Winter Model Discussion 18Z 5/2/13 onwards.

[Bristawl Si]

5 days away to a possible snow event for some of the UK and people in a panic over model runs today.

This is not an uncommon model trait - they often have a 'wobble' showing up slightly different scenarios days out.

Best wait until about Friday this week to judge if any snow event will happen Sunday/Monday.

After reading thru this morning's posts during my lunch break i still think this is one of the most sensible posts of the day, esp the last sentence.

In fact we could even be in a situ where things do not become clear until Saturday for Sunday/monday!

[Methuselah]

After reading thru this morning's posts during my lunch break i still think this is one of the most sensible posts of the day, esp the last sentence.

In fact we could even be in a situ where things do not become clear until Saturday for Sunday/monday!

Even if you do say it yourself, BB?

[chris55]

BB did you even realise you were quoting your own post? lol.

[JCP]

BB did you even realise you were quoting your own post? lol.

What is wrong with people today?!

I see Steve now has his own stalker too, lol!

[Jason M]

Just looked through the GFS 06Z ensembles. There is a very strong and coherent signal for high pressure to our NW from 300 hours out. Clearly this is deep FI and the models are struggling with detail this weekend, but i've not seen such a coherent set of late FI ensembles for a long while.

Will be interesting just to keep an eye on this to see if the signal starts to move through the time scales.

I noted with an almost complete lack of interest the debate on which model is best and which should be ignored this morning.

Jason

Edited February 6, 2013 by Jason M

[That ECM]

Just looked through the GFS 06Z ensembles. There is a very strong and coherent signal for high pressure to our NW from 300 hours out. Clearly this is deep FI and the models are struggling with detail this weekend, but i've not seen such a coherent set of late FI ensembles for a log while.

Will be interesting just to keep an eye on this to see if the signal starts to move through the time scales.

I noted with an almost complete lack of interest the debate on which model is best and which should be ignored this morning.

Jason

Brilliant, more t300 plus charts to go chasing, then a SW pops up at t72 ish and that's that. Still, love model watching so I will be following. Should know better but I think I prefer looking at the output than actual weather!!!!

[Ian Brown]

Looking at the ensembles its becoming pretty obvious to me that a shift E of the LP is going to occur like the UKMO/ECM. The 06Z was a colder run for my location which is why the precip didn't even reach the E. However you look below and it was colder than the mean.

http://modeles.meteo...run=6&runpara=0

So contrary to the Met O forecast I feel W areas are more likely to see rain. I feel the risk of snow is going to be mainly focused on central, maybe E areas.

Dave, it looks wrong unlikely to my eyes that many people will see snow, however far the front gets in. The air that it's coming into is not cold enough for a start. I would think at best a messy mix but if you are end up seeing snow from it you will have to see rain first before it all slips away and weakens.

[bluearmy]

Just looked through the GFS 06Z ensembles. There is a very strong and coherent signal for high pressure to our NW from 300 hours out. Clearly this is deep FI and the models are struggling with detail this weekend, but i've not seen such a coherent set of late FI ensembles for a log while.

Will be interesting just to keep an eye on this to see if the signal starts to move through the time scales.

I noted with an almost complete lack of interest the debate on which model is best and which should be ignored this morning.

Jason

Indeed jason - not since the ecm ens showed the upcoming period being colder than average about 10 days ago. seems to be one of those 'signals' that just repeats. hopefully wont be too late in the month but the likelihood of a sustained cold trough across nw europe grows by the run. if only we could get a big snowfall over the weekend and avoid a widespread thaw early next week, that could be a very interesting solution.

[Jason M]

Brilliant, more t300 plus charts to go chasing, then a SW pops up at t72 ish and that's that. Still, love model watching so I will be following. Should know better but I think I prefer looking at the output than actual weather!!!!

My thoughts as i typed the post as well. Just what we all need isnt it! nonetheless its a very strong signal and i'm saying that from just looking through the ensemble members. GP said much the same earlier with the anom charts.

Jason

[Jason M]

Indeed jason - not since the ecm ens showed the upcoming period being colder than average about 10 days ago. seems to be one of those 'signals' that just repeats. hopefully wont be too late in the month but the likelihood of a sustained cold trough across nw europe grows by the run. if only we could get a big snowfall over the weekend and avoid a widespread thaw early next week, that could be a very interesting solution.

Oddly, I just get the feeling that this might be a little different. We kept being told about heights over greenland etc and like most on here i'd got to the stage where i just think.. been there, bought the T shirt etc. They are worth scrolling through though because for the first time this winter its there on the vast majority of ensemble runs.

[That ECM]

My thoughts as i typed the post as well. Just what we all need isnt it! nonetheless its a very strong signal and i'm saying that from just looking through the ensemble members. GP said much the same earlier with the anom charts.

Jason

Often people ask me what the weather will be like tomorrow as they know I am interested. Normal reply, no idea but BFTP recons it's going to get cold from about the 24 th!!! All very interesting they say but is going to rain this afternoon? Go check the meto site I say because unless snow is forecast I have little interest and therefore no idea. I guess many a poster would fall into this space.

