General Model Output Discussion

[J10]

Saturday 1pm UKMO temps

Not exactly mild away from the SW

I noticed that earlier, and much cooler than the GFS as well.

As for the potential Easterly, the Jet Stream still seems to be south (certainly on GFS charts), but the High Pressure over Greenland isn't there at the moment, which is concerning.

But going by this winter so far anything is possible.

Ladies and Gentleman, a unanimous decision on points, the still undefeated Northern Hemisphere pressure champion, in the Red Corner,

"The Siberian High". (For showing more aggression for the the majority of the run). I'll get my coat and go and lie down in a dark room for half an hour!

Regards,

Tom.

As per my previous post I'd call it a split decision.

[cuckoo]

Looking at how far to the East the air is being sourced from there might not need to be a deep cold pool nearby. We could just tap into the -40°C air over Mongolia

[Nick F]

Hmm, the other day when the GFS 18z "pub run" (what does that mean? the forecast team went to the pub and got plastered?) came out and showed a warmer trend many of the cold lovers were decrying it and saying don't take any notice of the pub run, it's usually no good etc, but tonight, because it shows a colder aspect, it's suddenly got more respect than a hoodie with a tank? A certain lack of objectivity with the assessment of the models perhaps?

I think because it has followed in a similar vein as the 00z, 06z and 12z up to t+180 wrt an easterly developing next week, it perhaps demands more respect this evening

GFS very bullish today with the easterly - which makes me raise an eyebrow and can't be dismissed for sake of fairness, so will be interesting if ECM falls in line in the morning for once, it is not always right of course.

[phil nw.]

Extended Ecm Esms. for London 2m temps.

http://www.meteogrou...-tt6-london.gif

Getting less cold untill midweek then a slight drop for around 3 days before a trend up again,according to the average.

Edited January 13, 2010 by phil n.warks.

[WhiteFox]

This does not look likely from the current setup- the more likely way for the easterly to go the "way of the pear" would be for it to be situated too far east leaving Britain in a no-man's land, which is still a possibility, about 30% for now.

Indeed. The trend in recent years (say the last twenty or so ) has been for the Atlantic to keep any developing block from the continent too far East. I do recall some pretty close shaves over the years, with the period around Boxing Day 2005 springing to mind as a recent example, but the trouble with relying on being the 'terminus' of a large high pressure from the continent is that it only takes a very small adjustment for the block to be just too far east and we end up with a brief Easterly followed by a col or south to south westerlies as the Atlantic pushes back. Of course, they can deliver in spades, but it's a fairly high risk journy to cold (although I guess you could say that about all routes to cold prior to this winter). Maybe this time will be different?

[derrylynne]

Amazing that a few days ago the GFS was rubbish - it was not delivering what was wanted - and the ECM was god - now this week it is vice versa.

When the GFS was consistantly going for a breakdown in the cold - it were rubbished as useless - as the ECM were going for cold. Till at short notice it went along with the GFS.

The GFS was of course right. The one thing I have noticed is the GFS is consistantly correct with trends. It trended the cold before Christmas at F1 along with the breakdown to something milder. It trended the cold after Christmas - and trended the current breakdown. And now is trending a colder again. When the GFS goes for trending mild again maybe good to remember this instead of rubbishing it because it is not what you want to see....

Edited January 13, 2010 by derrylynne

[nick sussex]

As everyone knows i like a good easterly especially for my location down here in sw France but i'm not really convinced by the output and it might need a couple of attempts if its going to happen, i think theres a good chance of at least some surface cold but it might need that shortwave to run ese to help advect the coldest air westwards and thats too far out to be sure of.

So IMO the juries out on this one, I would be slightly happier if it was the ECM going for the easterly with the GFS saying no as we've been led down the garden path once too often with the gfs and it's easterlies.

I think sometimes people see the Siberian block and think it's a foregone conclusion that this will ridge far enough west, but this is very rare, we see Scandi highs verify much better and i would be more confident if this was shown in the output.

