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reef

Model Output Discussion

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A fresh new thread for discussing the models.

If you want to discuss the potential cold spell:

If you want to ramp:

Or have a moan:

The team have been flat out trying to keep this thread tidy, so much so that we havent had the time to move off-topic posts. If you want to see your post stay, then think for a moment where it should go before you hit the post button. Also, theres been some downright nasty comments and a lot of bad attitudes in the previous thread. This wont be tolerated.

Thanks.

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May i ask if the latest UKMO charts are out yet? I can't find them for some reason.

If there is the same agreement, and the 00z is ok tomorrow (with the ECM) i think it's pretty much nailed on.

Lewis

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Think I found a crumb of comfort on the ECM 12z, there is a trigger low over iceland at T+240 hours that could pull down a N'ly :drunk: will it be there in the morning though?

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Anyone doing an all nighter tonight?

I'm thinking about it,i think the 0z runs will decide where we are going with this.

Would do but need some beauty sleep for the Xmas party tomorrow.

I just have a feeling the ECM is going to come back in line on the 00z. If it does I would say the cold spell is nailed. Intensisty, duration, percipitation etc all to be determined obviously... No doubt the GFS will then decide to throw a wobbly if the ECM plays ball though! :drunk: Not sure why I'm laughing, stranger things have happend with these charts! :o

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Cookie

All are pretty much agreed on the next 2-3 days with High Pressure moving Northwards, areas of Fog and Frost aplenty. Some showers into the South East on Sunday falling mainly as rain.

The BBC Weather Forecast looks like they used the UKMO Only upto T72 And for good reason they did not go any further than that as they will be awaiting new data. Their pressure charts showed the High trending to the North East whereas GFS Shows this more to the North West, ECMWF Having none of it though and keeping it closer over the Uk.

So in a nutshell GFS (Best for Snow) 2nd (UKMO) 3rd (ECMWF)As it stands atm

It remains to be seen which way the Beeb jump tomorrow after the 00z UKMO, But I have a feeling we will get a halfway house between the UKMO & GFS With a watered down version of the initial easterly followed by cold a cold easterly breeze with it getting interesting as the week goes on.

That good enough :drunk:

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The GFS has been suggesting this pattern (easterly, cold spell etc) for a while now and someone posted a GFS run from last saturday for today which was remarkably accurate. It is a concern that the ECMWF is not on board and that we have been here before but I personally feel that some areas will see snow next week and we will see some form of cold spell maybe not as severe as many would like.

'Nothing is certain', that is the interest with model watching and why there are so many differing opinions but it is important to keep a level head.

I'll just touch on the Ian Brown subject (sorry mods), I used to use the BBC Snow Watch in 02/03 to discuss the weather and Ian was most certainly a mild ramper even a wind up merchant, I'd imagine respected members like Stratos Ferric will verify. He very rarely goes into any depth in what he says and the only reason he is given any credibility is he always backs the form horse i.e mild which is 80% of the time is the case.

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The state of the models is as follows:

ECMWF- a run that is highly consistent with Ian Brown's modern winter theory, a topic of considerable controversy on here. High pressure stays on top of the British Isles for most of the run, with just a slight ENE'ly next Thursday bringing a few sleety showers for the SE, then as the jet powers up to the north the high sinks back south again, leaving us in a not especially cold, probably cloudy anticyclonic/northerly regime.

UKMO- Goes for a fairly cold easterly over the south on Monday/Tuesday which would probably bring some sleet and snow showers there, but mainly rain and sleet for eastern Scotland and north-east England. Shortwave slips down the North Sea at T+144 (next Wednesday) in an ideal position to bring the cold air across from the north-east thereafter. Cold spell well and truly on if the UKMO is right, in stark contrast to ECMWF.

GFS- The 12Z run had an easterly on Monday/Tuesday that looked like bringing numerous snow showers to East Anglia and south-east England but a wintry mix further north (especially near the east coast itself). Shortwave moved down the North Sea but largely fizzled out and was too far east to influence us, resulting in the high to our north sinking over us and scuppering the arrival of cold air from the northeast, similar to the ECM. However the 18Z then moved towards the UKMO evolution, keeping the Monday/Tuesday easterly "on" for southern areas in particular, and introducing a very cold ENE'ly behind the shortwave starting next Thursday/Friday.

So in conclusion, a lot of disagreement and confusion, but not a tremendous amount of support for the ECMWF solution from the teleconnections or the GEFS ensembles. The main problem is that Ian Brown's theory does have some truth behind it, the reinvigoration of the northern arm of the jet has been a repeated source of downgrades in the past, and so I don't think the ECMWF output should be ignored either.

