Model Output Discussion - 14th Jan 12z Onwards

[karlos1983]

Is this relating to today's runs? https://twitter.com/wsi_euroenergy/status/555754301394796544

[A.J]

I hope this thread isn't going to descend into despondency or chaos because of the ECM.

 

You simply can't trust an operational output .......

Indeed Nick, sage words!

 

I mean, it's just as well the model output doesn't dictate the weather, who'd think it?  (said with a wry grin and sense of irony) 

 

 

 

 

a few requests from the site team for members to think before posting, to stick to the thread title, and to utilize the relevant threads for one-liners/ramps/moans/will it snow in xxxxx?/off topic stuff...................and yes, those site team requests were definitely posted in English.......strange how members still don't understand them 

[Long haul to mild]

But Nick, the ECM is not on it's own here. The GFS backs it up. Compare the ECM and GFS at 240hrs. There is a reason why people are banging on about the JMA tonight. It's because the other models have backed off on the longevity of the cold .

Fair enough the charts are quite similar but T240 is absolutely light years away when there's so much uncertainty at reliable timeframes. It's quite possible they both have it wrong at that distance out, it wouldn't be the first time....

[Captain Shortwave]

The FAX charts have been released out to Sunday afternoon. Plenty of occluded fronts and troughs crossing the country over the period which could bring showers or longer spells of rain, sleet and snow to many areas. I wouldn't rule out a dusting of snow anywhere over the weekend. Friday and Saturday look pretty cold, Sunday into Monday the cold will strengthen its grip as a weak northerly flow sinks across the UK. I would think many parts of the UK on Monday will struggle to get above freezing with a sharp or severe frost in places along with freezing fog. 

Friday, Saturday and Sunday midday charts. Pretty representative with the 528 dam line clearing the whole of the UK and plenty of instability for showers to form in bands but also will pepper windward coasts.

 

This is all before the easterly as well.

Edited January 15, 2015 by Captain shortwave

[Long haul to mild]

Tbh i think its just what the 12z have picked up on today on gfs-ecm.To ignore it would be silly"not that anything will varify up to 96 hrs"but its there.Looking at the nhp before today any solid lasting easterly was a long shot imo.Cold snap is on its way but looking at the overall pic looks a long shot to get a lasting easterly in towards the uk.Hopefully later tonight 47-62 synoptics will be on offer

Your last point hits the nail on the head, this place would be full of cold rampers then, who would no doubt be as overly optimistic as those currently seeing a breakdown are too pessimistic!

The timeframes for the breakdown are ages away, there is a reason most forecasters won't go beyond five days; it's fraught with difficulty.

Edited to remove dratted autocorrect: can't see many "cold rappers" being on here later

Edited January 15, 2015 by Long haul to mild

[Carlrg]

TBH, Model Output Discussion needs leaving as is. Since when has it been an elitist forum?

 

The 12z GEM not showing starting to return to mild untill well into FI, T234 H. Bound to change.

 

Edited January 15, 2015 by Carlrg

[nick sussex]

But Nick, the ECM is not on it's own here. The GFS backs it up. Compare the ECM and GFS at 240hrs. There is a reason why people are banging on about the JMA tonight. It's because the other models have backed off on the longevity of the cold .

 

If its a new solid trend then we'll see the same outputs replicated over the next few days,however even the ECM and GFS are cold upto day ten. The ECM is already trying to disrupt the troughing to the west at day ten as you can see a shortwave starting to develop at the base of that.

 

 The ECM isn't even that bad later on , my suspicions re the ECM are just its complete departure from its earlier output upstream which clearly shows theres going to be more changes. 

[Nouska]

Is this relating to today's runs? https://twitter.com/wsi_euroenergy/status/555754301394796544

 

Read the more detailed blog entry from Dr Ventrice.

 

http://www.wsi.com/blog/energy/new-gfs-operational-model-in-todays-12z-run-reverses-the-anticipated-pattern-over-the-n-atlantic/

 

In light of the 12Z ECM, his last paragraph may be more applicable.

[chris55]

The issue is the NWP doesn't appear to be struggling tonight? From what I can see there appears reasonable cross model support that any E'ly will be a brief affair before the high topples to a mid lat position. Chances of reverting to something more sustained circa 10% IMO as I've rarely seen this happen once the models latch on to a toppling scenario. In fact 10% is being generous. Put it this way, I'd be stunned if we saw a reversal of the trend witnessed today.

 

The fact that not even Steve Murr can post the day 10 ECM chart with a positive is a true indictment of just how filth that scenario is.

