Model Output Discussion

[Iceberg]

to be honest Ice its not too clear just how much precip there is going to be-based on GFS very little-based on Met then maybe rather more-I'm reluctant to post saying much as some will mis read it and think lots of snow!

I'm waiting to really make my mind up for how the 12z deals with later in the week, all 3 models that is

not ducking the issue-just not totally sure of how the end of the week is going to pan out.

Cheers John, like you I am unsure, IF it came off as per the METO and ECM then fantastic, but the GFS not agreeing is a bit of a nag, hopefully the 06Z will come round more and there will be more support/agreement on the 12Z for wed/thur/fri (it is after all not that far away now ! )

[West is Best]

Fabulous runs from all 3 main models. Not remotely worried about a GFS breakdown at T200+. What a great week ahead cold lovers have looking at these models! The pick is clearly ECM, but the others are tasty too.

[TEITS]

After viewing the models this morning I nearly leaped off my chair in joy they are that stunning. I shall explain exactly why that is.

Ever since this cold spell emerged i've always said that if the ECM disagreed with the GFS then I would look at the UKMO and see which model it supported. Now this morning the UKMO definately trends towards the ECM which in my opinion is excellent news. Furthermore the UKMO would bring joy to many locations as I shall explain.

http://www.wetterzentrale.de/pics/Rukm1201.gif

http://www.wetterzentrale.de/pics/Rukm1441.gif

The +120 shows a ESE,ly which would bring snow showers especially to NE England/ E Scotland especially on higher ground. However the +144 chart is a peach of a run for E Anglia/SE. Now I do not know why some refer to this as being dry because let me tell you I don't need a model to tell me showers would develop from this. If the UKMO +144 verified you would see heavy, prolonged snow showers giving some very large snowfall amounts, especially E Anglia, Lincs, SE, E Midlands.

Beyond the E,ly and the cold spell continues although im not going to focus on that at the moment.

Overall this morning the runs are excellent. We still have some way to go yet and next weeks E,ly could still change. However the trend is much better today than yesterday and lets hope this continues.

[Polar Continental]

Well quite a debate this morning on which model has this easterly programmed correctly. The overall evolution on the ECM is a dream, and I would love that to verify.

To be honest though, I am tending to agree what TM and John have said this morning, with the GFS solution, mainly because this is what we have come to expect from our easterlies over the last 15 years or so. I really hope that the ECM is right though, and I would be so happy to be wrong in my thinking. Fingers crossed eh.

Having said all that, the GFS is still good for cold, but not some much for snow.

[johnholmes]

hi Sn1

IF the operative word being IF the models are correct then snow showers possibly even spells of snow are likely but that is why I am holding off for the moment-precip charts, as I know to my cost trying to get Watches and Alerts out, is notoriously difficult to pin down both amounts and where. Snow adds several other dimensions to it, will it won't it etc.

Most of the parameters show +ve for snow but its the precip occurring we need, and more than slight.

I'm out for much of the day but will be back to update my blog this evening and will do my best to give a constructive take on what seems most probable.

Edited December 13, 2009 by johnholmes

[Snowstorm1]

hi Sn1

IF the operative word being IF the models are correct then snow showers possibly even spells of snow are likely but that is why I am holding off for the moment-precip charts, as I know to my cost trying to get Watches and alerts out, is notoriously difficult to pin down both amounts and where. Snow adds several other dimensions to it, will it won't it etc.

Most of the parameters show +ve for snow but its the precip occurring we need, and more than slight.

I'm out for much of the day but will be back to update my blog this evening and will do my best to give a constructive take on what seems most probable.

Thankyou very much John i will read your blog this evening! Lets hope gfs follows the ecm!

[Iceberg]

GFS out in the next hr so lets see if it follows GFS/ECM at the 72 to 144 range. Personally I am thinking it will back track somewhat towards them.

[Snowyowl9]

After viewing the models this morning I nearly leaped off my chair in joy they are that stunning. I shall explain exactly why that is.

Ever since this cold spell emerged i've always said that if the ECM disagreed with the GFS then I would look at the UKMO and see which model it supported. Now this morning the UKMO definately trends towards the ECM which in my opinion is excellent news. Furthermore the UKMO would bring joy to many locations as I shall explain.

http://www.wetterzentrale.de/pics/Rukm1201.gif

http://www.wetterzentrale.de/pics/Rukm1441.gif

The +120 shows a ESE,ly which would bring snow showers especially to NE England/ E Scotland especially on higher ground. However the +144 chart is a peach of a run for E Anglia/SE. Now I do not know why some refer to this as being dry because let me tell you I don't need a model to tell me showers would develop from this. If the UKMO +144 verified you would see heavy, prolonged snow showers giving some very large snowfall amounts, especially E Anglia, Lincs, SE, E Midlands.

Beyond the E,ly and the cold spell continues although im not going to focus on that at the moment.

