Model Output Discussion - 10th Jan Onwards

[Bobby]

Genuine question relating to the models. If the meto are seeing 10/15% poss of an easterly then that would suggest that the ECM GFS and UKMO have about 1 in 8 chance of producing a run that shows that outcome. If we then take the morning output from last Wednesday when there was cross model agreement, is this more coincidence when modeled at t144 plus?If we then see further runs showing consistency then this would suggest the % chance of it happening have increased or I am I wrong?Thanks in advance.

 

I believe Ian F said yesterday that even if we got an easterly Met Office thinking is that getting deep cold in and having it persisting is even more highly unlikely, it's a real long shot. Realistically I think we have to look beyond this opportunity and into late January-February for the next chance of a cold spell. Plenty of time left and anything could happen by February. Not sure this wild goose chase is worth the bother to be honest.

[Buzz]

It's constant! We keep thinking 1step forward but then it's two steps back again! Stuck in a miserable rut!

 

It's not really though - as is often the case here people look much too far ahead and take it as gospel. This leads to the usual mood swings. It's been going on for many years and is highly unlikely to ever change.

[Panayiotis]

It depends what products they're using, the ensembles are generally often split with an easterly and don't normally jump fully across until much nearer the time, its not like a northerly toppler which is much easier to model.

 

Also when the UKMO mention easterly we're not getting the full story because for them an easterly might be the deep cold variety, some of those solutions may show a more se with an undercut but they won't class that as perhaps a proper easterly.

 

At the moment and given tonights outputs I'd put a deep cold easterly at still only around 20%, a snow event with a se undercut at 60%, an undercut with cold extending 50%.

 

If the trough disrupts favourably to the west and the UK continues to sit at the cold/milder boundary that does have a chance of giving some snow events.

 

IMO a proper easterly that people want to see is that one with deep cold uppers that can deliver snow showers, in terms of a slacker easterly flow I'd put the percentage higher but I think what the UKMO might be using is the deeper cold variety, maybe Ian F will clarify this later.

I like those percentages! Ian did say that there was a "10% chance of a colder E/SE'rly" but we will see tonight what they think about their own run in the fax....

Anyway back to the discussion, the latest CMA looking good at 144hrs -168hrs:

'Faux' easterly as Nick likes to call it, followed by the undercut @168hrs and with -3C uppers/SE flow, snow could be seen (even at lower levels) if there is any PPN related to the low:

Also with all the models updated, there seems to be a broad consensus that a NW flow will develop after with low pressure to the N/NW, an Atlantic ridge and lowered heights over Europe:

Edited January 14, 2014 by Panayiotis

[bluearmy]

just as yesterdays 12z ecm op was implausible (unlikely) around iceland with the high heights, so todays is with the low ones at days 7/8. that probably means the depth of the surface low is overdone. less pressure on the block will mean the trough not as far east when it disrupts se. perfectly in line with earlier thoughts as to where we are. solidly in line with the general ens guidance, despite the swings back and forth on the ops. nicks comments re undercutting is the way forward and a very stressful one for us i'm afraid becasue the way the trough disrupts and exactly what track it takes will be sooo difficult to pin down !

[nick sussex]

just as yesterdays 12z ecm op was implausible (unlikely) around iceland with the high heights, so todays is with the low ones at days 7/8. that probably means the depth of the surface low is overdone. less pressure on the block will mean the trough not as far east when it disrupts se. perfectly in line with earlier thoughts as to where we are. solidly in line with the general ens guidance, despite the swings back and forth on the ops. nicks comments re undercutting is the way forward and a very stressful one for us i'm afraid becasue the way the trough disrupts and exactly what track it takes will be sooo difficult to pin down !

Lol! yes whilst this thread is all in together at the moment, there could be a severe case of IMBYISM breaking out shortly if we see westwards corrections and more favourable trough disruption.

 

Given the paucity of snow so far it could get very ugly in here!!!

