Model Discussion Thread - January 13th

[ukpaul]

The question is - has the GFS movement happened as part of a back down towards the UKMO (as far as it goes) and ECM which will continue in other runs, or is there some sort of halfway house that all will converge on?

Although the idea that none is completely wrong and that the only viable answer is for then both to be a bit wrong is seemingly logical, this very human assumption need not be the case. Many times there is no middle way, just one that is right and others that are not. In this instance I think it's worth looking at the background signals, they've suggested that the PV should be further West than GFS pushes it but what about ECM's Greenland High, does that have any support to it?

[phil nw.]

Totally agree Chiono, there has not been any more or less disagreement in the models than it normal, it purely that people are looking in detail at tiny meso features at T5000 (slight exaggeration, but you get the drift).

I don't understand why people don't sit back a bit and look at the upper more permanent features outside the short time frame.

I agree wrt to the 500hPa patterns but in the near term -say next 4-5days the discussions should be centred around the direction and flatness or otherwise of the flow because of seemingly minor differences.

My post earlier was pointing to this to show the GFS was similar to it`s earlier runs and following this through-- compared to the ECM- resulted in a less cold medium term.

The charts i posted does show the ECM more bullish digging that cold trough into Europe and to only focus on 1 frame where they were similar was rather blinkered.

We all know that the 00z ECM was a colder run and all i was doing was illustrating the early differences.

Edited January 13, 2012 by phil n.warks.

[ChartViewer]

The question is - has the GFS movement happened as part of a back down towards the UKMO (as far as it goes) and ECM which will continue in other runs, or is there some sort of halfway house that all will converge on?

Although the idea that none is completely wrong and that the only viable answer is for then both to be a bit wrong is seemingly logical, this very human assumption need not be the case. Many times there is no middle way, just one that is right and others that are not. In this instance I think it's worth looking at the background signals, they've suggested that the PV should be further West than GFS pushes it but what about ECM's Greenland High, does that have any support to it?

Hi good post and one I suspect we will see.....Halfway house. However im nagged by ECM Op and all ensemble suite very bullish at there progged forecast...very interesting model watching...However it really isnt a true GH is it just a ridge moving North?

I saw a true GH last December...this surely cannot be mentioned in the same breath as that?

Regards

[cold snap]

We may still see some changes but time is getting short as the first part of the evolution is so close now.

Post of the day for me and this sums things up.pretty much.i would be shocked now if i dont see ecm back down later on

GFS is still okay mind.but cant resist the energy from the west.

UKMO is not so good.

A nail biting Ecm coming up.could be crucial

Edited January 13, 2012 by cold snap

[lorenzo]

Looking at things on a smaller scale, I think the low leaving the East coast US is key at the 144 time frame.

Will be interesting if tonights ECM run follows it's earlier trend. Or things end up flatter as per the GFS 12z having looked promising up until about 72-96hrs.

ECM GFS

Looking through the ensembles a couple of eye catching runs.

P11 nearly there with a split and p17 showing a healthy NW SE flow on a strong jet.

Perhaps the ecart highlights the volatility as close as 156hrs, you can see not only a half way house between the models, but uncertainty across the suite. Guess where - right over the UK !

Edited January 13, 2012 by lorenzo

[Cheshire Freeze]

Having looked again, I'm not so sure the UKMO is in the GFS camp....having studied both 144 hour charts, the only feasible difference between all 3 models is that low heading out from the east coast of Canada. The GFS wants this negatively tilted and heading out on a se/e trajectory whereas the UKMO ejects this as a much more rounded feature which will aid WAA and a slight amplification of the jet come 168 hours, possibly just enough to get the Greenland ridge.

[k19]

Post of the day for me and this sums things ups.pretty much.i would be shocked now if i dont see ecm back down later on

GFS is still okay mind.but kind resist mre energy from the west.

UKMO is not so good.

A nail biting Ecm coming up.could be crucial

Really cannot see the ECM evolving in to the GFS much at all. If you consider the ECM does only 2 runs a day, it has consistently shown the same solution. If it does back towards the GFS I suspect it will be to increase ridging of the azores high up to Greenland.

[Isolated Frost]

Really cannot see the ECM evolving in to the GFS much at all. If you consider the ECM does only 2 runs a day, it has consistently shown the same solution. If it does back towards the GFS I suspect it will be to increase ridging of the azores high up to Greenland.

http://www.ecmwf.int/products/forecasts/d/charts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa%20and%20Temperature%20at%20850%20hPa!192!Europe!pop!od!oper!public_plots!2012011300!!/

Copyright ECMWF.

These, along with the n-hemi view of the ECM, are the most important NWP guides. You can take a look at the N-Hemi and N america ones in there as well.

I am loving the comparison maps on NW, very useful indeed, especially during such cross-model disagreement. The 500hpa, strat and mjo are the fellows to watch, keep an eye out for posts from GP, JH, Phil n warks, Lorenzo and chionomaniac especially when it comes to these factors.. I see the ECM 12z similar to yesterday's, but perhaps less progressive.. that upper trough is vital, as is the progression of the PV.

[phil nw.]

Looking at things on a smaller scale, I think the low leaving the East coast US is key at the 144 time frame.

Will be interesting if tonights ECM run follows it's earlier trend. Or things end up flatter as per the GFS 12z having looked promising up until about 72-96hrs.

ECM GFS

Looking through the ensembles a couple of eye catching runs.

