Model Output Discussion - 26th December - 1st January

[johnholmes]

The UKMO looks a complete mess upstream within 96hrs so let's just wait and see what the ECM does.

why on earth does it look a mess-how about an explanation Nick, there are a lot of folk who have no idea what you mean, me included?

To me it seems a logical carry over from the T+72, 48?

the explanation

Its a mobile westerly upper flow, thus at times the models will show temporary troughs and ridges in the upper pattern. This is exactly what the models are showing, nothing 'a mess' in it whatsoever. As each minor fluctuation in the trough-ridge set up runs east so events upstream prevent any major buckling thus the upper pattern tends to 'warm' out is the expression as the upper trough runs east. Another one then takes its place and a similar result ensues. Just once in a while the flow allows a minor buckling to develop slightly more, this then affects what is happening beneath it (including the surface) and a mild SW flow develops ahead of the low to be followed by a colder WNW possibly even briefly cold NW flow before it all resets.

Quite how that can be described as 'a mess' I'm far from clear-it seems pretty clear what is happening to me. Hope my attempt at an explanation may help some who are not too sure about synoptic charts. I'm not getting at anyone just trying to get ALL of us to comment on the model and explain a little if possible.

Edited December 27, 2011 by johnholmes

[ICETAB]

It's only out to T168! Are you looking at the northern hemisphere charts?

Looking promising for a colder pattern on ECM at T216. Blocking appearing to our north?

[Grimsby Snow Lover]

Looking promising for a colder pattern on ECM at T216. Blocking appearing to our north?

Looks ok to me as, nothing bone chilling but we knew that anyway. We are on the north side of the jet throughout and as you have pointed out pressure is still building over the pole, I wouldn't really say it following the GFS. By day 10 the jet is running well south and hights over Europe look less strong. Cold zonality would be my call, which would at least make things feel seasonal.

http://www.wetterzentrale.de/pics/Recm2401.gif

Edited December 27, 2011 by Grimsby Snow Lover

[Tim Bland]

Whilst not ggreat for deep cold the ECM looks good for some marginal snow events under low pressure and -5 uppers down to the channel islands. I would rather have this than cold and dry

[phil nw.]

Looking promising for a colder pattern on ECM at T216. Blocking appearing to our north?

No blocking but a colder angle to the jet to bring Pm air flooding south as a chunk of the vortex tranfers to Scandinavia.

http://www.meteociel...H1-240.GIF?27-0

This is colder zonality with the jet pushed south of the UK with the stubborn Heights over Iberia pushed west into the Atlantic.

It is day 10 so it comes with the usual caveats but it`s a trend ECM Strato output has been showing-with heights falling into Europe.

I wont take this ot but anyone interested i refer to my post in the Strato Thread.

Edited December 27, 2011 by phil n.warks.

[ukpaul]

ECM steady as you go in being very consistent with its output, looking very different to GFS once more.

Anyway, after being blown away tomorrow (I'm up north at the moment), it will be interesting to see what the GFS decides to do with this period once it moves out of low res.

EDIT: People really should look into the technical discussion thread as it puts variations in current output into useful perspective.

Edited December 27, 2011 by ukpaul

[weatherguy]

A step back on the 12z ECM from the 0z from what I can see; northern blocking is still present but it doesn't look as convincing in how it is brought about, or as strong...I fear that this is eventual split of the PV is just being postponed after each run.

However, keeping some perspective in here, looking at trends the prospects do look much better than what we have endured over the last month or so, and long term signals are looking encouraging - May take a bit more patience mind you.

[Uncle_Barty]

One reason for a big spread on the ensembles could be simply due to being in different cycles of a zonal flow.. Either in the middle of a warm sector or post cold front. It does not always mean a modelmis struggling!

This is a very good point.

Taking the London ensembles for example.. look at the pressure rather than the T850, it's a better guide as to what is going on.

Follow each individual perturbation - (even the operational and control) show a similar shape but out of phase with the others. The majority show a zonal pattern with lows moving across from time to time.

I also see one or two mentioning the ECM as similar to GFS.

Take a look at the Northern Hemisphere chart - OK it's at T+240 so in early-medium FI

ECM:

GFS:

ECM has been consistent for a few runs now in showing some amplification of the general pattern, and tonight is no different.

Edited December 27, 2011 by Jim_AFCB

[k19]

This is a very good point.

Taking the London ensembles for example.. look at the pressure rather than the T850, it's a better guide as to what is going on.

