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

[phil nw.]

Happy New Year to you all.

 

Here we are then a new thread for the new year.

 

No clear sign of a pattern change yet but the later ECM and 06z GFS starting to favour some heights towards Scandinavia.

It will be interesting to see how the 12z runs deal with this.

 

In the meantime more wind and rain from this relentless train Atlantic lows and fronts with only brief breaks.

 

The usual requests for on topic and friendly exchanges.

 

Thanks all.

[Summer Sun]

The latest NAO update remains unchanged with it staying around neutral for the first half of this month

 

 

The latest AO update has it flipping between negative and neutral for the first half of this month

 

[SnowBallz]

Loosely model-related - I suppose - but I thought I'd share with you all that I was talking to a colleague a few weeks ago about, amongst others things (like the mid-seasonal prognosis) rather bland stuff like NWP model performance.  That, in part, came from discussion around what the likely improvements would be when GFS receives its major overhaul in April 2014.  For quite some time, it is acknowledged that the performance of the GFS has been - relatively speaking - disappointing, and there's been a lot of discussions around why - for instance - verification is consistently behind, primarily, the ECMWF suite.

 

I wasn't aware until recently, but but an experiment was carried out not too long ago into why this under-performance was evident.  It is worth noting that NOAA attribute a great level of professional respect to their peers at ECMWF, and so enlisted their help to review and breakdown GFS.  What was found was extremely interesting.  The model itself, ie: GFS and its ensemble compatriot, GEFS, behave in very similar ways to that of the ECMWF model.  So, in that case, why do they differ?  Well, interestingly, it all depends on the initialisation data - and not so much on the algorithms.

 

How was this proven?  Well, in very basic terms, ECMWF masked across a set of their initialisation data - so that it would fit with the GFS criteria - and waited to see what would happen to the output.  Unexpectedly, the verification of the output was consistently almost 10% higher than the GFS running average.  In short, it proved that the performance of GFS isn't so much about the model in terms of mathematics or its physics, but more the depth and variety of the data which is currently being applied to it.

 

It will be interesting to see how the 'new GFS' operates in the Spring.  It will enact considerable upgrade to the definition and layering within the current model.  It's taken them 18 mths to synchronise initialisation of the 'new' model with the 'old' one, but as far as I'm aware, they both run completely in parallel now.  This is ahead of the NOAA's complete refresh of their supercomputing capability in 2015, which I hear will break new ground, with some talk about harnessing the cloud; pooled computing, that sort of thing.  I'm sure more will leak out through 2014, so keep your eyes peeled.

 

Finally, I would like to wish a very Happy New Year to you all!  I do hope that, while extreme weather brings interest to us all, that we are saved the disastrous effects that we've all witnessed especially over the last couple of months.

 

And with that, it's time for a drink (...or two, possibly three)

 

SB

[Summer Sun]

GFS 06z ensembles continue to show rainfall easing during the latter half of next week, looking at the 850's they don't look too far away from average out to the 17th

 

[Neilsouth]

It's nice to see an interest in the models even if we are still unsure which way we are going with the weather. I think a lot of people are kind of blinded by the fact that our previous winters have had some form of very cold weather pre christmas or at the least very frosty weather. Savour the fact that the 90's had temps up to 15C during the wettest spells, I haven't seen a 15C with rain for a very long time. To be honest I'm also glad that we are getting all this wind and rain now, rather than starting middway through jan atleast we have a high chance of atleast one bout of snowfall through the next three months

 

The pattern will change just look at all the signs that the experts have been posting!

 

Atleast if it does turn much colder, we've got plenty of wet ground to slide across

[bluearmy]

in relation to SB's post above, if NOAA took the results of the experiment seriously, then I guess they will be doing something re the data input. (I'm sure I heard this type of anecdote before re the starting data of ECM v gfs). I wonder if sylvan can enlighten us as to when we might see the parallel on meteociel??

[Frosty.]

Great to see the chances of a more wintry second half to January are firming up more and more, I really couldn't understand why there were comments yesterday saying there was no sign of cold...anyway very encouraging met office update for coldies, The more wintry tone is not that surprising because the GEFS mean has been looking progressively colder by mid month for a few days now..what a promising start to the new year, we might get our snow fix in a few weeks.

