Model Output Discussion - 1st - 7th January

[kold weather]

models STILL struggling with the stratospheric set-up, until this is settled take any run with a pinch of salt no matter what it shows.

ECM ensemble mean is the most agressive yet and looks far more amplified then the 06z GFS ensembles, which by and large do keep a flatter pattern.

GFS still looks in lala land with its forecast of a strengthennig PV again...depsite the fact that big warming is forecasted and another set of MT waves are due to set off soon as well...so that looks a slightly baffling call. The ECM is not as agressive either but then again the big event is probably a little too soon for it to show on the ECM in any real guise.

People should read GP's thoughts, there is a reason why him and a few others are getting quite loud about mid-late January, just going to be a painfully slow evolution though I'm afraid!!

[Thundery wintry showers]

Again no sign of any cold or snowy weather in the reliable timeframe but some "teases" from the ECMWF in FI. The ensemble mean points at an evolution to a cyclonic north-westerly type, while the operational has an Arctic high heading towards Scandinavia- a setup which usually results in very cold airmasses and easterly winds being located over the near-continent with the main question being how far west it gets. The fact that the ECM FI gives two "options" shows how uncertain things are out there.

However there is very little uncertainty about the week ahead. A mild cloudy day under Tm air tomorrow for most, although the southeast may hold onto colder brighter weather until late afternoon, then a dry sunny and chilly day on Saturday before more mild cloudy damp weather rolls in from the west on Sunday. Next week looks likely to be mild, cloudy and drizzly for most, with too little continental air input to allow much sunshine to come through in southern areas, though as usual if we do see much in the way of sunshine it will mainly be in southern and eastern England. All in all not a huge amount of weather in store for us, in stark contrast to the week just gone.

[Weather Boy]

Groan. Some people never seem to learn. From my relative inexperience of the models and this thread, I have learned the following:

1. Never trust one run, unless looking at the very near future.

2. When there is a pattern change emerging, the models will chop and change, and try different things out, meaning that they swing back and forth.

3. Therefore, when looking at a change 10+ days out, do not get over-excited when something appears to be happening that you are hoping for, nor go wrist slitting when the projected change that you want is binned on one run.

Therefore, the fact that the 06z ensembles are not catching on is as predictable as some folk's reaction to it.

It is clear from posts of those who know far more than me, that a change of some description away from the Atlantic zonal train is afoot, it's just a matter of working out precisely what the change will be and then ironing out detail. It's completely wrong to say that the pattern change is dead and buried just because one set of ensembles are unenthusiastic about it.

[Robbie Garrett]

Bomb situation! 40mph sustained across the whole of the country! I'd love to see snow again, but this Atlantic is now on fireee!!!

[bluearmy]

The ecm ens for london mid month appear to be keen on at least a two day toppler as av maxes fall to around 5/6c though clustered below with scatter above. slow recovery thereafter.

http://www.meteogroup.co.uk/services/ensemble-forecast.html

[ribster]

Bomb situation! 40mph sustained across the whole of the country! I'd love to see snow again, but this Atlantic is now on fireee!!!

Shall I call the fire brigade? I bet that chart looks very different come the 17th, as the post above mentions, some will never learn.

Edited January 5, 2012 by ribster

[TEITS]

I know this is the model discussion thread but in my opinion discussing the charts in the medium range is a pointless exercise at the moment. Having said this there are a couple of things that make little sense to me. The first is the GFS modelling around the Arctic because given whats occuring in the Stratosphere it makes no sense to have such low heights across the pole in F.I. The second is the Met O outlook for the end of Jan because in my opinion HP over the UK bringing settled weather is the last thing I would expect. If I was a betting man I would say we have two options for the end of Jan and that is either cold zonality or a real blast of N,lys via blocking becoming established over Greenland.

I wonder what the ECM +240 chart will look like tonight because you can guarantee it will be completely different!

[Robbie Garrett]

Shall I call the fire brigade? I bet that chart looks very different come the 17th, as the post above mentions, some will never learn.

I post a chart that doesn't show cold? Which I've done for the last few weeks and I get had a go at! I am mealy just showing what could happen on the 17th, for all I know it could be -30*C in London with raging snow!! It could be the complete opposite and 30*C in January (if it can happen the other way it can happen the other way) or it could show as this run shows.

This has been a consistent theme on the model runs, and I am enjoying it!!!

Edited January 5, 2012 by Robbie Garrett

[Jason M]

Groan. Some people never seem to learn. From my relative inexperience of the models and this thread, I have learned the following:

1. Never trust one run, unless looking at the very near future.

2. When there is a pattern change emerging, the models will chop and change, and try different things out, meaning that they swing back and forth.

