Model Output Discussion 17th Dec.2013-12z onwards.

[Mucka]

The NAE has been mentioned this morning and here is its interpretation of possible transient snowfall tomorrow.

 

 

An awful lot going on with the weather at the moment, especially if you are forecaster and details matter with strong winds, heavy rainfall, possible flooding and even snow all needing to be pinned down along with the weather for the big day. Phew!

 

Even so, there is room enough here for the relentless search for blocking and cold even while the UK is under siege from Atlantic storms and of course folk have the ability to discern between posts, so how about blocking prospects? 

Ian F rather dismissed the idea of any cold signal being in the MO last night but I will plough on regardless. Certainly there is no cold signal within the ensembles as such but there is still the signal for an increased  possibility of pressure rises through Scandinavia in the run up to New Year however it worth emphasising that this signal is still rather weak with the zonal express still more likely to continue into the New Year and even if we are onto something there are no guarantees that blocking will lead to a cold spell for the UK. 

So on the face of it not worth getting excited about but worth mentioning I think because part of the fun of model watching is picking out these signals and seeing if they develop or simply get blown away by the PV. I mention it again today because the GEM is now also picking up on this potential

 

 

Now it may well be this chart or similar is not repeated but it does underscore there is a window of opportunity to get some form of blocking started as we head to the New Year. What often happens with these situations is the models are too progressive with the idea of blocking when they first pick up on the potential and the Atlantic wins out but the signal returns again a little later.

I don't make forecasts but I would argue that there is no reason to expect January to continue as December ends as the jet likely sinks South giving the chance of troughing into Europe and increased amplification of the pattern - I wouldn't be surprised if we are looking at a potential cold spell as early as the second week .

 

I will await Ian Ferguson's updates on the long range signals over the next few days with increased interest to see if there is even a sniff of blocking developing into January. 

 

Okay so that is a crystal ball territory again and the here and now has plenty to offer so I return you to your normal programming.

Edited December 18, 2013 by Mucka

[AWD]

Worth noting the EURO4 model differs from the raw NAE, with snowfall forecast further SW, over the moors of Devon & Cornwall especially;

Interesting times ahead though, a respectful possibility of some white stuff for some lucky southerners!

[Frosty.]

The Gfs 06z op run shows a stormy and wintry spell on christmas day, after a relatively quiet start to the day with some wintry showers across the northwest, heavy rain and gales sweeps north and east with a spell of snow across northern england (especially the hills) working north into southern / central scotland overnight into boxing day, cold, wet and wild, and for some...white.

Edited December 18, 2013 by Frosty.

[swfc]

poor 6z imo and the pv looks pretty rampant in fi.unsettled and widy sums it up on the current mo

[Cecil Hogmanay Melchett]

All i can say regarding 06z gfs is pass me the sick bucket.

 

Unfortunately After a very very stormy and mostly wet christmas i think the pattern for the early part of Jan is now starting to slowly reveal itself,and it isn't what coldies want to see with the PV limpeted to Greeny and HP building across Europe once again.

After rereading the METO long ranger yesterday they maywell have been hinting at the remergence of the Euro high talking of dryer weather in the SE and more unsettled to the NW.

Might sound dramatic but im starting to have worries about winter 2014.

[Frosty.]

Some will disagree but the Gfs 06z op run looks rather wintry at times to me, especially from christmas onwards into early next year, rather cold and stormy with knife edge rain / snow events and squally wintry showers with snow on hills and icy patches.ok it's not a severe siberian icy blast but at least it's not mild sw'ly mush either.

Edited December 18, 2013 by Frosty.

[terrier]

Dont think people should worry too much what the gfs 06z is showing. Its renound for been the worst run of the day. And even if we do get a wet mild winter nothing any of us can do about it. And at least we all save on heating lol. Just hope these storms over the xmas period get downgraded. Because dont think any of us want to see those charts come to fruition. Especially with many of us traveling over the festive period.

