Model output discussion - Post SSW - Will it turn cold?

[Daniel*]

GEM is great

so we have GEM / CFS / NAVGEM / ICON / JMA / UKMO & CMA on side. Against GFS and ECM. 

[snowfish1]

3 hours ago, Seasonality said:

I think the problem is that the crucial stages are actually within what would normally be the relatively 'reliable' shorter range, yet we've no agreement. Frustrating indeed.

Bang on post 

[comet]

Lol at the ECM. Never seen such poor inconsistency as this from the model. Some of the old rules are the best, if something works leave it alone. They should have kept that in mind years ago.

Deep cold and heavy snow now showing up regularly in the ens and this is the direction of travel regardless of any shortwaves etc, we should be concentrating on. Strat in total control over next few weeks, no need to get any more technical than that.UKMO  run on the money this morning. ECM in the bin.

Edited February 15, 2018 by comet

[Man With Beard]

ECM ensembles at D10:

ECM op has about 10-15% support. 

Another 30% have a big low to the west of the UK, stalled by a block to the east - probably like GFS, milder air from SE coming

The rest (50%-60%) have significantly blocking either to the NE or N

[ALL ABOARD]

Just to clarify BBC week ahead forecast is derived solely from ECM.

[Daniel*]

Just now, Man With Beard said:

ECM ensembles at D10:

ECM op has about 10-15% support. 

Another 30% have a big low to the west of the UK, stalled by a block to the east - probably like GFS, milder air from SE coming

The rest (50%-60%) have significantly blocking either to the NE or N

The odds are stacked with the easterly contrary to popular believe. 

[Badgers01]

2 minutes ago, ALL ABOARD said:

Just to clarify BBC week ahead forecast is derived solely from ECM.

But also with human input ?

[frosty ground]

2 minutes ago, Daniel* said:

The odds are stacked with the easterly contrary to popular believe. 

By day 10 they are, but the short term AKA day 5 UKM is what is being discussed more.

[Nick F]

Well the SSW is certainly causing model mayhem this morning, what really catches my eye, comparing GFS/EC/UKMO, is at t+120 the total absence on GFS of the deep low to the NW of the Azores - while EC and UKMO have it. Also, there are differences close to the east of the UK, as low drops south on the eastern edge of the ridge trying to build NE, UKMO develops an upper low over mainland Europe and high over Scandi - bringing an easterly flow, GFS and EC don't.

GFS, EC and UKMO at t+120

Given such large discrepancies at t+120, even at H500 level, would have low confidence beyond this timerframe. UKMO was first to pick up the brief blocking that brought the E/NEly cold snap earlier this month, so perhaps it might again have the best handle, if it keeps it up on subsequent runs, shame there are no UKMO ens to look at!

 

[Purga]

To add to this, the 0z ECM run has limited support in its ensembles. There's still a good easterly cluster + a SE'ly cluster (less cold). The op's solution of mild SW'lies received virtually no support.

[carinthian]

3 minutes ago, Nick F said:

Well the SSW is certainly causing model mayhem this morning, what really catches my eye, comparing GFS/EC/UKMO, is at t+120 the total absence on GFS of the deep low to the NW of the Azores - while EC and UKMO have it. Also, there are differences close to the east of the UK, as low drops south on the eastern edge of the ridge trying to build NE, UKMO develops an upper low over mainland Europe and high over Scandi - bringing an easterly flow, GFS and EC don't.

GFS, EC and UKMO at t+120

Given such large discrepancies at t+120, even at H500 level, would have low confidence beyond this timerframe. UKMO was first to pick up the brief blocking that brought the E/NEly cold snap earlier this month, so perhaps it might again have the best handle, if it keeps it up on subsequent runs, shame there are no UKMO ens to look at!

 

The UKMO latest model run develops the Easterly very quickly early next week. Even the latest 84h fax chart shows heights building over Scandinavia and lowering over Western mainland Europe . So the 96h fax when it is next updated will be crucial to see if the raw output has the trigger shortwave on its charts. If that the case , I would back UKMO at that shorter time scale. Fingers crossed for you guys !

C

[jvenge]

GEFS Mean anomaly.

The trend is not your friend this morning, if the GEFS is to be believed. Colder air not making it far enough west and if it did, what does isn't cold enough. Then need to rely on the percentage play being significantly wrong to give a cold easterly.

Disclaimer: I make no claims that the GEFS is close to being correct. 

[Met4Cast]

ICON stays consistent, shortwave goes South and we have an Easterly by day 5.

So first model out of the gates says "I'm not backing down".

 

[The Eagle]

ICON coming close to joining the dark side. No shortwave dropping down west of Scandi, but somehow may just hold it together.

[stodge]

Morning all

Groundhog Day it would seem with more shattered nerves and thrown toys after the evening runs failed to live up to the expectations and hopes of a number of the more excitable participants. As usual, if the chart wasn't showing storm force easterlies and -20 uppers at T+6, people were "calling time" on the cold spell and having the useful half-baked whinging, whining and moaning which belongs in the other thread.

Anyway, before I'm dispatched there, my morning summation of the medium term output which today takes us to Sunday February 25th or T+240 to its friends.

Starting as always with ECM 00Z OP at this time:

A very different evolution from previous days and I'm not sure why. Any attempt to build heights to the NE has been scrubbed and instead the Atlantic is firmly in charge with an LP pushing NE well to the north of the Faeroes and a mild SW'ly between that and heights over Europe. One thing worth noting from the Northern Hemisphere profile is it seems the LP has detached a part of the PV and while that doesn't seem able to encourage mid-Atlantic ridging it would like the residual vortex much weaker. That being said, it's a significant shift away from the modelling of previous days and it will be interesting to see where this sits in the ECM Ensembles.