[mulzy]

Worryingly the Chinese model is showing an easterly at day 6:

 

 

Hope I haven't jinxed it - I'll get my coat!

[cheeky_monkey]

Likely outlook for Canada

 

Likely outlook for the UK

 

 

Unless the Scandi pumps iron !

only is some parts of Canada where i live this will be me with those charts

[Tim Bland]

Some of the Pro's don't think much af the battleground snow possibility. This is from Liam Dutton

"@liamdutton: Whilst it'll be chilly at times during next 7 days, there's no sign of any notable cold or snow. Mild & wet the theme so far this winter.

[tonbridgemole]

Hello here we go again..easterly

[Ali1977]

I think people should face facts, there is now nothing cold, as in snow and hard frosts going to happen in the next ten days, or longer. Unless meto is on board, these possible cold scenarios will not happen. That 10% chance is the lowest possible chance I can imagine meto will give, can't imagine they will ever say 0%....

[Duane S.]

Seriously, I give up. Not with winter, not even with this 'Easterly' but with trying to pre-empt what any model is going to output next! We've seen far greater model inconsistencies than this through the years but this is, I don't know, I can't put my finger on it, all a bit weird... I know, not very scientific but it has been like the weather has ground to a halt. I remember reading somewhere recently about a longwave pattern involving a quad low pressure setup (across the hemisphere) where this can effectively occur. 

 

We need a kickstart from upstream. Signs are promising, especially liking the MJO at last looking like it will wake up from the circle of 'meh' and most going into high amplitude (and benefial for HLB) phase 7. That forecast big surge of WAA Polewards off the Eastern Pacific should shake things up a bit downstream later on and at last a consistent warming forecast in the Strat, maybe not an impending SSW (yet) but it can only help.

 

I suppose at least we are not being teased with severe Arctic charts and then having them snatched away last minute. Perhaps it is a reflection on the state of this winter that we are chasing, almost obsessively at times, any sort of continental feed! All part of the fun I suppose

[bluearmy]

Some of the Pro's don't think much af the battleground snow possibility. This is from Liam Dutton"@liamdutton: Whilst it'll be chilly at times during next 7 days, there's no sign of any notable cold or snow. Mild & wet the theme so far this winter.

 

tbh, the initial trough will struggle to undercut cold enough surface flow because europe isnt cold enough at the moment. if it disrupts across us and is slack, then we will develop our own little cold pool over a couple of days. hills favoured under those criteria bit not exclusively. its the second trough beyond day 7 which has more chance of undercutting surface cold off the continent. i note the ecm ens mean is a bit east, but the anomoly is backed a bit west and the spreads show its 'game on' as to where it will sink.

 

and further to some of the posts above - its january - we dont need deep cold to create the conditions for snowfall.

 

the ecm op just past generates maxes sat onwards of 3c, 2c, 3c, 7c, 3c across the midlands and n england. the 7c in the brief warm sector. what if that were backed west a hundred miles - it isnt far.

Edited January 14, 2014 by bluearmy

[johnholmes]

Some links and comments about what we have and why, and what might be in store towards the last third of January?

 

A week ago what were we expecting? Many felt that a very cold easterly pattern was likely.

 

I posted a pdf into the technical thread (and the model thread on 8 January) in which I tended to follow, not necessarily the idea of a full blown easterly but more that of depressions taking a more southerly track.

Pdf link below

http://forum.netweather.tv/topic/76236-in-depth-model-discussion-and-summaries/?p=2890645

 

 This would have put the UK into a colder pattern than had been the case as far as the first week of the month. Behind the lows then some quite cold air at times around its northern flank that would give some snow although chiefly on high ground. To an extent this has happened, certainly if I look at my temperatures on my weather diary, quite often double figures in the afternoon between 5-8^th but single figures and much closer to my average of 7.0C. No snow and few frosts of either variety, indeed only one air frost so far this winter. So not a blinding success but better than having gone for the bitter easterly pattern.