[Iceberg]

Yet another run showing the xmas/boxing day storm, 06z has it entering at 955mb and exiting at 940mb. So still some quick intensification going on which will drag down the 925 winds well. For the UK and France this is shaping up to be the big storm and imho Christmas news and will be far more on forecasters minds than whether we get a few hrs of transient snow.

Its still far too early to judge how likely, but the low that forms it when it exits the US is within T144 and the controlling low is within T144.

[Nick F]

Are we talking about the 06z Nick?That run is slightly different to the 0z ..

There is a signal from high res models for for an active trough to bring snow to lower levels across S Wales, central and eastern England in heavier bursts, though it remains to be seen whether there'll be any settling below, say, 200m. 06z looks wrong side of marginal still. As others have mentioned, will be down to now casting.

[Cecil Hogmanay Melchett]

Some will disagree but the Gfs 06z op run looks rather wintry at times to me, especially from christmas onwards into early next year, rather cold and stormy with knife edge rain / snow events and squally wintry showers with snow on hills and icy patches.ok it's not a severe siberian icy blast but.at least it's not mild sw'ly mush either.

Karl i love your optimism and take on the models but i think we need to be a tad more realistic here.

The outlook for coldies is shocking.

For storm enthusiasts the outlook is very interesting but for those wanting cold and snow its as bad as i have seen it for quite a while.

As i alluded to in my previous post i'd wager we see a re-emergence of the slug high in response to the flat upstream pattern as we enter January.

God i hope im wrong here btw!

There is a signal from high res models for for an active trough to bring snow to lower levels across S Wales, central and eastern England in heavier bursts, though it remains to be seen whether there'll be any settling below, say, 200m. 06z looks wrong side of marginal still. As others have mentioned, will be down to now casting.

Cheers Nick

Any longer term thoughts, ihave a bad feeling about the early part of Jan-

[karyo]

The gfs 6z is still showing a warming in the stratosphere over Asia around 250hours but it doesn't look as significant as yesterday. That in itself won't be able to distrupt the vortex unless it gets upgraded in future runs or unless it is the first in a series of warmings.

Something to watch anyway.

Karyo

[Cecil Hogmanay Melchett]

The gfs 6z is still showing a warming in the stratosphere over Asia around 250hours but it doesn't look as significant as yesterday. That in itself won't be able to distrupt the vortex unless it gets upgraded in future runs or unless it is the first in a series of warmings.Something to watch anyway.Karyo

 Karyo gfs06z paints a horrid picture longer term and added to that the ECM mean at 240h looks abysmal as we hit the back end of December.

Surely this Atlantic onslaught has to run out of steam,doesn't it?

[warrenb]

We are talking about horrid charts, whereas the charts and ENS paint a picture that is perfectly normal for the UK. Look at the average for the ENS and the 30 year average, almost bang on.

I have looked at my weather records for last winter, and we didn't get any below average temp weather down here until the middle of January.

 

It doesn't snow every day in the winter in the UK.

[Severe Siberian icy blast]

Karl i love your optimism and take on the models but i think we need to be a tad more realistic here.The outlook for coldies is shocking.For storm enthusiasts the outlook is very interesting but for those wanting cold and snow its as bad as i have seen it for quite a while.As i alluded to in my previous post i'd wager we see a re-emergence of the slug high in response to the flat upstream pattern as we enter January.God i hope im wrong here btw!Cheers Nick :)Any longer term thoughts, ihave a bad feeling about the early part of Jan-

Yes if your focusing on the northern hemisphere with the PV looking strong it doesn't look good. But taking the 06 litterely it shows cold zonality with a much more north westerly element to the weather after Xmas , so in this instance I tend to agree with frosty. Yes it shows the euro high in deep fi but I really don't care what it's showing after 240hrs because it never happens anyway . I have seen hints of a pressure drop over Europe towards Italy recently, it happened yesterday , forget what run now . With the jet way south , and the MJO on the move (see technical thread) , that points toward a major pattern change into the new year . But cold zonality can be fun for some , and tomorrow's snow chances is very reall , and could well happen again with the jet way south .

