Model Output Discussion 1st January 2014-06z onwards.

[Radiating Dendrite]

Given the synoptic set up, so long as you are under -1 850s you should see snow with winds coming off the continent and a low dew point. The perfect example of this was March last year!

[That ECM]

K'thom, the wetter London ens are for a grid point in the channel (no idea why it's not been fixed after all these years)As far as ECM is concerned - getting far too close for my liking to game over at day 4 as the Atlantic and scandi low heights almost phase together. This run would be a snow machine if we already had embedded cold and this was the Atlantic trying to get in. However, it looks like a snow on hills job and in the north of the UK away from coastal counties. Gem looks too clean in its solution for me, given the complex nature of ukmo and ECM. I'm afraid I doubt Exeter are going to jump to a wintry update this morning apart from stating the risks and the likelihood of upland snowfall. days 4, 5 and 6 are where we need to pin this down and that's where the ops just begin to lose their reliability in favour of the ens mean. The result of this being that the ens are unlikely to be in the right place at day 4 so their evolution through day 6 will not be accurate enough for us to see what's likely. The ops are clearly not going to give strong guidance at day 6. The trend is certainly away from a clean undercut but it could be that a messy one might just find us the right side of cold enough. Far too risky though!I'm ignoring the run post day 6 as there seems little point in concentrating on detail that far out when the initial phase could go very differently. I would draw your attention to the back end of the ECM run where a pulse of low heights drops in from the nw. That has been an extended ens theme on the anomolys and as I've stated before, if it the pattern is backed west far enough, that's a sustained cold pattern, even though it might not look so great on the height/anomolys/slp mean.

Hi BA, would you put up some UKMO output. I am not able to see this mornings output? Thanks

[Polar Maritime]

The theme is still there, and still many small details will change so i would't get to hung up on them,  especially past D5. 

Edited January 9, 2014 by Polar Maritime

[Jason T]

Looking nice and frosty saturday night into Sunday morning.

 

[Liam J]

Some disappointment from the 00z runs - whilst we are looking at some of the best charts we've seen all winter it's much to early to be counting chickens before they have hatched, good post from Bluearmy a few back ^ to finely balanced to call either way, save yourself from shredded nerves! ATM I'm just looking forward to some frosts, not had one here since November!

 

More runs needed

Edited January 9, 2014 by Liam J

[Average Joe]

Out of all the output, I would only take the GEM this morning. I really hope we can correct this south west a bit. I have to be honest, screw the battleground for now as my goodness the prospects for the flooded regions in the south would be incredibly grim here. If it's the wrong side of marginal then there could be days upon days of rain here.

Appreciate you thinking of those of us underwater still. I hate being the Snow Grinch, but I'm really hoping it waits till things have dried up a bit. (Sorry Mods)

[Frosty.]

Looking forward to those beefy snow showers steve mentioned earlier

Edited January 9, 2014 by Frosty.

[shaky]

Well the ecm shows uppers below zero for most and with a continental flow am sure wherever the battle takes place across the uk it will fall as snow!!at the moment I say midlands northern England!!high chance the 12z this evening could correct south though!!

[Cecil Hogmanay Melchett]

Oh dear.

Models are putting more energy into the northern arm this morning.

Still good runs for those up north but starting to look very dodgy for those in the south especially.

Eagerly awaiting Fergie/meto thoughts but i doubt very much the further outlook is going to be jaw dropping.

[Cecil Hogmanay Melchett]

Well the ecm shows uppers below zero for most and with a continental flow am sure wherever the battle takes place across the uk it will fall as snow!!at the moment I say midlands northern England!!high chance the 12z this evening could correct south though!!

I hope so,still good for Scotland but those colder uppers really struggling to get in on the 0z runs.maybe the experts can shed more light on projected precip types,looks like mainly rain across much of the south as it stands?

[Jason T]

Looking forward to those beefy snow showers steve mentioned earlier

 

 

Low coming in Sunday night pushing into cold air.

 

[The Eagle]

Not surprised following the 12Z ECM ensembles. The more astute will have spotted lowly NAVGEM going exactly the same way last night with more trough disruption and just a little extra impetus in the jet stream enough to force the colder air northeastward. Potential is still high but there is no doubt about it things have slipped in the low res time frames. 

 

 

Will be hoping for better later on.

Edited January 9, 2014 by The Eagle

[Frosty.]

Low coming in Sunday night pushing into cold air.

 

Let the battle for middle earth commence. I think this is potentially going to become a very tricky period for forecasters early next week with knife-edge rain to wet snow catching people out and then cold air delivering the knock out blow and winning next week bringing real winter to the uk at flippin last!!!.

Edited January 9, 2014 by Frosty.

[Jason T]

Let the battle for middle earth commence. I think this is potentially going to become a very tricky period for forecasters early next week with knife-edge rain to wet snow catching people out and then cold air delivering the knock out blow and winning next week bringing real winter to the uk at flippin last!!!.

 

Good post Frosty, Just pulled this from Twitter.Long way out but WOW. Hold on to your seats.

 

[winterof79]

This is as far as ECM goes

http://www.meteociel.fr/modeles/ecmwf/runs/2014010900/ECH1-240.GIF?09-12

http://www.meteociel.fr/modeles/ecmwf/runs/2014010900/ECH0-240.GIF?09-12

http://www.meteociel.fr/modeles/ecmwf/runs/2014010900/ECM1-240.GIF?09-12 heights sliding south

 

A good winter chart especially so considering what we have endured so i am happy with the output.

