Model Output Discussion 5/12/2012 18Z onwards - the one after THAT ECM

[Frosty.]

If one more person moans about snow potential, I think they should have a temporary ban. They are posts that keep clogging up the thread when it has been made perfectly clear that precipitation is perhaps the hardest thing to forecast, especially at this range, and the majority of the time it will crop up in the short term. The cold must come first! Jesus....

Exactly, how many people would have believed we would have seen so much snow around this week, there have been some surprise snowfalls, just imagine how much more there is likely to be during next week, and it won't be melting either. The models today have been every bit as good as yesterday from a cold perspective, infact the models have upgraded the snow potential for next week in my opinion. I can hardly wait for the freeze to start.

[Jupiters Winter]

So if we seen this T240 chart last night what would have our conclusions have been? T144 and after will see huge changes. I suggest wnjoy the refinements of reliable timeframe for now as plenty is on offer with allsorts of twists and turns right down to T48 with these sort of setups.. even in reliable timeframe.

Edited December 6, 2012 by Jupiters Winter

[Alex95]

It is also worthless looking at GFS precipitation charts for next week. They handle convective easterlies/northerlies quite badly, so if I was using them as my main tool for next week I wouldn't be that excited myself, let alone people away from the North Sea! They gave me zero precipitation yesterday, but in reality there was a decent snow event.

[phil nw.]

Well now having viewed the ECM we can see that we have good agreement on the 500hPa pattern at T120hrs which takes us to the point of the North Easterly colder air moving in with -6 to 8C uppers.-probable snow showers coming into the east.It will feel bitter.

Just an idea on what the picture may look like from 12z GFS

The surface features further on will continue to vary run to run- so as others have said including GP many times- refer to the mean outputs for the later frames for trends.

The main point is the cold block is here and will develop an NE type of pattern early next week bringing in even colder air.

The interest now is to see how this will develop through the coming days.

Once these easterlies establish we can often get minor troughs or shortwaves in the flow that can give some decent snowfalls anywhere,not just on eastern coasts.

However these little features often do not show up until quite short notice so if the overall pattern looks dry now this can easily change with time.

[Harsh Climate]

Not true, you are falling for what the GFS PPN charts are saying and they are far short of the finished article. Nobody knows what the snow risk is until very close to an event, to imagine that you can up to 204h shows a gross misreading of charts. Shortwaves, disturbances, those are not modelled at this far out. surely events from recent years tell peole that they should never rule out snow when the uppers, dew points and ground temps are good enough.

Hopefully people will have the patience to wait and see.

lol I haven't even looked at the precipitation charts, I know from experience that a good easterly with quite tight isobars (like previous 2 gfs runs) is much better than a very slack flow (like on gfs 12z)!

And who said I'd analyzed every detail upto 204h lmao, just made a brief comment on it as I'm comparing that run to the previous 2/3 and obviously when the run shows a change from blocking to zonality your going to mention it..

[Penicuikblizzard]

Big difference in the charts from last night, they could all change yet again, all in the air at present although GFS has a habit of picking up trends!!

[snowblues]

I would of thought it would be fairly normal for the models to show the atlantic trying to move in on the later stages.The models have only just latched on to the cold idear fully.There must be some atlantic signals still left over.Any way makes model watching a bit more interesting for the cold v mild battle.

[Geordiesnow]

I think the model runs are fine, there is going to be slight changes within the detail but that is expected, not every run is going to look as stella as the previous run, especially as we go through to the medium range and that is no matter what weather pattern we may have.

I like the ECM in particular in the short-medium range, the strongest easterly and very cold uppers, much less marginal that previous runs. The UKMO is a MASSIVE improvement for cold lovers compared to yesterdays 12Z output.

Although some sort of easterly flow looks likely from that low heading southwards, how long it lasts and what strength is all yet to be decided, so we may see upgrades but we may see downgrades, all part of the weather but the trend is a cold one regardless though.