 

 

Personally I disagree with that statement. If we get some consistency in the next 24/48 hours regarding this evolution then Id take note . Day 6 plus is when we get the topple, and although GFS and ECM agree on this i dont see UKMO going the same way to be honest, so as I said more consistent runs needed to firm up on things. 

 

  

[Long haul to mild]

The FAX charts have been released out to Sunday afternoon. Plenty of occluded fronts and troughs crossing the country over the period which could bring showers or longer spells of rain, sleet and snow to many areas. I wouldn't rule out a dusting of snow anywhere over the weekend. Friday and Saturday look pretty cold, Sunday into Monday the cold will strengthen its grip as a weak northerly flow sinks across the UK. I would think many parts of the UK on Monday will struggle to get above freezing with a sharp or severe frost in places along with freezing fog. 

15-24h.gif15-48h.gif15-72h.gif

Friday, Saturday and Sunday midday charts. Pretty representative with the 528 dam line clearing the whole of the UK and plenty of instability for showers to form in bands but also will pepper windward coasts.

 

This is all before the easterly as well.

I imagine that occlusion across the SE corner on Sunday could be of some interest to those of us still in the "two year wait"!

But yes, lots of little features likely to pop up for most of us in the next few days which may give some snow if marginality can be overcome.

[Jason M]

With 80% of said energy going N. Useless.

Don't think I've ever seen a day 10 ecm verify. Without the ensembles the opp run isn't much use to anyone in isolation.

In addition GFS doesn't really have a proper control or ensemble suite at present as they are based on the old GFS version. It's therefore difficult to know what's going to happen longer term.

Wouldn't get too down hearted yet :-)

[swfc]

Your last point hits the nail on the head, this place would be full of cold rappers then, who would no doubt be as overly optimistic as those currently seeing a breakdown are too pessimistic!

The timeframes for the breakdown are ages away, there is a reason most forecasters won't go beyond five days; it's fraught with difficulty.

Would that be "ICE-T" :rofl: :rofl: Sorry.Yes i take your point but the 500mb charts ete are prob along with the fax the best guide imo

[IDO]

The latest from Dr Cohen is that he links next week's cold to the minor SSW of a week or so ago. He believes that the trop will be favoured for a negative AO for Feb barring a low anomaly over the Barents-Kara area. Although Euro-asia is mostly to benefit from the warming other areas could get helpful blocking:

 

https://www.aer.com/science-research/climate-weather/arctic-oscillation

[Long haul to mild]

Would that be "ICE-T" :rofl: :rofl: Sorry.Yes i take your point but the 500mb charts ete are prob along with the fax the best guide imo

Haha yes, that was a great autocorrect lol!

Yes, I certainly think the fax charts could be like a box of delights over the next few days; troughs likely to pop up very quickly.

[Tamara]

< ....underpins both the weak height anomaly modelled to our N/NE around day 6 and then Phase 8/1 GWO orbit favours assisting the Atlantic pattern to provide amplification and trough disruption thereafter which *should* prevent the pattern flattening. This retrogression phase of the Pacific pattern and the slowing of westerly wind momentum occurring close together add up to reduced and buckled jet flows in our sector and so are supportive of the increasingly colder and more wintry outlook.

 

On this basis, the Azores High *should* not be too much of a spoiler as it is withdrawn further west into the Atlantic - with troughing sliding SE just ahead and against its more amplified shape and engaging resident cold air.

 

Much will depend on how bellweather a height anomaly to the N and NE we can secure
 

Edited by Tamara תָּמָר, 13 January 2015 - 17:58 .

 

That 'bellweather' word copied and pasted - tut!  

 

So, the stage is set for the first proper widespread cold spell of the winter. I'm not here though to post on individual model outputs and associated snow potential from this weekend and of course through next week   

 

As interesting and full of anticipatory hope as it is for many of us, I will wait for a closer now-cast, as there are a myriad of possibilities on a UK micro regional basis that won't be answered within the chaotic nature of the upcoming trough disruption until we get into the focus of the short term high resolution modelling circa 24/36 hrs. Also besides, there are already plenty of good people doing that anyway with interesting analysis without me adding any further purpose and useful insight to it

 

Asian M/T set to provide some further very important tropospheric/stratospheric interest in the next 10 days - and this aligns with further significant atmospheric signals that will determine whether our much more benign Atlantic jet patterns sustain an amplified profile, or attempt to flatten out. The second scenario however, I do think, has to be seen within the context of the polar field becoming finally more and more amenable to taking up that sustained -AO profile we have been waiting for. It seems a long time within the context of expectations since the start of winter - at least if we exclude the METO in this respect

 

Beyond further beneficial vortex attack, the net result of the +MT is also going to be to see the atmosphere respond by removing westerly energy transport and drop angular momentum once again. But, contrary to fears of further Nina-esque pattern spoiling leading on here, this is where it might get interesting and may not necessarily follow the late December route of flattening the pattern out sustainably and leading us back to prolonged westerlies.

