Model Output Discussion

[bluearmy]

I've missed a lot of the comments today but the GFS 12z output (op and parallel) is tending towards the middle ground between the steller runs we have been seeing and the ECM 00z. remembering that the ecm 12z of yetserday went some way towards the GFS evolutions i would think we saw the worst case scenario from ecm this morning, the best case scenario on gfs this morning and the 12z's will offer us a better picture of what is likely next week.Of course this is still a way off and the real cold may well retrogress back towards us over the next few days output. however, as we approach verification, if the pattern begins to downgrade across models, we should take notice of it and not dismiss it. it is, after all, the form horse for the cold to be east or south when it finally arrives.

[kold weather]

To some extent yes NS, but it depends on what the other op models are showing.

Ensembles really picking up on the trend for a strong low in the Atlantic trying to push up...that is what the global teleconnections would suggest and then it just depends on whether the cold is strong enough...of course the 12z suite tends to be the one that can overdo low pressure cells.

[Snowaddict]

GEM 12Z has 850's of -5 heading into the southeast corner at T+114..

Can't see past T+120 on Meteociel but definite retrogression taking place... Shortwave due north looks to be sliding down into Scandi eventually but that's not very certain up to T+120..

Anyone with the link out to T+144?

[johnholmes]

Height rises don't seem as good in Russia. if the height rise isn't as strong will it allow free western flow of the cold air?

wrong direction - the change in pattern is being driven by events way west of here-have a look at my blog where I try to explain it

[Frosty.]

I guess we won't know for sure until thursday's 12z runs, that appears to be the tipping point as to whether we are in for cold spell to remember, the ingrediants are all there but they are all jumbled up at the moment but I do get the feeling the models are beginning to get cold feet following the recent stellar runs, a new trend shortening any potential wintry snap maybe..time will definately be the judge of that.

Edited December 8, 2009 by Frosty039

[cold snap]

The problem with the 12z is that it takes so long to bring the proper cold to the UK (not till 240 hours) that many things can go wrong till then.

We want the cold spell to come nearer, not get delayed!

Karyo

Best Post this afternoon.the pattern has not changed in 24 hours i think

Its just been put back by GFS ,GFS not as keen to bring this in as quick as we would like

[snowmadchrisuk]

Best Post this afternoon.the pattern has not changed in 24 hours i think

Its just been put back by GFS ,GFS not as keen to bring this in as quick as we would like

Does anybody know why the UKMO is late this evening , are they changing the colours on the charts

[johnholmes]

I wonder if there is any point in me trying to inject a touch of realism.

Apologies for those who love the ups and down s of each run.

But IF you really want to see what the GFS model is actually trying to do at long time scales STOP comparing run to run.

It does NOT work and I'm not repeating what I've said over the past 5 years as to why-please trust me I do know what I'm talking about.

At closer time scales, and the closer the more effective by all means follow and compare run to run, but beyond, and its a varying time scale depending on a all kinds of factors, say beyond T+144 as an average.

I'll put my thoughts, for or against what happens after this weekend into the blog this evening once I'm able to use the NW versions of GFS and ECMWF along with UK Met for the shorter time scales.

[on the coast]

I wonder if there is any point in me trying to inject a touch of realism.

Apologies for those who love the ups and down s of each run.

But IF you really want to see what the GFS model is actually trying to do at long time scales STOP comparing run to run.

It does NOT work and I'm not repeating what I've said over the past 5 years as to why-please trust me I do know what I'm talking about.

At closer time scales, and the closer the more effective by all means follow and compare run to run, but beyond, and its a varying time scale depending on a all kinds of factors, say beyond T+144 as an average.

I'll put my thoughts, for or against what happens after this weekend into the blog this evening once I'm able to use the NW versions of GFS and ECMWF along with UK Met for the shorter time scales.

Its been said before but we are spoilt for choice with weather charts. Beyond +72 is not good but i am as guilty as anyone

as looking beyond this and taking it as gospel. Bloody internet!!

[cyclonic happiness]

The 12z ensembles for warwickshire are pretty good still IMO with a good deal of scatter from early on but, and overall cold run.

Control is a bit of an outlier midrange, but still good.

[Alex95]

All the ingredients are there for a very cold and snowy spell, but the trouble is they're slightly misaligned on the 12z operational. You can't ice a cake before baking it, if the weather tries something like this we'll almost see a very wintry spell indeed, but we'll actually be left with drizzle.