I can understand why members will be disappointed that the trend from last nights ECM run has not really been picked up yet, but I don't think some members are helping themselves when they compared the potential charts to those of 62/63, 87 and 1991. Just wait and see if these charts actually verify before comparing them.

[phil nw.]

Well well.. ECM at T216 backs the GFS, with a hefty low pressure developing in the Atlantic ! But more alarmingly the arm of

Northern blocking from Scandi across to Greenland has collapsed. It just isnt there. And the Scandi High is retreating away

east into Russia on a NW/SE trajectory.. One has to say the runs today are a trend in the wrong direction, and tonights ECM

is a long way removed from the epic ECM of yesterday. All eyes on the Pub run to see if this can provide some kind of back

up to the developing trend from around 8 days out. Cold is still on the cards in the short term, albeit, the NNE winds seem to be

firming up rather than the stiff easterlies shown on earlier runs.

You are quite at liberty to comment on any chart PE but why not post on all the outputs?

You would be able to give a more balanced view on trends etc-especially if you looked at the ens means and other models apart from the GFS.

Actually the ECM T240 indicates a renewal of heights around Greenland.

Edited December 6, 2012 by phil n.warks.

[Buzz]

Worth analysing [FI charts] yes, worth taking overly seriously if unsupported no.

And there's the rub - if they are analysed and snowmageddon is 'predicted' then that's ramping, and as the charts are FI that inevitably leads to the usual gnashing of teeth and throwing toys out of prams from the inexperienced viewers when the NEXT run doesn't show such a snowfest.

I just think that it causes more problems in this already unstable thread. All analyses should be confined to within 180 hours (if that).

But this is kind of OT so I sincerely apologise to the mods - however, I feel that it IS very relevant to this thread and the various mood swings.

[dr snow]

Whilst i agree to an extent that this is the model output discussion thread and so it's fair game to discuss the models it certainly does nothing for alot of peoples blood pressures and stress levels! Think as has been mentioned previously on numerous occasions the models will change quite wildly the further we go into FI. The anomoly charts are much less volatile and for a really balanced view as ever, would suggest everyone reads John's pdf.

The GFS can be the most volatile in FI and we all know it's desire to wind up large lows in the Atlantic. As for it being a trend setter isn't it bound to be as it produces 2x as many runs as the other models? - less of a trend(perhaps apart from northerlies) and more due to more outcomes each day? Simon

[weather eater]

for those wanting a view on what upper air pattern we may be in 6-15 days from now the link below is my view on things and a stab at what the surface may show

http://forum.netweat...99#entry2435199

Excellent John and I have to say far more informative than those attempting to put over much flesh on the bones of the synoptic guess work made by model projections post 120hrs. Whether mild and wet, cold and dry or cold and snowy the 18z will be out in three hours time, it will show another evolution and another round of hype vs despair bickering will ensue . I’ve found the trick is to skim read.

Edited December 6, 2012 by weather eater

[Robbie Garrett]

Very good agreement out to the end of next week at the moment on colder weather, precipitation doesn't look great no, but then hasn't the GFS under-cooked and overcooked values before?

[Gibby]

Good evening. Here is tonight's report on the 12z output from GFS, UKMO and ECM for today Thursday December 6th 2012.

All models show a deepening depression moving quickly SE over Scotland to lie off the coast of SE England by lunchtime tomorrow. A band of rain and hill snow is marching SE over the UK currently followed by wintry showers and a switch of wind direction from West to North later in the night. Tomorrow will see a cold and strong Northerly flow with wintry showers down Northern and Eastern coastal counties. Later winds decrease from the West as a strong build of pressure moves in from the West. A dry start to the weekend is likely as High pressure close to the South settles the weather down for a while with frost at night. On Sunday and Monday cloudier weather will move down over the North and East with occasional rain or wintry showers on Monday with the weather remaining on the cold side.

