Model Output Discussion 4th Dec.2013-12z onwards.

[Gavin Hannah]

Well the CFS 12z is another beauty following yesterdays 12z:

 

 

Model filth lol ...... Where's the drooling icon when you need it lol.

[NorthernRab]

Well the CFS 12z is another beauty following yesterdays 12z:

 

A true north easterly there, with enough of an angle to ensure the heavy snow reaches this far west to Inverness and beefs up the showers as it crosses the sea, an early Christmas present delivered directly from the Norwegian neighbours up in Tromsø! 

 

We can but dream! Although it does reflect the superiority of a gradually migrating Scandinavian high moving towards Greenland for delivering UK wide snow 

[SMU]

Slowly but surely the models are backing North & Slightly west-

 

We started 2 days ago with mostly a Euro high with the odd Sceuro block- now we have mostly Sceuro blocks with a few Scandi highs in the mix ( like GEM)

 

THe models do not resolve energy moving SE through Scandi very well & usually catapult them towards Greece, then as T144 arrives the see less movement SE & start moving things SW-

 

Can we get the full bifta full easterly- Possibly not, but remember the forecast is for a Scandi block- which if we get the right shape has the chance to retrograde back.

 

Im sure of note tonight is the gradual moderation of warmer temps forecast-

 

The Theta E charts show this well with the cold surface continental air trying to feedback in westwards

http://modeles.meteociel.fr/modeles/gfs/runs/2013120418/gfs-6-138.png?18 - not quite getting there though.

 

Also the Berlin ensembles beginning to create large scatter- once on the very Western periphery- now all of a sudden in the mix

http://www.wetterzentrale.de/pics/MT8_Berlin_ens.png

 

 

Poor ECM tonight & poor recent form, which now we are 24 hours away seemingly the GFS was closer to the mark, which is surprising but undeniable from the predicted outcome......

 

S

Edited December 5, 2013 by Steve Murr

[Ali1977]

Not a good GFS , thought/hoped it might edge towards colder solution this morning .

[Ali1977]

Interestingly, the GEM sticks to its guns producing an eastily

Epic one at that....come on ECM!!!

And is that the UKMO also heading towards an eastily ???

Edited December 5, 2013 by Ali1977

[Mucka]

Interestingly, the GEM sticks to its guns producing an eastily

 

Yup GFS is just producing random MLB in FI while GEM output is consistent with previous runs.Doesn't mean its right, especially since we haven't seen it supported by other models or even their ensembles really.

 

Anyway here it is

 

 

Heavy snow for many, especially the S and East and only going into the freezer from there with at least a decent cold spell ahead.

[That ECM]

Yup GFS is just producing random MLB in FI while GEM output is consistent with previous runs.Doesn't mean its right, especially since we haven't seen it supported by other models or even their ensembles really.

Anyway here it is

Heavy snow for many, especially the S and East and only going into the freezer from there with at least a decent cold spell ahead.

UKMO At t144 is ok. Just shows how the high positioned higher produces and yet in the wrong place does not.

Some great posts from others previous. Little changes will make big differences. The changes may not happen but sometimes we are looking for big changes for us to experience what most would like. I have been saying for awhile now that people who can write of the next few weeks based on the output are not looking at the bigger picture. In the mean time we, in the most part, are having a dry and settled period.

Edited December 5, 2013 by That ECM

[Mucka]

UKMO looking pretty good by 144. Link up nearly achieved with a slack SE flow. Not quite GEM standar but very much a step in the right direction.

 

 

Hopefully ECM will look a good deal better than recent efforts this morning.

Edited December 5, 2013 by Mucka

[Cecil Hogmanay Melchett]

Well GFS is terrible that much is true.

UKMO offers a little more hope ..

 

GEM is sensational...

 

In other words,a lot of water to go under the bridge before we know conditions for the run up to Christmas.(Im still going for a high in or near our locale,conditions on the ground could well be cold but if I suspect that would be inversion related cold as opposed to upper air cold.

As ever,we'll see........

[shotski]

Yup GFS is just producing random MLB in FI while GEM output is consistent with previous runs.Doesn't mean its right, especially since we haven't seen it supported by other models or even their ensembles really.

 

Anyway here it is

 

 

Heavy snow for many, especially the S and East and only going into the freezer from there with at least a decent cold spell ahead.

 

Maybe no support from the other models (at the moment) but the 500mb anomaly charts would seem to be pointing

in the wright direction.

 

Shotski

[That ECM]

http://images.meteociel.fr/im/9871/ECH1-120_bvq5.GIF

Will it link up??

http://images.meteociel.fr/im/530/ECH1-144_wlq6.GIF

Not this morning Josephine!! Second time I have heard this, this morning.

Not much PV on Eastern side tho.

