Model Output Discussion - 26th December - 1st January

[Grimsby Snow Lover]

And there was I, having looked through the models this morning thinking to myself how each day the likelihood of a cold period post mid jan increases. (caveat - not necessarily fo our part of Europe). Then o read this thread and realise it must b all a dream!

I suspect that some of your thoughts are based upon the fact that nothing tangible seems to be getting any closer. Well the models are often a bit progressive when it comes to a pattern change and the pattern we have been in is certainly well set. I really cant see where the despondency is coming from. I even see an island runner next week that could cause a lot of problems for the north of the uk. three gefs members have a cut off greeny block by the end of their runs. The mean trends colder without an obvious flip in the other direction. I keep reading mild but beyond the weekend, not sure why.

Having viewed this morning GFES and ECM I was thinking the same. After this weekend I wouldn't describe the weather as being mild, particulary as we are on the colder side of the jet.

[IDO]

Having viewed this morning GFES and ECM I was thinking the same. After this weekend I wouldn't describe the weather as being mild, particulary as we are on the colder side of the jet.

Depends where you are. Looking at the 2m temps from Birmingham south, GFS (till 13th Jan) has no frosts and max temps sometimes around 11c; lowest max around 4c and that was during the night on two occasions! In January that sounds mild. Of course Aberdeenshire is a different story, but isn't that always?

[mountain shadow]

Have to agree with the previous two posts. The models are clearly showing a colder pattern as a result of a PV split with a lobe shifting into Scandanavia. The height rises polewards are increasingly evident and this can only be positive as the month progresses.

[Duane S.]

I thought it would be another day or so before ECM came back on board with GFS but it does now look like both are modelling zonality all the way. Very little snow, some for the heights of Scotland but all transitional. With the SSW a misnomer, stratospheric warming never looking like penetrating down to an influential level, it has always been hope rather than synoptics that have driven the sighting of cold. However this only takes us to mid-January and there are signs (AO, strat. warming again) of a better pattern, and it will not take much to favour us with cold zonality. However getting a prolonged cold spell with that raging Jetstream is not going to be easy; but there are signs we will at least get a shot.

"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds darkness has always got there first, and is waiting for it."

No, the ECM has not 'come back on board with the GFS'. It may have toned down its thinking but there was always more than an air of inevitability that it would anyway. Have a look at the ECM and GFS and +168, similarites as is always going to be the case but glaring differences as well!

The ECM STILL says potential potential potential. Even the GFS looks healthier than a couple of days back! It does look very likely now that vortex disruption in one guise or another will occur and this can only be a good thing even if we don't end up on the receiving end of any cold air, this time around. The caveat to this is though that it will all be of little use if we do not see the angle of the jet move to a more meridional one and as such the bulk of the jet is not whistling above us at hundreds of miles an hour!

[Cecil Hogmanay Melchett]

And there was I, having looked through the models this morning thinking to myself how each day the likelihood of a cold period post mid jan increases. (caveat - not necessarily fo our part of Europe). Then o read this thread and realise it must b all a dream!

I suspect that some of your thoughts are based upon the fact that nothing tangible seems to be getting any closer. Well the models are often a bit progressive when it comes to a pattern change and the pattern we have been in is certainly well set. I really cant see where the despondency is coming from. I even see an island runner next week that could cause a lot of problems for the north of the uk. three gefs members have a cut off greeny block by the end of their runs. The mean trends colder without an obvious flip in the other direction. I keep reading mild but beyond the weekend, not sure why.

Surely our part of Europe is what we are interested in??Why would i be interested in cold for MInsk or Sofia for example?

I can see where the despondency is coming from most of the UK has seen little or no frost letalone snow,and thats likely to remain that way until second week of jan at the earliest(yes some elvated northern areas may see something next week if ecm is correct).

Three gefs members,hmmm that leaves about 9 that dont.GEFS 0z ensembles scream zonality to me.

I hope your optimism is proved correct in the long run BA but i for one ain't seeing it.

