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

[bluearmy]

Any news on the NAEFS? Hasn't updated since Tuesday.

You can view it on wetter under 'ens'. Its the 40 member option. The anomolys on wz are more sensitive than meteociel so be a little careful.

[nick sussex]

Synoptically the GFS 18hrs run is trending towards the ECM at 168hrs, the polar profile and upstream across the USA and Canada however not enough of a dig south of energy into the mid Atlantic.with less amplification.

 

This really is the main sticking point going forward, that PV to the west needs to be as elongated as possible. Not bad from the GFS 18hrs run but its still a long haul to get enough amplification upstream.

 

I think for the timebeing a surface feed from the continent still looks the most likely outcome, it would need a large westwards correction aswell as a stretched and negatively tilted troughing set up to the west to give a chance of something more wintry.

 

We'll see in the morning whether theres any movement in the models.

[Cloud 10]

You can view it on wetter under 'ens'. Its the 40 member option. The anomolys on wz are more sensitive than meteociel so be a little careful.

 

Nice one BA.

 

Wetter : Wetterzentrale : Top Karten : Prognose - Ensemble Europa

[Mucka]

ECM London ensembles not overly exciting but better than this mornings with a few cold options toward the end.

 

[Panayiotis]

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Edited December 5, 2013 by Panayiotis

[SMU]

When I first presented the Idea of a scandi high around a week ago, then over the few days leading up to that long post Monday the proposal was a ridge thrown into Scandi that gets cut off with undercutting, well I think that we do get the scandi high, however as MANY will agree, sometimes to get the cold to the UK ( Upper cold ) it sometimes takes 2 even 3 attempts & the third one is often linked in with a polar high-

 

It seems that many may be looking at the wrong place on the maps - in terms of the azores low to undercut-

 

Please remember this straight forward bit of info to get deep cold into the UL ( not just surface cold)

you will only ever get undercutting & a sustainable high If there is a polar high to force a split in the jet ( or a Siberian high ridging west) to join the ridge in the atlantic moving NE-

No polar high usually = a high that meanders around as a sceuro high-

 

here are some examples of what to look for- Svalbard is the focal point.

then the following charts

 

http://modeles.meteociel.fr/modeles/reana/1947/archivesnh-1947-1-21-12-0.png

http://modeles.meteociel.fr/modeles/reana/1947/archivesnh-1947-1-22-12-0.png

http://modeles.meteociel.fr/modeles/reana/1947/archivesnh-1947-1-23-12-0.png

 

Also,

 

http://modeles.meteociel.fr/modeles/reana/1956/archivesnh-1956-1-28-12-0.png

http://modeles.meteociel.fr/modeles/reana/1956/archivesnh-1956-1-29-12-0.png

http://modeles.meteociel.fr/modeles/reana/1956/archivesnh-1956-1-30-12-0.png

 

& finally

http://modeles.meteociel.fr/modeles/reana/1987/archivesnh-1987-1-7-12-0.png

http://modeles.meteociel.fr/modeles/reana/1987/archivesnh-1987-1-8-12-0.png

http://modeles.meteociel.fr/modeles/reana/1987/archivesnh-1987-1-9-12-0.png

 

So we shouldn't be looking SW we should be looking NE for the key indicators:

 

Vertical ( or near vertical) ridging towards Svalbard

Energy diving S/SE over scandi whilst the ridge builds on Northwards

Polar heights ridging OVER the pole or from Russia to support the block & cut the atlantic off

 

The ECM shows SOME of the signals tonight especially at 216 & 240 - but it does require that element of vertical advection

 

 

Possibilities on the cross polar ridging.

 

 

If you look at our chances they come at intervals 192 & 240 for better chances of deep cold.

 

 

 

In summary tonight-

A week of meandering southerly / SE flow with generally cold conditions at the surface especially for the England-

My projected 'fun' maps were 13/14- but maybe it will be 14/15.

 

The key being persistent spells of ridging up to the pole looks to be the start of the domino effect to cold down the line.

However the stumbling block being if the advection is not quite northerly & any low moving up the blocking cuts off the conjoined highs by 'getting through the gap' & moves ESE into any wave of energy trying to come SW over scandi then its not going to happen.....

 

S

[SylvainTV]

Any news on the NAEFS?

 

Hasn't updated since Tuesday.

 

Oops fixed. Sorry !

[Swave Snow]

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Absolute Monster.  I would imagine extremely dangerous SNOW HURRICANE OBLITERATES THE UK and IRELAND Chances of actually happening? 0%

[SW Saltire]

So when's the 'zonal train' arriving? oh, it's been put back yet again i see, right...

