Model Output Discussion 1200 hrs 15/11/14

[Nick F]

The GFS forecast for the MJO takes it through 4-5-6-7-8, by which time it is close to the origin and often small amplitudes give little guidance of how the 500mb pattern might show. If we take a mean of 6 and 7 with decent amplitude, phase 6 shown

http://www.americanwx.com/raleighwx/MJO/MJO/DecemberPhase6all500mb.gif

This would suggest some kind of 500mb ridge west of the UK with only the slightest -ve anomaly east of the country. This is perhaps what some of you are inferring in some of the posts. Again I would suggest that after 14 days then the probability is currently about 20-25%. Obviously this might change over the coming days in which case it would be relected by a consistent change in the anomaly charts. We have to wait and see in my view if this does happen. I do believe that any initial cold outbreak is going to come from west and not east.

 

Certainly the probable mean H500 pattern 8-14days, but this masks waves in the upper westerlies that may bring brief/transitory northerlies to the UK, the classic Nly topplers. But agree, next 14 days cold from the east unlikely. Beyond, we could see a shift of the low height anomalies over Greenland and potential for -AO and even -NAO, given background signals, but pure speculation for now.

Edited November 28, 2014 by Nick F

[bluearmy]

the back end of gfsp whilst unlikely to be anything but fun to look at, has an astonishing Siberian high SLP. Almost the whole of the eastern side of the NH above 60N.

The new London ECM ens show that the op may be a little previous and plenty of cold runs around the 10th.

Edited November 28, 2014 by bluearmy

[Nick F]

Am I reading this correctly Nick? The amplification shows up quite well on the dynamic tropopause potential temperature chart. Of course it's better to run the sequence.

Chart courtesy weatherbell

 

Yep, can see the CAA into the amplifying trough over eastern N America and corresponding WAA downstream over the N Atlantic.

[knocker]

Yep, can see the CAA into the amplifying trough over eastern N America and corresponding WAA downstream over the N Atlantic.

 

Thanks for that and that's how I read it. Trying to get the hang of these charts as they can be very useful.

Edited November 28, 2014 by knocker

[Weathizard]

Just had a look through the 18z ensemble panels at 168-240 and in all honesty the ECM looks all out on its own, I've looked at most individually and there is a couple that are similar in evolution to the 12Z ECM but nothing anywhere near as good as that, theres some nice cool charts though certainly and some potential mind. Could be the ECM leading us up the Garden path again but the disparity at day 6 is quite ridiculous, as Nick said earlier: a large egg has already been prepared for whichever model folds in the overnight runs. By day 9 would have nasty zonal or a massive entire continent high pressure cell

[Nouska]

Is this the local version of the tropopause chart you linked above? This from the ECM rather than GFS.

 

For Nick, Reading ensemble. http://i.imgur.com/VNItd6Z.gif

 

 

http://brunnur.vedur.is/kort/ecm0125/2014/11/28/12/ecm0125_nat_pt4pvs2_2014112812_240.png

 

[blizzard81]

Just had a look through the 18z ensemble panels at 168-240 and in all honesty the ECM looks all out on its own, I've looked at most individually and there is a couple that are similar in evolution to the 12Z ECM but nothing anywhere near as good as that, theres some nice cool charts though certainly and some potential mind. Could be the ECM leading us up the Garden path again but the disparity at day 6 is quite ridiculous, as Nick said earlier: a large egg has already been prepared for whichever model folds in the overnight runs. By day 9 would have nasty zonal or a massive entire continent high pressure cell

Assuming the ECM op is wrong tonight, isn't it time the ECMWF put some time, cash and energy into sorting out it's over amplification issues. It has been suffering from this bias for at least a few years and is more than obvious.

[blizzard81]

Just for info: UKMO have modified 12z GM (versus raw/unmodified output seen on public websites) to make ridging more prominent out towards E/SE towards T+132, preferring the GFS 12z solution into that timeframe (and equally preferring as signalled in earlier UKMO-GM run).

That's the worst bit of news on this forum tonight for coldies.

[knocker]

Is this the local version of the tropopause chart you linked above? This from the ECM rather than GFS.

 

For Nick, Reading ensemble. http://i.imgur.com/VNItd6Z.gif

 

 

http://brunnur.vedur.is/kort/ecm0125/2014/11/28/12/ecm0125_nat_pt4pvs2_2014112812_240.png

 

 

Looks like it. The WAA is a tad different but some of that will be difference in scale.