Follow each individual perturbation - (even the operational and control) show a similar shape but out of phase with the others. The majority show a zonal pattern with lows moving across from time to time.

I also see one or two mentioning the ECM as similar to GFS.

Take a look at the Northern Hemisphere chart - OK it's at T+240 so in early-medium FI

ECM:

GFS:

ECM has been consistent for a few runs now in showing some amplification of the general pattern, and tonight is no differenrt.

Perhaps the ensembles from Nuuk would give a better indication of any model hint at blocking

[nick sussex]

The UKMO at 96hrs is a mess of shortwaves, the definition of MESS can be several things, cluttered, disorderly etc which basically sums up that chart!

And anyway it wasn't backed by the ECM which was my point!

The previous "mess" leads to this at 120hrs by the UKMO.

http://www.meteociel...=120&carte=1021

Compared to this by the ECM

http://www.meteociel...map=1&archive=0

Edited December 27, 2011 by Osbourne One-Nil
Pack it in please.

[Isolated Frost]

And we build heights in the west-us due to the sub-t ridge building from the north-west over there, 1055mb high projected by tonight's ECM, couple that with the temperature gradient off the east coast and we have a low building, and bitterly cold northerlies across much of the e-central US. PV remains mostly intact but loses some intensity on latest ECM again... cold polar north-west and west winds late on with that PV displaced... cooler zonality on the return I'd think for early-mid jan.

[phil nw.]

Emotions seem to running high this evening and some posts have had to be deleted.

Please keep to Model Discussion people otherwise it` spoils it for others.

Please use the PM system if you wish to sort out any issues.

[snow drift]

Anyway, there is alot of disagreement between the models and alot to be resolved but I would rather see small step changes to what we have been viewing recently. I think cold zonal weather for awhile.

Edited December 27, 2011 by phil n.warks.
I agree but OT comment removed

[Cecil Hogmanay Melchett]

Anyway,not great this evening on the model front,patience continues to be the watchword and its pretty obvious the first 10 days of jan are going to be a right off for northen blocks,maybe the the second half will produce

Edited December 27, 2011 by Paul
Removed the off topic stuff

[Uncle_Barty]

Perhaps the ensembles from Nuuk would give a better indication of any model hint at blocking

There you go....

No sign of any blocking up there on GFS.. but then we knew that!

[nick sussex]

Wow pour yourself a few espressos the updated NOAA discussions go on and on!

http://www.hpc.ncep.noaa.gov/discussions/pmdepd.html

In a nutshell theres some uncertainty with the progression and amplitude of troughing upstream.

I've just pulled out the 12hrs updates:

THE 12Z/27 GFS/GEFS MEAN PERSISTED IN A GENERALLY PROGRESSIVE

FLAVOR IN ITS FORECASTS. THE GFS SEEMS TO OVERPLAY ONE IMPULSE

REACHING THE E COAST SAT DAY 5 GIVEN ITS FAST WESTERLY

ENVIRONMENT...WHILE IT SHOWS ONLY MODERATE DEVELOPMENT TO THE NEXT

TROUGH REACHING 85W BY SUN. IT HAS EVEN BACKED OFF IN AMPLITUDE

HERE FROM ITS 06Z/27 RUN. THE 12Z/27 UKMET WAS IN SNYC WITH THE

GFS ON THE MAIN FEATURES ACROSS THE COUNTRY THRU MON DAY 6.

THEN COMETH THE 12Z/27 CANADIAN...HANDLING THE PATTERN ACROSS MOST

OF THE LOWER 48 FROM DAY 4 ONWARD VERY SIMILAR TO THE 00Z/27 ECMWF

WITH SPECTACULAR DIGGING/CLOSING OFF ALOFT NEAR THE LOWER MS VLY

EARLY TUE. THE SCORE IS EVEN WITH THE 12Z CANADIAN/00Z AND 12Z

ECMWF/00Z/27 ECENS MEAN PITTED AGAINST THE 12Z/27 GFS/GEFS

MEAN/UKMET. THE NEW 12Z/27 ECMWF PLAYS UP A DIFFERENT SHORTWAVE

IN THE AMPLIFYING CENTRAL/ERN TROF TUE/WED BUT HAS THE SAME IDEA

AS PREVIOUSLY...FORECASTING THE A DAY 8 STORM FOR THE E COAST

INSTEAD OF DAY 7. WITH THIS MUCH SPREAD AND UNCERTAINTY FINAL

GRAPHICS ARE STAYING UNCHANGED...HEAVILY WEIGHTED ON THE BACK END

TOWARDS THE ECENS MEAN.

