Model Output Discussion - January 12th.

[SP1986]

zonality does attempt to set up in the 18z, but it doesn't have much chance of sustaining, I'd say in that case to take a punt, Greenland high developing into the later run allowing northwesterlies in.. easterly.. probably not in this particular run. This run is probably more like the GFS 12z ensemble mean?

[Tom Montalbano]

Very similar really to its 12z run out to t162. Keeps high pressure close to UK, with heights not falling over Europe that much but in the last few frames signs of the PV easing west away from Greenland.

Regards,

Tom

Edited January 12, 2012 by TomSE20

[danm]

Subtle and small differences up to 168 on the GFS.

The 18z shows the arctic high exerting more of an influence over the PV over Greenland, forcing it to break up into 2 separate 'lobes':

Compare this with the 12z for the same time where the arctic high is exerting less influence and the PV is more intact around Greenland:

The quicker the PV breaks up over Greenland, the quicker the high over the UK will retrogress or build a ridge up towards Greenland and the quicker we see a switch to NW/N winds.

A small step, but in the right direction.

[nick sussex]

In your own time GFS.

Signs of life at last as it splits the PV in the higher resolution output helped by the Arctic high, that was painful to watch and seemed to take hours to get any interest.

[BLAST FROM THE PAST]

T168, maybe a hint here that the trough will start to dig SE ? PV splits? Thus far this run is all about slight changes which lead to big differences or just another version of the GFS rollercoaster. Its a slight shift but way slower than others. GFS rollercoaster again with back to square one. Goodnight

BFTP

Edited January 12, 2012 by BLAST FROM THE PAST

[mountain shadow]

The GFS is slowly but surely being dragged to the ECM. The PV is moving away, should be a colder FI.

Edited January 12, 2012 by mountain shadow

[danm]

We're slowly getting there. PV breaking up more quickly than it did with the 12z as the arctic high exerts more influence. PV splits and a trough moves SE into Scandi more quickly, with the UK high retrogressing towards Greenland:

Compare with 12z:

[nick sussex]

At 192hrs its decided we've had too much excitement for the evening and wants to reform the PV!

What can you say! If you're being optimistic at least it hinted at some interest which is more than can be said for the 12hrs run.

After that the PV and Greenland make up after a squabble and the resultant lower resolution slide into the abyss ensues!

[danm]

Funnily enough, after a few encouraging signs, the 12z looked a lot better in FI!

A poor end to the 18z, even compared to the 12z! The high never retrogresses, the trough that started to dig into Scandi almost evaporates and the high builds back across us!

Oh well....at least there were some more encouraging signs within t168.

Edited January 12, 2012 by danm

[Cecil Hogmanay Melchett]

Well GFS is absoltely refusing to enter any notion of blocking over Greeny after the high to the NE gets shunted away.

This model cannot be ignored as its often been very wrong when in conflict with ecm but also sometimes its correct.

Tomorrow hopefully will provide more confidence.

[lorenzo]

At 192hrs its decided we've had too much excitement for the evening and wants to reform the PV!

What can you say! If you're being optimistic at least it hinted at some interest which is more than can be said for the 12hrs run.

After that the PV and Greenland make up after a squabble and the resultant lower resolution slide into the abyss ensues!

It was almost like it woke up from a sleep, caught the important bits of the film ( 12z ECM) then dozed off again.

Normal service resumed, perhaps 00z will give some much needed clarity?

[SP1986]

18z was a little predictable somehow, but whether this is part of an evolution to ECM or a settlement into the 'halfway house' regime, is anyones guess until tomorrows runs.

[Cheshire Freeze]

One thing is for sure, either the ECM or GFS is going to look like a real prat after this....the differences start at 72 hours!

[phil nw.]

Well i had seen enough by T144 to see that it would stick with it`s star player-the Azores High.The energy is still being ejected east and flattens the pattern.

No agreement yet then on the short term developments.

[Just Below Zero]

http://cdn.nwstatic.co.uk/gfsimages/gfs.20120112/18/336/h500slp.png

Seems a familiar chart.

Who would have believed that the 18z had taken up vows of abstinence as a new years promise

[damianslaw]

At 192hrs its decided we've had too much excitement for the evening and wants to reform the PV!

What can you say! If you're being optimistic at least it hinted at some interest which is more than can be said for the 12hrs run.

After that the PV and Greenland make up after a squabble and the resultant lower resolution slide into the abyss ensues!

A case of the GFS doing its usual when a pattern change is imminent and it is very uncertain of how things pan out - i.e. charge up the PV and let zonality rage... its the GFS default position, it will continue to yo-yo around in its coming runs on its output longer term - but to my eyes these long term synoptics it keeps throwing up appear to contradict with its medium term developments i.e. mid atlantic heights building north. Not often I say this but the suggestion of PV quickly reforming and increasing over greenland is very unlikely to verify and therefore I seriously question the credibility of GFS at present.