Overall this morning the runs are excellent. We still have some way to go yet and next weeks E,ly could still change. However the trend is much better today than yesterday and lets hope this continues.

Great post and yes excellent UKMO this morning a much longer spell of E-lys.

Fax chart will be changing again after last nights.

http://91.121.93.17/pics/brack2a.gif

[Altostratus]

There is no reason to be despondent this morning. The ECM and UKMO are excellent, with snow over many parts of the country. Could even be some heavy falls in the south were these runs to verify. The details of this will invariably change between now and then, but it will certainly be turning much colder and it is looking increasingly likely that at least some snow will fall later this week IMHO. Too early to say where exactly, but if eastern parts of the country receive nothing out of this cold spell I will be very surprised.

You have to side with the ECM and UKMO over the GFS in this situation. It would take a very brave person to side with the GFS. The GFS looks to be back to its usual trick of being over-progressive IMO. I could be proved wrong; if that’s the case, kudos to the GFS.

[Shunter]

NOAA highlighting poor run 2 run model consistency in their early morning discussions. They are favouring the ECM current solution for the US though.

http://www.hpc.ncep.noaa.gov/preepd/preepd.html

[TEITS]

ECM control run is even colder than the operational!

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

Back to the GFS and if this is going to trend towards the UKMO/ECM don't expect this to happen in one run. I have found in the past that if the GFS does trend towards the Euros then its a slow backtrack with each consective run.

As the period in question is between +96/+120 I don't expect this to be resolved until tomorrows 12Zs. However lets hope the Euros remain with this trend because the longer they do the more likely the GFS will backtrack.

[Terminal Moraine]

Sorry TM, have to disagree with the last bit, Meto and ECM are showing alot of instability for Thursday, with LP moving across the south, GFS is the only model giving little snow come the end of the week.

Cheers

Yes,Ice, I was hedging my bets a bit with that low, waiting for a few more runs to see how much model agreement there was on its track and intensity. GFS hardly shows it at all whereas the Meto in particular have it as a much more developed feature.

There is certainly the potentital for some snow in the south from this and I wouldn't want to be in John's shoes in deciding when, or if, to put out an alert.

All eyes on the 06z.

[kold weather]

The GFS is subtly different again in FI this morning, the results are still the same due to the massive low it pumps up in the Atlantic, but the orientation of the jet is different upto 228hrs and if the northern block holds for longer and if the Atlantic low is weaker, AKA ECM then we won't be quite so quick out of this pattern as the GFS would have us believe.

On a personal level, the 0z UKMO would be great as would the 0z ECM for just the sheer length of the cold spell, the ECM would have us locke din cold till xmas thats for sure.

The key as always is to watch what the upper high does over Greenland, simply put the longer it stays, the better for the UK.

[PB22]

ECM control run is even colder than the operational!

http://www.knmi.nl/e...E_06260_NWT.png

Back to the GFS and if this is going to trend towards the UKMO/ECM don't expect this to happen in one run. I have found in the past that if the GFS does trend towards the Euros then its a slow backtrack with each consective run.

As the period in question is between +96/+120 I don't expect this to be resolved until tomorrows 12Zs. However lets hope the Euros remain with this trend because the longer they do the more likely the GFS will backtrack.

Hi Dave, hope you are well.

Already plenty of showers coming in off the North Sea here this morning, so people don't need to worry about precipitation amounts as that will come naturally if we can get the easterly up and running.

I totally agree with your sentiments about GFS and a possible trend towards UKMO and ECM, it will tend to happen over the course of a few runs...from my experience of doing the model summaries, I found that if UKMO and ECM are painting a similar picture, then GFS usually follows. Not to say it will happen this time, but I'd rather have UKMO/ECM showing what they are showing this morning than the GFS on its own.

Another thing I would add is that the ECM ensembles seem to have a better handle on the early part of this week, whereas GFS still has some wide scatter, so I would suggest that ECM may be better placed to predict what comes next...

[weather eater]

Once again we're looking forward for decent cold. The easterly is looking good but considering what we could have got (and I'm sure we would have got 20 years ago) it's nothing special.

I doubt it in mid December, I'm not sure I've ever seen a set up like this in mid December. The overall trend is good this morning ECM and UKMO excellent, why dont we see how things develop and evolve then we can have the inquest afterwards. As a long term poster OP you should know better than to jump on the upgrade, downgrade merry-go round method of model watching. I understand that past disappointments can colour the thinking, we all do it, but you have to put the here we go again feelings out of your mind and treat any new situation on its own merits.

Edited December 13, 2009 by weather eater

[Duane S.]

Having watched the models inthe following order, GFS, ECM, METO I have to say I went from a bit dejected to very pleased to absolutely delighted. Shame they are just models projecting the future but if the ECM and METO (& I'm glad it's these two) are onto something then some serious fun and games to be had towards the end of next week.