P11 nearly there with a split and p17 showing a healthy NW SE flow on a strong jet.

Perhaps the ecart highlights the volatility as close as 156hrs, you can see not only a half way house between the models, but uncertainty across the suite. Guess where - right over the UK !

Yes the orientation of the jet in the early stages is where the models differ somewhat and this is key to how cold any incursion from the north would be in a few days.

The sharper that Scandi trough can get the deeper it will get into Europe and pull colder air down thats why the 00z ECM was better for this..

The GFS and to an extent the UKMO keep the flow more West to East and therefore that Azores High stays closer to the UK and would at least delay things.

Edited January 13, 2012 by phil n.warks.

[cooling climate]

Looking at things on a smaller scale, I think the low leaving the East coast US is key at the 144 time frame.

Will be interesting if tonights ECM run follows it's earlier trend. Or things end up flatter as per the GFS 12z having looked promising up until about 72-96hrs.

ECM GFS

Looking through the ensembles a couple of eye catching runs.

P11 nearly there with a split and p17 showing a healthy NW SE flow on a strong jet.

Perhaps the ecart highlights the volatility as close as 156hrs, you can see not only a half way house between the models, but uncertainty across the suite. Guess where - right over the UK !

The positive from the GFS run out to t144 is that it now deepens this energy as it comes towards the eastern seaboard of the US but is to progressive with it. The ECM and the UKMO hold this back more allowing more

of a chance of ridging from the Atlantic northwards.

Edited January 13, 2012 by cooling climate

[Pixel]

I've been interested in the differences between the GFS 6z and the 12z Jet and z500 model forecasts over the last 7 days for a randomly chosen date of the 19th January and have laid out the their projections below:

...also done this with the stratos, precip (must be bonkers!) and the 850 temps too but wont bore you with those (-:

I just wanted to see where Fantacy Island (FI) was located! - The projections for the 19th seem to be narrowing down a bit - but as you can see they were all over the shop early on. Is Fantacy island located around 150 hrs away or is it more like 72 hrs!

Of course a lot more finer detail will evolve between now and the 19th so I'll be lurking here a while longer to learn more.

Big question tho… should I now follow the GFS or UKMO for the detail on the 19th - daddy or chips? :lol:

or the ECM maybe?.. oh I just can't decide

Edited January 13, 2012 by Pixel Precipitation

[Tom Quintavalle]

Yes, the situation at t144 is crucial to events further down the line. This mornings ECM had a weaker feature near Labrador at t144, by t168 it loses its shape as a ridge extends on its eastern flank towards Greenland.

GFS has this low exiting Labrador quicker and flatter at around 975mbs.

UKMO holds back this feature a little further west and a bit deeper at 970mbs but it doesnt appear as if its going to get as far east as GFS, giving a more amplified look, with a ridge developing to its east, trying to ridge towards Greenland.

Eyes down for the ECM, with baited breath! Come on Europe, its like the Ryder Cup all over again!

Regards,

Tom.

[Cloud 10]

I would be surprised if the ecm backed down now when its showing ensemble mean charts like the

one below at 168 hrs.

I am still prepared to be surprised though!

ECM 12z sticks to its guns at +120hrs.

Edited January 13, 2012 by Cloud 10

[trisnow]

When would the new ECm start showing on here please? http://www.netweather.tv/index.cgi?action=ecm;sess=

Is it nearer 7pm? Thanks

[ChartViewer]

When would the new ECm start showing on here please? http://www.netweathe...ction=ecm;sess=

Is it nearer 7pm? Thanks

Out to T96 now knife edge stuff

[trisnow]

Out to T96 now knife edge stuff

Really? At t96 I am seeing Friday 00z? thought I should be seeing 12z Friday.. I am new to this

[coldwinter]

Link to meteciel chart viewer:

http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=1&type=0&archive=0

Ryan.

[TEITS]

Better agreement from the Aberdeen ensembles of it turning colder from the 19th.

http://cdn.nwstatic.co.uk/ensimages/ens.20120113/12/t850Aberdeenshire.png

Slightly less agreement further S.

http://cdn.nwstatic.co.uk/ensimages/ens.20120113/12/t850Cambridgeshire.png

Starting to get a clearer picture of what may happen. Shall explain after i've viewed the ECM.

[ChartViewer]

Link to meteciel chart viewer:

http://www.meteociel...ype=0&archive=0

Ryan.

Eh yes thats what im viewing

[ukpaul]

Looks like a slightly "less good" ECM out to t120 so far.

The pattern seem to be marginally flatter, with less ridging.

Those are for two different times, twelve hours apart, there should be notable differences.

[AWD]

Azores high closer to the UK on the ECM, less amplified and trending more towards the GFS!

[coldwinter]

Eh yes thats what im viewing

Linked for trisnow.

Ryan.

[danm]

Those are for two different times, twelve hours apart, there should be notable differences.

Yep just noticed that myself. apologies.

[BLAST FROM THE PAST]

Yep just noticed that myself. apologies.

And t144 is on target. Atantic wedge ridging upto Greenland meeting artic High wedge, SW ejecting into SE Europe.....looking good PV split and main bit sent to Canada

BFTP

Edited January 13, 2012 by BLAST FROM THE PAST

[chicken soup]

http://www.meteoc

iel.fr/modeles/ecmwf.php?ech=144&mode=1&map=0&archive=0 looks good at 144