Theres still a chance but we do need the Atlantic to play ball here and the PV to not set up too close.

Regarding those charts from the nogaps, yes that is also a plausible solution but i'd much prefer examples drawn from models that don't fit into the cannon fodder model section! Regarding the ECM versus GFS debate as to who picked what trend the ECM has been the most consistent apart from one run over the last few weeks, maybe it's having a wobble or maybe it's right this time but if the GFS was so good why is it still getting beaten by the ECM and UKMO. I do get tired of this debate, the ECM is the best global model proven time and again by the verification stats. It can of course go wrong and isn't perfect but generally goes AWOL less often!

Edited January 13, 2010 by nick sussex

[derrylynne]

That's a nice warm fetch. lol..

Just managed to look at the pub run and myself I am going along with the GFS. If only the trend has shown to be correct of previous weeks. Also it goes along with my methods of using solar. Hopefully we can get rid of some of this snow we have down now in the valleys during the short thaw coming, we have a foot of snow here. But am expecting more of the white stuff before next week it out. We will see but this winter is far from finished...

[LomondSnowstorm]

That's a nice warm fetch. lol..

That's why we don't look at the NOGAPS model

Anyway, really a brilliant 18Z this evening, with snow potential right down the east coast of Britain and quite far inland also. After the +168 period the models are all over the place, but the main thing is getting the easterly in place to start with.

The ensembles are yet again a bit above the operational run, but since this appears to be a pattern as of late I'm not too concerned - the main thing is the number of runs which stay around or below the -5 line later on in the period:

The 00Zs will be intriguing, given the differing outputs on offer from the 12Zs. However, my guess is that the ECM will back down, as it looks a bit out of place with the other major models in keeping the high completely out.

Night all,

LS

[casparjack]

Hmm, the other day when the GFS 18z "pub run" (what does that mean? the forecast team went to the pub and got plastered?) came out and showed a warmer trend many of the cold lovers were decrying it and saying don't take any notice of the pub run, it's usually no good etc, but tonight, because it shows a colder aspect, it's suddenly got more respect than a hoodie with a tank? A certain lack of objectivity with the assessment of the models perhaps?

No that's balanced scientific analysis - if it shows cold!!

Oh dear or dear......Barmy or what! Unlikely.

Balmy I think is more appropriate!!

That isn't too different from the ECM in its latter stages...

As everyone knows i like a good easterly especially for my location down here in sw France but i'm not really convinced by the output and it might need a couple of attempts if its going to happen, i think theres a good chance of at least some surface cold but it might need that shortwave to run ese to help advect the coldest air westwards and thats too far out to be sure of.

So IMO the juries out on this one, I would be slightly happier if it was the ECM going for the easterly with the GFS saying no as we've been led down the garden path once too often with the gfs and it's easterlies.

I think sometimes people see the Siberian block and think it's a foregone conclusion that this will ridge far enough west, but this is very rare, we see Scandi highs verify much better and i would be more confident if this was shown in the output.

Theres still a chance but we do need the Atlantic to play ball here and the PV to not set up too close.

Regarding those charts from the nogaps, yes that is also a plausible solution but i'd much prefer examples drawn from models that don't fit into the cannon fodder model section! Regarding the ECM versus GFS debate as to who picked what trend the ECM has been the most consistent apart from one run over the last few weeks, maybe it's having a wobble or maybe it's right this time but if the GFS was so good why is it still getting beaten by the ECM and UKMO. I do get tired of this debate, the ECM is the best global model proven time and again by the verification stats. It can of course go wrong and isn't perfect but generally goes AWOL less often!

I too share your concerns tonight, the ECM was a major disappointment, I was really expecting it to confirm what my 'gut' was telling me, but it couldn't have been more different.

Anyway, let's see what the 00z says in the morning...

[johncoolj]

how cold do you think it will get looking at charts to me looks like the east winds wont be around much over next 2 weeks maybe 3 days seems the west winds or south west winds rule uk and ireland for next 2 weeks

which sucks

[Thundery wintry showers]

Amazing that a few days ago the GFS was rubbish - it was not delivering what was wanted - and the ECM was god - now this week it is vice versa.