[ITSY]

yup real comical differences between ECM and GFS. certainly the op and control were on the colder side of their ensembles - its hard to know quite who will blink first. GFS 18z plays with late FI again bringing in a very late easterly - but still out in lala land. the morning should tell us more, certainly GFS wants to continue the mild theme and ECM is generally cooler with their op and control playing with fire. This seems to have been an FI event for a while now though - originally the 15th, then 19th, then 21st and increasingly further back...hopefully not a sign of things to come.

[PolarWarsaw]

Im not sure about anyone else as Im literally only a 'model discussion' viewer. But I cannot remember ever seeing a period in model output that consistently chopped and changed. If we see a complete mild-washout I still have realistic hope that the following could be the next ice age and the vice versa with tonights ECM and the 18z. It wouldnt surprise me to see the ECM0z reset to something like mild and the GFS turn to everyone's screens blue tommorow. Im looking forward to the point in time that we do get some cold air over our shores but It really wouldnt surprise me if everyone wakes up dissapointed with the 0z's.. it is friday the 13th after all...

Here's hoping for a cold set across the board tommorow.

[Zakos]

Surprise surprise, as soon as the low res output begins, the russian high get pushed back east, and the arctic high randomly collapses and is replaced by an intense PV.

I would personally go with the ECM output. Not because of coldie bias, nor because i think it is neccesarily a better model than the GFS.

But, I think the GFS has been to inconsistent lately to inspire any real confidence in it.

[SP1986]

GFS does actually follow in the footsteps of the ECM... at 372 hours!

http://www.wetterzen...s/Rtavn3721.png

edit: sorry, I checked a 12z charts.. but still, closer to a easterly.

[Jason M]

Frame for frame a very similar run in many ways to the 12z. Strong consistency from GFS IMO, although this doesnt mean its right of course.

Logic points to the ECM being closer to correct, but I think the tendancy to simply bin GFS is risky as whilst it may have struggled recently its still one of the big three! My main concern is that this run is so similar to the last one! Has GFS nailed it?

Some positive signs in the early / mid part of the run with pressure higher over Greenland.

Jason

[snowlover2009]

Lets not get too down on the gfs run. It is step closer to the other models and thinking about it, it is on its own with no support. I think it will be all change by the 00z or tomorrow. Lets just say I wouldn't be surprised if the ecm turns mild and gfs gos uber cold as ever, just to be a pain in the backside. It could also be a bit of an outlier, we will see. But as said, it is pushing slowly to the other models. The rest of the models aren't following the gfs which is good and the gfs only a day or two was showing some great synoptics for the end of next week/weekend.

[on the coast]

Frame for frame a very similar run in many ways to the 12z. Strong consistency from GFS IMO, although this doesnt mean its right of course.

Logic points to the ECM being closer to correct, but I think the tendancy to simply bin GFS is risky as whilst it may have struggled recently its still one of the big three! My main concern is that this run is so similar to the last one! Has GFS nailed it?

Some positive signs in the early / mid part of the run with pressure higher over Greenland.

Jason

I have noticed in the past the 18Z has a habit of the change to come. GFS not budging and ECM not moving either? Classic morning runs coming.

[snowlover2009]

Frame for frame a very similar run in many ways to the 12z. Strong consistency from GFS IMO, although this doesnt mean its right of course.

Logic points to the ECM being closer to correct, but I think the tendancy to simply bin GFS is risky as whilst it may have struggled recently its still one of the big three! My main concern is that this run is so similar to the last one! Has GFS nailed it?

Some positive signs in the early / mid part of the run with pressure higher over Greenland.

Jason

Yes, but the ecm painted a very cold scenario this morning and has kept with it this evening. The other models seem to be supporting it.

I have noticed in the past the 18Z has a habit of the change to come. GFS not budging and ECM not moving either? Classic morning runs coming.

It is usually the case. People being disheartened by the 18z and come the morning, all the models have good agreement in cold weather. I am looking forward to the morning.

[Zakos]

A case of the GFS doing its usual when a pattern change is imminent and it is very uncertain of how things pan out - i.e. charge up the PV and let zonality rage... its the GFS default position, it will continue to yo-yo around in its coming runs on its output longer term - but to my eyes these long term synoptics it keeps throwing up appear to contradict with its medium term developments i.e. mid atlantic heights building north. Not often I say this but the suggestion of PV quickly reforming and increasing over greenland is very unlikely to verify and therefore I seriously question the credibility of GFS at present.

Agreed. If you look at the GFS from about 168-174 hours, heights begin to rise over western Greenland fuelled by the arctic high.

Then, for no apparent reason, the powerful Arctic high dissapears and is by a very quickly reforming PV. (as you point out)

Even to my untrained eye, this looks like an incredibly unrealistic outcome.