The 500mb anomaly charts are a bit of a mix over the last week or so, see the current 00z issue from ECMWF-GFS below

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

It shows the model with a 500mb flow north of west into the UK with +ve heights over the Atlantic and –ve heights SE of Greenland into a trough still shown over western Europe. All the models have indicated this type, to some degree or other for over a week. They have also shown a ridge over Scandinavia although not consistently. In that it has changed position to a more westerly area now and then but overall at latitudes well north some kind of block. There has also been a tendency to show –ve heights south of this in various positions, sometimes NW of the UK, sometimes almost over the UK and a few days ago south of the UK. So there is little wonder that the synoptic models at distances out into the last third of January keep coming up with various ideas both in how they show the upper flow (follow the deep black line, it is the 552dm height line at 500mb) let alone surface positions of highs and lows beneath this.

At least the 12z today from GFS and ECMWF is pretty much a similar idea and does fit with the anomaly charts. They all show some kind of ridge, surface and upper over the Atlantic and trough/low into western Europe. In my view at 240h this is as close to what we may well experience on that date (24^th January) as anything they may show between then and now.

As to what happens beyond that then of course this is where a degree of hope casting where folk use their heart rather than their head to make out the colder option will happen. Talk of trough disruption or whatever phrase folk like to use, undercutting etc. Well how likely is it that the low shown developing at 240h will run ESE and allow air from NE Europe to flow west?

Below is the last NOAA 8-14 day chart I have, available only a few minutes ago.

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

It continues with the theme the NOAA outputs and to a large extent the other two have consistently given over the past 3-4 days. That is status quo in terms of the upper pattern. No need for me to detail this as it is clearly seen on the link above. IGNORE the red and blue dashed lines (the height anomalies) and concentrate on the green lines. These are the direction and some idea of the speed of the winds the model expects around 500mb, approximately, 18,000 ft, out into the final third of January. They give a good idea why Exeter suggests what is it? Colder interludes between each low. I can see no reason for there to be any marked change in the upper air pattern, and I am looking way west even beyond Alaska, to change this in any hurry. The major trough pattern is currently in a fairly slow moving pattern and at the moment there is nothing I can see to really disturb this other than a major surface low developing to temporarily altering this before it goes back to what it is currently showing, see Extra 500mb chart for 12z today below (link), that is broadly speaking an upper flow over much of the Atlantic into the UK and western Europe just north of west. Don’t get sucked in by the upper trough in the Atlantic, play the sequence out to 96h and see how it ends up in the major trough region, western Europe.

http://www.netweather.tv/secure/cgi-bin/premium.pl?action=gfs;sess=cc4caa9dcee23e9679fd850c5aa4a5fe

 

I suspect that the 120h Fax from last evening is going to be a pretty fair type of indicator over much of the time for the disposition of weather in the next 7-10 days at least.

 

So to put some meat on this=cold at times with rain bands and fairly windy with frontal zones especially in the west and NW. Some snow both ahead of frontal bands briefly but chiefly on higher ground from about the north Midlands north and scattered wintry mix showers for most now and then, again snow on the higher hills (probably a good spell for the Scottish ski resorts if there is not too much wind at times), with quieter intervals giving some frost, possibly fog patches in the south where the winds will always be lighter. But no major cold outbreak from any direction in the 6-15 day time frame.

Sorry about that folks, I could be wrong, which would not be the first time nor the last.

Edited January 14, 2014 by johnholmes

[Paul White.]

Some of the Pro's don't think much af the battleground snow possibility. This is from Liam Dutton"@liamdutton: Whilst it'll be chilly at times during next 7 days, there's no sign of any notable cold or snow. Mild & wet the theme so far this winter.

Well my glass is half full and he does say "notable" which implies they may be some about and looking at the model output I don't think anyone would dismiss the chance of a cold and snow outbreak in the next ten days.

