Winter Model Discussion 06Z 10/01/13>

[Snowfan50]

Yes that seems to be a problem.

Without that even with a PV split it will be hard going to develop sustained cold, I think theres alot of uncertainty with so many features.

The PV lobe where does it drop south upstream.

The full latitudinal trough they mention , will that occur, we certainly could do with that.

The Alaskan ridge, PNA, NOAA last night mentioned that the models want to build pressure over Greenland but that this doesn't teleconnect with the pattern in the east Pacific.

Alot of questions and as yet no clear answers.

Where is the place to view the NAO forecasts?

[SMU]

ensemble watch

5,9,10,16,19,20

all move to the euros ( CONTROL IS HALFWAY)

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=102&code=10&mode=0&carte=1 10 is the best

in Summary a SWING to the euros in the 06z -

so the mean will be lower than the 00z-can someone save the London 00z & compare the 00z next to the 06z you will see...

the GFS slowley moving- the 06z isnt the best model to do that

S

[bluearmy]

NOGAPS is not flip flopping. It's the same as the 00z. Are you denying the ECM has moved toward the GFS? It clearly has. GFS is by far the most consistent now. I am not saying no chance. If the 12z has some miraculous turn around fair enough. Right now even the most biased would acknowledge we have moved toward the GFS this morning and the GFS is most consistent and frankly at 84 hrs is most likely to be right. You disagree with this. Let's see what the 12z's come up with but I really think GFS has this unfortunately.

There is a facility to compare runs on meteociel (active live compere). you can see the past few runs of nogaps have offered different solutions re the shortwave. as far as trending ecm/gfs etc etc is concerned, the ecm op has taken the shortwave further east but the ens have solidified on the op solution from last night across the uk closer to ukmo gm. to the west, i am very prepared to accept a solution from ecm upcoming which is trending more mobile and closer to gfs, whereby the undecut is further north and splits the uk re any snowline. however, if gfs trends towards the other models (which it surely will to an extent) then its atlantic mobility currently showing will look a bit different aswell. we have had these disagreements in the past at short range and no single model or group of opinions is ever right.

[johnholmes]

All models that are able to show data for T+72 here > http://www.meteociel...0&ech=96&size=2

GFS is on it's own...

I've not seen that before-could be quite useful to save/bookmark-thanks

[mulzy]

ECM Ensembles for London still cold (with op on the mild side at days 5,6 and on the cold side in FI), though a big shift to warmer when compared to last night's frigid set.

Edited January 10, 2013 by mulzy

[Tim Bland]

ECM Ensembles for London still cold (with op on the mild side at days 5,6 and on the cold side in FI), though a big shift to warmer when compared to last night's frigid set.

With the ECM ensembles trending milder and the gfs colder we could potentialy reach a halfway house soon. Im a bit confused as to what this will look like synopticaly but looks like the most likely outcome IMO

[SMU]

ECM Ensembles for London still cold (with op on the mild side at days 5,6 and on the cold side in FI), though a big shift to warmer when compared to last night's frigid set.

the reason for the mild spike is reading will be on the milder side of the front that runs through MON- if the ENS was say further east- maybe kent then that would be a lot flatter-

however ECM would need to correct west for all to see snow

UKMO is the best

S

[Bobby]

The GEFS ensemble mean is flatter again than the 00z.

Mean at +168 looking like the Atlantic is in charge

With upper means at +168 around -1c for most. Hardly cold.

I very much doubt the GFS and it's ensembles are so wrong so consistently.

Edited January 10, 2013 by Bobby

[nick sussex]

Where is the place to view the NAO forecasts?

You can look at them here but these are simply a bi-product of the GEFS rather then done separately.

So if the GEFS is wrong then the NAO forecast will be to.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index.html

[bradymk]

I just simply can't believe the lack of Greenland/Iceland heights!! Just goes to show anomalies and mjo's etc are useless.

Dont confuse anomalies with pressure, there will still be a positive anomaly over greenland because it will still be higher than normal, all anomalies are just deviation away from the mean and the mean is probably quite low for greenland so even a weaker PV will register as +ve heights

[SP1986]

All the ensembles shifting shows is the variability with each run, as you expect with a higher degree of uncertainty.. no model is moving towards this or that.

