Winter Model Discussion - Cold Hunting - 20th Dec

[Bristawl Si]

Have to say the medium range is looking rather disappointing to me.

http://modeles.meteo...-21-1-240.png?0

http://www.meteociel...1-240.GIF?21-12

So it seems we shall have to wait until we are into January before any significant cold spell could affect all of the UK. However despite all the promising teleconnections/stratosphere predictions I would advise members to be cautious until this actually appears on the model output. Another reason why im saying this is the Met O predicted the 2009, 2010 cold spells from some distance away and yet their 16-30 day forecasts continue to suggest more of the same i.e zonal. So whatever positive signs some are detecting on here the Met O don't agree.

Agreed TEITS.

Sounds like you're not pinning your hopes on the '10th Jan' then?

[Ian Brown]

Have to say the medium range is looking rather disappointing to me.

http://modeles.meteo...-21-1-240.png?0

http://www.meteociel...1-240.GIF?21-12

So it seems we shall have to wait until we are into January before any significant cold spell could affect all of the UK. However despite all the promising teleconnections/stratosphere predictions I would advise members to be cautious until this actually appears on the model output. Another reason why im saying this is the Met O predicted the 2009, 2010 cold spells from some distance away and yet their 16-30 day forecasts continue to suggest more of the same i.e zonal. So whatever positive signs some are detecting on here the Met O don't agree.

Dave, were you expecting any better when you looked at the NWP this morning ? It's a progressive pattern with an active jet and one that is hard to shift and essentially typical of late Dec/early Jan.

Have the METO long range outlooks performed as well over recent months as they did with that spell 2 years ago ? I don't think they have.

We are now dependent on the various teleconnections which may change matters into January, but don't forget we have been here before with what 'should' happen, but seen the Atlantic just roll on regardless.

[tollgateiow]

This was the UKMO 16-30 forecast issued on 6th December for the period we are in now, completely the opposite of what we have I would say....

UK Outlook for Friday 21 Dec 2012 to Friday 4 Jan 2013:

Temperatures by both day and night are most likely to be below average during this period, with a greater incidence of overnight frost and, at times, fog or freezing fog. The signal for rain and snowfall amounts during this period shows a high degree of uncertainty, however, on balance, slightly drier conditions compared to average are favoured for most of the UK. Even though there is a drier-than-average signal for much of the UK, where precipitation does occur, there is a greater chance that it will fall as snow compared to normal.

Updated: 1136 on Thu 6 Dec 2012

[TEITS]

Agreed TEITS.

Sounds like you're not pinning your hopes on the '10th Jan' then?

Nope not yet.

I like to see this potential to actually be visible in the GFS/ECM outputs at a sensible timeframe before I get my hopes up. Im also rather concerned that the neutral NAO which has persisted this month looks to carry on into Jan.

[Southender]

Would love to be in Reykjavik, Stockholm or Oslo over the next couple of weeks. It looks seriously wintry for those guys. Unfortunately they seem to have stolen winter. Let's get this year out the way and look at January with renewed optimism. Something will come eventually.

Edited December 21, 2012 by Shrimper

[Carl46Wrexham]

Would love to be in Reykjavik, Stockholm or Oslo over the next couple of weeks. It looks seriously wintry for those guys. Unfortunately they seem to have stolen winter. Let's get this year out the way and look at January with renewed optimism. Something will come eventually.

Yeah...more rain ...............err I'll get my coat!

[Cecil Hogmanay Melchett]

Well its beginning to look like we can write off Dec as a snowless month for most,i don't actually think the overall pattern has been that bad for Dec but the Atlantic went up a notch at exactly the wrong time in retrospect.I suspect we will get another bite at the cherry into January but again patience will be required,i have said some time ago i'd really like to see the back of that block to the NE and i stand by that,OK the block is keeping things frigid to way to the east but with so much energy in the Atlantic theres little or no chance of anything coming from Siberia to the UK!!

Soas it stands we can pretty safely write off 1/3 of winter,fingers crossed for change next month,after the wet and miserable summer we really dont want a wet miserable winter as well.

[Cecil Hogmanay Melchett]

Those heights across Europe are now being modelled consistently in FI,the longer term pattern is not exactly appealing to be honest and transient cold snaps from the NW look best bet as we head towards early January,as matthugo has suggested this morning.

[karyo]

I'm not sure why Matt Hugo persists in tweeting the latest from the ECM 32-dayer with such gusto... it's been a complete waste of time so far this season.

