Model Output Discussion - 8th December Onwards

[Methuselah]

Another success for the Met-men? Haven't John Holmes, Ian Ferguson and OldMetMan been suggesting just this scenario, for some time?

[Uncle_Barty]

Well the baggies managed the great escape several years ago in the prem, why can't we see it in the models??! After all they decided to snatch this away from right under our noses without warning. Why can't it do it again? After all , what the models are hinting at this morning is more in line with the teleconnections and strat conditions, along with fitting the bill within gp's forecast.

Sums up the models at the moment - boing!! boing!!

I still remain unconvinced - of anything - right now; whatever any individual model run might suggest...

This.

Whatever happens, nothing in the models suggest anything other than turning milder in the South. Likely to be rain right from the off IMBY, just hope for the sake of those a serious flood risk that things continue to back away as they seem to have done over the past 2-3 sets of output.

[OldMetMan]

Another success for the Met-men? Haven't John Holmes, Ian Ferguson and OldMetMan been suggesting just this scenario, for some time?

Hi Rybis, I did think it would be possible because of the uncertainty over the strength and direction of the Atlantic southern jet. GFS appears to be mostly out on its own so far today with the UK Met inclining the same way.

Having said that, what's the betting it will flip back to it's previous ideas in subsequent runs today?!

By the way, I would still like to know whatever happened to the model thread we were using before this one yesterday which seems to have mysteriously vanished. I see that the mods have been archiving so could you please throw some light on it mods?

Thanks.

[nick sussex]

FI is at T-72hrs!

You can see here too much phasing with shortwave energy near the UK and its much harder to develop enough energy going se.

[bluearmy]

Well the 06z op hasnt swung the penulum any furrther as it gently drifts back to where we probably expected it to be when we went to bed last night. One run - just like the 00z.

[Davey80]

The whole thing is stuck from 102hrs so far. Massive massive tight low much further west by hundreds of miles and a stronger russian high. Neither will give in.

We may have southwest winds for a few days but a slight turn to the Southeast from a freezing europe will change the weather type very quickly.

Seems like my suspicions were right like night with the turnaround and airflow becoming more southeasterly

[UV-RAY]

This mornings models have a 78/79 look to them, undercutting lows and any mild struggling to push North. I'm still far from convinced that this will actually happen, as my opinion on how models handle cold blocks is, "they don't".

[Methuselah]

Hi Rybis, I did think it would be possible because of the uncertainty over the strength and direction of the Atlantic southern jet. GFS appears to be mostly out on its own so far today with the UK Met inclining the same way.

Having said that, what's the betting it will flip back to it's previous ideas in subsequent runs today?!

By the way, I would still like to know whatever happened to the model thread we were using before this one yesterday which seems to have mysteriously vanished. I see that the mods have been archiving so could you please throw some light on it mods?

Thanks.

'Morning OMM. You could well be right about that. What are the odds against any particular digital solution being the right one, do you think?

Don't know the history behind yesterday's thread, though - I was away in the Land of Nod, by then...

[Cloud 10]

Well the 06z op hasnt swung the penulum any furrther as it gently drifts back to where we probably expected it to be when we went to bed last night. One run - just like the 00z.

It looks better when compared to yesterday's!

yesterday's.. today's..

And this is the 06z...

@Oldmetman

Regarding yesterday's thread,i fear it has been consigned to cyberspace as there was lots of

toys been thrown out of prams which resulted in a very good poster deciding not to post in

the model thread anymore because of the cold bias in here,which is a damn shame in my view.

Edited December 9, 2012 by Cloud 10

[Mucka]

Look's like a few have got the day after the night before out of their systems this morning and a more positive mood is sweeping through the forum.

Steve back to himself as well which is always good stuff.

I missed Yesterdays dramas but read a post stating Ian wasn't posting anymore, that would be a real shame.

The thing is the Pro's must surely realise there is a cold bias on forums such as this and though we all enjoy discussing the weather, model output and technicalities we are mostly big kids at heart looking for extremes, especially snow and they themselves for all their added knowledge and access to extra information come to places like this and twitter because they are enthusiasts too. So I think it is unrealistic to expect a whole forum to modify its behaviour toward a more restrained and moderate approach and better just to roll with it and see it for what it is - hopefully Ian will have second thoughts and be back posting soon if indeed he ever said he wasn't going to.

I've been blathering on about the breakdown being over progressive since it was first modelled and that although warmer air would get in, the far NE would possibly hang on to below average temps, at the surface at least, and that there was a chance of colder heading back in from the NE some 5-7 days after the breakdown of cold with blocking attempting to re-establish itself to our North. We have seen some progress in that direction from the models today but I'm not convinced the models are "flipping" - just moderating the signal for the breakdown.

One thing I have learned is that when the models pick up a new signal they always over cook it at first and slowly refine it to something slower and less dramatic as the time nears whether that is for cold or a breakdown or a storm. Actually if we take note we will see the models show uncommon scenarios far more frequently than they actually occur. Seems obvious but worth bearing in mind when we are looking out beyond 120.