[blizzard81]

Never mind black Friday, I think it could be black Saturday tomorrow morning for coldies after reading that post by Fergie - for the next 2 weeks anyway. The UKMO 12z agreed totally with the ECM 12z so the fact that the Meto have modified the run cannot be good news!

[kumquat]

Never mind black Friday, I think it could be black Saturday tomorrow morning for coldies after reading that post by Fergie - for the next 2 weeks anyway. The UKMO 12z agreed totally with the ECM 12z so the fact that the Meto have modified the run cannot be good news!

If we get what is being portrayed across the models everything is looking great for coldies. (as long as they have a little patience.) Europe and the UK getting steadily colder, dryer and low heights gradually moving East out of NE Canada / Greeny. It's not snow within the next two weeks but it's a great set-up for 3rd week of December onwards (with some potential before then for upper levels to the north). Compared to last year's muck this is heaven on a stick.

[chionomaniac]

Just for info: UKMO have modified 12z GM (versus raw/unmodified output seen on public websites) to make ridging more prominent out towards E/SE towards T+132, preferring the GFS 12z solution into that timeframe (and equally preferring as signalled in earlier UKMO-GM run).

Love the fact that the UKMO prefer the normally disregarded GFS one of the few times that we would prefer them not to....LOL

[Chris K]

Never mind black Friday, I think it could be black Saturday tomorrow morning for coldies after reading that post by Fergie - for the next 2 weeks anyway. The UKMO 12z agreed totally with the ECM 12z so the fact that the Meto have modified the run cannot be good news!

 

Maybe so!

 

However, it doesn't mean the output all the way out to T+132 time frame is suddenly dead certain to verify as shown in today's run... It just means that after their analysis, they have modified the output to something they feel is a more likely evolution at this time.

 

A lot can change in 5 days...and that goes for any time of the year.

Edited November 29, 2014 by Chris K

[blizzard81]

Maybe so!

 

However, it doesn't mean the output all the way out to T+132 time frame is suddenly dead certain to verify as shown in today's run... It just means that after their analysis, they have modified the output to something they feel is a more likely evolution at this time.

 

A lot can change in 5 days...and that goes for any time of the year.

Tomorrow mornings runs will go a long way to answering our questions.

[SE Blizzards]

 

GFS 18Z - mild outlier day 7 through to day 10.

 

Make of that what you will.

 

Goodnight.

[Tamara]

Major amplification on the ECM tonight with a connection opening to the arctic High. This would sure accelerate the feedback processes..if it happened

 

We know that ECM is prone to over amplification but this is exactly the type of evolution we are looking for further down the road to lead us to the important next step to a colder pattern - and with wave breaking feedbacks in the atlantic sector.

 

To illustrate this further, see how at day 10 (if we assume at face value the ECM operational verified) the heights are building again over Scandinavia.

 

Pattern re-cycle following the transfer of energy across the pole as modelled this week - and much as I mentioned in my post a day or two back

 

Its a case of if/when this happens. Very arguably not when ECM suggests here, but it does show the template for the way ahead as we go through December.

The ECM was clearly never likely to fit amongst model consensus at this time. The winking smiley was a clue   

 

But in context of the longer term (which is where I consistently set my stall) it had enough appeal (and relevance) to make me break a habit and post an individual model chart.

 

The copied post is self explanatory and forms the context of what might have appeared to be a little ramp-ette 

 

Don't take intra day modelling too seriously and literally. Usual henpecking advice I know  but have a good weekend

Edited November 29, 2014 by Tamara תָּמָר

[BlueHedgehog074]

 

GFS 18Z - mild outlier day 7 through to day 10.

 

Make of that what you will.

 

Goodnight.

Quite encouraging to see the operational model being at the top end of that ensemble graph between the 7th and 9th December with regards to the 850 hPa temperatures. Although in FI, that would probably suggest that the GFS has overdone the mild(ish) flat Westerly flow between that period. I guess as some have said, quite a few aspects to solve (such as the uncertainty of amplification upstream) before we have a better idea where we could head in the near future.

With the NOAA dumping the GFS solution while, at the same time, the UK Met Office siding with it, perhaps we might even just end up with some kind of middle-ground solution between the GFS's generally more flattish pattern and the more amplified solutions offered from the likes of the ECMWF/GEM etc. Just a possibility, though.

[Sean19]

Didn't know where else I could put this, but Jamstec's November update isn't very encouraging. 