[legritter]

Very interesting Model watching coming up especially If some cold uppers do appear .each day new possibilitys and new Synoptics to talk about .And with Christmas still 7 days away the synoptics for that day could change quite significantly .So for some thinking this Winter is Doomed from a coldies perspective ITS ONLY JUST BEGUN ,about ten weeks left plus the bonus of March ,The hunt is on ,Stellas at the ready  i,ll have a half .

[Frosty.]

Very interesting Model watching coming up especially If some cold uppers do appear .each day new possibilitys and new Synoptics to talk about .And with Christmas still 7 days away the synoptics for that day could change quite significantly .So for some thinking this Winter is Doomed from a coldies perspective ITS ONLY JUST BEGUN ,about ten weeks left plus the bonus of March ,The hunt is on ,Stellas at the ready  i,ll have a half .

Agreed, not long ago it looked like we were staring down the barrel at a mild benign euro high dominated horror show and we would now have nothing to talk about, at least we have plenty to discuss now.

[carinthian]

Very interesting Model watching coming up especially If some cold uppers do appear .each day new possibilitys and new Synoptics to talk about .And with Christmas still 7 days away the synoptics for that day could change quite significantly .So for some thinking this Winter is Doomed from a coldies perspective ITS ONLY JUST BEGUN ,about ten weeks left plus the bonus of March ,The hunt is on ,Stellas at the ready  i,ll have a half .

 

More interesting for you guys in the UK. Model watching here is becoming boring in Middle Europe. Endless sunny days with pressure constant for days on end at 1035mb. No snow in sight until Christmas Day. Snow cover becoming thinner with temperatures rising with height. Still well below freezing in the valley, currently -5c there and +6c on the ski slopes. I hate these synoptics over us, send some of your copious preciptation from Southern England. I will swop the sunshine we have !

 C

Edited December 18, 2013 by carinthian

[Summer Sun]

A new model for people to use now is the UKMO euro 4 which is now available here http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=euro4&MODELLTYP=1&VAR=prec&HH=3&BASE=-&WMO=&ZOOM=0

[Cloud 10]

A small selection of Boxing day charts from the 06z ensembles,although not for the faint hearted!

 

http://modeles.meteociel.fr/modeles/gens/run/gens-2-1-192.png?6

 

http://modeles.meteociel.fr/modeles/gens/run/gens-11-1-192.png?6

 

http://modeles.meteociel.fr/modeles/gens/run/gens-15-1-192.png?6

 

http://modeles.meteociel.fr/modeles/gens/run/gens-20-1-192.png?6

[nodrog]

Where can I find historic weather models... I want to compare this Christmas with 1995.

[Methuselah]

Where can I find historic weather models... I want to compare this Christmas with 1995.

 

Try the Archive TL: http://www.netweather.tv/index.cgi?action=gfs;sess= 

[SE Blizzards]

Where can I find historic weather models... I want to compare this Christmas with 1995.

 

http://www.meteociel.fr/modeles/archives/archives.php?day=20&month=12&hour=0&year=1995&map=4&mode=2

[Froze were the Days]

A small selection of Boxing day charts from the 06z ensembles,although not for the faint hearted!

 

http://modeles.meteociel.fr/modeles/gens/run/gens-2-1-192.png?6

 

http://modeles.meteociel.fr/modeles/gens/run/gens-11-1-192.png?6

 

http://modeles.meteociel.fr/modeles/gens/run/gens-15-1-192.png?6

 

http://modeles.meteociel.fr/modeles/gens/run/gens-20-1-192.png?6

Haha! 920mb low!! I'll eat my right leg off if it get's that deep, but have to say it looks like somewhere could get a battering in that period.

Edited December 18, 2013 by Froze were the Days

[shedhead]

Where can I find historic weather models... I want to compare this Christmas with 1995.

Try here TL........http://www.wetterzentrale.de/topkarten/fsreaeur.html

 

Looks very different to whats expected this time next week.

 

Edited December 18, 2013 by shedhead

[summer blizzard]

UKMO interestingly has the weakest primary low and probably lends itself to a higher chance of snow from the secondary.