When the GFS was consistantly going for a breakdown in the cold - it were rubbished as useless - as the ECM were going for cold. Till at short notice it went along with the GFS.

The GFS was of course right. The one thing I have noticed is the GFS is consistantly correct with trends. It trended the cold before Christmas at F1 along with the breakdown to something milder. It trended the cold after Christmas - and trended the current breakdown. And now is trending a colder again. When the GFS goes for trending mild again maybe good to remember this instead of rubbishing it because it is not what you want to see....

I understand the desire to pull people up for saying "model X is good because it shows what I want to see" etc, but the above suggests some confirmation bias in the opposite direction. The GFS certainly didn't handle the last few days' weather better than the ECM- for a long time it had high pressure on top of Britain last weekend followed by a straightforward breakdown from the west to mild south-westerlies. In contrast, the ECM had the pattern right, but overdid the staying power of the cold upper air.

Similarly the ECMWF was much better at handling the Christmas period. GFS was continually far too progressive at both breaking the cold down prior to Christmas and preventing it from coming back south again towards New Year.

And regarding the comment about ECM being god this week- in fact tonight's outputs have the GFS showing an outlook that is far more favourable for cold/snow lovers than that of the ECM, in contrast with the past 4-5 sets of runs.

[cj114]

Personally, I will also thank John H for his reply [even though it got deleted yesterday] I am quite happy for a break in the harsh weather.

We had breaks in the 70's and 80's then re-loads would arrive later.

Time to remember what the Garden looked like green is one. The second being not having to dress like Scott of the Antarctic to go out each day. Never mind the chaos of the roads where people don't know how to drive in Snow and ice.

Sorry, but bring on the mild for a while, god knows our Gas bills need a break, we will be paying them off until the next winter. lol

[kumquat]

Nobody really knows - that is what makes this winter's synoptics so fascinating. Nor do the models. Its a 48 hr game of catchtup.

[Blizzardo]

GFS still going for an Easterly this morning from Tuesday but it all looks a little half hearted with it never really getting a hold and the Atlantic pushing in again by Friday. It seems to me with pressure building over Canada and the situation of the PV everything might be a bit too far East for a potent Easterly to be able dig in next week.

The thing thats clear about this Winter though is that cold is never too far away so loads of possibilities.

Waiting on the ECM with interest.

Edited January 14, 2010 by Blizzardo

[Eugene]

GFS 00Z OP one of the coldest runs though and UKMO 00Z is poor.

[Eugene]

ECM 00Z is better though, more runs needed i feel and to be honest if it doesnt come off who cares, we've had loads of snow and cold for ages now, do people expect heatwaves all summer long no of course not so why the same in winter but cold.

[robert]

ECM 00Z is better though, more runs needed i feel and to be honest if it doesnt come off who cares, we've had loads of snow and cold for ages now, do people expect heatwaves all summer long no of course not so why the same in winter but cold.

This is model thread, do you have to talk about heatwaves in winter lol

Edited January 14, 2010 by robert

[Duane S.]

A Siberian high pressure affecting us here in the UK is a very rare thing and the charts are starting to show why. In order for it to start to benefit us we will need the Polar Vortex to help us out (amongst other things).

If the progged split is only a brief separation before it regroups back over Greenland then it isn't going to happen and we will likely be stuck in some form of Southerlies. I favour a bit of an East/West split (although neither that mild nor cold) and as TWS has been pointing out, the UK in general stuck in a bit of a no-mans land.

[PB22]

A very poor set of 00Z runs if you are looking for a return to cold and potential snow next week.