 

http://www.jamstec.go.jp/frcgc/research/d1/iod/2007/forecast/temp2.glob.DJF2015.1nov2014.gif

[Mucka]

Love the fact that the UKMO prefer the normally disregarded GFS one of the few times that we would prefer them not to....LOL

 

Especially when the GFS overdoes the Azores high ridging in IMO though when there is disagreement with the Euros it always seems to be a halfway house solution.

 

For me the GFS and the parallel are churning out the equivalent of ensemble mean charts at the moment and it is inconsistent with the way it is modelling the Arctic high while its ensembles are even weaker hence my earlier post about ignoring GFS ensembles until it pins down the arctic high better.

 

I will say now there is virtually no way the pattern will be as flat as GFS and GFS (p) have it at day 10 though whether it is amplified enough to give the UK a proper cold shot is another matter. I expect it to change over the next couple of days and show a more amplified pattern heading into the second week of December with an Atlantic ridge or perhaps UK high if we can't get the pattern far enough West.

 

Whatever happens though no models are really showing storms and strong winds and heavy rain, just brief unsettled showery periods for the North and perhaps some night frosts so though a cold signal would be nice things still looking far better than last years nightmare.

Edited November 29, 2014 by Mucka

[Mucka]

12 hours later I wonder if MetO still prefer GFS to their own model because UKMO still has some Atlantic ridging while GFS is flat as a pancake.

Anyway spot the odd one out.

 

 

Decent UKMO and certainly a nice finish to the GEM.

 

Edited November 29, 2014 by Mucka

[BLAST FROM THE PAST]

 

 

UKMO at t144...and counting...

GEM still wanting ridging and then a nice NW/SE feature with a Scandi Block 

See what ECM brings to the table

 

GFS and MetO go for global warming...I mean flatter milder pattern 

 

 

 

Edit...GFS(P) heading same way?  Much slower though as at t240

 

 

 

BFTP

Edited November 29, 2014 by BLAST FROM THE PAST

[knocker]

The (P) still going for a key role played by the Azores ridge, removal of the Scandinavian block by T96 and lows zipping around to the north. Ridge extending further north at end of run. Temps in the latter half of the run below average.#Charts courtesy weatherbell

Edited November 29, 2014 by knocker

[MR EXTREMES]

 

 

UKMO at t144...and counting...

GEM still wanting ridging and then a nice NW/SE feature with a Scandi Block 

See what ECM brings to the table

 

GFS and MetO go for global warming...I mean flatter milder pattern 

 

 

 

Edit...GFS(P) heading same way?  Much slower though as at t240

 

 

 

BFTP

ecm sticking to lastnights idea this morning not much closer though about the same but good not to see its dropped the idea wanna see this in the t96 hrs 

 

but i would say the low dropping down the north sea is a little futher east but the important thing is its throwing heights into the nh.

 

see alot of people this the azores heights is a hinder but in many a good winter has also aided in a colder setup.

im still excited but still very skeptical for now.

Edited November 29, 2014 by emotional rollercoaster

[MR EXTREMES]

pv slowly draining over to our northeast surely fingers crossed no garden path antics but is there ridge going up into greenland !!!!!!!!!!!!

 

ooooooo greenland could make us white land.

its a nice run by the ecm but still the little details out that far that make this evolution possible but very complicated.

nice run but i want to see this at a closer timeframe before i get my eddy the eagle googles on for the world record ramp 

but i must say its the way forward alot of us have been talking about with the lows dropping down the eastern side of the uk and heights to our west northwest and very much like the run up to winter 09/10

 

as you can see the pv has relocated with the biggest section of pv over the eastern side excellent run slowly but sure its coming into place.

 

im not posting about the gfs its a horror story but the one thing about the gfs is its love for zonal so we have garden path ecm and the over excited gfs but on the flip side another good run by the ukmo 

 

out of all of them the ukmo is a model i would have more faith in even tho the grinch at the ukmo want to steal a white christmas lol but it is the best model and as soon as you see a good run 9 times out of 10 its normally on the money.

mind you i think it might be best to wait until tomorrow evening to really see where this is heading.

Edited November 29, 2014 by emotional rollercoaster

[knocker]

One change on the GEFS anomaly is the movement of the Russian section of the vortex to Iceland although this dissipates on later frames leaving a broad band of weak positive heights eastern seaboard into NE Europe with a weak trough north of the UK. Just to add yesterdays ECM ops is in the bin.

Edited November 29, 2014 by knocker