Maybe it is not what we want to hear but it has done pretty well all year. The only notable mistake was the failed easterly but let's face it easterlies have a high chance to fail unlike southwesterlies!

Karyo

[Bobby]

06z GFS continues the Beast from the West, looks more like the ECM this run. About as zonal charts as you're likely to see, can write off December I think although there could be some surprises from PM air from the NW. Hills in the North could get quite a bit of snow in fact.

Anyway the main issue is definitely the rain, high res NAE and NMM give up to 2 inches more rain across the same flooded areas tomorrow and plenty more to come.

NMM:

NAE:

Edited December 21, 2012 by Bobby

[Posh12]

Fed up of hearing this has failed that has failed I rely on you guys to explain what the models are showing now and in the reliable time frame come on more nativity less negativity thank you.

[Troubleatmill]

Fed up of hearing this has failed that has failed I rely on you guys to explain what the models are showing now and in the reliable time frame come on more nativity less negativity thank you.

But unfortuntely Posh12 that is exactly whats happend, the models were showing a great chance for sustained cold at times over the last few weeks, but it has failed and now we are looking at a rather zonal outlook in the reliable time frame, i.e spells of Rain some heavy, breezy and mild to average temps, long term is open to anything, this is where we look to the Likes of GP for a insight into the drivers of our weather and what they are doing 'currently' that would, could or should effect us 'longer' term

Edited December 21, 2012 by Nick JB

[SnowBallz]

Not what the EC32 is showing for January according to Matt Hugo.

To be honest, everything seems to be contradicting at the moment!

Just keeping everything crossed that GP is right!

So, it's not what the EC32 is showing today for January, but - as we've seen this season - there's just as solid a chance that 'what the EC32 is showing for January' will change again next week.

I quite understand Matt posting updates, but - ironically - he's just passing evidence over, which suggests it's a model well worth applying a heavy degree of caution to. It simply isn't performing well enough to be afforded such respect, or referenced to so frequently.

The fact of the matter, is that no model has been that impressive this season; all have made errors - some more serious than others; all continue to propose different ideas and all continue to make relatively large calculation corrections. So, it's a word of caution to all models here: not just the EC32.

So why is this happening? Well, from my understanding of mathematics, you'll develop a logical algorithm which - in the broad sense - will be governed by several different scientific principles, which are then converted into mathematical equations (the calculations themselves) and then the boundaries (the thresholds) So, in the main, this will be your base (and probably is for the GM)

To localise the model, you then also need to programme prevailing patterns, which would then give a degree of artificial guidance to calculations. This would probably be several layers which adjusts the boundary fields, therefore giving calculations some sense of 'where to go next'.

You then collate data, throw it into the model and see what Aladdin's lamp does with it.

I think the prime suspect for 'error', would be where an algorithm is given 'intelligent data' which artificially influences what it would otherwise mathematically wish to do. But you do need this, otherwise chaos theory would - by definition - ruin all of your hard work. So, it is a necessary evil.

However, if you think about it, some of that 'intelligent data' - historical tendencies; recent, mid, long-term, etc - isn't exactly set in stone; just because, for instance, UK winters have been relatively mild if you analyse the last 25yrs or so, doesn't ergo mean that pattern is fixed and will continue. But there will be an element of a false bias towards this being so, and - in statistical terms - I would totally agree with having that.

Personally (but what do I know!?) I do think our winters are changing. I think they're becoming colder - in relative terms you'll appreciate, and milder patterns (equally relative) look less commonplace. Aside from good old cyclical change, there are so many reasons as to why that might be happening; but I wonder how quickly a NWP model with bias towards a 'milder' evolution can react to that?

I honestly don't know the answer to that question, but I can hypothesise that - without human correction - such bias would continue, even in a pattern change, as that's what the algorithm is programmed to do. Perhaps you can overlay a further 'bias correction' layer, in order to realign? Immediately though, I think doing that would increase risk, as you don't really know how strong +/- to modify; you can't, it would be a matter of subjectivity, and necessarily that scientific.