[Bristawl Si]

BB did you even realise you were quoting your own post? lol.

yes!! Lol

[Frosty.]

The models are favouring a colder than average pattern for the next few weeks although within the reliable timeframe the max temps on the thermometer won't be that cold, generally between say 3-6c which at the lower end of the scale brings the risk of wet snow as temps would drop from those levels once the snow starts falling for any length of time. The reason I say that is because sunday brings a higher risk of snow from the west, it may start as rain or sleet, it may remain as rain or sleet in the west at least but in central and eastern areas it could turn to wet snow and begin to accumulate as temps, initially around the 3-4 celsius mark (38f), begin to drop to nearer 1-2c and possibly to -0c 31f if there is a spell of heavy snow developing. Saturday looks mainly dry, bright and rather cold but we really do need to keep an eye on sunday as there is a chance of significant snow in large parts of the uk depending on the precise track of the low, early next week should see the rain/sleet/snow mix clearing southeast and then a cold bright day on tuesday with widespread frosts early and late, it also stands to reason that the areas which get a covering of snow will be colder than those which don't and then further into next week becomes more unsettled with the risk of sleet and snow continuing but probably more likely to be rain in the southwest and more western locations.

Edited February 6, 2013 by Frosty039

[SMU]

"GFS - didnt even look."

I think this is my first - and possibly my last, once it's removed - post under new membership; currently living in Beijing, although I've been following this (model discussion) forum for approaching a decade.

Steve, you are a VERY respected member on here. And I, myself, have a lot of time for your (along with others') analysis. There's no question you can interpret the info available to us, and you have a very friendly posting tone. But I am GMT+8 - so when the GFS rolls out at (approx) 3.30am in the UK, the first thing I do is look to see who is up for it.

Given you were logged-on/monitoring at the time, I can't imagine why you would say you didn't even look at it - surely the temptation would be too much (and is it not the only run filtering out at that time?) Forgive me, I genuinely mean no offence, but I know a shortwave from a shortcrust, and 'tis the former that might well scupper any (immediate) chances of a prolonged cold spell. The GFS run has progged this, and makes for very uncomfortable viewing for snow/cold lovers. Might as well tell it as it is, despite our yearnings for a sustained E'ly feed, or N/E'ly with some significant heights over Greenland (my personal preference).

As is the case every single winter, people almost invariably ignore (or try to ignore) a bad run. I'm sure there are others on this forum who just want an honest appraisal, and particularly those who can't yet read charts and are trying to learn. To an extent, I am one of them. I really do just appreciate an honest appraisal of what's being shown, beyond my own limited understanding.

OK, I'm done now. My apologies if I've upset/offended anyone; that was not my intention.

I would say I'll get my coat. But perhaps I'll only need a cardigan.

HIYA=- & Welcome-- dont make it your last post, & I doubt it will removed.

What we have on the forum is a real mix of new & old people & when newer members come on board I guess its hard to see the wood from the trees.

Your right I did look at the GFS 00z - 1 maybe 2 charts this morning at 4am as I was up not very well.

I studied the UKMO frame by frame & parameter by parameter - Because I believe that this model warrants the time of day where the GFS has proved that it doesnt really even deserve comment,- however I am assuming that of course everyone knows why I am making that assumption.

After following the AVN model that moved to the GFS its the same ol same ol- with the model not resolving the shortwaves & certainly not able to break the jet into smaller chunks-

The bias will always be one of a sinuous jet with no fractures.

If we look at the forum as a whole in that mix you have people that do post the daily analysis - Like gibby for instance who commentates on all the runs.- So what I see is people should make up their own minds who they follow & glancing in on others that they like to read.

I think I dont make any bones in my posts I only see the GFS as a useful tool for forecasting in limited situations- however im sure all will agree that in early december I picked a GFS 10 day chart & said it would varify better than the ECM. which It did.

When I log on to the runs I already have an inbuilt assumption on what a model will show in certain scenarios & 'generally ' thats not far wrong.

I guess what frustrates me a little is seeing the same people giving credibility to something that doesnt warrant it.

We can essentially forget the stats, as the stats & model statistics are not focussed on our little plot. They are broad brush for the NH, so some of the GFS errors are smoothed out around the globe, however for the UK the European models will around 95% of the time varify better than the GFS.

& for the times the GFS is better the euros are not usually more than a day behind.

So - rather than leave- stay on the forum.

Find the poster that you enjoy reading the most & look for their content, I guess I have a lot of people that really enjoy my posts, but equally those of you from an objectivity point of view find my arguements rather 1 sided....

& just to claify my views are of whats going to be expected not JUST on cold.

As for ignoring a bad run- NO, ignore a bad model.............

regards

S

Edited February 6, 2013 by Steve Murr

[SMU]

On a lighter note the other half asked whats going on in the S'fatersphere today which brought a smile to my face.

[That ECM]

On a lighter note the other half asked whats going on in the S'fatersphere today which brought a smile to my face.

Just for fun. What about the 12z's any predictions? SW etc?

[SMU]

Just for fun. What about the 12z's any predictions? SW etc?

