Model Output Discussion - The final stretch to Christmas

[KyleHenry]

Loving the latter part of this GFS(P) run, for amusement purposes. From Russia With Love....the low on this chart over Poland is heading towards us from the East, under the Scandi high.

 

 

Then at the end of the run it drops the PV on top of us.....

 

 

As I said, probably for amusement purposes only!

It's a possibility wave 1 ongoing in stratosphere pushing PV Canada bound at present.

Wave 2 coming round from Pacific side could in effect push it our way or towards central Arctic Ocean. Where the down well goes is uncertain for 14 days approximately.

[SW Saltire]

I've been watching the GFS opp in recent days and its been a complete joke. Every single time it hits low res it spins up zonality pretty much instantly. In some cases its so marked that an observer could be fooled into thinking the model is forcasting that the earth will start spinning faster on its axis!!Maybe we will go zonal, but there will be no kudos for the GFS opp here. The GFSP's higher resolution in the crucial 192 to 240 range is important. Also GFS Control is essentially the old opp run with slightly changed starting data if I recall correctly. No shock therefore that it just does the same as the Opp run.GEFS rolling out and a more marked attempt to build heights to our NE yet again.I've seen worse charts than this......http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=14&mode=0&carte=0Its not without some support either.

It's an argument that has raged on for seemingly ages (and I've only been following this forum since December 2010 - a good month to pick

The fabulous post from Steve M last winter that analysed the situation Of that northerly (anyone remember?) where he stated the '2/3rds' idea.

That the ECM had amplified the pattern too much by 1/3 and the GFS had moved 2/3rds of the way to the ECM.

Perhaps it's quite telling that the GFS is hinting at the Scandi High considering (it has been suggested that) the PV may be on the move and as a result, one would expect an over progressive reaction, with a ramping up of the Atlantic (that probably won't come to fruition). Therefore, to not show Atlantic domination in FI is promising and is not 'usual conditions'.

However, on the other hand, have we seen real promise for a block...? No. Therefore, any increase in westerly energy may be enough to blow away our short window of opportunity to get a high established.

I think some forecasters call this a 'fluid' situation.

I'll leave the discussion to far more intelligent members than myself, it's making for a great read.

The only thing I would say is for people to try and keep their blood pressure lower by stopping jumping to conclusions after one set of runs. Quite a few mornings I thought all hope was lost, the the 6z would show promise an the 12z would be all over the place and vice versa.

I for one will be happy when the old GFS is removed. It has its moments but overall it would be a source of much frustration and like pulling teeth to get it to 'smell the coffee'. Highlighted by one (ex) poster very frequently....

The incoming 'low' will have huge reprecussions for the following weather and therefore, models will continue to be inconsistent until a consensus is found.

Let's hope the ECM/UKMO idea of renewed amplification behind the low occurs an we can get a high established

Edited December 23, 2014 by SW Saltire

[Downpour]

Sanity because 99 times out of 100 we get the Atlantic. Even in this "promising" winter we had a CET of +2c in November, currently at +1.1c. I know it was more than likely to be a backloaded winter, if we indeed get cold, but GFS has been pretty good so far at predicting the FI despite the bigger picture. 

 

 

Evidence? I'm not aware that GFS verification stats this winter have been notably better than any other models. Happy to be corrected. 

 

As for November, November is not winter, not by the UKMO, nor by the cosmos. 

[Frosty.]

I've lost faith with the met office and their super computers,yesterday and last night it was snow showers and now it's dry with fog and frost, no mention of snow and then back to the Atlantic. The models make my blood boil with their teases and constant let downs..Merry Christmas

[IDO]

Evidence? I'm not aware that GFS verification stats this winter have been notably better than any other models. Happy to be corrected. 

 

As for November, November is not winter, not by the UKMO, nor by the cosmos. 

 

No November is not officially, but there was significant mid-latitude cold in a relatively blocked period. The US was the main beneficiary and as Nov 2010 shows there can be cold in our locale. The same reason March is not classified as Winter but we can still get colder weather than December!

 

I didn't say GFS verified better than other models, I said it had been pretty good with the long wave pattern in FI.

 

London 2m temps: 

 

As expected the op and C at the milder end and the P at the colder end.

Edited December 23, 2014 by i'm dreaming of...

