Model Output Discussion; into 2015

[nobble]

Is Saturdays potential snow event still a possibility ?

[Mucka]

The clear trend seems to be for low pressure to dig further South in the second week of Jan possibly giving a good snowfall event in the North at some stage.

After mid month all the signals, including Fergies update, appear to be for the mean trough to be more NE of UK with potential for an Atlantic ridge to form.

 

We have had a few false starts already to this Winter but the final 3rd of Jan looks like a good window of opportunity to finally get some WAA toward Greenland and strong Atlantic block, perhaps a Greenland high.

 

Otherwise it is a case of sit tight and wait for a more coherent signal.

[I remember Atlantic 252]

Is Saturdays potential snow event still a possibility ?

 

not for low levels in the south, sno' chance, Peak district, pennines, scottish hillz, the only place to get snow Saturday

[Frosty.]

NW is useless for widespread snow though, with NW sure Scotland, N Wales and the Cheshire gap would do ok but that's it, we need a NE/E to send us into the freezer and give us the deep snow everyone on this forum wants

Yes but no but..the nw would just be the beginning, as teits said, eventually more towards the ne and east with a completely changed (vastly improved) Northern Hemisphere profile. I believe the tide will turn by second half of January or at least by the last quarter.

Edited January 1, 2015 by Frosty.

[Gustywind]

agree John, NW winds and cold zonality is useless for the south under say 250m asl

They probably would've been okay historically, jan 84 I think saw decent snow throughout the country from cold zonality. Nowadays warmer sea temps render north westerlies largely useless except for far north and mountains. Even northerlies aren't as sure fire as they used to be these days.

Think you'd have to alter the rhyme I grew up with 'when the north wind does blow we shall have snow', to something like 'when the north wind does blow, only the north be guaranteed snow'.

[Summer Sun]

Is Saturdays potential snow event still a possibility ?

 

GFS P has backed away from snow for parts of Wales and high ground in northern England, parts of Scotland should see some leading edge snow before turning back to rain

 

 

yesterdays 12z to compare

 

Edited January 1, 2015 by Summer Sun

[Tamara]

With the very inauspicious entrenched pattern stuck for the time being - it makes it too susceptible to set the tone of posting during 2015 on an unduly negative and disillusioned note. At least, in the context of the weather patterns and discussions in this thread anyway

 

We glean useful and very valuable insight from Ian F into the stochastic processes that the METO adopt in longer term model ensemble assessment and perusal of background drivers. These form an obvious professional benchmark of opinion as a means to manage expectations within the thread, going forward, of what we might expect to see from forthcoming NWP output

 

In addition, on an amateur weather enthusiast level, as a means of participating on a forum website, there are many who provide their own very useful and easy to read summaries up to 10 days (occasionally longer) based on face value model and ensemble data.

 

All such summaries and appraisals therefore, are subject to changing according and depending on how this data evolves from day to day, or, sometimes ( depending on how much Shannon E is present! ) over a few days.

 

It is sensible and not unreasonable, within the chaotic nature of weather modelling, to adopt this approach and avoid uneccesary speculation in the process.

 

On the basis that the intended remit of this approach is to provide a seamless reflection of model output (apparent) viccisitude and variance, then chopping and changing of posts and summaries from one to another can be easily accepted and forgiven by the thread audience as not being any reflected emotional human reactional viccissitude to erratics within model output

 

Now, to turn to what unfortunately seems much harder to forgive.

 

With all that has been said thus far, I do wonder where we would be if, in order to adopt safety first belt and braces approaches, we abandoned amateur investigation into 'specialist' aspects of weather pattern study such as the relationship between the stratosphere and the troposphere and how this fascinating interaction influences and changes direction of future weather patterns; the framework role Atmospheric Angular Momentum plays in tracking the global consequences of subseasonal weather phenomena (GWO) that encompasses the MJO and mid-latitude processes like meridional momentum and mountain torques?