It is also worth mentioning that at least 80-90% of the ensembles go for 850s below -5°C for the 17th, and the operational is a massive mild outlier for the 17th.

[snowray]

I wonder if there is any point in me trying to inject a touch of realism.

Apologies for those who love the ups and down s of each run.

But IF you really want to see what the GFS model is actually trying to do at long time scales STOP comparing run to run.

It does NOT work and I'm not repeating what I've said over the past 5 years as to why-please trust me I do know what I'm talking about.

At closer time scales, and the closer the more effective by all means follow and compare run to run, but beyond, and its a varying time scale depending on a all kinds of factors, say beyond T+144 as an average.

I'll put my thoughts, for or against what happens after this weekend into the blog this evening once I'm able to use the NW versions of GFS and ECMWF along with UK Met for the shorter time scales.

I look forward to that John.

Must say I gave up reading the hundreds of posts, the trend remains there for colder weather next week, the details of which are still too far out, but I remain positive.

Yes, UKMO is running very late, I wonder whats cooking there? Maybe a bit of hair pulling and knashing of teath at the Met Office this evening ay?

[Mark Bayley]

If we compare 12z to 12z or 6z to 6z like JH suggests then the GFS ensembles are an upgrade from yesterdays 12z set with the mean dropping even lower! So that's one good positive tonight. The ensembles do run in a lower resolution however the overall trend is very good!

Yesterday 12z

Today 12z

EDIT: Fixed

Edited December 8, 2009 by mark bayley

[snowmadchrisuk]

The 12z ensembles for warwickshire are pretty good still IMO with a good deal of scatter from early on but, and overall cold run.

Control is a bit of an outlier midrange, but still good.

For Leicester between the 16th and the 19th it is a total mild outlier with not 1 other member supporting it. Also for that period the mean is heading towards -10 850's with lots going for -15 .

Edited December 8, 2009 by snowmadchrisuk

[johnholmes]

Yes, UKMO is running very late, I wonder whats cooking there? Maybe a bit of hair pulling and knashing of teath at the Met Office this evening ay?

quite possible although I would tend to favour a problem somewhere down the line of getting from the Exter Ops room out on to the net?

[cyclonic happiness]

I look forward to that John.

Must say I gave up reading the hundreds of posts, the trend remains there for colder weather next week, the details of which are still too far out, but I remain positive.

Yes, UKMO is running very late, I wonder whats cooking there? Maybe a bit of hair pulling and knashing of teath at the Met Office this evening ay?

Maybe they are trying to "hide the decline"?

Late meto runs do tend to be good ones don't they?

[snowmadchrisuk]

The pressure chart shows very nicely that it clearly expects pressure to be further North and lower pressure to our South

http://charts.netweather.tv/ensimages/ens.20091208/12/prmslLeicestershire.png

Edited December 8, 2009 by snowmadchrisuk

[Mark Bayley]

quite possible although I would tend to favour a problem somewhere down the line of getting from the Exter Ops room out on to the net?

Its starting to update now

http://www.meteociel.fr/modeles/ukmo2.php?ech=6&carte=1021

Hopfully it will be good!

[cyclonic happiness]

Weenie bit further west at 70hrs?

[NorthantsSnow]

Its starting to update now

http://www.meteociel.fr/modeles/ukmo2.php?ech=6&carte=1021

Hopfully it will be good!

We can't see what's happening to our north and west on this one though.

[Cal]

12hrs UKMetO at 72hrs

00hrs UKMeto at 72hrs

[Harsh Climate]

Woahh just senn the 12z gfs esembles!

http://charts.netweather.tv/ensimages/ens.20091208/12/t850West~Yorkshire.png super if you ask me, with the control run and op run generally on the mild side..

Lets hope the ukmo n ecmwf play ball 2

[NorthantsSnow]

Looks like there might be a problem with the UKMO past T72. Blank charts on Wetterzentrale.

[cyclonic happiness]

Looks like there might be a problem with the UKMO past T72. Blank charts on Wetterzentrale.

Try meteociel...here you go

http://www.meteociel.fr/modeles/ukmo2.php?ech=6&carte=1021

[Guest North Sea Snow Convection]

I don't know how the rest of the output is going to go - but UKMO t96 looks very good to me