[Gibby]

Good evening. Here is the report on the 12 midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for tonight Tuesday January 14th 2014 taken from http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models show a warm front crossing the UK as I type with rain spilling East across the UK in rapidly turning milder weather. The South then becomes drizzly later in the night and at first tomorrow while the North sees the early night rain and hill snow continue throughout with any snow turning back to rain. Tomorrow shows a cold front moving East over the UK with showery rain as it goes clearing to showers in the West later. The rest of the week and weekend is typified by the close proximity of Low pressure with showers or longer spells of rain, heavy in places with some drier and brighter spells as well most likely towards the East and NE.

 

GFS then shows next week with colder weather making it's way across the UK from the East briefly with the threat of some wintry showers for a time as Low pressure fills it's way SE over France. It isn't long before the pattern reverts to form with Atlantic wind and rain on fronts crossing East in association with depressions to the North takes hold once more. Throughout the run apart from the brief colder interlude early next week temperatures will remain close to average with a rather chilly and strong breeze at times.

 

The GFS Ensembles reflect the operational run quite well tonight with unsettled and changeable weather expected for all areas through most of the time. A brief colder interlude is shown within the ensembles too early next week though most members that support this go the way of returning milder air back soon afterwards.

 

UKMO closes it's run with filling Low pressure sliding SE across the UK and on over Europe leaving very slack conditions across the UK with a legacy of cloud and patchy rain or even sleet in places as things turn rather colder.

 

GEM shows a ridge of High pressure building NE towards Southern Britain early next week with early week rain clearing to a drier and brighter phase in the South for a time. Later the weather returns changeable and wet at times again as further fronts and attendant Low pressure moves East to the North of the UK. By the end of the run winds have swung NW with sunshine and showers, wintry in the North.

 

NAVGEM shows a similar trend to GEM but develops the ridge less and further South meaning the path to continued Atlantic dominated weather over the UK is easier with further Low pressure areas crossing East over or to the North of the UK with rain and showers at times in average temperatures.

 

ECM shows largely changeable weather continuing next week. A drier interlude looks likely under a weak ridge at the start of the week before further Atlantic Low pressure continues to deliver rain at times in very average overall conditions for January though it could turn rather colder at times later next week.

 

The ECM 9 and 10 Day Mean Charts look very similar to this morning with a trough strecthing SE down the East of the Uk from Low pressure to the NW and SE and High well to the SW and NE. Scrolling between the two days shows little overall change with the Azores High notably strong.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

http://www.wetterzentrale.de/pics/Reem2401.gif

 

The Jet Stream continues to flow to the South of the UK and Southern Europe over the coming week. Later in the output it appears that the flow may strengthen while moving across the Atlantic into the UK before once more progressing into Southern Europe.

 

In Summary tonight the indecision remains with regard to specific weather detail next week as approaching Atlantic depressions split with one portion sending energy NE while some energy moves SE across the UK with resultant slack pressure at times under Low pressure. As is alwas the case under these synoptics weather details are always hard to pin down with some rain and showers inevitable with some snow on Northern hills while other areas see dry and bright weather at times too. There is still some hope that something might develop from the East should more energy spill SE from these depressions than is currently shown but with the Atlantic remaining strong and some indication of a Jet flow strengthening later next week the favourite option remains for unsettled and Atlantic based weather to continue to run the show over the British Isles for the time being.

Edited January 14, 2014 by Gibby

[Captain Shortwave]

I think people should face facts, there is now nothing cold, as in snow and hard frosts going to happen in the next ten days, or longer. Unless meto is on board, these possible cold scenarios will not happen. That 10% chance is the lowest possible chance I can imagine meto will give, can't imagine they will ever say 0%....

Well given that even the professionals are mentioning high uncertainty, then I think your fact is just an opinion, for which some of the models disagree with. 

The point is we don't really know where we are heading, even beyond about day 3 at the moment apart from the next approach low will disrupt with x amount going north east and y amount going south east, the value of x and y being critical to what happens over the UK. Given the operations are all over the place and giving no realistic trend then I would say that all options are open.