I'll feel more confident if the 06z can trend, even a little bit, towards the Euros this morning though.

[TEITS]

but I'd rather have UKMO/ECM showing what they are showing this morning than the GFS on its own.

Quiet agree mate.

I always appreciate your views on the models because not only do you provide a balanced view but your experience with the models is invaluable.

I strongly urge members to follow Paul B posts on this thread. Last night it must of been very difficult for new members to understand what the hell is going on. So with this in mind stick with Paul B, Nick Sussex, Steve M, John H.

Speaking of Steve M are you still doing a model tracker?

[kold weather]

As TEITS mentioned erlier in this thread, usually in situations where things are uncertain between the GFS/ECM you can use the UKMO as a sort of middle ground. I tend to find that whatever situations its supporting gives more confidence to the other models solution. Whilst this doesn't always work out, its a good guide usually.

Also a quickie on precip, the models never seem to get a good indication of how snowy its really going to bre till generally 48-72hrs out, I've seen times where the models have been horribly on the low side of what has actually occured.

[PB22]

There are still differences as soon as T+72 over the handling of this shortwave coming down Tuesday night/Wednesday.

ECM 00Z has it centred somewhat further east than UKMO and GFS, whilst there is little to choose between the UKMO 00Z and GFS 06Z:

http://www.wzkarten.de/pics/Recm721.html

http://www.wzkarten.de/pics/Rukm721.html

http://www.wzkarten.de/pics/Rtavn661.html

[Bristawl Si]

Interesting model runs this morning, after yesterday evening's 'frustrations' for some.

Has anyone else noticed how the models seem to predict scenarios a week+ before the actual date, then backtrack, but as we get nearer that day (let's say this Thursday coming, as an example) the models 'go back' to what they were predicting originally for that date? Get that? No, i didn't think so.

OK, here's another stab at it - Last Wednesday 9th the models were predicting a real easterly blast, fair bit of snow for Friday 18th, Saturday 19th, but then over last couple of days backtracked slightly - now they seem to get nearer to what they were originally forecasting the closer we get to those days.

[TEITS]

I doubt it in mid December, I'm not sure I've ever seen a set up like this in mid December. The overall trend is good this morning ECM and UKMO excellent,

Indeed WE and this I feel is being overlooked.

This is a stunning set up for Mid Dec. If members checks the archives, with the exception of 1981, you wouldn't find many other set ups like this one at this time of year.

The reason is simply down to the strength of the jet. You will find that blocking has always been most frequent in Feb/March which is why blocking rarely develops in Dec. Infact I have a weather book that was written in the 1940's and in this book the author mentions that snowfall is more likely in April than Dec. This I would agree with!

[Duane S.]

Interesting model runs this morning, after yesterday evening's 'frustrations' for some.

Has anyone else noticed how the models seem to predict scenarios a week+ before the actual date, then backtrack, but as we get nearer that day (let's say this Thursday coming, as an example) the models 'go back' to what they were predicting originally for that date? Get that? No, i didn't think so.

OK, here's another stab at it - Last Wednesday 9th the models were predicting a real easterly blast, fair bit of snow for Friday 18th, Saturday 19th, but then over last couple of days backtracked slightly - now they seem to get nearer to what they were originally forecasting the closer we get to those days.

Yes I understand what you are saying and yes I agree with you. It does seem to often happen that models will pick up a trend early on, go a bit haywire in the mid-term then pick up on what it was predicting prior, as we get towards a more reliable time-frame.

Edited December 13, 2009 by s4lancia

[PB22]

Interesting model runs this morning, after yesterday evening's 'frustrations' for some.

Has anyone else noticed how the models seem to predict scenarios a week+ before the actual date, then backtrack, but as we get nearer that day (let's say this Thursday coming, as an example) the models 'go back' to what they were predicting originally for that date? Get that? No, i didn't think so.

OK, here's another stab at it - Last Wednesday 9th the models were predicting a real easterly blast, fair bit of snow for Friday 18th, Saturday 19th, but then over last couple of days backtracked slightly - now they seem to get nearer to what they were originally forecasting the closer we get to those days.

Yes, this tends to happen quite often, more so than people think. All part of the rollercoaster ride that is model watching!

GFS 06Z out to T+102:

http://www.wzkarten.de/pics/Rtavn1021.html

I'd say an easterly now for the end of the week is more or less nailed on now. Details such as intensity, etc will be determined over the next few days.

[Neilsouth]

Hi all , how is it looking this morning? are we still on for an easterly?

Sorry just woke up , overslept after a rough night

[Lewis]

Hi all , how is it looking this morning? are we still on for an easterly?

Sorry just woke up , overslept after a rough night

An easterly by a majority of the models, the latest 06z GFS rolling out now, downgrades the easterly again, and shunts everything back east and south, and it's more like a SSErly than an easterly, still blooming cold though mate.