Edited January 1, 2014 by Frosty.

[lassie23]

New years eve was model watching doom, all of a sudden we have hope from the scandi high and an upgrade in stratospheric warming. Woohoo!

[Stuie]

What sort of ridge is this!?

[Frosty.]

 

 I hear will break new ground, with some talk about harnessing the cloud

 

 

 

I hope they can invent a snow making machine for the whole of the uk between dec - march after they harness the clouds

[Ali1977]

What sort of ridge is this!?

A good one ....

[MR EXTREMES]

has the ukmo got a problem with its later data ?

[Stuie]

A good one ....

 Shame the ECM is on its own with it. The GEM sort of goes for it.

[Weather Boy]

A good one ....

Or out another way, a Steve Murr sausage!I have been surprised at how slowly the models have reacted to evident changes not just in the strat but in the troposphere around the pole. However, I ought not to because in my few years' experience of model watching they often seem to be uncertain, contradictory and inconsistent when a change is coming, especially a strat induced one.It seems to me that, judging by the models' behaviour, some kind of change is inevitable. Only minor questions such as when and a change to what remain! It seems highly likely to be colder conditions with a more continental rather than Atlantic flow. However, in our position adjacent to the ocean, it could easily be a 'close but no cigar' situation, or it could be the start of a very significant, even famous, cold spell, or of course somewhere in between.At this range it will be some while before we can discern which scenario is more likely.

[Mucka]

has the ukmo got a problem with its later data ?

 

 

Possibly 

 

I can't get ECM London ensembles either, if someone else can could you post please.

[bluearmy]

Possibly 

 

I can't get ECM London ensembles either, if someone else can could you post please.

no doubt erroneous but there will be no issue with the slp charts - it will be data transfer problem to meteociel.

Typically, the ECM extended ens fail when we want to see them!

also, there really should be no sign of possible events in the strat feeding down into the trop as yet on the extended modelling.

[Stuie]

Possibly 

 

I can't get ECM London ensembles either, if someone else can could you post please.

 

Edit: Sorry not ECM.

Edited January 1, 2014 by StuieW

[picog]

CFSv2 thinks it will be wetter than average through to April! It was certainly right about December's rain.

http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/euPrece1Mon.html

[Summer Sun]

Possibly 

 

I can't get ECM London ensembles either, if someone else can could you post please.

 

Not updated today yet this is yesterday's

 

 

Best we have for now is this from Holland

 

Edited January 1, 2014 by Summer Sun

[AWD]

So we got the London GEFS, the De Bilt EC ens, but not the London EC ens as asked for?

Not updated on my usual source.

[itsnowjoke]

CFSv2 thinks it will be wetter than average through to April! It was certainly right about December's rain.http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/euPrece1Mon.html

Lets hope its real cold then.

[phil nw.]

The ECM graph for London still showing yesterdays date.

A link to another Dutch site is the best i can find at the moment.

http://www.weerplaza.nl/15daagseverwachting/?type=eps_pluim&r=midden

 

click the links above the graphs for ECM/GEFS and comparison data.

A quick glance for over there shows the ECM suggesting  colder temps towards the end of it's run with low dewpoints so possible Easterly influence?

GFS output less cold and dry as expected from the earlier charts so likely continuing westerly effect.

[Mucka]

GFS 12z trickling out. Looks as though it is going to continue with the trend of building heights to our NE and also with the depth of trough.

Already looking very different to UKMO at just 84h in those regards!

 

 

With each of three main models handling ridging both East and West differently, which will blink first?

For the moment GFS staring hard.

 

Edited January 1, 2014 by Mucka

[keithlucky]

Signs of stalling LP as pressure builds over the N East .LP strugging to make westwards progress at 120

Edited January 1, 2014 by keithlucky

[IDO]

The stronger upper Scandi ridge = weaker Atlantic Ridge. So GFS and ECM diametrically opposed. GFS at T150:

 

 

This stalls the Atlantic for a while, see where it goes from here.