Model Output Discussion - 30th November onwards

[cooling climate]

Well the ECM has to be taken seriously after another consistent

run also bearing in mind the UKMO has moved towards the ECM

solution this evening.

I would say though that the GFS can not be completely ignored no

matter how much we would like to and so unless this model comes

on board then a more watered down version of what the ECM is

showing would be the more likely.

[Methuselah]

So there we have it----

 

my last post until tomorrow- 12 hours down the line from the 00z & nowhere closer to any consistency-

 

A couple of points to note- ASSUMING the ECM/ UKMO blend is correct with a strong Northerly then if you look over ensemble watch you will see that the 3 12z ensemble suites from the GFS have been hopeless- & perhaps the alcohol induced 18z has been the best-

 

The disagreement between the UKMO & ECM isn't resolved, however even if they meet in the middle the UK is still cold, just 1 day less so than the ECM-

The UKMO 144 shows energy spilling over the top, so thus cutting off the feed but by all means not a toppler.

 

 

Long term, the ECM 12z has been progressive before So I reserve the right to say that its to progressive again this eve flattening the profile to much @ 192.

Scandi heights feature ZERO in the models- but don't rule them out....

 

Hopefully IF things do pan out the euro way then we will put the GFS in its place once & for all- however IF the ECM backs the flat GFS pattern I will never discard the GFS again in an amplified outlook.

 

Have a good eve- The 18z has been the best amplified run so far- so expect big differences to the 12z....

 

 

S

There we have, what?

[stewfox]

deleted

Edited November 30, 2013 by stewfox

[The PIT]

UKMo and GFS very close at T144 High slightly further south than the UKMO but that's it.

[Purga]

Right, but after 3 full days of cold... 3 days is plenty thank you very much and it will feel very seasonal! Also, that chart you have posted is not mild, not at the surface and even the uppers aren't very high. They're within the expected range for the time of year

Joe, I said 'here comes the mild' refering to the trend after te High sinks.

[weatherguy]

Haven't even bothered looking at the GFS, having read Nick's post from the NOAA.

 

Just popped in, ECM seems to be sticking to its guns well enough, bringing bitter cold down from the north for a fair few days - with the real cold sticking round for a good 5 days, possibly longer with anticyclonic conditions and cold ground temps.  Not much snow potential in that run other than perhaps NW scotland, though we always say get the cold first and you never know what features may pop up last minute and bring some snow.  

 

All in all, a respectable cold snap/spell looks likely considering winter is only just beginning - Nothing extraordinary*, but enough to keep us interested at this early stage...Plus it's good to see the run ending with HP dominating once more; the zonal train is running late this year it seems, lets hope it's held at station for much of winter 

 

*though perhaps I'm being unfair with uppers as low as these, from a Northerly in early winter 

 

Edited November 30, 2013 by weatherguy

[Cheshire Freeze]

UKMo and GFS very close at T144 High slightly further south than the UKMO but that's it.

 

No, they're nothing alike....as you well know seeing as you've posted the UKMO and GFS charts in a way that's hard to even make a comparison. Here they are in the same format...

 

 

 

As has been said already, the GFS piles all of the energy of the LP over the block whereas the UKMO doesn't.

 

For once let's have some FACTUAL discussion rather than made up cobblers or casual remarks which add nothing to anything. ECM by far the best outlook tonight within the 144-168 hrs range, energy heads N parallel to the blocking rather than cutting across it. UKMO goes for a middle ground solution with some energy over the top. GFS cuts the LP east across the block and we don't really have a N'ly as a result. There you go, summarised in a couple of sentences.

Edited November 30, 2013 by CreweCold

[gottolovethisweather]

Hi GTLW

 

Its not the feature itself - Its the way its trough axis is tilted-

 

@120 The GFS & is tilted EAST- the UKMO is tilted NE & the ECM @ 120 is tilted NORTH-

 

Small angles of change- huge repercussions.

 

 

Here is tonights ECM 144 V the GFS 144-

 

Is there ever was a polar opposite this will be it.