[JoeShmoe]

Again, trend continues mid-long term of HP settling somewhere near the UK with the jet running over the top, charged by the PV in NE Canada/Greenland. Will no doubt be a cold surface high but as yet little sign of that HP retrogressing until changes happen upstream (perhaps strat led). Also interesting how relatively warm continental Europe is

 

Short term some fleeting interest in this LP Sat but as the MetO have said focus more on winds than any widespread wintry ppn away from elevation

[mushymanrob]

IDO, both the ECM and UKMO agree at 120 hours. If the GFS is right I will jump into the North sea naked on Christmas day.

 

 

..... but t120 hours is next sunday, 3 days after christmas day! the gfs 06z isnt too far off those models anyway... so which gfs were you referring too and what time?

[mushymanrob]

the gfs 06z looks very plausible to me....

post storm ridge, collapsing into a bartlett type high. colder uppers then the ecm sun/mon but becoming mild as the ridge collapses

 

 

and is an evolution supported by these charts, so imho is to be taken reasonably seriously.

 

 

[snowking]

Rob you seem far too keen to see Barry naked!

Just a couple of observations. The hints of height rises over or to the ENE of the UK remain - and this is still ultimately the direction I see things heading in.

The killer detail will be deciphering how much energy goes above and below any potential block...and with the main thrust of the vortex stratospherically at least being pushed, via wave 1, over to our sector of the Northern Hemisphere that energy balance is something that NWP is likely to continue to struggle with over the coming days. This is then further complicated by both downwelling and upwelling wave 2 potentially in around 10-15 days time which could once again throw energy budgets and direction in to a little bit of a chaotic state for the poor old models.

We have already seen plenty of over-suggesting of height rises by the GFS(p)...but equally we should remember the known westerly bias of the GFS, and more especially the tendency of the GEFS to reintroduce zonality, when faced with a block, far too quickly.

So overall then expect plenty of chopping and changing of outputs to continue for the next few days and beyond...and I'm sure that will correlate to the mood in here too...

SK

Edited December 23, 2014 by snowking

[inghams85]

My forecast from 10 days ago of cold from the 28th is still playing out beautifually.

 

Stage 1 - Snow from the fleeting Northerly (locations impossible to forecast as yet)

Stage 2 - Uk high preserving the cold and snow

Stage 3 - Scandinavian heights - Good to see the trend grow

Stage 4 - The relocated Pv over in Canada to undercut the block as it sends energy south in the atlantic

 

***** For stage 4 its important to understand that no model has the ability to forecast the undercut from T-300 or even T-192.......so be patient once this stage hits the reliable watch the Scandinavian High send the jet stream and low pressures further and further south and under.... All FI is futile at the minute. Ignore the output

[inghams85]

Rob you seem far too keen to see Barry naked!

Just a couple of observations. The hints of height rises over or to the ENE of the UK remain - and this is still ultimately the direction I see things heading in.

The killer detail will be deciphering how much energy goes above and below any potential block...and with the main thrust of the vortex stratospherically at least being pushed, via wave 1, over to our sector of the Northern Hemisphere that energy balance is something that NWP is likely to continue to struggle with over the coming days. This is then further complicated by both downwelling and upwelling wave 2 potentially in around 10-15 days time which could once again throw energy budgets and direction in to a little bit of a chaotic state for the poor old models.

We have already seen plenty of over-suggesting of height rises by the GFS(p)...but equally we should remember the known westerly bias of the GFS, and more especially the tendency of the GEFS to reintroduce zonality, when faced with a block, far too quickly.

So overall then expect plenty of chopping and changing of outputs to continue for the next few days and beyond...and I'm sure that will correlate to the mood in here too...

SK

Absolutely....... Your on the same page as me. Will be funny to watch the models consistently back away from zonal as FI coes into range. A known issue for most of the models in this situation and one Steve Murr has spent his life showing people on the forum

[phil nw.]

At this stage if i was a betting man i would say the GFS op is too fast with the flattening upstream and therefore with the return of the westerlies after the Holiday.

As early as T96hrs or T90hrs on the 06Z GFS there are subtle differences with the split of energy off the Canadian vortex.

ECM                                                    UKMO                                                GFS Op   

 

The euros have much stronger trough extension se and therefore no early flattening of the Atlantic ridging towards S.Greenland.Notice on the GFS how this ridging is poor and already forward leaning(positive) indicating that it wont hold out for long.

If the frames are run through after that point we can see that the GFS solution is to build a more southerly located high and of course the northern jet pushes this away quite quickly.