I've a good friend who works down in Exeter, and apparently they'd like me to do some work for them; just bits and bobs which they just don't have the resource to research - but more from a climatological sense. So this opportunity should - at the very least - allow me greater insight, and I'm really looking forward to it. I start next July, so unfortunately you'll have to listen to prattle on 'till then

Anyway, those are my musings on NWP model performance; if they add something great - if they don't, I apologise! Such exciting things I talk about

[Posh12]

But unfortuntely Posh12 that is exactly whats happend, the models were showing a great chance for sustained cold at times over the last few weeks, but it has failed and now we are looking at a rather zonal outlook in the reliable time frame, i.e spells of Rain some heavy, breezy and mild to average temps, long term is open to anything, this is where we look to the Likes of GP for a insight into the drivers of our weather and what they are doing 'currently' that would, could or should effect us 'longer' term

Fair comment thanks

[Weathizard]

Absolutely dreadful charts at the moment, from my prospective right now I'd love to just have a massive UK high over us dominating proceedings. The rainfall I fear will be catastrophic for some, its just absolutely endless for us on the South coast especially, its bad enough here let alone in the south west. I just hope the teleconnections are correct because this sort of zonal train is not only very difficult to get out of with high pressure to our east, but could bring seriously damaging rains.

[johnholmes]

Fed up of hearing this has failed that has failed I rely on you guys to explain what the models are showing now and in the reliable time frame come on more nativity less negativity thank you.

hi

Why not read the Net Wx Guides as a background to what the models can and cannot do? It seems a touch unfair to make the comment you have-all are doing their best to interpret the models, have a go your self after doing the reading? It is fun honest!

May I ask a favour-can you put your nearest town in your avatar please-thanks?

[Luke McDonnell]

Hi,

Havent posted on here for a while but I have been keeping an eye on proceedings in this place and I was particually fascinated by the failed Easterly episode and the fact that it seemed to be scuppered at the last minute and it even had a good level of teleconnection and other backround factor support.

I am just wondering from this do you think a sudden increase in solar activity could be to blame for the faliure of the Easterly and the rather Atlantic controlled pattern since? I do know that a sudden increase in solar activity can ramp up the jetstream. GP hinted at this in one of his posts implying that an increase in solar activity was recorded at the end of November and that could been at least partly to blame for his december forecast not going totally to plan.

So do you think solar activity could have been the "wild card" this month in the fact that it could have overridden the backround signals (including the strat etc.) resulting in a milder more Atlantic dominated month that expected?

Luke

[Frosty.]

The Gfs 06z shows a wintry spell next week, at least for northern britain and in particular the far north of britain with some ice days, even a few colder days further south with frost and ice risk and with a southerly tracking jet with lows moving east into the residual cold air, the northern side of the lows would produce snow, arctic air flirting with northern scotland for most of the 6z run with at least cold zonal for them and a mix of cool/cold zonal further south but with some milder intervals as the pattern becomes flatter at times. A lot more rain to come with flooding but for some parts of the north, a more wintry mix with sleet and wet snow at times, and also some colder showery days with plenty of snow for scottish hills and mountains.

To put things another way, the northern view of next week would be more positive with polar air predominating and wintry showers with sharp frosts from as early as christmas day, a nationwide milder interval close to the end of the month and then colder again.

[bradymk]

Hi,

Havent posted on here for a while but I have been keeping an eye on proceedings in this place and I was particually fascinated by the failed Easterly episode and the fact that it seemed to be scuppered at the last minute and it even had a good level of teleconnection and other backround factor support.

I am just wondering from this do you think a sudden increase in solar activity could be to blame for the faliure of the Easterly and the rather Atlantic controlled pattern since? I do know that a sudden increase in solar activity can ramp up the jetstream. GP hinted at this in one of his posts implying that an increase in solar activity was recorded at the end of November and that could been at least partly to blame for his december forecast not going totally to plan.

So do you think solar activity could have been the "wild card" this month in the fact that it could have overridden the backround signals (including the strat etc.) resulting in a milder more Atlantic dominated month that expected?

Luke

Hi Luke, I am hoping to do some analysis of this and look into it a bit more and see whether we can prove/disprove any Null hypothesis. Before i begin, my opinion is that yes the sudden increase in solar activity did have an influence on the "failed" easterly. Not sure whether it was an overriding factor but imo it certainly influenced it. But i will now and try and find out more and see whether there is enough evidence to back this up.

[Posh12]

hi

Why not read the Net Wx Guides as a background to what the models can and cannot do? It seems a touch unfair to make the comment you have-all are doing their best to interpret the models, have a go your self after doing the reading? It is fun honest!

May I ask a favour-can you put your nearest town in your avatar please-thanks?

[Posh12]

Not a bad idea John I will. On mobile at the mo so will add location when home ( skegness) enjoy your posts.