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What is amazing Paul is how the models haven't nailed on the easterly even at 72-84hrs...however I remember this occured with the easterly of December 2005 as well and it was only at 72hrs out that all the models finally came onboard.

I really am exactly 50-50 as to what happens, its hard to ignore the GFS and UKMO as they have barely moved at all (the UKMO backed down for just one run) whilst the ECM has had nothing to do with this cold set-up from the start so thats something to remember. However equally history does suggest the northern arm will win out and also the ECM is a very good model, often a trend setter in fact.

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for someone who is trying to catch up.

can anyone give me a quick summary as to what the models are saying at the moment re the cold snap?

Hi cookie,

The gfs, ukmo, nogaps, gem and probably more I haven't mentioned are currently predicting a cold spell rather than a snap, and a prolonged spell with intensifying cold and increased snow risk by the middle to end of next week onwards. The ECMWF has been the fly in the ointment today, not buying into a snowy and very cold spell at all for 2 runs in a row, it's been showing HP glued to the BI with the easterly shown as a weak and brief feature and the subsequent Northerly blast deflected across the north sea and well away from the uk due to the anticyclone being too close to the western side of the uk. Hope that helps. :drunk:

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Cookie

That good enough :drunk:

Thanks mate :o

The state of the models is as follows:

Thanks just what I was after :)

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Evening all

Just catching up with the model output, it seems the ecm has caused mayhem this evening! Haven't had a chance to look through all the pages so not sure if this has been covered.

In this evenings NOAA discussions in their extended outlook they go with the gfs 06hrs ensemble mean.

Theres a divergence of opinion between the gfs and ecm in how they handle the eastern USA trough which of course downstream affects western Europe.

Overall the ecm seems the odd one out across the general model guidance, however its not post 144hrs but before this that we see differences so this is a concern. It could be the ecm is too flat with the jet upstream and the gfs too amplified here so perhaps they're both wrong, in this instance a sensible way forward would be to side in the middle and perhaps think a possible scenario is a litle give from both models.

The ecm ensembles still look okay but theres increased scatter here and not the deep cold of a few days back, however i think we have to expect that the models are going to have difficulties with a rather unusual synoptic set up.

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So in conclusion, a lot of disagreement and confusion, but not a tremendous amount of support for the ECMWF solution from the teleconnections or the GEFS ensembles. The main problem is that Ian Brown's theory does have some truth behind it, the reinvigoration of the northern arm of the jet has been a repeated source of downgrades in the past, and so I don't think the ECMWF output should be ignored either.

Thank god I'm not the only one on here who has a balanced view of the computer models. If Ian Brown wasn't being so 'controversial' would we all really be getting so wound up? I agree with Ian (TWS) here - the ECMWF shows one of a multitude of possible outputs here. Whilst teleconnections don't necessarily support it in detail we have to be acutely aware that minor differences in synoptics and local conditions can have a profound effect on what weather we experience in our own gardens (read imby)

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Evening all

Just catching up with the model output, it seems the ecm has caused mayhem this evening! Haven't had a chance to look through all the pages so not sure if this has been covered.

In this evenings NOAA discussions in their extended outlook they go with the gfs 06hrs ensemble mean.

Theres a divergence of opinion between the gfs and ecm in how they handle the eastern USA trough which of course downstream affects western Europe.

Overall the ecm seems the odd one out across the general model guidance, however its not post 144hrs but before this that we see differences so this is a concern. It could be the ecm is too flat with the jet upstream and the gfs too amplified here so perhaps they're both wrong, in this instance a sensible way forward would be to side in the middle and perhaps think a possible scenario is a litle give from both models.

The ecm ensembles still look okay but theres increased scatter here and not the deep cold of a few days back, however i think we have to expect that the models are going to have difficulties with a rather unusual synoptic set up.

I wish there was a "like" or "kudos" button a la facebook or twitter. Level heads and calm, considered thought required here! One model does not represent the be all and end all - (am I wasting my breath here?) Manage your expectations against the following backdrop - regardless of AGW and the "christmas pudding/winter" snow is as rare as rocking horse poop in the UK!! There I said it - just because the ECM doesn't agree with the GFS doesn't mean it's wrong.

Currrent global teleconnections suggest that the ECM may be barking up the wrong tree but the statistical nature of these models give it an equal chance of being right if you take just model output as your sole basis for a forecast.

Jeez I hope I am wrong (NW second biggest ramper after Coast)

:drunk:

Oh sorry I'm third in the queue after Coast and TEITS :o

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Nick,

Any thoughts on the FAX? Seems to be some conflict as to which model they look to be backing.