[wolvesfan]

Evening all,

ECM similar to 00z keeping us on the cold zonal path with the uk north of the pfj.output for me isn't as bad from a cold perspective as some fellow model watchers are making out.ECM may well have us on a path to some proper cold,but as we've seen before it's not going to be a quick transition, i for one think we are on the right track though.

[Bristawl Si]

Thinking back over previous years, differences in the various model outputs (GFS, ECM, etc) over a forward-looking period of 8 days plus, has sometimes signalled that the models are indicating some kind of pattern change in the not too distant future. But presently the inconsistency can indicate they are struggling to find a consensus.

If we all remind ourselves of GP's forecast for the winter, mid-Jan onwards is the period for a possible change to colder and maybe snowier scenarios UK-wide. That period is still 2 weeks plus away and in model terms, may not start showing up for another 10 days or so.

[kev238]

I think the most telling thing for me this winter is the complete lack of eye candy in the later reaches of models. Even in milder winters gfs can be relied on for some stella charts in the post 300 output, yet I can't recall seeing an operational with anything like dream synoptics!

For me, I can't see a quick way to cold. Maybe the last ten days of January will deliver something, but we have an awful lots of changes that need to happen to make this possible, and these changes dnt happen quickly in my opinion!

[syed2878]

Hi guys a bit mixt up here and i hope u guys can help me. Some of u r saying that the models r hinting to wards cold and g.p's forecast is on track. On the same thread others r saying there's no sign of cold and looking at the met they not pointing to any patern change to cold. On their 16-30day outlook they forecasting mild to avrage and some cold for the north. Its all rather confusing.

[leicsnow]

Thinking back over previous years, differences in the various model outputs (GFS, ECM, etc) over a forward-looking period of 8 days plus, has sometimes signalled that the models are indicating some kind of pattern change in the not too distant future. But presently the inconsistency can indicate they are struggling to find a consensus.

If we all remind ourselves of GP's forecast for the winter, mid-Jan onwards is the period for a possible change to colder and maybe snowier scenarios UK-wide. That period is still 2 weeks plus away and in model terms, may not start showing up for another 10 days or so.

If you take mid-Jan as being the 15/16th, then if GP's forecast is going to be correct we have to wait at least another 3-4 days for the models to start showing, and as you said it could be up to 10 days. Otherwise, mid-Jan could mean 10-20th January but there you go.

Edited December 27, 2011 by Tellow

[Richie V]

I think the most telling thing for me this winter is the complete lack of eye candy in the later reaches of models. Even in milder winters gfs can be relied on for some stella charts in the post 300 output, yet I can't recall seeing an operational with anything like dream synoptics!

For me, I can't see a quick way to cold. Maybe the last ten days of January will deliver something, but we have an awful lots of changes that need to happen to make this possible, and these changes dnt happen quickly in my opinion!

If I was to have to produce a forecast based on all runs of all models today I could sum it up in just three words.... MILD AND WILD. I've not looked at any models for at least 8 days now and there seems very little in the way of difference on offer from then to the now! Highly zonal all the way in one shape or another for now seems (dare I say it ) The form horse..... Damn, I hate that expression.

I wish you all the happest new year, god bless you all.

Edited December 27, 2011 by Richie V

[bluearmy]

I dont think Exeter have updated the 30 dayer as they would now do on a Tuesday. The 30 dayer reflects Thursday's 32 day run which was rather different in tone to what it's been showing over the past few runs. Unless they update tomorrow, I think you will have to wait until Friday. so I wouldn't take much from the 30 dayer at the moment.

I am surprised how consistent the ECM is in fi re it's appetite to drive the trough into Europe. Contrary to some of the posts I've read on here this evening, the ECM isn't following gfs and vica versa. Given what NOAA say in their update, the fi ECM ens mean of mid Atlantic ridge and scandi trough look the favourite for next week. that wouldn't be too far from where the ncep suite is headed anyway at T192 (if we ignore low res post this point).

[J10]

ECM at T+240 looks like being quite wintry with very low heights with a sector of the Polar Vortex seemingly pushing across to Norway,

At the very least ECM suggests cool zonal if not cold zonal.

As others have said GFS keeps pretty much the status quo, with only the odd colder interlude.

[Cloud 10]

The ECM operational run fits in well with the ensembles at least.

Yesterdays 12z ensembles for comparison.