 

In addition to sharing enthusiasm of favourite weather types, the potential extra value (if we want to use it) of a format such as the MOD thread, is a free platform to push boundaries of the science and progress individual and collective learning. Invariably, in putting such study into practice, error rates increase - but such error rates are in turn, surely, not any superficial and self indulgent loss of personal ego, 'reputation' and pride, but are instead a reward to be grabbed with both hands and learn further when things go wrong in this way?

 

Through the natural human process of error - future analysis can be improved, and personal experience and knowledge (that can be shared to help others) is enhanced.

 

Reading between the lines in trying to evaluate how model output might evolve within such a chaotic system means many worthy longer range predictions, based on relevant data sources, also contain at least an least an element of paradeigma, in addition to the examination of 'specialist' drivers

 

These provide the reader with an illustration of similar occurences and outcomes based on a historical set of data and drivers that match the trend period under analysis - and extrapolated forward as a means of base prediction.

 

These are bound to be prone to error as they cannot foresee unexpected divergences, such as has occured in how the patterns have evolved this winter (!!) and is now exposing a large difference in outcome between previous expectations based on thorough analysis of starting conditions in Autumn 2014, and the reality of what we see here in the models at T0 on the first day of 2015 and as expected to continue, probably at least, throughout the period up to at least t240

 

It is easy to see how 'audience-unpopular' progressive methods of longer term analysis can become - when such divergence and lack of accuracy emerges. This has much to do with initial expectations of the reader not being met, especially when the predictions have been made with a key weather preference inbuilt into them....

 

Most of us are guilty of that, at least at some time, and we would be kidding ourselves first and foremost if we deny this fact, more than we would be trying to kid anyone else..

 

However, this takes us back to the dual benefits of the MOD thread being both a platform to indulge in sharing enjoyment of weather preferences - riding the hopes together of seeing favoured synoptics arriving in output - and the other benefit of learning and progressing knowledge through pushing the boundaries by using specialist 'weather tools' to make predictions.

 

Both benefits should remain possible to achieve without recourse or recrimination when errors occur, and individual expectations carried within predictions are not met. In that respect, it is essential that predictions made balance both the preferences (the fun!!) and the realistic objectivity.

 

Taking the 'weather preference' element out of the thread (whatever that preference may be) would lead to a very sterile and monochrome clone. On the basis that all members are human and have a myriad of individual personality, this is unrealistic to expect.

 

As a voluntary website to participate in, no-one earns a wage here, so there is a luxury to indulge in both weather preference and hopefully objective study and prediction as a learning tool. However, as much as 'entertaining' any prospective audience keeps things buzzy and interesting, there is also a responsibility to make predictions realistic and objective and leave ego and reputation issues to the side (if there are any). This all helps avoid recriminations and backlash (toys out of the pram) when things don't verify according to plan.

 

A professional organisation such as the METO does not have the luxury of eschewing individual fads, in advertising its services, and has to suspend such indulgence and remain 100% objective at all times.

 

I think, imvho, remembering all these aspects could make this thread an easier place to participate in.

 

I also think in the context of this post, that the update that Lorenzo made yesterday evening wrt the progress of the net weather winter forecast (to date) deserves a huge amount of credit - and excellently epitomises the intended message of this post where hopes and preferences meet and jive with objective and factual scientific evaluation.

 

*Despite things not going to plan, so far *, and with 2/3 of winter still remaining  , I think expectations should be properly managed and premature statements in obituary should be well and truly suspended.....

 

Just my latest 23,000 word + collective for the first day of 2015, as a way forward, and I hope that the nature of the post in terms of its well meaning message is not considered too off-topic

 

Happy New Year  

Edit: Ha , thanks stew - I dunno, ..them typo's  !   

Edit 2: See *... *   Excepting of course the METO forecast  Well done to them thus far  

Edited January 1, 2015 by Tamara תָּמָר

[That ECM]

^^^^^^^^ If only those who got it right all the time could post then no one would... Love reading your posts... Happy New Year to all....