Edited December 6, 2013 by SW Saltire

[georgiedre]

Just a quick question for experienced people here. With cold air filtering into ne UK what impact could this have? As I seem to remember that when cold air filtersinto place it is hard to get rid of so could this help the building Of high pressure to our ne??

[alexisj9]

Absolute Monster.  I would imagine extremely dangerous SNOW HURRICANE OBLITERATES THE UK and IRELAND Chances of actually happening? 0%

GFS did show todays storm 2 weeks ago, just saying. Normally you would be right, it's fl and too strong like most fl GFS storms.

[Swave Snow]

GFS did show todays storm 2 weeks ago, just saying. Normally you would be right, it's fl and too strong like most fl GFS storms.

 

I agree, but if it was even a quarter of what is shown it would still be severe

[Kentspur]

http://www.ukweatherworld.co.uk/forum/index.php?/topic/49348-the-severe-winter-of-1928-29-a-special-report-with-times-articles/

I wonder if we will get a repeat of this winter similarities to how that winter began in December with the northerly followed by a high to the east

[Biggin]

So when's the 'zonal train' arriving? oh, it's been put back yet again i see, right...

 

 

loving this, one can but dream tho

 

Edited December 6, 2013 by phil nw.
removed ot remark

[Gavin Hannah]

I thought Bullseye got cancelled? Thats a dart board and a half lol

[TSNWK]

00z GFS pretty much the same. Attempts made to ridge into scandi, but then sucked backed into the euro high. Low res is poor for coldies.

00z metoffice looks poor to me for coldies,limpet high just to east,south east. Maybe a little downstream interest with heights a little higher north of Iceland and a negative tilt to a low presure south of Greenland.

00z ECM bit like GFS in my view, has a go at attempting to ridge into scandi, but then drops back into Europe. 240 chart looks poor going forward, with vortex pumping away over Greenland.

Basically we are kinda of in a up and down barlett situation, instead of the text book left to right barlett.

Edited December 6, 2013 by TSNWK

[Ian Brown]

A poor ECM and if we get to the position shown at T240 it's a very long way back from there.

[Snowman.]

http://www.meteociel.fr/ukmo/runs/2013120600/UW144-21.GIF?06-06. UKMO

[Cecil Hogmanay Melchett]

A poor ECM and if we get to the position shown at T240 it's a very long way back from there.

Pretty much sums up my thinking IB.

Im afraid its all eyes on the strat thread, we are going to need something to dislodge that angry looking PV.

[lorenzo]

A poor ECM and if we get to the position shown at T240 it's a very long way back from there.

 

Ian,

 

Please can you provide some clearer analysis or discussion to explain your view point. Or, it will just mean anyone can pick any chart and say right once we get to 264 on the GFS its nailed, or once we get to 144 on UKMO its a long way back, or that 300 chart on CFS is likely. It's cherry picking.

 

It's clear you have a reason for repeatedly writing such 'long way back from there' statements, however until anyone actually knows why....we will never be in a position to either counter or support your thoughts.

 

FWIW, wave 2 activity in the strat is looking interesting this morning, the slower jet profile at 168 on ECM will probably re-appear on the 12z, so long way back from wherever that is, I don't think this will be the case.

 

Anyway hopefully you can enlighten us..

[bluearmy]

With ref to steve's post last night, i'm looking sw because i dont see a let up in the vortex energy headed from Canada to siberia. That means a 'sausage' type high needed just to our north and an undercut to advect the cold west. Having said that, the ecm this morning was headed gingerly in steve's direction until the atlantic didnt dig enough jet energy southeast and the flow went ne across the top of the block.

Ukmo carving out a fairly deep atlantic trough by day 6.

[Frosty.]

P19 (GEFS 18z) would bring us a white christmas, the other is a brief N'ly toppler but with perhaps a reload further on. Otherwise, the 18z ensembles are not worth talking about, either anticyclonic or flat atlantic zonal.

Edited December 6, 2013 by Frosty.

[Radiating Dendrite]

Personally I think we are starting to see some small baby steps from the models in the mid range (ECM, UKMO) to a more favourable situation for the second half of the month.

 

At the moment too much energy is going into the northern arm of the Jet, but slowly some models are transferring this energy into the southern arm.

 

Hopefully the 12zs will continue with this theme later on.

[Frosty.]

I'm trying really hard to bring all us coldies something to cheer on the models, I will keep looking guys.

[Frosty.]

P19 (GEFS 00z) would bring us a white christmas, the other is a brief N'ly toppler but with perhaps a reload further on. Otherwise, the 00z ensembles are not worth talking about, either anticyclonic or flat atlantic zonal.

correction, that was the flippin 18z