A look at the London 2m Temp ens shows the split in the evolution between the ECM and GFS suites

 

which underline that the cold hangs on longer under the ECM solution with that mid-latitude block further north.

 

Of course no guarantee that the Euros are correct but this shows how differences in modelling a split in the distribution of the jet can show downstream later in our weather.

Edited December 23, 2014 by phil nw.

[IDO]

I've lost faith with the met office and their super computers,yesterday and last night it was snow showers and now it's dry with fog and frost, no mention of snow and then back to the Atlantic. The models make my blood boil with their teases and constant let downs..Merry Christmas

Yes it was a surprising update yesterday as it has always looked (from GFS ensembels) that the rain would bring in a warm sector and the best we were going to get was backend snow if the LP dropped South through the UK. lots of ifs and buts especially when GFS were pushing the system into the North Sea. Maybe they were looking at the ECM/MOGREPS/UKMO take on it and ignoring the GFS. Not a mention of the S word for Saturday and the 16-30 day is Atlantic driven with not a mention of even lower probability for a colder outlook. In line with the LRF so no shock really.

[festivalking]

I've lost faith with the met office and their super computers,yesterday and last night it was snow showers and now it's dry with fog and frost, no mention of snow and then back to the Atlantic. The models make my blood boil with their teases and constant let downs..Merry Christmas

 

Blimey when Frosty goes negative things are the wain. Come now Frosty you are great value, keep your pecker up!

[492]

the gfs 06z looks very plausible to me....

post storm ridge, collapsing into a bartlett type high. colder uppers then the ecm sun/mon but becoming mild as the ridge collapses

 

Rtavn1202.gif Rtavn1802.gif

 

and is an evolution supported by these charts, so imho is to be taken reasonably seriously.

 

610day.03.gif 814day.03.gif

These later charts make better viewing.. even the GFS shows some noteworthy buckling near the UK and E Pacific.  

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[Barry12]

 

 

..... but t120 hours is next sunday, 3 days after christmas day! the gfs 06z isnt too far off those models anyway... so which gfs were you referring too and what time?

 

It would be very unusual for the models not to agree at 72 hours though...if they don't I will have to postpone the dip to boxing day/the weekend

[Gibby]

Personally I don't think the models have done that bad a job on predicting all the options that could of been on the table with regard to predicting a possibly major cyclogenesis event such as the one likely after Christmas given that this was picked up on by the output quite a while back now. True it has been watered down thankfully in recent days than what was a few days back The positioning of the Low has also been changing run to run and model to model and that may continue for a while yet. The one thing that a lot here strive to see is of course is snow but this has not been shown in any way other than a blink and you miss it type affair on any output lately and that stance is maintained this morning.

It looks most likely now that the UK will be most likely be affected by a UK High of some sort delivering the heady mix of frost and fog and probably below average daytime temperatures too, particularly over England and Wales. It looks odds on favourite now for pressure to be more likely to rise to the East of the UK as we head towards and after the New Year and as I said in my report earlier this comes with a risk of shifting the High too far South later as the Jet roars over the top bringing a slow return to milder Westerly winds with rain at times to the North and West. However, there is a definite trend that each run currently seems to be exploring the chance of building any UK or near European High pressure into Scandinavia later. This could provide dividends for cold with time and is far more likely than any pressure rise across Greenland in the short term covered by the output currently. It's all a game of chess though and the pendulum could swing either way in a continuing fascinating period of synoptics this Winter.

 

The one thing I can say with reasonable confidence is that any chance of a severe snowy period across the UK within the next two weeks look very unlikely given the theme shown from current output runs. However, frost and ice lasting all day for some with potential freezing fog patches too could at least add to the seasonality of the period for many.

Edited December 23, 2014 by Gibby

[Jason M]

Absolutely....... Your on the same page as me. Will be funny to watch the models consistently back away from zonal as FI coes into range. A known issue for most of the models in this situation and one Steve Murr has spent his life showing people on the forum

It was puzzling to me in recent days that we were not seeing heights suggested to our NE given the low dropping down over us. That it is now starting to be modelled is a good sign IMHO. That said, I would be very wary indeed of assuming this will go our way. If we do end up in 10 days where the GFS opp suggests its goodbye much of January from that starting point and my CET guess will be in the + plenty range for Jan. Its also notable that Steve hasn't been posting much of late. This could of course be because he has better things to do, but it doesn't suggest he's seeing anything great coming up. Hopefully that will change this evening ;-)

[mushymanrob]

Rob you seem far too keen to see Barry naked!