[MR EXTREMES]

Having looked through the models jan already is becoming a right of for a realistic wintry spell effect most parts of the uk.

With only northern and western areas likely to enjoy some form of wintry excitement.

But what is striking is that the upper 850s are pretty chilly if not cold for the favoured parts of the uk.

However as I suggested feb is a month that normally shows more relaxed zonal period there for towards the end of jan could start to show something different.

Although right now the favoured areas could well enjoy some exciting moments through most of the rest of jan.

But certainly would not rule out a possible northern hemisphere flip whether this favours more of the uk is up for debate the models I would say are not the worst but I have suggest the Azores is a prominent feature although slight movements can make big differences.

Happy new year guys and gals

[blizzard81]

With the very inauspicious entenched pattern stuck for the time being - it makes it too susceptible to set the tone of posting during 2015 on an unduly negative and disillusioned note. At least, in the context of the weather patterns and discussions in this thread anyway

 

We glean useful and very valuable insight from Ian F into the stochastic processes that the METO adopt in longer term model ensemble assessment and perusal of background drivers. These form an obvious professional benchmark of opinion as a means to manage expectations within the thread, going forward, of what we might expect to see from forthcoming NWP output

 

In addition, on an amateur weather enthusiast level, as a means of participating on a forum website, there are many who provide their own very useful and easy to read summaries up to 10 days (occasionally longer) based on face value model and ensemble data.

 

All such summaries and appraisals therefore, are subject to changing according and depending on how this data evolves from day to day, or, sometimes ( depending on how much Shannon E is present! ) over a few days.

 

It is sensible and not unreasonable, within the chaotic nature of weather modelling, to adopt this approach and avoid uneccesary speculation in the process.

 

On the basis that the intended remit of this approach is to provide a seamless reflection of model output (apparent) viccisitude and variance, then chopping and changing of posts and summaries from one to another can be easily accepted and forgiven by the thread audience as not being any reflected emotional human reactional viccissitude to erratics within model output

 

Now, to turn to what unfortunately seems much harder to forgive.

 

With all that has been said thus far, I do wonder where we would be if, in order to adopt safety first belt and braces approaches, we abandoned amateur investigation into 'specialist' aspects of weather pattern study such as the relationship between the stratosphere and the troposphere and how this fascinating interaction influences and changes direction of future weather patterns; the framework role Atmospheric Angular Momentum plays in tracking the global consequences of subseasonal weather phenomena (GWO) that encompasses the MJO and mid-latitude processes like meridional momentum and mountain torques?

 

In addition to sharing enthusiasm of favourite weather types, the potential extra value (if we want to use it) of a format such as the MOD thread, is a free platform to push boundaries of the science and progress individual and collective learning. Invariably, in putting such study into practice, error rates increase - but such error rates are in turn, surely, not any superficial and self indulgent loss of personal ego, 'reputation' and pride, but are instead a reward to be grabbed with both hands and learn further when things go wrong in this way?

 

Through the natural human process of error - future analysis can be improved, and personal experience and knowledge (that can be shared to help others) is enhanced.

 

Reading between the lines in trying to evaluate how model output might evolve within such a chaotic system means many worthy longer range predictions, based on relevant data sources, also contain at least an least an element of paradeigma, in addition to the examination of 'specialist' drivers

 

These provide the reader with an illustration of similar occurences and outcomes based on a historical set of data and drivers that match the trend period under analysis - and extrapolated forward as a means of base prediction.

 

These are bound to be prone to error as they cannot foresee unexpected divergences, such as has occured in how the patterns have evolved this winter (!!) and is now exposing a large difference in outcome between previous expectations based on thorough analysis of starting conditions in Autumn 2015, and the reality of what we see here in the models at T0 on the first day of 2015 and as expected to continue, probably at least, throughout the period up to at least t240

 

It is easy to see how 'audience-unpopular' progressive methods of longer term analysis can become - when such divergence and lack of accuracy emerges. This has much to do with initial expectations of the reader not being met, especially when the predictions have been made with a key weather preference inbuilt into them....