[Cecil Hogmanay Melchett]

Good post Frosty, Just pulled this from Twitter.Long way out but WOW. Hold on to your seats.

 

which model is that jason?

[Polar Maritime]

Reading Lorenzo's update in the stratt thread, the Polar Vortex looks like it's going to get another rattle soon which is good news.

[Frosty.]

This is as far as ECM goes

http://www.meteociel.fr/modeles/ecmwf/runs/2014010900/ECH1-240.GIF?09-12

http://www.meteociel.fr/modeles/ecmwf/runs/2014010900/ECH0-240.GIF?09-12

http://www.meteociel.fr/modeles/ecmwf/runs/2014010900/ECM1-240.GIF?09-12 heights sliding south

 

A good winter chart especially so considering what we have endured so i am happy with the output.

The last time I was as happy as this with the models from a cold perspective was last march / april winter is coming..bring on those beefy snow showers, thames streamers and severe frosts.

Edited January 9, 2014 by Frosty.

[Hotspur62]

As others have pointed out in last few days it may take more than 1 attempt before we get widespread cold in UK.The models don't seem quite as good to me as yesterday evening but there is still potential in the Longer Term.If I was a betting man, I would say Northern England Northwards will have cold enough temperatures for snow from Tuesday and as time goes by these temps will fall further South possibly by 20th.To me we need embedded cold for a few days and higher heights in Scandi.That's my take on things and more to do with years gone by as much as what models show.At least we are in the ball game from a cold perspective and amazing how things can change so quickly.This time last week there was a lot of despair in this forum.Now there is hope.

[Jayces]

Good post Frosty, Just pulled this from Twitter.Long way out but WOW. Hold on to your seats.

 

 

15 days away, hmmm I'll eat my hat if that happens as shown. Models this morning have quite a big shift at day 10 let alone day 15.

[Cecil Hogmanay Melchett]

carol kirkwood just said chance of snow in the north next week,but lots of uncertainty - hopefully we will see upgrades in the days ahead

[BlueHedgehog074]

The 00Z GEM appears to continue to provide a 'first class' Easterly for the UK with some quite chilly 850 hPa temperatures thrown into the flow, while the Easterlies/South-Easterlies from the likes of the ECMWF look more like standard class and is indeed somewhat delayed.

Kinda hoping since the flow is still from the continent, that any possible snow from the likes of the ECMWF could still fall to some low levels, but it could be a bit on the tight side. Not a complete disaster for cold and snow fans this morning (especially with that encouraging GEM) and there's still enough room for the quality of some of these Easterly flows to improve. But it could just turn out to be one of those 'short term pain = long term gain' sort of scenarios.

Edited January 9, 2014 by DiagonalRedLine

[Blizzardof82]

I made the mistake of waking up and coming on here and twitter 1st before looking at model output myself, all still looking good for colder weather and prospects of snow for many next week.

 

This chart doesn't look too shabby  

Edited January 9, 2014 by Blizzardof82

[snowking]

Well i've lost track in recent winters of the number of times i've checked the forum first thing in the morning thinking ohh dear there must have been some pretty serious downgrades only to take a look at the models for myself and realise that in fact there has been very little change since yesterday and all the deterministic runs are displaying this morning are the variations within the ensembles that we have been seeing for the last 36 hours.

 

Deterministic modelling is not as good as it was at say 0z yesterday but I think some people need to try and get their head around what NWP is trying to model here. Attempting to model the physics of two streams of jet energy travelling in two different directions running in to a blocking high is a ridiculously complex equation. There were various members yesterday trying to impart wisdom from years past to tell everyone that whilst face value model output was looking exceptionally good it would be some days yet before we would be able to determine the final outcome. We see models struggling enough to calculate fairly straightforward situations a week in advance, never mind something like this. When Ian F said yesterday that in terms of ensembles it was essentially a 50/50 split (with just a tad more on to the cooler side of the fence) he wasn't saying that for the sake of it, that really is what you get with situations like this, particularly against the background of how strong the jet stream has been.

 

All I can say is it's a good job I am not a newer member attempting to decipher what on earth is going on because the conflicting messages this morning have been something else. What I would say to any newer members for now is this - wait until the weekend before drawing any major conclusions. The only certainty for now is that temperatures at the surface are going to drop in comparison to recent weeks.

 

On the subject of the actual outputs yes the GEFS ensembles are certainly not as good as yesterday but two crucial points to make here. First of all once again both of the higher resolution outputs (det. and control) are still firmly in the colder camp - when you're dealing with splits in jet energy those are going to be the more likely to resolve things correctly, though even within these as we have seen with the ECMWF this morning, expect some variation through the next few days on how much energy travels north/south. And finally, whilst we're on the subject of resolution, please correct me if I'm wrong but last time I checked the GEFS were running at a resolution of 55km out to 192? Well when you consider that, for example, the NAVGEM has an operational resolution of 35km, and how very little we take it's output seriously, you start to see the potential issues (in the interest of balance it should be noted that the NAVGEM issues could also be model physics related).

 

But overall the point here is not to take any output you see as gospel until towards the weekend when we should hopefully start to see some consistency between outputs.

 

SK

Edited January 9, 2014 by snowking

[shedhead]

'It's all relative' seems the most apt term this morning, because whilst the overall sense of disappointment is understandable, I  don't think one of us would have refused the overnight runs this time last week. What we've seen slowly develop across the last 24hrs is nothing more than an adjustment to the original signal, the overall pattern going forward remains largely unchanged, but it does perfectly highlight just how the MO and this forurm handle potential cold spells post T +144hrs in diametrically opposing ways.