 

Slow indicated progression of the GWO through phases 1/2 corresponds to a weak and amplified polar Jetstream in the Atlantic. It also supports therefore the cold pattern holding through next week at least.

 

Further progression forecast into Phase 3, should it verify under tanking -ve momentum, does trigger a signal to flatten the pattern from upstream, adding energy back to the Jetstream and therefore not hard to see why some modelling might be anticipating this as we approach the day 10 period and beyond.

 

Other than the obvious point that we are at the start of a long anticipated cold spell and there is no point in dwelling in breakdowns (!)   the polar field is changing beyond the likes of late December to an increasingly sanguine one (underpinned by +MT)  and is also supported by increasingly shortening wavelengths as we hit the second half of winter. These seasonal and trop/strat induced factors have different possible implications to further negative AAM tendency than we saw back then which led us to zonal yuksville through this first half of January.

 

There is the alluring and credible suggestion that GWO Phases 1 and 2 might form an allegiance state for recurring Atlantic amplification and trough disruption beyond the coming week. In tandem with further vortex disturbance this actually supports the idea of renewed retrogression of high amplitude ridging occuring even if the Atlantic High eventually collapses on the back of an easterly next week - that follows the upcoming wintry speckled trough disruption phase.

 

Eyes on the stratosphere, the polar vortex.....and importantly also the GWO and where it goes after what looks a supportive protracted 1/2 phase. The further we head towards and into February under this Phase state, the more likely it becomes to lock us into repeated Atlantic amplification and trough disruption.

 

This, instead of any flattening of the pattern leading us back to prolonged westerlies.

 

Too soon to be sure yet, but I suspect if this happens at all, it will be a transitory phase leading back to renewed amplification in the Atlantic and cold returning from the north.

 

The worm, I cautiously think, has turned.

 

But lots to look out for and enjoy for some time to come anyway

 

 

[Duane S.]

Shows how good a cold spell we have in prospect if a run we would have sold our grannies for 10 days ago, aka the the 12z ECM op, causes such an outpouring of grief and despair by some.

A cold period is nailed. Yes a few signs it may be on its way out by next weekend but it is simply way too far away to start throwing toys out of prams.... It is on a bit of a knife edge, the swing to a milder scenario later on could easily flip back within 24 hours to an easterly solution. All to play for the end of the month and into January.

Personally I think it is MJO assisted as per the Meto take when you consider we are currently running in high amplitude phase 6 and likely to make it through 7 before petering out well into the Pacific. But it is likely to be just as much down to the effects of the minor SSW that has been and gone which although didn't actually achieve full SSWness in terms of u wind reversal at 60N 10hpa, the temps at that level did hit a record warm temp in the strat polar cap. That arguably makes up for it only being a 'minor SSW' by definition and unlike the more direct MJO forcing on the troposphere( when there is a coupling as there seems to currently be), this strat event could spread its influence well into the month of February in terms of anomalous warm Arctic conditions and continued outflows of cold into lower latitudes (us if we get lucky)

[chris55]

I hope this thread isn't going to descend into despondency or chaos because of the ECM.

 

You simply can't trust an operational output that goes from this on its 00hrs run:

 

T192hrs:

 

ECH1-192.gif

 

T168hrs on the 12hrs:

 

ECH1-168.gif

 

Although we don't have the 12hr steps theres a chasm between both runs, I think we best wait to see the ECM spreads and ensembles later on.

 

This is the point i was trying to get across earlier. We absolutely need to see some consistency between runs before we can be confident of any eventual outcome. Taking one run in isolation is a fools game, the longer term is a marathon away in this situation. Also the shorter term is uncertain with regards to sliders and the depth of the "driver low" potentially ushering an easterly. So as i said earlier, consistency in the mid term will be needed to have any confidence in the NWP at that range.   