 

Most of us are guilty of that, at least at some time, and we would be kidding ourselves first and foremost if we deny this fact, more than we would be trying to kid anyone else..

 

However, this takes us back to the dual benefits of the MOD thread being both a platform to indulge in sharing enjoyment of weather preferences - riding the hopes together of seeing favoured synoptics arriving in output - and the other benefit of learning and progressing knowledge through pushing the boundaries by using specialist 'weather tools' to make predictions.

 

Both benefits should remain possible to achieve without recourse or recrimination when errors occur, and individual expectations carried within predictions are not met. In that respect, it is essential that predictions made balance both the preferences (the fun!!) and the realistic objectivity.

 

Taking the 'weather preference' element out of the thread (whatever that preference may be) would lead to a very sterile and monochrome clone. On the basis that all members are human and have a myriad of individual personality, this is unrealistic to expect.

 

As a voluntary website to participate in, no-one earns a wage here, so there is a luxury to indulge in both weather preference and hopefully objective study and prediction as a learning tool. However, as much as 'entertaining' any prospective audience keeps things buzzy and interesting, there is also a responsibility to make predictions realistic and objective and leave ego and reputation issues to the side (if there are any). This all helps avoid recriminations and backlash (toys out of the pram) when things don't verify according to plan.

 

A professional organisation such as the METO does not have the luxury of eschewing individual fads, in advertising its services, and has to suspend such indulgence and remain 100% objective at all times.

 

I think, imvho, remembering all these aspects could make this thread an easier place to participate in.

 

I also think in the context of this post, that the update that Lorenzo made yesterday evening wrt the progress of the net weather winter forecast (to date) deserves a huge amount of credit - and excellently epitomises the intended message of this post where hopes and preferences meet and jive with objective and factual scientific evaluation.

 

Despite things not going to plan, so far, and with 2/3 of winter still remaining  , I think expectations should be properly managed and premature statements in obituary should be well and truly suspended.....

 

Just my latest 23,000 word + collective for the first day of 2015, as a way forward, and I hope that the nature of the post in terms of its well meaning message is not considered too off-topic

 

Happy New Year

Well I was planning to go on a walk Tamara but I have run out of time now lol. Happy new year.

[Jason M]

Sorry mods bit off topic last one on this but we'd need much colder air entrenched from a NNE source before we saw Cheshire streamers giving snow to SE...NW winds wouldn't get us cold enough to see snow would they?

Just to answer this, yes a polar maritime flow can be cold enough to see snow to low levels even in SE England. It's certainly not a given though. If ever there was going to be the chance of such an outcome, a PM flow in mid January would be close to perfect timing as it maximises potential. That said though, I wouldn't be getting excited personally as it is very much an outside chance in terms of snow potential for much of the country.

The biggest issue with PM flows tends to be longevity. Whereas an easterly is often coldest lowest down in the atmosphere it can take a bit longer for any warmer air lower down to mix out with a maritime sourced flow and often the airmass has changed before that happens. Hence why we see -8c at 850 but only for a 24 hours or less.

Anywhere in the North West though with just a little elevation and frankly they should be very interested in such a set up.

[bluearmy]

Nowt wrong with a mean norwester within a broad trough scenario. You will get disturbances running along the base of the trough. If you have cold air already embedded then the results are obvious. It doesn't necessarily mean a scandi trough, Atlantic ridge and clean sustained nw flow. (Certainly not across 51 members)

Anyway, that particular discussion was re two weeks away and I expect plenty of water to flow under the bridge before then.

[shaky]

Is Saturdays potential snow event still a possibility ?

i asked fergie earlier but hes not replied yet!! Assume we gona get nothing out of that shortwave then even though both the gfss have moved it southwards!! Weird that cos i thought that would increase the chances further south and place the cold air further south aswell! !