GFS

http://modeles.meteociel.fr/modeles/gfs/runs/2013113012/gfsnh-0-144.png?12

 

ECM

http://www.meteociel.fr/modeles/ecmwf/runs/2013113012/ECH1-144.GIF?30-0

 

Note the difference of 850s for the

 

ECM

http://www.meteociel.fr/modeles/ecmwf/runs/2013113012/ECH0-144.GIF?30-0  -10c

GFS

http://modeles.meteociel.fr/modeles/gfs/runs/2013113012/gfsnh-1-150.png?12 0c

 

Its been a difficult evening- but the GFS either way has had X2 shocking 12z on the trot-

 

S

 

Thanks Steve, you couldn't do a graphic/paintjob thing to illustrate it a bit better to me. I'm sure it will also help others whom are learning too. I'll see if I get what you're saying in the meanwhile. So often its better to see such things in pictures than in words. Thanks again anyhow.

[UV-RAY]

Weather models are not horses !

Looks more like My Little Pony.

[Frosty.]

No downgrades here, this is better than the gfs and ukmo 12z...... this is another sensational Ecm run, the 12z looks just as potent as the 00z and last night's 12z..Being a rampant coldie I would take this run now as things stand and just hope it slowly grows in duration as we go through next week. This run would bring a lot of heavy snow showers, especially across the north & east of the uk with a strengthening Arctic airflow which only subsides later next weekend, the first rush of cold air is hitting scotland just after midweek and then it's hello to the first sharp taste of winter with snow, ice and severe frosts, the following week would also be cold with freezing fog and frost the further south and east you are

 

Another 10 then.......

[The Post-modern Winter]

Joe, I said 'here comes the mild' refering to the trend after te High sinks.

Again though, it's not actually mild is it? I'd imagine temperatures would remain below average? Or am I misreading the charts?

[bluearmy]

It was always going to be that though. I'm starting to trust the Met O a lot more with mid-range forecasts. They will sometimes side with the GFS and will sometimes not side with it, unlike some on here to think it's the gospel. Met O going for a a 3-4 day cold spell, GFS going for a 0 day cold spell, I think it's becoming very clear that GFS should be rubbished for this cold spell.

Snowy, Ian f can probably confirm this but Exeter will probably use gfs modelling less than a dozen times a year. They have no need to. ECM and ukmo plus ens on each plus mogreps. Infant, it's likely less than 12!

[gottolovethisweather]

Worth looking at that T+144 UKMO chart that I highlighted earlier and comparing to the ECM

 

So here is the UKMO chart again - remember the 75% of energy in the form of the shallow depression over the ridge:

 

UN144-21.GIF

 

Well it's not there on the ECM which will keep the cold flow more meridional and it will last longer.

 

ECH1-144.png

 

With no agreement like that FI is well inside that timeframe as well!!

 

It renders the earlier difference of opinion quite pointless also. Good to have debate though.

 

Sorry to bother Chio but on that ECM chart, is that what be deemed as an undercutter hence the WAA moves North with the High in the following charts?

Edited November 30, 2013 by gottolovethisweather

[SMU]

Sorry no time this eve

[suxer]

There we have, what?

 

 

There we have, what?

Most of your posts are one liners with no model input .

 

Do you think the high pressure will flatten ala GFS (one or two day cold spell)or ridge further north ecm(three or four day cold spell)?

[ChartViewer]

Most of your posts are one liners with no model input .

 

Do you think the high pressure will flatten ala GFS (one or two day cold spell)or ridge further north ecm(three or four day cold spell)?

95% flatten....Oh im not ABNS....But it will flatten given the strength of the PV ...not really what I want to see. But flatten after a 4 cold day snap...hardly memorable.

Edited November 30, 2013 by ChartViewer

[chionomaniac]

Sorry to bother Chio but on that ECM chart, is that what be deemed as an undercutter hence the WAA moves North with the High in the following charts?

Not really a good example to show an undercutter, gltw. I can't say that it isn't at that point but can't say that it is either. A very weak attempt at some form of WAA occurs so I wouldn't use that as an example.

[Joe Levy]

Joe, I said 'here comes the mild' refering to the trend after te High sinks.