[IDO]

No, the ECM has not 'come back on board with the GFS'. It may have toned down its thinking but there was always more than an air of inevitability that it would anyway. Have a look at the ECM and GFS and +168, similarites as is always going to be the case but glaring differences as well!

The ECM STILL says potential potential potential. Even the GFS looks healthier than a couple of days back! It does look very likely now that vortex disruption in one guise or another will occur and this can only be a good thing even if we don't end up on the receiving end of any cold air, this time around. The caveat to this is though that it will all be of little use if we do not see the angle of the jet move to a more meridional one and as such the bulk of the jet is not whistling above us at hundreds of miles an hour!

That is a nice snapshot and taken out of context looks promising. But now roll on the ECM to the 7th Jan; it now mirrors the GFS (zonal), although it is slightly out of sync and has the Jetstream slightly more favourable. Nothing from the snapshot on Jan 7th promises anything in the short term apart from the continuum of average UK winter weather.

[Duane S.]

Surely our part of Europe is what we are interested in??Why would i be interested in cold for MInsk or Sofia for example?

I can see where the despondency is coming from most of the UK has seen little or no frost letalone snow,and thats likely to remain that way until second week of jan at the earliest(yes some elvated northern areas may see something next week if ecm is correct).

Three gefs members,hmmm that leaves about 9 that dont.GEFS 0z ensembles scream zonality to me.

I hope your optimism is proved correct in the long run BA but i for one ain't seeing it.

That's a very blinkered way of looking at things HD. To say why would we be interested in weather for x y z is like saying why bother trying to forecast the weather? The arrival of cold weather in x y z coupled with other factors could indicate said cold weather heading our way and let's face it 19 out of 20 times cold weather DOES need to hit other parts of Europe before we are affected anyway!

That is a nice snapshot and taken out of context looks promising. But now roll on the ECM to the 7th Jan; it now mirrors the GFS (zonal), although it is slightly out of sync and has the Jetstream slightly more favourable. Nothing from the snapshot on Jan 7th promises anything in the short term apart from the continuum of average UK winter weather.

Disagree again. The ECM +240 is now a very decent looking chart, even more adrift from the GFS, that screams potential...

GFS...

ECM...

[IDO]

That's a very blinkered way of looking at things HD. To say why would we be interested in weather for x y z is like saying why bother trying to forecast the weather? The arrival of cold weather in x y z coupled with other factors could indicate said cold weather heading our way and let's face it 19 out of 20 times cold weather DOES need to hit other parts of Europe before we are affected anyway!

Disagree again. The ECM +240 is now a very decent looking chart, even more adrift from the GFS, that screams potential...

GFS...

ECM...

We will disagree but all I see is a West to East movement with the Jetstream looking very strong pushing that Low away and the following output would have us influenced by the SW HP, much like the GFS, till another Low moves in. As I said slightly out of sync, but much of the same with no sign of that raging jetstream slowing the procession of LP's cutting through Northern Britain followed by brief HP influence.

Edited December 28, 2011 by i'm dreaming of...

[Glacier Point]

I'll add this to counter some baffling model assessments this morning.

GFS ensemble mean at day 7 showing a highly amplified upstream circulation:

Note the greatest height anomaly is over Svalbard indicating strong undercutting of the upper trough through Scandinavia.

ECM op continuing to advertise the upper trough dropping south and east from Iceland (as per thoughts). Ride to the west, becoming increasingly amplified, including the GEFS suite.

NAO trending solidly down to neutral values by mid month.

Let the consistent and now growing model concensus trend be your friend here.

[Cecil Hogmanay Melchett]

I'll add this to counter some baffling model assessments this morning.

GFS ensemble mean at day 7 showing a highly amplified upstream circulation:

Note the greatest height anomaly is over Svalbard indicating strong undercutting of the upper trough through Scandinavia.

ECM op continuing to advertise the upper trough dropping south and east from Iceland (as per thoughts). Ride to the west, becoming increasingly amplified, including the GEFS suite.

NAO trending solidly down to neutral values by mid month.

Let the consistent and now growing model concensus trend be your friend here.