GFS then shows Low pressure over Eastern Germany and the Southern Baltic at 144hrs with an increasingly cold NNE drift over the UK. Wintry showers would gradually increase in number and area as the week passes with winds turning more SE later and freshening as frontal boundaries approach from the SW with a spell of snow moving North by the weekend. FI tonight shows milder conditions steadily becoming established with deep Low pressure areas stuck over the UK bringing rain and strong winds at times with hill snow only in less cold conditions.

The GFS Ensembles show a definitive cold spell through the coming week with some snow at times for some. The operational was a warmer member than most of the pack though the slow warming trend that is shown is undoubtedly being skewed by the differential clusters of warm and cold members so could be disregarded.

The Jet Stream shows a SE moving flow continuing for the next two or three days over the UK and down into Southern Europe. By the middle of next week and beyond the main flow is directed West to East across the Atlantic to Northern Spain and on into the Med.

UKMO for midday on Wednesday shows High pressure well established to the North of the UK with Low pressure near Eastern Germany and other Low pressure to the SW. A slack but cold and raw wind from the NE or East is likely with occasional wintry showers, mostly of sleet and snow likely especially in the East.

ECM tonight shows a Low pressure cold pool near Germany at the same time point with High pressure close to the NW and way to the NE of the UK. Many areas would likely be dry and cold with a few wintry showers of sleet and snow in the East. These then extend steadily West to other areas with time turning to snow generally as they enhance. At the end of its run it looks like the UK is setting up to be the battleground for a snowy breakdown but as shown with High pressure of 1060mbs over Russia and Low over the Med the attack from the West would likely slide SE across SW districts bringing appreciable snowfall here, confirmed at 240 hours.

In Summary tonight the weather is set to turn cold everywhere. The process will be slow but constructive with the block holding firm up to the North. With that comes the chance of slider Lows off the Atlantic and cold pools drifting slowly West from Europe delivering what would be some copious snow events for some at some stage late next week. Modifications to the pattern will no doubt change over time and there will no doubt be some milder runs shown in the output but overall the pattern looks set for some time with any changes as usual with these setups looking likely to come from the SW with time. Frosts will of course be a nightly event for all inland locations through the period of this cold spell.

[snow drift]

You need to take the IMBY ism out of your posts, no one in the SE moans when you get a good run-

The ECM 240 moving onto 264 will show heights over Iceland just +VE enough to keep the trough disruption over the UK- the only real mild air is sadly for Ireland- the nearer you are to the continent the colder it is.

I will book you in for B&B at folkstone.....

S

Gosh JS you have upset him. Booked you into a Band B at Fokestone!!!!!

So Broad agreement where we are in T120 and that is good news. After, who knows? Compare run to run. Well yesterday's 12z ECM T216 and T240 look a little different to today’s!! So I Guess we can say that is still to be resolved.

Edited December 6, 2012 by snow drift

[mcweather]

Whilst i agree to an extent that this is the model output discussion thread and so it's fair game to discuss the models it certainly does nothing for alot of peoples blood pressures and stress levels! Think as has been mentioned previously on numerous occasions the models will change quite wildly the further we go into FI. The anomoly charts are much less volatile and for a really balanced view as ever, would suggest everyone reads John's pdf.

The GFS can be the most volatile in FI and we all know it's desire to wind up large lows in the Atlantic. As for it being a trend setter isn't it bound to be as it produces 2x as many runs as the other models? - less of a trend(perhaps apart from northerlies) and more due to more outcomes each day? Simon

I couldn't agree more Dr Snow. The GFS is a pretty ludicrous model in some ways. I,m not saying it can't pick up trends be they cold or mild but it churns out some much stuff that almost every day in winter you can find everything outcome from the blow torch to the siberian express somewhere in its ops or ensembles. It would be highly improved if it reduced its runs to twice a day and kept to 240 like the ECM.

[Bristawl Si]

I couldn't agree more Dr Snow. The GFS is a pretty ludicrous model in some ways. I,m not saying it can't pick up trends be they cold or mild but it churns out some much stuff that almost every day in winter you can find everything outcome from the blow torch to the siberian express somewhere in its ops or ensembles. It would be highly improved if it reduced its runs to twice a day and kept to 240 like the ECM.