Yes I appreciate that but I more meant that it's not worth thinking about the end of the cold spell before it's even begun!

[fergieweather]

Snowy, Ian f can probably confirm this but Exeter will probably use gfs modelling less than a dozen times a year. They have no need to. ECM and ukmo plus ens on each plus mogreps. Infant, it's likely less than 12!

No they employ all NCEP output in every assessment including 18z runs etc. Regularly see them cited (pretty much every day) in comparative analyses from Ops Centre. Never seen likes of Canadian GM, NAVGEM, OzBOM, CFS etc used however. Only EC, GFS, JMA & ARPEGE alongside UKMO suite of NWP products.

[gottolovethisweather]

Not really a good example to show an undercutter, gltw. I can't say that it isn't at that point but can't say that it is either. A very weak attempt at some form of WAA occurs so I wouldn't use that as an example.

 

Ok, Thanks it sounds like I'm partly correcct but as you say, as the run developed it went a bit pear-shaped for coldies which I must say I didn't expect. This HP signal doesn't seem to go away, but then again its the timescale in between that counts.

Yes I appreciate that but I more meant that it's not worth thinking about the end of the cold spell before it's even begun!

 

For some it is. Best move on now. Move along the bus please all.

[radiohead]

I think the 18Z GFS could well deliver a "better" run since the 12Z op was with the milder group of ensembles on the 7th and pressure (just about) higher than all the ensembles on the 6th.

[SMU]

Thanks Steve, you couldn't do a graphic/paintjob thing to illustrate it a bit better to me. I'm sure it will also help others whom are learning too. I'll see if I get what you're saying in the meanwhile. So often its better to see such things in pictures than in words. Thanks again anyhow.

 

There we go- easiest way is open the 3 links together & compare the system off the east coast...

 

GFS 120

 

ENE

http://modeles.meteociel.fr/modeles/gfs/runs/2013113012/gfs-0-120.png?12

 

UKMO 120

 

NNE

http://www.meteociel.fr/ukmo/runs/2013113012/UW120-21.GIF?30-18

 

ECM 120

 

NNW

http://www.meteociel.fr/modeles/ecmwf/runs/2013113012/ECM1-120.GIF?30-0

 

Going NNW means the trough axis is Negatively tilted, where as the UKMO is positive & the GFS is very positive- IE flat as a witches T*T

 

 

S

Edited November 30, 2013 by Steve Murr

[bluearmy]

No they employ all NCEP output in every assessment including 18z runs etc. Regularly see them cited (pretty much every day) in comparative analyses from Ops Centre. Never seen likes of Canadian GM, NAVGEM, OzBOM, CFS etc used however. Only EC, GFS, JMA & ARPEGE alongside UKMO suite of NWP products.

quoted in comparative analyses, yes, but i was thinking more about it being used ahead of the euro output re the forecasts.

[Methuselah]

Most of your posts are one liners with no model input .

 

Do you think the high pressure will flatten ala GFS (one or two day cold spell)or ridge further north ecm(three or four day cold spell)?

That is exactly why I try to ask simple questions, S. IMO, why is that? is a perfectly valid question to ask...I do see a two-, maybe three-day cold snap - nothing in the models really goes against that assumption...? I might well be wrong, if that is the case, then so be it...Would you prefer that I asked the very same question in ten lines, as opposed one?

[Ian Brown]

There we go- easiest way is open the 3 links together & compare the system off the east coast...

 

GFS 120

 

ENE

http://modeles.meteociel.fr/modeles/gfs/runs/2013113012/gfs-0-120.png?12

 

UKMO 120

 

NNE

http://www.meteociel.fr/ukmo/runs/2013113012/UW120-21.GIF?30-18

 

ECM 120

 

NNW

http://www.meteociel.fr/modeles/ecmwf/runs/2013113012/ECM1-120.GIF?30-0

 

Going NNW means the trough axis is Negatively tilted, where as the UKMO is positive & the GFS is very positive- IE flat as a witches T*T

 

 

S

 

 

This basically sums it up, in other words a compromise is of no use, to get a decent northerly then we need the ECM to be correct and there is zero margin for error in that output.