Nothing in that graph to suggest the azores high going anywhere fast GP,i understand that the trough digging into Europe is a positive development but until we see the Atlantic profile alter brief PM shots is the best we canhope for?

[nick sussex]

For those still viewing the GFS as the trendsetter, another day and another GFS run not used by NOAA in their morning update.

INCREASINGLY MERIDIONAL FLOW WILL LEAD TO AMPLIFIED TROUGHS ACROSS

THE EASTERN PACIFIC AND GREAT LAKES/EAST WITH RIDGING ACROSS

WESTERN NORTH AMERICA SANDWICHED IN BETWEEN. MOST OF THE GUIDANCE

AGREES ON THIS PATTERN...OUTSIDE THE 00Z GFS WHICH IS BROAD AND

FLAT WITH THE EASTERN TROUGH DESPITE THE AMPLIFIED RIDGE UPSTREAM.

I'ts still hard to explain why this model seems to have such a loyal group of supporters when its operationals of recent days have been met with nothing but criticism over in the USA who continue to ignore their own homegrown model in favour of the ECM.

[bluearmy]

Surely our part of Europe is what we are interested in??Why would i be interested in cold for MInsk or Sofia for example?

I can see where the despondency is coming from most of the UK has seen little or no frost letalone snow,and thats likely to remain that way until second week of jan at the earliest(yes some elvated northern areas may see something next week if ecm is correct).

Three gefs members,hmmm that leaves about 9 that dont.GEFS 0z ensembles scream zonality to me.

I hope your optimism is proved correct in the long run BA but i for one ain't seeing it.

HD - more than two weeks away. How can anyone know how a developing cold pattern will affect different parts of Europe. how the pattern will eventually evolve isn't yet clear. If you want specifics, I suggest you call James madden !!

[Severe Siberian icy blast]

It looks as strong as +ve NAO as you can see, going forward all we could get is indeed the occasional PM shots as per earlier this month.

Not according to the graph posted by GP, Ian, as we look for trends then thats as strong a trend we'l ever see, its very strange Ian that when i see your name at the top before i read the post i already know the nature of the post from you. Mild blinkers 24/7 and it must be soooo fustrating for eveyone on hear.

[Nick F]

ECM does appear to have some consistency now in splitting away eastwards part of the polar vortex from Greenland towards Scandinavia and NE Europe, if only we can get sufficient amplification upstream coming out of N America, then we may see a more sustained cold snap from the north.

However, low heights are modelled to remain over NE Canada/Wern Greenland - which would continue to drive a strong zonal westerly flow with low pressure systems moving east across the N Atlantic cutting off any deep cold air reaching the UK.

So for now, it's a case of getting the best out of cold zonality that will come along - which will always tend to benefit the north in terms of settling snow.

[lorenzo]

I agree that the trend for the NAO is moving to neutral then negative.

In reference to the strongly positive see the spikes in December.

http://policlimate.com/climate/ecmwf_nao_bias.png

[weathe20]

Just read this thread, from a newbie perspective it is totally confusing. Some people obviously dont have a clue what they are looking at or talking about when it comes to the models. No consistancy for a newbie to learn anything.

[bluearmy]

The GFS is a tremendous tool and whilst no model will be correct all the time, for me it remains the first port of call.

Ian, I note you felt that the p/v would disrupt and that we would be in the wrong side for cold after that. (resonable shout). Are you still of this opinion or do you think the mobile flow will continue throughout jan?

Edited December 28, 2011 by chionomaniac
removed deleted section

[nick sussex]

The GFS is a tremendous tool and whilst no model will be correct all the time, for me it remains the first port of call.

All models go through good and bad periods and I certainly wouldn't want to see the end of the GFS, it's at least very generous with the info released to the public.

And it keeps this thread moving through the daytime and late evening when we'd have nothing else to talk about!

The only measure we can use to judge it is by the verification stats, the ECM remains top.

Edited December 28, 2011 by chionomaniac
removed deleted section

[mountain shadow]

Just read this thread, from a newbie perspective it is totally confusing. Some people obviously dont have a clue what they are looking at or talking about when it comes to the models. No consistancy for a newbie to learn anything.