I'm not very good at reading FAX but ecm and gfs/ukmo are like chalk and cheese at 120h,surely it cant be that hard to tell?

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Anyhow,

Had some good fun yesterday/tonight on netweather, shame about some of the thread trashing, but the mods did there job superbly.

I promised i would stay up for the 00z to a few peeps but i'm afraid the carlsberg has officially finished me off.

Fingers crossed for the ECM in morning, let's hope it agrees with the GFS and UKMO.

Good night everyone,

Take care,

Lewis

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Poster Iceberg claims:

This is all wrong. It produces charts at 3 hourly intervals out for the first few days, then 6 hourly beyond that. It's just not available for free.

Agreed J07 - folks do your research before hammering the ECM model -

25 November 2009 ECMWF has pioneered a system to predict forecast confidence. This system, operational at ECMWF since 1992, is the Ensemble Prediction System (EPS). A new leaflet on EPS has been published on the ECMWF web.

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Well the GFS00 looks a peach of a run up to T144 aint bothering after that.

GFS certainly sticking to its guns anyway about the Easterly.

Lovely charts to look at and by next Thursday most of the Country under -10 air

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Might not get home from work Monday if the Netweather precipitation is anything to go by, its gonna snow all day as far West as Bristol and reaching Devon at times according to the GFS 00z. The -5 850 has cleared most of the UK and most of South East Ireland by 15:00 Monday 14th. Certainly doesn't look like any climbdown to the ECM position with my eyes!

h850t850eu.png?dopvhost=charts.netweather.tv&doppl=0f139ea344324a9f&dopsig=22a5093d70a4bd24e7d8d20e1162258b

I know I have to take these precip charts with a pinch of salt but here's midday Monday 14th according to the GFS 00z - sorry, couldn't resist:

prectypeuktopo.png?dopvhost=charts.netweather.tv&doppl=0f139ea344324a6e44624a3e95a7417544624a03&dopsig=5c9a3d0828614c55918af5974edb9922

And all hell breaks loose on Thurday as expected!!

h850t850eu.png?dopvhost=charts.netweather.tv&doppl=0f139ea344324682446246d295a74d8d446246fa&dopsig=b16baba689920258eeadf08efc011794

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Agreed J07 - folks do your research before hammering the ECM model

http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Wind%20850%20and%20mslp!192!Europe!pop!od!oper!public_plots!2009120400!!chart.gif

Ok i did and ECM was showing this for today just a week ago :lol:

Very wrong indeed, fact is GFS picked up a retrogressing high first.

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Well the GFS00 looks a peach of a run up to T144 aint bothering after that.

GFS certainly sticking to its guns anyway about the Easterly.

Lovely charts to look at and by next Thursday most of the Country under -10 air

Indeed excellent.

If the Ecm doesen't verify now,thens its credibility is finished as a top model.

And no its hasn't just been one run,nonono.gif its been all over the place over the last week,its output every 12 hours has chopped and changed so much this week,its beyond a joke.

How so many people have been blindly following it and ignoring the other models,which have all gone against it is beyond me.

Fantastic from both gfs and meto this morning,ECM your last chance to save your credibility is loomingmellow.gif

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Woke up very early to be pleasantly surprised with the GFS 00Z, would perhaps have prefered the initial northeasterly but you can't complain about those charts really. Hopefully the ECM stops fooling around and comes on board, if it does then I think the ramping can really begin.

LS

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Yes i totally agree with everything you say in your post sleety, spot on ECM has been very temperamental indeed and the chart i posted wasnt just a one off too it showed similar mild southerlies for today on other runs last week too but we have cold calm conditions over us, someone on TWO says UKMO 00Z is poor well it looks similar to GFS T+144 hrs to me and it doesnt show any atlantic breakdown at all, GFS 00Z is excellent as it keeps it cold throughout with reloading HP to our north, i think a breakdown will come eventually though as you are very rarely going to get more than two weeks of cold weather at a time in the UK.

http://www.wzkarten.de/pics/Rukm1441.gif

http://www.wetterzentrale.de/pics/Rtavn1441.png

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Hot of the press, ECM is backtracking going from the first map of this run already, YESSSSSSS

UKMET has leaned a bit towards the ECM 12Z position but not enough to spoil things.

GFS very nice indeed, GFS alternative a belter.!

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ECM now has the low and cold coming from the east on Wed/Thur Next week, total backtrack.

All three models now bring considerable snow from the middle of next week onwards, With ECM perhapes a little better than METO now.

WE HAVE MODEL ARGEEMENT ON SNOW!!!!!!!

Given it's track record over the last few days I am not I would trust ECM in the later stages of the run.

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