I would say don't get too hung up on what the output shows today and this evening but take note of tomorrow evenings output, that will be close to the correct solution as far as the breakdown goes. Hopefully we will all see at least some transient falls of snow/

Edited December 9, 2012 by Mucka

[Summer Sun]

No one can argue this morning that the past 24 hours have saw some changes from GFS

06z yesterday morning for the 14th

And this morning's run

Now maybe its just delaying the inevitable but the north (NE England and Scotland) is in a much better position for a snowy end to the week than we were 24 hours ago

[Frosty.]

This mornings models have a 78/79 look to them, undercutting lows and any mild struggling to push North. I'm still far from convinced that this will actually happen, as my opinion on how models handle cold blocks is, "they don't".

I have a feeling that whatever this run ends up showing, from the 00z's it wouldn't take much of an upgrade for widespread disruptive snow in the second half of the week with increasing amounts of undercut. It reminds me of the days before the internet when we could only rely on the bbc forecasts and sometimes when they said the outlook is turning milder, it would then change to becoming less cold and then staying cold. We could be witnessing a major model wobble now and then a change back to a cold outlook with snow and severe frosts.

[Isolated Frost]

Anyone seen the GEFS 00z suite? 120 looks positively snowy for many NEern parts, as well as many higher central parts; can't post charts as on mobile.

ECM ENS looks pretty similar but moves the trough belt NEwards leading to a mean west/north-west flow over southern parts. Another positive NW-SE tint of the jet axis- expect a similar scenario to the GFS 00z op which ejected an undercutting shortwave-

Don't get too hooked up on the Ops- your ensemble means are the best bet taking a large scope of possibilities..

[TEITS]

Don't get too hooked up on the Ops- your ensemble means are the best bet taking a large scope of possibilities..

Normally I would agree with you but not in this case. The situation we are currently in is likely to swing quiet wildly in my opinion and the Ops will lead the way. Also the ensembles will probably be split between some showing undercutting and others like the ECM. When you have a split like this the ensemble mean looks like neither clusters being shown.

[Methuselah]

This mornings models have a 78/79 look to them, undercutting lows and any mild struggling to push North.[...]

I think that you are right enough there, 7...And, going back further still, '78-'79 was very reminiscent of the 1960s; slider lows could, and did, turn up at the last minute - rain even reverted to snow on several occasions, and transitions were not always straightforward...IMO, computer models cannot easily visualize scenarios like this because they lack (for want of a better word) fuzziness...

[nick sussex]

It really is incredible the difference made by the phasing in terms of the 850's.

Quite unbelievable that for modern day models with their computing power and we have a situation where the outputs can't be trusted within T-72hrs!

[TEITS]

Obviously the 06Z does not want to send energy SE but if you flick between +96 and +144 you will see the HP to our E is actually backing W and slowly winning this fight.

http://modeles.meteo.../gfs-0-96.png?6

http://modeles.meteo...gfs-0-144.png?6

In these situations if the HP continues to back W then eventually you will see the undercut, its just a case of when!

Starting to happen.

At +162 the 06Z is actually better than the 0Z!

Edited December 9, 2012 by THE EYE IN THE SKY

[bluearmy]

Just a note - ukmo runs at very high res out to T72. I would take its T72 ahead of anything else. Thereafter, its lower res than gfs op so you get the picture re the post T72 charts.

[Isolated Frost]

Normally I would agree with you but not in this case. The situation we are currently in is likely to swing quiet wildly in my opinion and the Ops will lead the way. Also the ensembles will probably be split between some showing undercutting and others like the ECM. When you have a split like this the ensemble mean looks like neither clusters being shown.

That is a fair point but the clusters often will highlight the extremes and the ens mean will gauge the overall feeling quite well- the det has been swaying erratically and you have to urge real caution upon it- I'm not saying disregard the Ops but I am saying that in such a climate (no pun intended), we must look at the broad picture

[nick sussex]

I'm really not liking the look of these shortwaves developing, from a purely IMBY perspective I'm beginning to get visions of another storm!

[Frosty.]

All I know is, the models this morning are a lot more encouraging for at least a real battle than they were 24 hours ago, yesterday it looked like the atlantic was going to sweep in with no fuss, but now it looks like the cold block is up for a fight and it already looks like it will be battleground uk with heavy snow and drifting for some, maybe all of us if the upgrades continue.

[Snowman31]

the channel low is back again

[Davey80]

I think during this current situation we can gain a much clearer outlook by listening to the pros and looking at history in these blocking situations rather than relying on computer models. There is a trend now for cut of lows to develop to the south of the main low later this week, surely that is an indication the whole thing is going to slide under. Yes milder air may mix in for a few days but the block will be gaining in intensity all the time

[dragan]

yes, i believe that is a channel low?

[Jason M]

Just a note - ukmo runs at very high res out to T72. I would take its T72 ahead of anything else. Thereafter, its lower res than gfs op so you get the picture re the post T72 charts.

Didn't realise this. People should take note because it helps explain why meto 144 charts are generally not great.