for the period running upto mon 9th, after midweek.

who will blink first? which data will be right?

 

post-2797-0-85145900-1377931062_thumb.gi

 

post-2797-0-49348800-1377931076_thumb.gi

 

these charts (fri - mon) suggest a pretty changable picture with low pressure in charge, cool, breezy, with rain in the form of showers or/and frontal.

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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

00z ECM a lot keener than 00z GFS and UKMO in stalling an upper trough out west which pulls in a 15C 850mb plume north across the UK later next week. ECM maybe too slow with the trough, but too early to tell. More runs needed.

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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

Well well well..... here we are again

ECM differs from all the other models (GEM/GFS/UKMO) even at T96 showing a much more amplified upper ridge to our east and drops the trough underneath it. Fair to say the ECM is an absolute corker of a run with very warm uppers in circulation over the UK throughout with no sign of letting up as by day 10 the Scandi high has linked up with the Azores high.

Posted Image

 

Either way this is how the models are shaping up at day 5, the odd one out is very easy to spot

ECM

Posted Image

 

GFS

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UKMO

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GEM

Posted Image

 

It's ECM vs the world at the moment, but fair warning the last time this happened the ECM was spot on so I'm really not sure this morning.

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Posted
  • Location: Bristol
  • Location: Bristol

In 24 hours, we have gone from

Posted Image

to this

Posted Image

you couldn't make it up!

in reference to the 0z model, it keeps warm weather from start to finish, in contrast with the other models. More runs needed, but we'll probably still be in the dark!

Edited by draztik
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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Another corker from ECM with it showing things becoming hot and humid in the south later next week

 

Posted Image

 

It could also trigger some thunderstorms looking at the pressure

 

Posted Image

 

ECM once again ends on a warm note for all with the north more settled than the south

 

Posted ImagePosted Image

 

All in all the summer warmth continues

 

Posted Image

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Here is the latest on the models from Gibby

 

Good morning and welcome to my daily review of the outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Saturday August 31st 2013.

 

All models are now in solid agreement on the weather pattern for the next week over the British Isles. The last of a cold front is clearing the SE currently with a bright and fresh NW flow over the UK under strongly rising pressure from the SW. A couple of bright and fresh days are expected for all but more cloud in the North tomorrow as winds back Westerly. High pressure then builds strongly over Southern Britain through the early week while the North sees weak fronts deliver more cloud which may spill SE to other Eastern areas at times. By midweek the High over the South will of moved off to the East allowing falling pressure and a broad trough to move in from the West which hangs around in one form or another for the remainder of the week. Outbreaks of rain would reach the West late Wednesday, extending East to all areas Thursday. Some of this could be heavy and thundery and will be accompanied by a reduction in temperature values across the South from those of earlier in the week.

 

The Fax Charts confirm the above text well showing the trough approaching Western Britain on the 120hr chart as pressure falls on Wednesday.

 

GFS then decides to develop a North/South divide in conditions for the extended part of it's run with troughs crossing the North at times in occasional rain while our old friend the Azores High never strays far away from the South maintaining dry and bright conditions here with just very occasional light rain and temperatures well up to average if not slightly above. Once more unsettled weather on a national basis is indicated in the far reaches of the run.

 

The GFS Ensembles show a warm period in the South from the 2nd-6th before a cool off develops in association with more unsettled weather as documented above. However rainfall amounts over all parts of the UK are never excessive and some dry, bright and pleasantly warm feeling weather in brighter conditions can also be expected under uppers still a little above average later in the run.

 

The Jet Stream shows the flow riding over the UK High early next week before undulating South across the UK in association with the midweek trough. The trend thereafter is for a strong surge of the flow just to the North of Scotland with the chance shown of it migrating even further north again late in the extended part of the run.

 

UKMO today shows the trough having cleared East on Thursday leaving Friday with the UK under an unstable flow with pressure rising once more from the West. Showers could be expected in the North and East while the SW becomes dry again by Friday.

 

GEM today also shows a Northerly flow behind the midweek trough but moves on to show high pressure building back close to the South with any changeable conditions with further rain at times reserved for more Northern areas in a westerly breeze while the South sees more benign and bright conditions in average temperatures.