Model wise, the ECM ens from my viewpoint have ore members colder than the op in the mid range with better trough disruption. Though someone who can quickly view the postage stamps can agree and correct me otherwise.

Edited January 14, 2014 by Captain shortwave

[lorenzo]

Anyone fed up with the models etc etc etc. look no further.  Elemental Proof ( Meteociel crayolas vs. Science) that the ECM is yanking your chain, serving the US some rampaging cold.

 

Even the ECM Ens 850 hPa has a nice pseudo outline of the UK ( minus Ireland ) just for the fun of it.

 

 

 

 

 

 

 

 

[tight isobar]

Sorry, apart from high ground...I meant widespread and notable cold/snow

with huge miss modelling andwide divergence in any singular evolution for a colder scenario ATM the last thing anyone should be pinning there hopes ar probabilities on is snowfall. As all are aware this is areal headache at present as regards models. And we would need to be 100% of colder inflow before talk of the white stuff should even be flagged.

[UV-RAY]

Well after a forced absence it appears the models are still as confused as ever, but the favourable outcome still appears to a trough more or less sat over us with rain/cold rain being the form horse for lower elevations in England/Wales with any snow restricted to higher ground and at times lower elevations North of the Border. So it's as you were then, lots of promise but the same old same old continues.

Edited January 14, 2014 by Sceptical Inquirer

[Cheese Rice]

Don't know about a sustained spell of bitter cold ie an easterly but I'd say there's a very high probability of a frontal system stalling across the UK, bumping into relatively cold 850's and falling as snow. 

 

While a raging easterly appears unfounded for now (what with the core of cold pushing back east over NE Europe) we should be able to tap into some -5 850's. 

 

If I were to go a step further you could potentially see several frontal systems trying to push in giving many periods of snowfall. The block is putting up a fight so while at face value the output is underwhelming it has alot of potential. 

Edited January 14, 2014 by Cheese Rice

[lassie23]

The azores high is never going to be left alone to build north and that is why it does matter what is happening in America, when it comes to our weather.

[Earth Wind and Snow]

I think it looks likely that if we are to see any now next week it is more likely to come from a cold north-westerly rather than an easterly with northern and western areas especially high ground most prone - while GFS and ECM FI show the block receding eastwards somewhat, they do not show typical south-west to northeast zonality but rather lows diving down on a north-west to south-east axis - John Holmes anomoly charts would also back this up - I would love a screaming easterly next week but being realistic no model, met office etc. are on that page.

 

it is what happens after mid next week that will determine our weather for late Jan / early Feb - hopefully those south-east diving lows will trigger a rise of pressure to the west which would allow the block to the north-east become a bigger player as we enter the last third of winter proper and possibly our first proper cold spell. Tentative signs in some outputs for this to happen. Some encouraging signs also such as the pacific ridge coming more in to play and events high up in the stat could also aid us going forward.

 

This winter has really been a waiting game for us all searching for proper cold / possible snow - hopefully that wait is nearly over. maybe the GFS 18z will pull a rabbit out of the hat

 

EWS 

[Snowman.]

Another recent trend is after some yet more disruption to the PV amplification becomes strong over the pacific and starting to create so very 'pokey' highs towards the pole.

 

Open these two here.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014011412/ECH1-240.GIF?14-0

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014011412/gfsnh-0-240.png?12

 

Looking in the Pacific area you can see things they are pretty close in strength, shape and position. There is no need to be ticked off about recent outputs as the chance for a cold spell sooner or later is looking increasingly likely.

 

 

Just add to my post here is the mean.

 

Big yellow thumb sticking out there.

Edited January 14, 2014 by SN0WM4N

[swfc]

very subtle changes at the 90 hr mark on the 18z ie ridging not as strong and the low slightly further north,effect later on?Roy Orbison at 120hrs on this run

Edited January 14, 2014 by swfc

[Panayiotis]

I think the 18z will be different to the 12z with the Scandi high sinking by 114hrs:

Edited January 14, 2014 by Panayiotis