[chris78]

Not a bad idea John I will. On mobile at the mo so will add location when home ( skegness) enjoy your posts.

really sorry mods as I know not on topic but seemed appropriate in light of the above.......

people are always, rightly, being asked to include their location.....the mobile version which more and more people use does not list location next to posts....has anyone else mentioned this and can anything be done? Thanks

No problem if a mod wants to move this..but if you do a response via Pm would be greatly appreciated

Edited December 21, 2012 by chris78

[No Balls Like Snow Balls]

So, it's not what the EC32 is showing today for January, but - as we've seen this season - there's just as solid a chance that 'what the EC32 is showing for January' will change again next week.

I quite understand Matt posting updates, but - ironically - he's just passing evidence over, which suggests it's a model well worth applying a heavy degree of caution to. It simply isn't performing well enough to be afforded such respect, or referenced to so frequently.

The fact of the matter, is that no model has been that impressive this season; all have made errors - some more serious than others; all continue to propose different ideas and all continue to make relatively large calculation corrections. So, it's a word of caution to all models here: not just the EC32.

So why is this happening? Well, from my understanding of mathematics, you'll develop a logical algorithm which - in the broad sense - will be governed by several different scientific principles, which are then converted into mathematical equations (the calculations themselves) and then the boundaries (the thresholds) So, in the main, this will be your base (and probably is for the GM)

To localise the model, you then also need to programme prevailing patterns, which would then give a degree of artificial guidance to calculations. This would probably be several layers which adjusts the boundary fields, therefore giving calculations some sense of 'where to go next'.

You then collate data, throw it into the model and see what Aladdin's lamp does with it.

I think the prime suspect for 'error', would be where an algorithm is given 'intelligent data' which artificially influences what it would otherwise mathematically wish to do. But you do need this, otherwise chaos theory would - by definition - ruin all of your hard work. So, it is a necessary evil.

However, if you think about it, some of that 'intelligent data' - historical tendencies; recent, mid, long-term, etc - isn't exactly set in stone; just because, for instance, UK winters have been relatively mild if you analyse the last 25yrs or so, doesn't ergo mean that pattern is fixed and will continue. But there will be an element of a false bias towards this being so, and - in statistical terms - I would totally agree with having that.

Personally (but what do I know!?) I do think our winters are changing. I think they're becoming colder - in relative terms you'll appreciate, and milder patterns (equally relative) look less commonplace. Aside from good old cyclical change, there are so many reasons as to why that might be happening; but I wonder how quickly a NWP model with bias towards a 'milder' evolution can react to that?

I honestly don't know the answer to that question, but I can hypothesise that - without human correction - such bias would continue, even in a pattern change, as that's what the algorithm is programmed to do. Perhaps you can overlay a further 'bias correction' layer, in order to realign? Immediately though, I think doing that would increase risk, as you don't really know how strong +/- to modify; you can't, it would be a matter of subjectivity, and necessarily that scientific.

I've a good friend who works down in Exeter, and apparently they'd like me to do some work for them; just bits and bobs which they just don't have the resource to research - but more from a climatological sense. So this opportunity should - at the very least - allow me greater insight, and I'm really looking forward to it. I start next July, so unfortunately you'll have to listen to prattle on 'till then

Anyway, those are my musings on NWP model performance; if they add something great - if they don't, I apologise! Such exciting things I talk about

I would say quite simply that the error is caused by erm!!, wait for it........... THE WEATHER BEING THE WEATHER

The weather will always be one step ahead of the models and that will never change no matter how much science evolves.

Edited December 21, 2012 by No balls like Snow Balls

[Panayiotis]

Here are the ensembles for London, they are not that bad considering we are not in a blocked pattern. http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=&ext=1&y=&run=6&lat=51.94331983805668&lon=-0.8490566037735832&runpara=0

[Luke McDonnell]

Hi Luke, I am hoping to do some analysis of this and look into it a bit more and see whether we can prove/disprove any Null hypothesis. Before i begin, my opinion is that yes the sudden increase in solar activity did have an influence on the "failed" easterly. Not sure whether it was an overriding factor but imo it certainly influenced it. But i will now and try and find out more and see whether there is enough evidence to back this up.

Interesting so it goes to show that the current or recent state of solar activity should also be taken into account as well as your standard backround factors like the teleconnections (e.g. the QBO, ENSO) and the state of the stratosphere as one factor can override the other given the circumstances.