Edited December 5, 2013 by That ECM

[Roger J Smith]

Vast difference between GFS and GEM can be traced to how they resolve current extreme cold wedge over central N America. GEM maintains a sharp west-central trough and GFS breaks it down by day 6 with a return to more normal progressive pattern over N America. The GEM solution produces a low-energy frontal boundary well out into the Atlantic and this allows the Euro high to swell up and circulate bitter cold back from the residue of current incursion. Looks implausible and ECM more likely to resolve this complex situation correctly. I think the more likely outcome is generally mild (very mild western UK and Ireland) with some residual inversion related cold in east, but arctic air probably fated to stall out over Balkans and could end up in central Med.

 

This would place probabilities for days 6-10 (UK, Ireland) at 30% very mild throughout, 50% regional variations on mild theme, and 20% return to very cold in a week.

 

As for N American solution, GFS looks too fast to return to progressive but GEM looks too extreme in amplitude.

Edited December 5, 2013 by Roger J Smith

[bluearmy]

The 12z's will be interesting!

[Skeggy Winter Storm]

Clutching at straws i know but wasnt GEM first one to spot st jude storm earlier this autumn

[Ian Brown]

The GEM is a very poor performer in winter, I've said when it has been showing zonality against the others and I will say it again now that it is showing easterlies. We can discount it.

 

The GFS is very anti-cyclonic throughout but I feel it is wrong with the height extension Westward at around day 9 and the ECM is more likely with the gradual Atlantic incursion leading to more conventional zonality from around Dec 16.

[Cecil Hogmanay Melchett]

The 12z's will be interesting!

why nickl?

The ecm and gfs looks none to inspiring to my eyes>

[Frosty.]

Risk of the rain turning to sleet or wet snow later this afternoon and especially this evening across the hills in parts of northern england, wales & n midlands with a slight covering in places as the arctic air further north starts to dig further south and a widespread frost developing tonight as winds ease and skies clear but coastal snow showers for n & e scotland and down into ne england.

Edited December 5, 2013 by Frosty.

[bluearmy]

why nickl?

The ecm and gfs looks none to inspiring to my eyes>

 

i want to see where ukmo is sending the split flow day 6. upstream quite different to gfs/ecm and that has huge ramifications for us. gem is at the extreme edge of feasibility but ukmo could easily head towards it. not looked at the polar profile though - no time.

[phil nw.]

UKMO sends more energy south into that Atlantic trough at T144hrs.

This gives a little more ridging to our Euro high and orientates it at a better angle to enable that cold pool to get further west underneath from the Scandi trough.

http://www.meteociel.fr/ukmo/runs/2013120500/UN144-21.GIF?05-06

http://www.meteociel.fr/modeles/ecmwf/runs/2013120500/ECH1-144.GIF?05-12

http://modeles.meteociel.fr/modeles/gfs/runs/2013120500/gfsnh-0-144.png?0

 

Probably not enough for it to get to the UK later- but it would give us more of colder surface flow from the se. 

[Severe Siberian icy blast]

i want to see where ukmo is sending the split flow day 6. upstream quite different to gfs/ecm and that has huge ramifications for us. gem is at the extreme edge of feasibility but ukmo could easily head towards it. not looked at the polar profile though - no time.

Although the ECM looks very uninspiring , when we look at the polar profile in fi it's anything but , disrupted vortex there will high pressure well into polar regions . Maybe one to watch ?

[Frosty.]

Probably one of the most boring set of GEFS 00z perturbations I have ever seen, mostly an anticyclonic yawn from start to finish, only one worth showing..P16

[MR EXTREMES]

the gem anyone order a southern England ice storm lol.

so it looks likely a long wait for a pattern towards cold to setup but its looking likely cold nights and in the west warm uppers rather boring at the moment but lots can change by tonight.

Edited December 5, 2013 by emotional rollercoaster

[Summer Sun]

00z rain forecast for the south following on from last night with the potential still for 2 weeks of no rain

 

[nick sussex]

The shortwave that heads se into the Baltic is really an indicator of energy shearing away from that troughing to the west, as this happens pressure rises in between the gap, the 96 to 120hrs is critical to how the high orientates.

I was hoping we might see a bit more amplification this morning to bring this shortwave closer to the UK but the models are still overall too flat with the pattern. The UKMO is best of the big 3, even the ECM which has pulled out some really dreadful output for coldies isn't convincing in terms of resolutely sticking to one trend in its FI.

If you take both the ECM and its evil twin the GFS at face value upto 240hrs they both start to elongate the PV and desperately try and split the PV with one chunk to the ne.

Although high pressure near the UK looks a very solid trend for the next few weeks theres still alot of uncertainty as to how far north it will be and its orientation, which in turn makes a vast difference to the flow into the UK and the surface temps.

Edited December 5, 2013 by nick sussex

[Frosty.]

Ah well, at least we have these charts, normally at T+240 hours range but not this time...