 

 

lol.. rash promises made id like to see fulfilled! not that ill be there to see barry but he shouldnt make promises he wont keep!

 

These later charts make better viewing.. even the GFS shows some noteworthy buckling near the UK and E Pacific.  

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

true, point taken, i guess its down to preferance and i do prefer the noaa charts as they appear to be more consistent and less prone to sharper swings.

of course if theres pressure rise to our northeast it would be a good sign for those hoping for cold, but like the eastern blocking in november doesnt guarantee a cold spell. as ive just posted in ramps/banter, id like to see a (short lived) cold spell, winters not real winter without one.

[nick sussex]

If you were looking at this soley on operational runs then the GFS is wrong.

 

Every other model either takes the low se or south, so its ECM/UKMO/GFS P/GEM/NAVGEM against the GFS and at T120hrs you simply can't weight the GFS solution higher than those combined.

 

As for the GEFS its flat bias is well known, the ECM does have an overamplification bias but generally at T168hrs onwards. regardless of some of the derision I've happily dished out to the ECM over recent weeks when especially the ECM  and UKMO are on the same page at T120hrs then 99% of the time that's what verifies.

 

Those two together are more important than lets say the ECM/GFS.

 

All will be revealed this evening!

[Cloud 10]

The time seems to be updated sometimes long before the text. Reckon it needs sorting.

 

 

It would seem that its updated now.

 

I've lost faith with the met office and their super computers,yesterday and last night it was snow showers and now it's dry with fog and frost, no mention of snow and then back to the Atlantic. The models make my blood boil with their teases and constant let downs..Merry Christmas

 

[Smiler1709]

People talking about what might happen in two weeks is tragic. I bet my house that in 24 hours the models will look completely different in FI. Then different again in 48 hours and so on..... The amount of times I've read doom and gloom posts after the latest output only for 24 hours later people are quoting 62/63 winter and these snow storm charts then back to doom and gloom. Could go on and on and on.

[IDO]

If you were looking at this soley on operational runs then the GFS is wrong.

 

Every other model either takes the low se or south, so its ECM/UKMO/GFS P/GEM/NAVGEM against the GFS and at T120hrs you simply can't weight the GFS solution higher than those combined.

 

As for the GEFS its flat bias is well known, the ECM does have an overamplification bias but generally at T168hrs onwards. regardless of some of the derision I've happily dished out to the ECM over recent weeks when especially the ECM  and UKMO are on the same page at T120hrs then 99% of the time that's what verifies.

 

Those two together are more important than lets say the ECM/GFS.

 

All will be revealed this evening!

 

Yes but the GEFS have:

 

NASA:   Germans: 

 

Brazilians:   Indianians: 

 

Russians (last night):  

 

Looking at the ECM height bias you can see why their T168 chart(+) is unlikely to verify:

 

  

[mushymanrob]

If you were looking at this soley on operational runs then the GFS is wrong.

 

Every other model either takes the low se or south, so its ECM/UKMO/GFS P/GEM/NAVGEM against the GFS and at T120hrs you simply can't weight the GFS solution higher than those combined.

 

As for the GEFS its flat bias is well known, the ECM does have an overamplification bias but generally at T168hrs onwards. regardless of some of the derision I've happily dished out to the ECM over recent weeks when especially the ECM  and UKMO are on the same page at T120hrs then 99% of the time that's what verifies.

 

Those two together are more important than lets say the ECM/GFS.

 

All will be revealed this evening!

 

the problem i have with that nick is that the souteastward track of the low doesnt to me look mas plausible as the gfs's... but maybe thats the point, the gfs might be playing safe when the more unusual ecm (etc) track is closer to the mark.

[Captain Shortwave]

the problem i have with that nick is that the souteastward track of the low doesnt to me look mas plausible as the gfs's... but maybe thats the point, the gfs might be playing safe when the more unusual ecm (etc) track is closer to the mark.

Regarding the track of the low, the standoff is very similar to January 2013 where most models when for it dropping SSE across the UK and the GFS on its own with it pushing ENE into Scandinavia, the result that time was the GFS backtracked very late on and I suspect it will this time. Just my two cents and well it doesn't really solve the issue of delivering true cold to the UK as the most likely follow up to this is a cold high near the UK.

Edited December 23, 2014 by Captain shortwave