 

NAVGEM too shows a ridge of High pressure building across the UK late next week with fine if rather cool weather developing for all in the wake of a showery Northerly flow exiting East by Friday.

 

ECM continues to be slightly different from the rest developing a depression close to SW Britain midweek instead of a trough. This then sets up a spell of complex Low pressure close to the UK briefly before rising pressure from both the East and SW over the North brings drier conditions here next weekend and beyond. The South would continue to see some thundery showers close to filling Low pressure near Biscay.

 

In Summary there is good agreement now for next weeks pattern with the week summarised as being dry and bright with some rain or showers from midweek with average temperatures from then. In the following period things are not quite so clear cut as some output wants to bring a new Azores High back into play at least across the South while more Northern areas see rain at times. Alternatively ECM looks a little lonely in it's suggestions this morning but if verified would give the South some welcome thundery rain in the form of showers from midweek extending into the following week though High pressure looks like eventually winning through here too, this time from the NW.

 

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

 

 

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Posted
  • Location: Ashbourne
  • Weather Preferences: snow and cold
  • Location: Ashbourne

With the anomaly charts all in agreement of a trough situation and 3 of the models Barr the ECM showing latter stages of unsettled conditions I'm just wondering if the ECM has called this one wrong .

I don't know a great deal about the Anomaly charts do they get things wrong and produce incorrect DATA like GFS and other models seem to do ?

Edited by TootyFruity
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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

With the anomaly charts all in agreement of a trough situation and 3 of the models Barr the ECM showing latter stages of unsettled conditions I'm just wondering if the ECM has called this one wrong .

I don't know a great deal about the Anomaly charts do they get things wrong and produce incorrect DATA like GFS and other models seem to do ?

You would think so, but the ECM op is very rarely way off the mark within 5 days and when it shows a completely different solution to the others you need to give it full respect, we learnt this to our cost a couple of weeks back.

As for the ECM mean, well this is at T192 but shows quite nicely what's going on

Posted Image

 

ECM ens are starting to side with the op here, the mean has a low just to our south west.

Edited by Captain shortwave
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Posted
  • Location: Bristol
  • Location: Bristol

If the ECM 12z shows the same synoptic pattern as this morning, ill read more into it! Until then, im cautious as the model has been swinging between cooler autumnal weather and hot spells, in the matter of a day.

Edited by draztik
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Posted
  • Location: Fazendas de,Almeirim, Portugal
  • Weather Preferences: The most likely outcome. The MJO is only half the story!
  • Location: Fazendas de,Almeirim, Portugal

There is a computer model minefield in the further outlook with a high chance of them making a complete dogs breakfast over the low depicted for the latter part of next week. .

 

If one picks the bones through these for suggestions for what any trough may do next week, then there are plenty of them - maybe too many.

 

Impossible to start to give any detail beyond the weekend other than probably a fair warm start across the south, then some attempt at a more unsettled shot of weather (of some type) .

I have purely re-quoted my own post from a day or so ago as a way of continuity updating for how the models handle the trough for next week. The dogs breakfast analogy seems to have been proved reasonably accurate thus far, with lack of agreement still remaining as already well illustrated by others this morning amongst all the main modelsPosted Image .

 

They have all moved towards varying degrees of split energy and some trough disruption from the main upper trough towards Greenland and Iceland - as a cut off low feature is suggested to break away SE. However the amounts of trough disruption vary from fairly neglible f.e with the UKMO to quite considerable with the ECM.

 

If we look at the trusty updated EPS members this morning, they still suggest a lot of uncertainty in terms of solutions as to how the trough disrupts. We can see that modest support has shifted towards the ECM operational with about 40% in agreement with it this morning and the control solution is one of those members as a copy cat of the operational

 

.Posted Image

We can also see though that there is still good support amongst these very latest ECM ensembles for what the UKMO and GFS are sticking with this morning (at least up to the updating GFS anyway which is coming out at this time)

 

Two consecutive ECM operationals have dug the the cut off low south with greater split energy than the GFS and UKMO and the question remains will the trend be extended this evening with further increased ensemble support, or will it become evident that the ECM is overdoing the trough disruption and more energy stays north, so that a less defined feature disrupts across the UK (rather than into the continent) and thus the suggested plume is downgraded or removed entirely.