3. Therefore, when looking at a change 10+ days out, do not get over-excited when something appears to be happening that you are hoping for, nor go wrist slitting when the projected change that you want is binned on one run.

Therefore, the fact that the 06z ensembles are not catching on is as predictable as some folk's reaction to it.

It is clear from posts of those who know far more than me, that a change of some description away from the Atlantic zonal train is afoot, it's just a matter of working out precisely what the change will be and then ironing out detail. It's completely wrong to say that the pattern change is dead and buried just because one set of ensembles are unenthusiastic about it.

Having just looked through the models / ensembles etc I can't see any evidence of the pattern change your referring to? It just looks very zonal to me. The changes have been slight over recent days IMO. The odds of a UK high have receded somewhat but this is just because the jet is being progged to run at a slightly lower latitude rather than a full on pattern change, but high pressure to our south remains the key theme (or low pressure to the north depending on your preference). The other change of note is that the potential for an easterly has been discarded by the ensembles.

Whilst people can't disregard the chances due to one poor run, we have been seeing consistency run to run and day to day so based on what the models are showing the odds heavily favour 'no pattern change'. The interesting solutions have generally been in la la land amongst individual ensemble members.

Hopefully things will change mid month onwards, but were probably looking towards the 20th now as the earliest point at which this would occur and I am not seeing anything whatsoever in the ouput at present that makes me think a switch in the output is due. That said, others feel differently and I look forward to being proved wrong.

Jason

Edited January 5, 2012 by Jason M

[phil nw.]

Groan. Some people never seem to learn. From my relative inexperience of the models and this thread, I have learned the following:

1. Never trust one run, unless looking at the very near future.

2. When there is a pattern change emerging, the models will chop and change, and try different things out, meaning that they swing back and forth.

3. Therefore, when looking at a change 10+ days out, do not get over-excited when something appears to be happening that you are hoping for, nor go wrist slitting when the projected change that you want is binned on one run.

Therefore, the fact that the 06z ensembles are not catching on is as predictable as some folk's reaction to it.

It is clear from posts of those who know far more than me, that a change of some description away from the Atlantic zonal train is afoot, it's just a matter of working out precisely what the change will be and then ironing out detail. It's completely wrong to say that the pattern change is dead and buried just because one set of ensembles are unenthusiastic about it.

I don`t think anyone has said that any pattern change is dead and buried though WB.

In fact i think the postings have been on the whole very realistic today.

Yes some of us,including myself, have analyised and commented on the individual runs and explained what they show,that`s what this thread is all about after all.

It doesn`t mean any conclusions for the rest of January,beyond the next week or so are being drawn.

I think most members realise things change to run and keep an open mind.

My personal view for what it`s worth is that a change is just beyond the current modelling at present.However with the overwhelming evidence on the Strato warmings i would think it wont be long before the 500hPa charts start to change radically.

For now we can only comment on what is before us.

Edited January 5, 2012 by phil n.warks.

[Cecil Hogmanay Melchett]

The long range ecm ensembles are to be blunt,unremarkable.

The GEFS 0z and 06z ensembles are again,unremarkable.

Conclusion is the waiting goes on,and on.

[TEITS]

Whilst people can't disregard the chances due to one poor run, we have been seeing consistency run to run and day to day so based on what the models are showing the odds heavily favour 'no pattern change'. The interesting solutions have generally been in la la land amongst individual ensemble members).

Just my opinion but when we have seen such inconsistency from the ECM operationals the ensembles are completely useless.

[leicsnow]

Having just looked through the models / ensembles etc I can't see any evidence of the pattern change your referring to? It just looks very zonal to me. The changes have been slight over recent days IMO. The odds of a UK high have receded somewhat but this is just because the jet is being progged to run at a slightly lower latitude rather than a full on pattern change, but high pressure to our south remains the key theme (or low pressure to the north depending on your preference. The other change of note is that the potential for an easterly has been discarded by the ensembles.

Whilst people can't disregard the chances due to one poor run, we have been seeing consistency run to run and day to day so based on what the models are showing the odds heavily favour 'no pattern change'. The interesting solutions have generally been in la la land amongst individual ensemble members).

Hopefully things will change mid month onwards, but were probably looking towards the 20th now as the earliest point at which this would occur and I am not seeing anything whatsoever in the ouput at present that makes me think a switch in the output is due. That said, others feel differently and I look forward to being proved wrong.

Jason

Actually we saw some good model runs a couple of days ago, and some good ones around Christmas.

And yes it does look like everything is written off before the 20th, but not definitely.

[Frosty.]

The long range ecm ensembles are to be blunt,unremarkable. The GEFS 0z and 06z ensembles are again,unremarkable. Conclusion is the waiting goes on,and on.