I understand exactly where you are coming from. The best thing too do is learn to interpret what the models are saying and draw your own conclusions.

The models are all showing height rises around Zvalbard now in around 7-10 days time with subsequent disruption to the PV. The building blocks for a colder second half to the month are clearly building.

[Frosty.]

I got the impression from GP that the prospects of much colder weather will become a lot healthier but i'm still unclear about when?. I think the models are looking even better this morning for a spell of standard cold zoneality next week with cold westerly winds at times which may veer nw'ly at times, the north of the uk is initially favoured but as the jet is favoured to slowly sink south, we should have colder incursions reaching southern britain, remember how well Buxton did for snow in early december. It's all going to take time, the cold zonal flow will occasionally be mixed out with rPm or even Tm air at times.

[Grimsby Snow Lover]

I understand exactly where you are coming from. The best thing too do is learn to interpret what the models are saying and draw your own conclusions.

The models are all showing height rises around Zvalbard now in around 7-10 days time with subsequent disruption to the PV. The building blocks for a colder second half to the month are clearly building.

Well said MS. To add to what you have said I would also suggest looking at the GFES as well as I often find this paints a more realistic picture and can often backup any cold/mild shown by the operational. I do find the GFS useful upto the point the low resolution kicks in as more time than not the pattern is then far too progressive. One thing seems certain at the minute and that is that no sustained cold is shown in any model during the first week of January, but with hights building over the pole and Zvalbard the second week of January is anyones guess.

[chionomaniac]

Just read this thread, from a newbie perspective it is totally confusing. Some people obviously dont have a clue what they are looking at or talking about when it comes to the models. No consistancy for a newbie to learn anything.

I think that you have a point here.

The problem that we have here is that often these scenarios become a battle of the posters and their own agendas rather than a constructive analysis of the models. We are seeing that things are staying unsettled in the short term with a strong jet stream leading the way. However, we are not seeing consistent above average temperatures or below, rather a more mixed view.

Longer term there are signs that things could change as GP shows evidence . We are seeing the signs that the polar vortex is becoming more disorganised as we head into January. This is born out in the models around 10 days time - that is why the trend is for the AO to be finally reducing to average.

This will not automatically lead to a switch to colder conditions but we are heading in the right direction for colder conditions after.

The MJO forecasts are inconclusive as are the stratospheric consequences (of any warming about to take place). In my opinion in the presence of conflicting signals one cannot be confident either way what will occur once the ensembles show divergence.

Edited December 28, 2011 by chionomaniac

[TEITS]

Just read this thread, from a newbie perspective it is totally confusing. Some people obviously dont have a clue what they are looking at or talking about when it comes to the models. No consistancy for a newbie to learn anything.

I don't have much time to post on the models but my advice to any newcomers is to follow the posts from the more experienced members especially Nick S, GP. Have to say im very impressed with GP so far this winter and its his posts im closely following.

[nick sussex]

If you were being totally objective you'd say theres no clear verdict on what happens and the juries been unable to reach agreement!

Positives:

Lower heights in Europe

Some disruption of the PV

More amplified upstream pattern

Negatives

PV still looks reluctant to leave the Greenland area

Still no clear sign of any northern blocking

So you could say it looks a bit of a stalemate

Variables that might effect future output

Strat warming, how much effect will this have, theres no simple formula for deciding how this impacts on synoptics

Any pressure rises near Svalbard, will these place more forcing on the troughing over Europe

So a stalemate but with a few more hopeful signs, at day 10 the NH pattern is more favourable than for quite a while but it depends then on what happens to those positives and negatives.

Edited December 28, 2011 by nick sussex

[Bristawl Si]

I don't have much time to post on the models but my advice to any newcomers is to follow the posts from the more experienced members especially Nick S, GP. Have to say im very impressed with GP so far this winter and its his posts im closely following.

Agreed TEITS.

The above mentioned members, plus a couple more, are the only ones i really take notice of these days on here.

Probably a good time to sit back away from the models and come back early next week, when hopefully signs of any pattern change will be more 'visible'.