GEM 00Z at T+240:

Very different from ECM and much more in line with what we've been seeing of late. A strong very cold ENE'ly airflow covers the British Isles with HP to the north and a classic LP over the Gulf of Genoa. -8 uppers cover the British Isles with -12 uppers approaching the East Coast so you can guess the rest.

On then to the GFS 00Z OP at T+240:

Yet another evolution. The HP develops over Scandinavia but the orientation isn't quite there at this time to fully advect the very cold air westwards so we have a SE'ly flow across the British Isles and the Atlantic LP systems are clearly slipping SE towards Iberia which would be a welcome sign for cold weather fans. However, that's not what happens in further FI - the Atlantic trough and the Ukrainian trough expand and meet across the British Isles producing some curious synoptics with, I suspect, a lot of rain for the south and snow for the north but the cold wins out and pushes the Atlantic back so by T+384 the cold is firmly in charge.

GFS 00Z Control at T+240:

Nearer the GEM than its own OP and a very solid chart for the cold weather fans with HP over Scandinavia and the colder air seemingly coming toward us. In further FI, the HP retrogresses to Greenland and the Scandinavian trough comes into play leaving the British Isles in a cold NNE'ly airflow with perhaps the coldest air more to the east but certainly still pretty chilly.

The GEFS at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

Still looking very solid for the E'ly. If I was being picky, I'd certainly say 3-4 members had more Atlantic influence but no more.

GEM Ens at the same time:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=1&mode=1&ech=240

Mean looks solid and while there's more Atlantic influence than on GFS it still looks a solid suite for fans of cold.

I don't normally include the UK MetO charts because they go up to T+144 at best - yep.

In summary, we are still a long way from cross model agreement though both GFS and GEM have maintained their consistency. ECM's morning output will be a huge concern for cold weather fans and I can't explain it at this time. I glanced through the ECM members last night and found a solid majority backing northern blocking but the OP refuses to come on board and that will be a concern and rightly so. Having GFS and GEM solidly on side is a big plus and this morning's MetO output will have got many quite excited and given its reputation deservedly so.

The other point is the cold isn't being pushed back as some claim - as MetO shows the right evolution can get it in earlier but the timescale of the 23rd-25th has always been where I've looked and that remains on course for the majority of output this morning. I do think the longevity of cold has been improved this morning if that's any consolation.

I'm not going to dismiss the ECM output even if it is an outlier - it's an important model with solid verification numbers and it may be right. IF it is, it will deserve all the plaudits but this is still a long way from being nailed and I'm afraid for all of us the roller coaster is starting up again.

Buckle Up !!

[Rayth]

Never mind trying to get two models to converge , we can’t get two posters to agree on the same output .. doomed we are ! 

Edited February 15, 2018 by Raythan

[Frosty_wsm]

9 minutes ago, Daniel Smith said:

ICON stays consistent, shortwave goes South and we have an Easterly by day 5.

So first model out of the gates says "I'm not backing down".

 

 

8 minutes ago, The Eagle said:

ICON coming close to joining the dark side. No shortwave dropping down west of Scandi, but somehow may just hold it together.

Two posts one after the other with two different views, confused.com springs to mind! 

[Ruzzi]

11 minutes ago, Daniel Smith said:

ICON stays consistent, shortwave goes South and we have an Easterly by day 5.

So first model out of the gates says "I'm not backing down".

 

 

9 minutes ago, The Eagle said:

ICON coming close to joining the dark side. No shortwave dropping down west of Scandi, but somehow may just hold it together.

So which one is it?? 

[frosty ground]

10 minutes ago, The Eagle said:

ICON coming close to joining the dark side. No shortwave dropping down west of Scandi, but somehow may just hold it together.

 vS 

[Met4Cast]

Just now, Ruzzi said:

 

So which one is it?? 

The result is the same in both.

[Neilsouth]

1 hour ago, Seasonality said:

Indeed, and I have the highest regard for the met. But the point I was making in response to the earlier post still stands. If the Met are on board then I too remain happy!

Considering their weekly forecasts are changing from day to day, I don't hold much regard lol

[Penrith Snow]

For years now ECM has been churning out ghost easterlys that never verify and I suspect this time it has missed an easterly that will!

Likewise so often the models predict an easterly which ends up a slack UK High, this time I think it will be the other way round.

I always put more faith in the UKMO +144 than any other model and that's why I think this easterly unlike so many ECM ones is real.

Andy

 

[The Eagle]

GFS not shaping up to deliver anything quickly. 

[davehsug]

7 minutes ago, Penrith Snow said:

For years now ECM has been churning out ghost easterlys that never verify and I suspect this time it has missed an easterly that will!

Likewise so often the models predict an easterly which ends up a slack UK High, this time I think it will be the other way round.

I always put more faith in the UKMO +144 than any other model and that's why I think this easterly unlike so many ECM ones is real.

Andy

 

Must have improved a lot then. The UKMO 144 used to be notoriously poor and best ignored.

[khodds]

28 minutes ago, carinthian said:

The UKMO latest model run develops the Easterly very quickly early next week. Even the latest 84h fax chart shows heights building over Scandinavia and lowering over Western mainland Europe . So the 96h fax when it is next updated will be crucial to see if the raw output has the trigger shortwave on its charts. If that the case , I would back UKMO at that shorter time scale. Fingers crossed for you guys !

C

Thanks for this - when can we expect the fax to be out? Is it after 11 if I’m remembering correctly?

if an easterly is on the cards from T+96 then kudos to those who said the interest begins from the 18th/19th of the month. 

.....Bet it doesn’t happen though ?

Edited February 15, 2018 by khodds