The models are remarkabely unremarkable out to the medium range as they have been for the last 6 weeks apart from a few days here and there, hardly any low ground snow so far and a remarkable lack of frost but at least there is a chance of some frosty nights next week in the southern third of the uk as high pressure builds in, the margins are fine though as a moist, mild sw'ly flow will be across the uk but nearest the high, the winds will be light and if the skies are clear enough, there should be some chilly nights. After mid month the gfs wants to reset to the mild zonal dross with a few cooler spells to remind us it's mid winter.

[Matty M]

Models look very poor for cold prospects at the minute.

The next 7 days will be dominated by high pressure to our south with generally drizzly, rainy and mild

weather for UK & Ireland with no exceptional weather of any note forecast and no sign of any cold weather

on the horizon.

I don't expect much change, but do anticipate that once this strat gets going and AO gets negative that February

will offer better prospects for cold weather. But let us be honest, it couldn't be much worse for cold propsects the last

2 months, south of the Scottish border.

[nick sussex]

Just a few things to highlight from the updated morning discussions at NOAA:

HEIGHT ANOMALIES

AROUND D+8 SUPPORT AN EASTERN CONUS TROUGH VIA WESTERN ATLANTIC

RIDGING THOUGH THE WESTERN CONUS EVOLUTION IS LESS CLEAR.

MODEL AND ENSEMBLE SPREAD

INCREASES DRAMATICALLY BY THE END OF NEXT WEEK AS THE GFS/GEFS

MEAN SHOW A STRONG RIDGE ALONG THE WEST COAST AND THE ECMWF SHOWS

AN APPROACHING TROUGH. THE ECMWF ENSEMBLE MEAN IS RATHER FLAT SO

IT APPEARS ANYTHING IS ON THE TABLE AT THIS TIME.

Developments on the west coast of the USA will eventually feed into changes on the east coast of the USA which will then have a knock on effect in Europe as these effect where the Azores high goes.

We pretty much know the pattern upto 168hrs, theres solid agreement across the modelling for that but until we know the make up of that troughing in the east USA and how amplified this will be together with the pattern in the east Pacific and west coast of the USA then the output is likely to throw out wrong solutions past this point.

[Frosty.]

I'm a bit surprised at the meto update saying daytime temps will be around average next week because the models show a moist, mild sw'ly flow which is sourced from the Azores across most of the BI next week apart from nearest the high where the temps would be average with temps slow to recover after overnight slight frosts and fog patches, yet again though there is absolutely no indication of a pattern change to anything snowy, even out to early feb.

[Ruzzi]

I for one am not getting at all worried by the model output yet. There are many changing background signals therefore it is expected that the models will struggle to pinpoint an exact evolution right away, so there will ofcourse be chopping and changing. However, to me, the background signals are much more important than what the models show beyond T144 because the models change everyday day (some 4 times a day) where as at the moment we're seeing the background signals fall into place to suggest a shake up of the NH pattern, with a much greater "potential" for a route to proper cold.

On another note, if you look at this chart from 18th of January 1947:

We see a "similar" set-up to which many are predicting for a few weeks time, and I do believe that the background signals support this evolution i.e, The aleutian ridge, High pressure building over the Arctic, a possible transfer of part of the PV to Scandi, The AO and NAO trending Negative. Just 4 days after this chart, As we know, one of the most severe cold spells ever took over Britain. Now that cold spell is what signifies that winter and it didn't begin until the 22nd of January, so in a sense we still have over 2 weeks to make this winter very significant. I'm not in any way suggesting this is what will happen, however I just want to put into perspective how much of the winter we have left.

[Frosty.]

I for one am not getting at all worried by the model output yet. There are many changing background signals therefore it is expected that the models will struggle to pinpoint an exact evolution right away, so there will ofcourse be chopping and changing. However, to me, the background signals are much more important than what the models show beyond T144 because the models change everyday day (some 4 times a day) where as at the moment we're seeing the background signals fall into place to suggest a shake up of the NH pattern, with a much greater "potential" for a route to proper cold. On another note, if you look at this chart from 18th of January 1947: We see a "similar" set-up to which many are predicting for a few weeks time, and I do believe that the background signals support this evolution i.e, The aleutian ridge, High pressure building over the Arctic, a possible transfer of part of the PV to Scandi, The AO and NAO trending Negative. Just 4 days after this chart, As we know, one of the most severe cold spells ever took over Britain. Now that cold spell is what signifies that winter and it didn't begin until the 22nd of January, so in a sense we still have over 2 weeks to make this winter very significant. I'm not in any way suggesting this is what will happen, however I just want to put into perspective how much of the winter we have left.