Yes and is a model that the Meto do not take much notice of past 7 days i believe. That fact alone says a lot about its credibility in my view.

Edited December 6, 2012 by Bristle boy

[I remember Atlantic 252]

Never hear of CFS model mentioned on here, probably a crappy model, but shows a much better setup upto 240

[Neilsouth]

Yes and is a model that the Meto do not take much notice past 7 days i believe. That fact alone says a lot about its credibility in my view.

Are we now disputing the GFS model and using the Meto as reference, yet it was the METO which has back tracked TWICE in the last week or two?

[Bristawl Si]

Are we now disputing the GFS model and using the Meto as reference, yet it was the METO which has back tracked TWICE in the last week or two?

Erm...yes. Backtracked from what exactly?

U know as well as I that the Meto remains the UK public face of weather forecasting in the UK so have to be almost 100% sure of a weather event or forecast before publishing, otherwise they are jumped upon by people who have little or no knowledge of meterology.

[SilverWolf]

Quick question from a lurker with limited understanding, why are so many people moaning that the cold looks predominantly dry next week? Surely the models can't be fully trusted to make that call at this range - my memories of 2009/10's snowfalls is that they weren't really showing up 24 hours in advance as a definite event let alone days before? Please correct me if I'm wrong, on a steep learning curve on this forum. Thanks

[cold snap]

After reviewing the charts today I found myself doing this looking for any tiny mild hint and not even concentrating on the epic charts in front of me

It got me thinking

When the charts are very mild I look for any tiny hint of cold

Human nature I suppose ,it's all about the chase ,and never being completely sastified with the charts when, we view them we instantly draw together in are mind a better scenario ,this is what model watching is about

[offerman]

Just thought id send a pic over from here in Germany, if the charts are correct and the weather comes from the east, who knows we may get some of this later next week.

[bluearmy]

ecm and jma at day 7/8 both phase the trough to our east with the northern arm east of iceland/nw of scandi. is that likely? the energy headed further north was what was the initial indicator that the current period was not going to be as cold as initially looked possible. this time it seems clear we will have much colder air entrenched so any possible breakdown will be more 'interesting'. i'm taking note of this development in what is generally considered the early part of op fi as two models have it. nothing more than taking note. the ens sprreads on ecm this evening could be very tricky to read.

doesnt get much better than this. look at the anomaly on that high to our north and the mean 552 dam associated. will this just drift away as per some of the ops. methinks not.

Edited December 6, 2012 by bluearmy

[JCP]

All this moaning today yet we are still very much facing a cold to very cold setup get a grip people.

If people want to moan or rant about anything weather related it can be done here -

If you wish to discuss any potential snowfall this can be done here - http://forum.netweather.tv/forum/142-regional-discussions/

I am once again encouraged by the output today which get's us over that first hurdle of the sw tracking and sunk se by 90 hours which is now in the reliable and has shown no signs of taking a different route over the past few days so i can now 99% say that that is nailed on and penned in.

Beyond this is were we can potentially have a very cold setup & possibly snowy. All these details will not be confirmed until at least 48 hours time which is why there is no point in hanging on each run beyond reliability as it will change as the models firms up on what type of easterly we will see & as for experienced members stating ' Dry Run ' ect i think ' Come on how long have you been watching the models for? As you know as well as i that snowfall is unpredictable especially in a easterly flow as connectivity can often come into play'.

For those newbies out there and for those who are seeking answers regarding snowfall there is a learning facility available on n-w which is a brilliant learning tool to use & to gain knowledge.

But for the general rule of thumb you cannot tell no more than 24 hours out in this potential spell where we may well see connectivity from the east coasts then you cannot tell until it happens.

Hope that helps.

L-S

Do you have to use that font? I find it really hard to read, so just end up skipping the whole post, which is a bit of a shame.