[ANYWEATHER]

Evening Folks. Great Winter weather on the way. As I said last night something reminiscent of late December 2010 esque, from the charts today. Please folks don't get hung up about where or when it will snow and Im not gonna keep posting those words.! As somebody said today its an evolving situation , anyway Ecm  and gfs at unreliable timeframe @t+144  show stonking cold and potential snow, but as in most cases this will go down to the wire.......

[Long haul to mild]

Despite some of the concerns on here, tonight my thoughts are drifting (excuse the pun) back 10 days or so to the posts writing off ALL of January as zonal dross.

Whether you get a foot or a flake of snow next week, those posts were wrong and show that emotional overreactions to model runs are rarely useful. All the models now clearly show 7-8 day cold spell, that cannot be denied. It is only in FI that things diverge, as they so often do.

So let's keep looking at trends and patterns in the models because building knowledge is always a good thing, but none of us can ever pretend we know what the weather will actually end up doing in this wonderful country of ours

[BLAST FROM THE PAST]

< ....underpins both the weak height anomaly modelled to our N/NE around day 6 and then Phase 8/1 GWO orbit favours assisting the Atlantic pattern to provide amplification and trough disruption thereafter which *should* prevent the pattern flattening. This retrogression phase of the Pacific pattern and the slowing of westerly wind momentum occurring close together add up to reduced and buckled jet flows in our sector and so are supportive of the increasingly colder and more wintry outlook.

 

On this basis, the Azores High *should* not be too much of a spoiler as it is withdrawn further west into the Atlantic - with troughing sliding SE just ahead and against its more amplified shape and engaging resident cold air.

 

Much will depend on how bellweather a height anomaly to the N and NE we can secure

 

Edited by Tamara תָּמָר, 13 January 2015 - 17:58 .

 

That 'bellweather' word copied and pasted - tut!  

 

So, the stage is set for the first proper widespread cold spell of the winter. I'm not here though to post on individual model outputs and associated snow potential from this weekend and of course through next week   

 

As interesting and full of anticipatory hope as it is for many of us, I will wait for a closer now-cast, as there are a myriad of possibilities on a UK micro regional basis that won't be answered within the chaotic nature of the upcoming trough disruption until we get into the focus of the short term high resolution modelling circa 24/36 hrs. Also besides, there are already plenty of good people doing that anyway with interesting analysis without me adding any further purpose and useful insight to it

 

Asian M/T set to provide some further very important tropospheric/stratospheric interest in the next 10 days - and this aligns with further significant atmospheric signals that will determine whether our much more benign Atlantic jet patterns sustain an amplified profile, or attempt to flatten out. The second scenario however, I do think, has to be seen within the context of the polar field becoming finally more and more amenable to taking up that sustained -AO profile we have been waiting for. It seems a long time within the context of expectations since the start of winter - at least if we exclude the METO in this respect

 

Beyond further beneficial vortex attack, the net result of the +MT is also going to be to see the atmosphere respond by removing westerly energy transport and drop angular momentum once again. But, contrary to fears of further Nina-esque pattern spoiling leading on here, this is where it might get interesting and may not necessarily follow the late December route of flattening the pattern out sustainably and leading us back to prolonged westerlies.

 

Slow indicated progression of the GWO through phases 1/2 corresponds to a weak and amplified polar Jetstream in the Atlantic. It also supports therefore the cold pattern holding through next week at least.

 

Further progression forecast into Phase 3, should it verify under tanking -ve momentum, does trigger a signal to flatten the pattern from upstream, adding energy back to the Jetstream and therefore not hard to see why some modelling might be anticipating this as we approach the day 10 period and beyond.

 

Other than the obvious point that we are at the start of a long anticipated cold spell and there is no point in dwelling in breakdowns (!)   the polar field is changing beyond the likes of late December to an increasingly sanguine one (underpinned by +MT)  and is also supported by increasingly shortening wavelengths as we hit the second half of winter. These seasonal and trop/strat induced factors have different possible implications to further negative AAM tendency than we saw back then which led us to zonal yuksville through this first half of January.

 

There is the alluring and credible suggestion that GWO Phases 1 and 2 might form an allegiance state for recurring Atlantic amplification and trough disruption beyond the coming week. In tandem with further vortex disturbance this actually supports the idea of renewed retrogression of high amplitude ridging occuring even if the Atlantic High eventually collapses on the back of an easterly next week - that follows the upcoming wintry speckled trough disruption phase.

 

Eyes on the stratosphere, the polar vortex.....and importantly also the GWO and where it goes after what looks a supportive protracted 1/2 phase. The further we head towards and into February under this Phase state, the more likely it becomes to lock us into repeated Atlantic amplification and trough disruption.