Still without a strong Greenland High anchoring the block, you will never get prolonged sustained cold, plus wiith the energy from the Atlantic pushing against the high, it's not going to be a simple as 'here's the easterly'.

It will take something pretty amazing to deflect the energy from the Atlantic, for example a strong Greenland high.. if that's not there the energy will just simply ride over, eventually flattening the high.

The GFS for me is on the right track, unless it develops a more substantial block. Even the euros don't have anything I would deem a substantial block.. but maybe that will develop in later runs.

[SMU]

THE GFS MEAN is useless in this diverging pattern.......

S

[nick sussex]

The GEFS ensemble mean is flatter again than the 00z.

Mean at +168 looking like the Atlantic is in charge

With upper means at +168 around -1c for most. Hardly cold.

Very much doubt the GFS and it's ensembles are so wrong.

The problem with means in this situation is that you will get some dilution, because of the situation you will get energy over the top or underneath, little in between hence you could have a half way split between a ridge to the north, or one to the south which will skew the mean.

You're better off in this situation looking at each ensemble member.

Edited January 10, 2013 by nick sussex

[Weathizard]

ENS at 120 are a complete and utter shambles, useless. Can't believe we still have no idea where this is heading, mad.

PTB20 is nice.

Edited January 10, 2013 by Weathizard

[bradymk]

My take on this morning, an improved GFS ensemble situstion regarding the SW and like Steve said more on the 6z support the euro models solution and i think this will continue on the 12z. UKMO the best today and this has the highest resolution of all models up to t+72. At the moment, ECM not so good but still good, wouldnt take a big shift west and south to make it another very snowy run for everyone. I think we are moving towards a middleground situation here so still a cold week for me next week but maybe not as cold as it has been showing, both GEFS, ECM and CFS highlighting potential again for something even colder later but we need this fight off to be sorted first. Just like to add, Simon Keeling who I do rate highly is leaning towards the GEM today as he thinks it handles the ridge in the atlantic better. PS Matt H on the Full EPS suite "The other 40 members between Tue-Thu of next week either show a 'slider low' or the bulk of the members (21) show an E or NE'ly flow."

Edited January 10, 2013 by bradythemole

[johnholmes]

Dont confuse anomalies with pressure, there will still be a positive anomaly over greenland because it will still be higher than normal, all anomalies are just deviation away from the mean and the mean is probably quite low for greenland so even a weaker PV will register as +ve heights

Yes Adam you need to do some reading on what the anomalies actually show-used correctly and carefully they give a far more balanced view of what the upper air may be in the time scales involved. With reservations that goes for the MJO output as well. I do urge you to read up rather than discount them.

the post from me is directed to adamufc I think is the name NOT brady

Edited January 10, 2013 by johnholmes

[nick sussex]

Yes Adam you need to do some reading on what the anomalies actually show-used correctly and carefully they give a far more balanced view of what the upper air may be in the time scales involved. With reservations that goes for the MJO output as well. I do urge you to read up rather than discount them.

John what do you think of those comments from NOAA re the upstream pattern that I posted earlier.

It's looking very complicated!

Its on page 6 by the way.

Edited January 10, 2013 by nick sussex

[SMU]

last one from me before the 12s

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=0&code=5&mode=0&carte=1

middle ground solution- look how much snow there is

S

[Supercell 89]

I'm sorry but i'm not buying this 06z run at all from the GFS. Its throwing another wobbler like it did the other day, before it changed back to a colder pattern.

I don't think it will be cold Armageddon next week but nor do i think there will a full Atlantic onslaught but will be more in the middle, staying cold but turning unsettled at times maybe temperatures returning to near average values particularly further west and south. I do wonder if one of the reasons for the major changes from day to day is the GFS being to progressive in trying to bring in a breakdown then having to backtrack before trying to bring in another breakdown, i know its obviously trying to model other features as well but i can be to progressive even with cold charts for its own good sometimes.

Edited January 10, 2013 by Supercell 89

[Bobby]

The problem with means in this situation is that you will get some dilution, because of the situation you will get energy over the top or underneath, little in between hence you could have a half way split between a ridge to the north, or one to the south which will skew the mean.