A very good post but if i remember correctly, the met office were red flagging the big freezes we had last nov/dec around 2-3 weeks in advance of the event (s) but there is not a murmour or hint they will do the same this time, their current trend is towards anticyclonic with frost and fog by late jan/early feb.

Edited January 5, 2012 by Frosty039

[nick sussex]

A very good post but if i remember correctly, the met office were red flagging the big freezes we had last nov/dec around 2-3 weeks in advance of the event (s) but there is not a murmour or hint they will do the same this time, their current trend is towards anticyclonic with frost and fog by late jan/early feb.

Bear in mind Frosty that last Decembers freeze was easier to forecast for them , in this instance they have issued that 16-30 day outlook not knowing whether there will be a SSW and the effect this could have on the output. There is no simple formula for determining the effect of that on synoptics and because of this I'd treat that extended outlook with a bit more caution.

The forecasts might look like the same old story that we've seen for much of the winter but the background signals are changing, the stratosphere was almost at record cold levels and we saw this big cooling starting from November.

I'd just keep an open mind about the second half of the month as there is quite alot of uncertainty as to what happens to the PV and the limpet Azores high.

[Tim Bland]

A very good post but if i remember correctly, the met office were red flagging the big freezes we had last nov/dec around 2-3 weeks in advance of the event (s) but there is not a murmour or hint they will do the same this time, their current trend is towards anticyclonic with frost and fog by late jan/early feb.

Don't forget they mainly use extended ECM for their forecast which is mon and Fri, so hopefully a change tommorow!?

[kev238]

I guess it is more of the same in the short term with some quite mild weather showing its hand for the start of the next week with a moist cloudy flow being introduced from the West.

There are some signs of a pattern change after Mid Month, but I am unsure as to whether it will be enough to bring meaningful cold to the UK during the latter third of January given the dominant pattern so far this year.

[stratty]

:huh:

models STILL struggling with the stratospheric set-up, until this is settled take any run with a pinch of salt no matter what it shows.

ECM ensemble mean is the most agressive yet and looks far more amplified then the 06z GFS ensembles, which by and large do keep a flatter pattern.

GFS still looks in lala land with its forecast of a strengthennig PV again...depsite the fact that big warming is forecasted and another set of MT waves are due to set off soon as well...so that looks a slightly baffling call. The ECM is not as agressive either but then again the big event is probably a little too soon for it to show on the ECM in any real guise.

People should read GP's thoughts, there is a reason why him and a few others are getting quite loud about mid-late January, just going to be a painfully slow evolution though I'm afraid!!

Are'nt the stratosphere warmings already calculated in the number crunching that make up the different models we view? Therefore handling them exactly as they and us read them at present?

[Frosty.]

Bear in mind Frosty that last Decembers freeze was easier to forecast for them , in this instance they have issued that 16-30 day outlook not knowing whether there will be a SSW and the effect this could have on the output. There is no simple formula for determining the effect of that on synoptics and because of this I'd treat that extended outlook with a bit more caution. The forecasts might look like the same old story that we've seen for much of the winter but the background signals are changing, the stratosphere was almost at record cold levels and we saw this big cooling starting from November. I'd just keep an open mind about the second half of the month as there is quite alot of uncertainty as to what happens to the PV and the limpet Azores high.

Hi nick, yes you make a good point about the changing background signals but i'm just waiting for something realistically good to jump out of the models and surprise us, and as tim said, the extended Ecm will update tomorrow so hopefully something different and better will stand out. I'm disappointed how the ecm has changed overnight but it could look better again later, trying to keep my interest levels up and desperately waiting for a cold spell. Unlike last winter which was a dud after december, we still have plenty of time on our side and i'm still optimistic about february and even the first half of march can be included in that too.

[JP1972]

Hi nick, yes you make a good point about the changing background signals but i'm just waiting for something realistically good to jump out of the models and surprise us, and as tim said, the extended Ecm will update tomorrow so hopefully something different and better will stand out. I'm disappointed how the ecm has changed overnight but it could look better again later, trying to keep my interest levels up and desperately waiting for a cold spell. Unlike last winter which was a dud after december, we still have plenty of time on our side and i'm still optimistic about february and even the first half of march can be included in that too.

You say we have plenty of time on our side but the days are starting to get longer, and seeing as (at present) there is absolutely nothing of wintry interest on the horizon you have to wonder whether we will run out of winter before the SSW takes effect on our weather. That's if it has any bearing on our weather at all.

So far we have had only minor interest at the 240 stage, which stays at 240 when it actually appears at all. So being realistic it's not improbable that this winter delivers nothing more than we've already had in terms of wintriness and only continues to deliver what has already gone before (cold zonality favouring hills and mountains).