 

We should remember what happened last weekend here as a prototype example- and whilst there was a brief interval of very warm air, this was restricted to SE parts of England and the atlantic ridge was faster to push the plume away eastwards over the Bank Holiday weekend.

 

The upcoming scenario is almost the same as last weekend - and we observed that the plume suggestions leading up to the Bank Holiday proved to be exaggerated with the models, but especially the ECM overdoing the amplification and handling of the trough.

 

That doesn't inevitably mean the same will happen again - but in terms of the recycling pattern that we have seen through the latter part of the summer with cut off lows and otherwise predominating mid latitude ridges, then it is good reason to think that history might repeat itself once more.

 

Time as ever will tellPosted Image

Edited by Tamara Road
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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

Hmm I've dug into things a little deeper to see what could be causing the differences even at 4 days out, the key is not over our area of the world

take a look at these two charts, 

Latest GFS at T66 (so comparable to the ECM T72 chart)

Posted Image

 

ECM

Posted Image

 

There is a significant difference somewhere on this chart, the low over Eastern Russia, the GFS/UKMO and GEM all fill this feature, but the ECM has this low as a much more significant feature and keeps the low quite deep at T96, T120 and beyond. The result is pretty simple, it amplifies the ridge forming a Scandi high shown here

Posted Image

 

No other model supports this high but keeps a more central Europe feature which is a lot easier to break down from the west.

Shown here by the UKMO but other models are similar

Posted Image

 

For what happens to us at the end of the week into the weekend, we need to be looking east to this trough as it's the key which starts a chain reaction which disrupts the Atlantic train and provides an undercut set up.

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Posted
  • Location: Fazendas de,Almeirim, Portugal
  • Weather Preferences: The most likely outcome. The MJO is only half the story!
  • Location: Fazendas de,Almeirim, Portugal

It looks to me a case of how the jet stream energy from the trough over Greenland is ejected either north east, east or south east  upstream (to whatever varying degrees) is the larger of the factors than events downstream where the differences, that you rightly point out, are indeed apparentPosted Image

 

The building of higher pressure over Scandinavia certainly assists greater disruption of the trough SE'wards, but then I think the fact the GFS and UKMO don't build the high further northwards into Scandinavia is more to do with the energy being applied across the infamous GIN corridor than anything elsePosted Image

 

I do wonder if the GFS is going to very slowly and gradually move some way towards the ECM operational from here on in. And UKMO at days 5 and 6 is often prone to a few errors. That said, some kind of half way house between the ECM and the other models seems most likely for the reasons given above

Edited by Tamara Road
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Posted
  • Location: st albans
  • Location: st albans

the behaviour of the trough is becoming the standard theme of this thread.  just no firm idea how this is likely to play out as tamara posts above.  eventually, the trough will become the player and the ridges become less dominant. i did think next weekend seemed to be the time for this change but its now evident that this will not be the case. fascinating

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

musings on the 500mb anomaly charts into September?

 

 

What may be in store for September 13-31 august.pdf

 

copied into the slower thread as well

 

ps

One thing seems fairly sure though, there is currently no sign  of any countrywide heat and sunshine to match July!

The SE should fare reasonably well I would think, less so the further NW one lives, in terms of temperatures and rainfall?

 

just to clarify the discussion is in the 6-15 day time frame NOT the next 3-5 days!

Edited by johnholmes
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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Another increasingly warm to hot week is coming up next week as the summer warmth continues especially in the south

 

Posted ImagePosted ImagePosted ImagePosted Image

 

Night time temperatures also hold up very well in the SE with the mid to high teens widely in the SE

 

Posted ImagePosted ImagePosted ImagePosted Image

 

Some frosts may occur in rural areas in the north later next week if conditions were right looking at those temperature

 

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