As per UKMO- down the spine of the UK with the EAST missing out- prone spots the midlands etc.

Post that -10c moving back into the EAST & SE- difficult to second guess how low the heights will be & how unstable things get-

Putting odds of 75% that the ECM will look like the 12z yesterday & the GFS ensembles will move the mean for london down 1 or 2 degrees for the 12th of Feb.

Current is -6 c for that day. Expecting -7/-8c after tonights runs.

Expecting UKMO 144 to show the upper air cold pool over Europe closer at 144 that 00z 144- IE a continuation of the flow from the East.

S

Edited February 6, 2013 by Steve Murr

[LomondSnowstorm]

Can any of the more experienced members think of a winter with quite as many messy undercut setups as this one? It really has been a feature right through the winter and it seems to be almost every week at the moment:

It strikes me as odd that while the energy has often gone under heights to the northeast the pattern has never quite backed far enough west to advect deep cold from the continent, although we have had quite a few notable snow events so far this winter. The fact that these are relatively rare patterns and that the main trough disruption and consequent 'battle' is occuring right over the British Isles has made for some horrendous forecasting uncertainties and model switcharounds, and for the moment I don't think it's even possible to say where the front and hence the snowfall potential is likely to be on Sunday into Monday. We've seen corrections going both ways this winter as we've approached the time and I suspect even the NAE/NMM will be struggling a bit with it.

In the longer term we perhaps have a slightly better idea of where we might be heading, since, as others have pointed out, there are meaningful signs of Greenland height rises cropping up into FI:

[fergieweather]

Just for fun. What about the 12z's any predictions? SW etc?

Well, MOGREPS & EC EPS have remained in good broad agreement re a snowy breakdown (in repeated bouts) through first half of next week (with focus on central-southern-western districts) and thereafter a strong signal for W/SW unsettled regime to establish, albeit degree of cylonicity unclear. It would take a marked broadscale change to alter that story. Incidentally, UKMO have decided to dismiss GFS evolution into Sun-Mon as it bears no resemblance to EPS consensus. As of 00z solutions, EC remains the favoured outcome. Anyway, let's see how the next runs carry the tale forward.

[Rollo]

Hi LL,I have followed the charts here since I joined in I think 2004 and I absolutely agree with what you are saying,there appears to be so many chances of getting something really to sate we coldies appetites but it just appears that it does not happen and the charts promise" jam tomorrow" which does not materialise.

Giong back to the BBC days and even further when I received charts from the MO daily,I cannot remember a similar situation occured ,it certainly may but maybe the old memory is lettin me down. Normally a slider puts us in a very cold situation. Ah well as been said too many times the weather will do exactly as it wants.

[Pembroke Dangler]

As has been the case on countless number of times with these set ups, expect to see westward corrections on the closer runs from t76 down to t0. time and time again its done it and this seems another classic case where the models start stepping everything that little bit further west as we get to the time!!

[Tamara]

Seems to me there is a large difference between METO thoughts of a W/SW regime to establish and GP's thoughts of options of a mid atlantic ridge or Scandinavian High beyond the trough disruption etc into next week. The latter opinion suggests much greater amplification to the pattern and surely a fair resistance to the former progressive flatter solution. MOGREPS and ECM ensembles might be delicately poised here...??

Edited February 6, 2013 by Tamara Road

[phil nw.]

As usual, things getting a bit silly now. Why are we debating specifics at range (and also backwards).

Ecm op was the only forecast tool that progged an undercut at fi range. There is nothing else to debate. Next time a model goes out on a limb it could be gfs and it could be right. However, in the current pattern where it seems undercutting could be a recurring theme, is gfs likely to be the most trustworthy tool? As it happens, I don't think next week looks easy to call as there look to be too many bundles of energy and blocks fighting for supremacy.

Yes Nick your last sentence is very relevant and why too much emotion is being invested in some posts.

Modelling of the surface features will inevitably change run to run with the UK very much in the middle ground between the cold block and the Atlantic.

The ebb and flow at the boundaries will result in different ideas of detail and all the models have shown this recently.

I would ask some members to try and focus on model content and what they suggest when the 12z runs come out and not bore the rest of us to death with a continuing debate on which model is best.

It certainly isn`t going to influence what we eventually get.

[snowmadchrisuk]

Well, MOGREPS & EC EPS have remained in good broad agreement re a snowy breakdown (in repeated bouts) through first half of next week (with focus on central-southern-western districts) and thereafter a strong signal for W/SW unsettled regime to establish, albeit degree of cylonicity unclear. It would take a marked broadscale change to alter that story. Incidentally, UKMO have decided to dismiss GFS evolution into Sun-Mon as it bears no resemblance to EPS consensus. As of 00z solutions, EC remains the favoured outcome. Anyway, let's see how the next runs carry the tale forward.

I was shot down in flames this morning for suggesting such a thing as Atlantic taking over for a while from the W/Sw . Thanks for the update

[polarlow2]

What exactly is a 'slider'? Is it a low pressure system that comes up against the block and is forced to 'slide' underneath and away, rather than pushing through?