You're better off in this situation looking at each ensemble member.

I look at both and combine the two to get a general picture of what the ensembles are saying, generally gives a good idea of where things are going in my experience.

[Cloud 10]

The GEFS ensemble mean is flatter again than the 00z.

Mean at +168 looking like the Atlantic is in charge

With upper means at +168 around -1c for most. Hardly cold.

I very much doubt the GFS and it's ensembles are so wrong so consistently.

The same could be said for the ECM ensemble mean at the same timeframe.

[SnowBallz]

Hi Folks

A quick question from another lurker and newbie to the model thread! Would it be fair to say that if we are, as Ian F has alluded to, in an unprecedented situation, and we were to see, say a repeat of a winter like 1947, that this would be the first time our supercomputers have modeled such a situation and therefore we should expect to see discrepancies? Or should we expect better given the monies invested?

Apologies mods if this is deemed off topic!

Cracking thread, but all this info takes some digesting and getting used to, not sure if I'll ever get a complete grasp of it!

I would say that's boils down to the sheer matter of probability.

The governing algorithms will have a set of values that influences synoptic probability, in much the same way that you'll need to instruct an algorithm as to how the Earth rotates on its axis, and therefore what the prevailing (W~>E) pattern is. There'll then be thresholds which adjust prevailing probability, based on phenomenon such as SSWs.

However, I think understanding of SSWs themselves perhaps isn't established enough yet. In order to accurately mathematically model, using computational fluid dynamics, you'll really need to be quite sure of the data relationships involved, as - in an algorithm - if there's a high degree of doubt, it'll exponentially spoil. I would imagine that the boffins at Reading (ECMWF) are busy running developmental code, which would layer phenomenon such as SSWs into the operational algorithm. But there really does need to be a lot of research done into cause:effect, before you unleash a variable which - potentially - is very influential.

I wouldn't say it's so much a matter of money, but more a matter of scientific knowledge and geophysical understanding. Some of these relational processes and phenomenon are relatively new, and it takes time to carry out the proper audit of their scientific plausibility. What is important though, is the supercomputing ratio between Operational and Development. My understanding is that ECMWF are really exhausting their Developmental capacity, as Operational introduces more and more variables - net result being: less time to test and develop code. Ideally, you'd want a 70:30 ~ 80:20 split, but apparently it's now at a fairly critical 90:10.

All of that points to a fairly major upgrade in supercomputing power in the very near future, and - considering the high degree of success of ECMWFs NWP models - they make a very strong case for it. The JMA invested a staggering amount of money recently in a new supercomputer, and that's partly as to why UKMO have a high degree of respect for them, aligned to the fact that it runs the UK-UM base platform. The next UKMO upgrade is circa. 2015, and I wouldn't be surprised if there was even closer tie-in with ECMWF when this comes about.

Hope that's helpful?

SB

[Wadey]

last one from me before the 12s

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=0&code=5&mode=0&carte=1

middle ground solution- look how much snow there is

S

where would most of the snow be for according to that chart still learning

[chris78]

All the ensembles shifting shows is the variability with each run, as you expect with a higher degree of uncertainty.. no model is moving towards this or that.

Still without a strong Greenland High anchoring the block, you will never get prolonged sustained cold, plus wiith the energy from the Atlantic pushing against the high, it's not going to be a simple as 'here's the easterly'.

It will take something pretty amazing to deflect the energy from the Atlantic, for example a strong Greenland high.. if that's not there the energy will just simply ride over, eventually flattening the high.

The GFS for me is on the right track, unless it develops a more substantial block. Even the euros don't have anything I would deem a substantial block.. but maybe that will develop in later runs.

This to me seems a very important point...none of the output has what you could call a rock solid block.....as we know blocked patterns are hard to come by (sometimes very hard) wouldnt it be the sensible bet to assume we wont get a strong enough block this time either......surely when there is so much uncertainty and possible outcomes being shown only a nutter would back the cold snowy one....its hardly our default weather is it?

[Rocheydub]

I look at both and combine the two to get a general picture of what the ensembles are saying, generally gives a good idea of where things are going in my experience.

But there is NO middle road with this Bobby...

It either goes over the top, or underneath...both with very different outcomes.