[stewfox]

These are bound to be prone to error as they cannot foresee unexpected divergences, such as has occured in how the patterns have evolved this winter (!!) and is now exposing a large difference in outcome between previous expectations based on thorough analysis of starting conditions in Autumn 2015, and the reality of what we see here in the models at T0 on the first day of 2015 and as expected to continue, probably at least, throughout the period up to at least t240

 

It is easy to see how 'audience-unpopular' progressive methods of longer term analysis can become - when such divergence and lack of accuracy emerges. This has much to do with initial expectations of the reader not being met, especially when the predictions have been made with a key weather preference inbuilt into them....

 

I think, imvho, remembering all these aspects could make this thread an easier place to participate in.

 

Just my latest 23,000 word + collective for the first day of 2015, as a way forward, and I hope that the nature of the post in terms of its well meaning message is not considered too off-topic

 

Happy New Year

 

Input always appreciated , of course if we could look at the starting conditions for Autumn 2015 last year it would have made the 2014/15 winter forecast a lot easier    . 

[Banbury]

I'd imagine snow will be restricted to high ground in East Anglia :-)

It's actually not unknown to be fair as if conditions are right showers can filter down to the SE through the infamous 'Cheshire Gap'. Unlikely, but it can happen.

It did happen one year, snow showers came through the Cheshire gap and gave MBY a good covering in a very short space of time.......mid to late 80's

 

Rare though as you say

[carinthian]

There we go. 2014 officially the warmest in 247 years of measurement history in Austria. The NWP models start 2015 in the same warm vein over much of Europe. Temporary snow cover in lowlands soon melt away. Strange year here , highest accumulation of snowfall since 1975 in our winter at 1650m asl. Wet start to summer followed by a recording breaking heat and the mildest Autumn ever.Poorly Blighty, snow starved for 12 months in many places. Can we really get any cold anymore ? Keeping looking at the latest out-puts for hope, but just end up feeling totally miserable. Time to take a break and keep looking up at the sky and the horizon for divine inspiration to deliver from elsewhere. Maybe things can become cold later, but we always say that.

Happy New Year from Karten.

C

[nick sussex]

I think the issue today isn't so much what the pattern will be but whether its zonal mild or cooler zonal weather.

 

You can see both GFS's are going for more of the zonal mild, whereas the ECM has the jet further south and the Azores high displaced further to the west so will occasionally bring in some colder conditions.

 

You can correlate both options with the shape of the PV to the north, one rounded PV will lead to milder conditions , the ECM has the PV more stretched with more digging south of troughing to the east.

 

Regardless of what 850's the GFS shows at longer range if it shows some cold with the rounded PV then you can discount that solution as with time it will moderate any cold and take the jet further north.

 

Its unfortunate that we're really just discussing these options but we are where we are and until the PV relents then theres little sign of any lasting cold.

 

So its really a case of the more bearable cooler type zonality which at least has the chance of the odd surprise or the IMO very unpalatable GFS option.

 

We await the verdict over the next few outputs.

[mushymanrob]

Well just three days ago we were expected to get cold zonality after this weekend with very few milder incursions. Over the past few days all that promis is now ten plus days away, so hanging hopes on much pm, cold zonal, is in my view strawclutching. As things stand there will be some, but for it to dominate is surely chasing fi dreams until something more substantial enters the semi reliable time frame. Looking average to me for the next two weeks at least.

Edited January 1, 2015 by mushymanrob

[Sky Full]

.  

.....I think, imvho, remembering all these aspects could make this thread an easier place to participate in.

 

I also think in the context of this post, that the update that Lorenzo made yesterday evening wrt the progress of the net weather winter forecast (to date) deserves a huge amount of credit - and excellently epitomises the intended message of this post where hopes and preferences meet and jive with objective and factual scientific evaluation.

 

Dnespite things not going to plan, so far, and with 2/3 of winter still remaining  , I think expectations should be properly managed and premature statements in obituary should be well and truly suspended.....