The GFS 00Z brings in a brief east/south-easterly next week:

http://www.wzkarten.de/pics/Rtavn1201.html

http://www.wzkarten.de/pics/Rtavn1441.html

http://www.wzkarten.de/pics/Rtavn1681.html

But its a pretty tame affair, and a quick look at the ensembles shows it to be one of the coldest options whilst the ensemble set as a whole has drifted away from a potential colder scenario:

http://www.wzkarten.de/pics/MT8_London_ens.png

http://www.wzkarten.de/pics/MT8_Manchester_ens.png

http://www.wzkarten.de/pics/MT8_Aberdeen_ens.png

UKMO 00Z is even worse:

http://www.wzkarten.de/pics/Rukm961.html

http://www.wzkarten.de/pics/Rukm1201.html

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

ECM does bring a continental influence in, but again its a tame affair and wouldn't bring much more than rather cold and bright weather:

http://www.wzkarten.de/pics/Recm1201.html

http://www.wzkarten.de/pics/Recm1441.html

http://www.wzkarten.de/pics/Recm1681.html

GEM says no as well:

http://www.wzkarten.de/pics/Rgem1201.html

http://www.wzkarten.de/pics/Rgem1441.html

http://www.wzkarten.de/pics/Rgem1681.html

As does NOGAPS:

http://91.121.94.83/modeles/nogaps/run/nogaps-0-120.png?14-06

http://91.121.94.83/modeles/nogaps/run/nogaps-0-144.png?14-06

http://91.121.94.83/modeles/nogaps/run/nogaps-0-168.png?14-06

Finally, GME offers no hope either:

http://91.121.94.83/modeles/gme/run/gme-0-108.png

http://91.121.94.83/modeles/gme/run/gme-0-132.png

We may have a monster block to the east, but we also have an active Atlantic to our west now, and the Atlantic is increasingly looking like it will come out on top. I still maintain that unless heights to our northwest drop, the high to the east will struggle to exert its influence across us.

[Nick F]

We may have a monster block to the east, but we also have an active Atlantic to our west now, and the Atlantic is increasingly looking like it will come out on top. I still maintain that unless heights to our northwest drop, the high to the east will struggle to exert its influence across us.

Yes, unless that vortex over Greenland splits with its trough over the mid-N Atlantic, the Siberian High is really going to struggle to back west far enough to guarantee an easterly. And with the Atlantic trough aligned with a positive tilt (SW-NE) the polar jet is forced too far NE across western Europe too ... so we end up with a close but no cigar - especially the Euros.

GFS does show a brief easterly on Tuesday - which would still be cold enough to bring snow to the east, but for Aberdeen (with -10C T850s) and other eastern points - the 00z operational is a cold outlier by then.

Still time for this to turn around though, but Euros seem bullish with the close but no cigar scenario, which gives me less confidence in the easterly coming off.

[Frosty.]

And the danger of an increasingly active atlantic could be to push the scandi/russian block well away from the uk so we will revert to normal mild british conditions but we have had a great winter so far so now we must expect some rubbish.

[KTtom]

And the danger of an increasingly active atlantic could be to push the scandi/russian block well away from the uk so we will revert to normal mild british conditions but we have had a great winter so far so now we must expect some rubbish.

This certainly is the way the models are heading, and firmly away from the idea of a repeat of the last week. Just looking at the ensembles shows the vast majority moving away from a renewed cold event around 20/21st.

No point congratulating those who predict easterlies, or anything else for that matter until it actually happens.

[snowingtequila]

This certainly is the way the models are heading, and firmly away from the idea of a repeat of the last week. Just looking at the ensembles shows the vast majority moving away from a renewed cold event around 20/21st.

No point congratulating those who predict easterlies, or anything else for that matter until it actually happens.

The models to me seem to show that things are not clear at the moment and it could go either way. I don't think we can really say the moedls are heading either way because you could easily make the argument either way because they are unclear

[Shiny_Bottom_1]

However....

If we take the models as they are showing, as many did yesterday, the promise of an easterly is much less now.

The GFS 00z is by no means awful looking at ground temps. Of course, snow potential is but there is no blow torch situation.

What I did notice yesterday, which throwed a little concern, was the High Pressure some of the models had around the Bartlet (I think this is the correct area) and Europe.

Still, GFS only going up to the end of the month really, with possibilities of change, we still then have plenty of time left.