 

This, instead of any flattening of the pattern leading us back to prolonged westerlies.

 

Too soon to be sure yet, but I suspect if this happens at all, it will be a transitory phase leading back to renewed amplification in the Atlantic and cold returning from the north.

 

The worm, I cautiously think, has turned.

 

But lots to look out for and enjoy for some time to come anyway

As ever lovely expalanation but we still await, C'mon Tamara order the synotpics to do as they are told!!

 

BFTP

Edited January 15, 2015 by BLAST FROM THE PAST

[ANYWEATHER]

Still chasing the cold and much vaunted cold synoptics?  As ever lovely expalanation but we still await

 

BFTP

What are you on about? Please go to the model thread moan,,,    

[nick sussex]

I can totally understand some peoples frustration if they see the window for snow opportunities shortened.However  lets think of it another way if people just saw this evenings outputs upto T144hrs would they think that was an upgrade or downgrade?

 

Do we remember the ECM a few days back with the deep low dropping south which has now imploded, people have to view the NWP as something fluid rather than static.

 

And when you're just a few days out from some decent synoptics its best to concentrate on those smaller nearer time changes that can build up to deliver more longevity to the cold. Rather than looking at T240hrs and trying to work backward if that makes any sense.

 

Even if the ECM and GFS are on the right trend what if they've overeacted a little and are too flat? what happens to the trough at day ten to the west if thats a bit more amplified.

 

And at day ten the ECM still has low pressure over northern Italy, this does not correlate with mild conditions for the UK, there are certain bellwethers in the UK winter, low pressure in northern Italy is 99% of the time a correlation for cold.

 

So even with an ECM output which has departed from its 00hrs dramatically upstream its still cold, is that cause for some relief?

[SMU]

 

With 80% of said energy going N. Useless.

 

with respect CC your being overly pessimistic tonight, have we learned nothing from the ECM operational this week.

 

Only yesterday the 00z operational did the same thing on the 168 chart in the exact same location-

 

http://www.meteociel.fr/modeles/ecmwf/archives/2015011400/ECH1-168.GIF?00 only to be humbled by the ECM Mean.-

the same chart today-

http://www.meteociel.fr/modeles/ecmwf/runs/2015011512/ECH1-144.GIF?15-0 - so that's a low of 980 MB removed to nothing.

 

The same could have well been over phased tonight.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015011512/ECH1-144.GIF?15-0 ECM 144

 

http://www.meteociel.fr/ukmo/runs/2015011512/UN144-21.GIF?15-17 UKMO 144-

UKMO has more ridging & the jet diving SE - which is ideal....

 

 

If we go to the 240 chart & assume its verifying then the core of the energy is moving NE, however that's what it does in Scandi High scenarios-

The ridges follows the WAA & eventually the Easterlies are forced back underneath the high.

We are already cold & somewhat snow covered at that point so I see no cause for concern.

*What is also a factor prior to this is if there is a low heading across Iceland ENE at around 168 then the chances are it will get elongated more so & bring snow to more people...

 

So whilst there needs to be some realism in the thread that it *could* sink quickly- there should also be some optimism based on past experience of what's actually happened & also what models have also done.

Feb 2012 ( at the start ) was a good case in point- the ECM & other models sunk the high quickly yet it hung around for 10 days...

 

so, take a chill pill & watch the fun & games unravel -

 

PS heres your snow in cornwall........

http://en.vedur.is/photos/atlant_evr_urkomuspa/150115_1200_132.png

 

& heres your potential early doors snow in the SE

http://en.vedur.is/photos/atlant_evr_urkomuspa/150115_1200_72.png

 

Cheers

S

[IDO]

Looking at the ECM clusters at D5 they are showing more confidence than this morning, clusters reduced from 6 to 3, so uncertainty has reduced considerably (sadly). The op is aligned to the control with 31 member support so it looks like up to D5 good confidence especially as it is D6 when the Atlantic ridge busts the trough. Cluster 2 has the LP system more blown up and further west so I am not buying that and cluster 3 looks nuts. So all in all it does look like an eureka moment from the ECM ensembles and a flip to a more progressive collapse of the trough. The mean supports that:

 

 

 

Clusters: http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2015011512!!/

Edited January 15, 2015 by i'm dreaming of...

[Troubleatmill]

Think the FI postage stamps for the 12z GFS show that anything can happen with this cold spell later next week? Could go mild, could stay cold, why worry when they dont know?