 

Just my latest 23,000 word + collective for the first day of 2015, as a way forward, and I hope that the nature of the post in terms of its well meaning message is not considered too off-topic

 

Happy New

Very well said. Everyone on here looks for model output which predicts their favourite weather - this is only natural - and nobody should have a go at anyone who gets it wrong as a result (which is everyone). We should all be grateful for the regular contributors to this forum who do their best to interpret the models scientifically and we should try to learn from any mistakes - it might lead to more accurate forecasts in the future. Happy New Year to everyone and may 2015 turn into a snowfest for all.

[Jason M]

Erm, slight difference on the 12Z METO run. Keep looking at it, as it looks wrong . Where on earth has this come from??

 

http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=72&carte=1021

 

 

GFS at 72 hours

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=72&mode=0

 

Surely METO has blown a gasket (although as a rule I pay a lot of attention to METO at that range!!!!!)

 

 

Edit: Its def blown a gasket as you simply cant get from the 72 hour to 96 hour charts in that timeframe!!!

Edited January 1, 2015 by Jason M

[Mucka]

I think the issue today isn't so much what the pattern will be but whether its zonal mild or cooler zonal weather.

 

You can see both GFS's are going for more of the zonal mild, whereas the ECM has the jet further south and the Azores high displaced further to the west so will occasionally bring in some colder conditions.

 

You can correlate both options with the shape of the PV to the north, one rounded PV will lead to milder conditions , the ECM has the PV more stretched with more digging south of troughing to the east.

 

Regardless of what 850's the GFS shows at longer range if it shows some cold with the rounded PV then you can discount that solution as with time it will moderate any cold and take the jet further north.

 

Its unfortunate that we're really just discussing these options but we are where we are and until the PV relents then theres little sign of any lasting cold.

 

So its really a case of the more bearable cooler type zonality which at least has the chance of the odd surprise or the IMO very unpalatable GFS option.

 

We await the verdict over the next few outputs.

 

Hi Nick,

While I agree GFS often overdoes depth of troughs and how much cold air will penetrate South I still think there is good reason we could be affected by a deep trough in the run up to mid month with colder air air penetrating further South than is usual in a zonal set up.

My thinking is that there is scope for a heavy snowfall in the North (albeit temporary) in that period which hopefully will be enough to herald a pattern change (not immediate) as the jet digs further South and the Atlantic slowly relents.

We will know more in a few days once it comes inside the 10 day range.

Edited January 1, 2015 by Mucka

[cheshire snow]

not for low levels in the south, sno' chance, Peak district, pennines, scottish hillz, the only place to get snow Saturday

The forecast at midday on news 24 showed quite a wide area

of snow Manchester northwards, the presenter said snow could

Get down to low levels, and was been monitored closely by the

MO

C.S

[itsnowjoke]

Very well said. Everyone on here looks for model output which predicts their favourite weather - this is only natural - and nobody should have a go at anyone who gets it wrong as a result (which is everyone). We should all be grateful for the regular contributors to this forum who do their best to interpret the models scientifically and we should try to learn from any mistakes - it might lead to more accurate forecasts in the future. Happy New Year to everyone and may 2015 turn into a snowfest for all.

loving your post and your optimism hope a snowfest occurs but for now rain and wind a good start to 2015

[shaky]

The forecast at midday on news 24 showed quite a wide area

of snow Manchester northwards, the presenter said snow could

Get down to low levels, and was been monitored closely by the

MO

C.S

well that might have changed according to the latest gfs runs!! The low is even further south and now crosses the m4 corridor instead of the midlands! !

[Eugene]

Erm, slight difference on the 12Z METO run. Keep looking at it, as it looks wrong . Where on earth has this come from??

 

http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=72&carte=1021

 

 

GFS at 72 hours

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=72&mode=0

 

Surely METO has blown a gasket (although as a rule I pay a lot of attention to METO at that range!!!!!)

 

 

It's correct upto T+36 hrs then goes faulty until T+96 hrs where it corrects itself.

Edited January 1, 2015 by Eugene