Model Output Discussion: 12Z (02/12/12) And On...

[swfc]

Bank that chart at 240hrs.Just to note for those concerned with the ukmo at 144 hrs ecm and gfs are all nearly in agreement at that timescale!!!!

[IDO]

Well no surprise, we said the Atlantic will keep up a fight and on the GFS 0z it does. Only for the south though so there should be some good snow for the north when the two lows track south/SE Friday and late Saturday. Maybe some sleet for over 300 feet in the south.

Another delay for the wintry arrival. The second low doesn't go SE and instead goes east marrying with another low already there. This allows the ridging to move NE, from the Atlantic:

http://cdn.nwstatic....192/h500slp.png

http://cdn.nwstatic....372/h500slp.png

into the UK, and bring cool settled weather to most (D9). It remains over the UK for the next 6 days+, at times bringing in colder uppers. However not what the potential promised. The GEFS:

http://cdn.nwstatic..../t850London.png

Potential still there to keep the cool/cold right through FI. As said, a hiatus until the PV decides where it is going. The mean better in the medium term than the op as well:

~ECM showed via their ensembles yesterday that most routes lead to some degree of cold and the 0z this morning is another option:

http://www.meteociel...1-216.GIF?03-12

So short term for the south, cool this next seven days with low chance of snow below 300 feet (on this run). Several chances for the north and lot colder there:

http://wxmaps.org/pix/temp4.html

The SW has close to average mean surface temps. Scotland 0 to -5c. The rest just cool. The middle map is the promise, with most of Europe going cold/v.cold in week 2, except us, of course, yet. Just need that easterly now.

Edited December 3, 2012 by i'm dreaming of...

[Iceberg]

Continuing very cold models this morning and the saying all roads lead to cold couldn't be more true. The general n.circulation pattern look overwhelming even if short measo scale features so any interruption is very short lived. The ECM 12z yesterday has an arctic circle high from Alaska, across Russia all the way to Iceland, covering over half the global at tht point with reversal winds.

All of the models show something cold and potentially snowy, ens is in good agreement with tightly clustered 70% or so cold members.

We just need to chill and see how it gets there

[Paul_1978]

Bank that chart at 240hrs.Just to note for those concerned with the ukmo at 144 hrs ecm and gfs are all nearly in agreement at that timescale!!!!

Also worth remembering that the UKMO was the last to come on board last week during the major pattern shift when everyone on the board was reaching for the Prozac. ECM picked it up first, UKMO last.

So the fact the UKMO is still showing something different is not a concern to me - it will sing from the same hymn sheet as the others shortly.

[Cecil Hogmanay Melchett]

delicious ecm this morning!!

that run really does bring in some extensive northern blocking and southerly tracking jet stream.fingers crossed.

[TEITS]

Fasinating looking at the model output because despite disagreements at +144 the eventual outcome continues to be blocking to our NE with a decent E,ly developing. Obviously we have an underlying signal that is pointing the models in this direction.

As you can see at +144 the GFS/UKMO/ECM differ with regards to the LP with the ECM inbetween the UKMO/GFS.

http://www.wetterzentrale.de/pics/Rtavn1441.png

http://www.wetterzentrale.de/pics/Rukm1441.gif

http://www.wetterzentrale.de/pics/Recm1441.gif

Ideally we want this LP to move as quickly SE ASAP. Simple reason being the quicker it does this the quicker the E,ly develops with less chance of complications. The ECM +240 chart really is a peach and its a shame we don't see later timeframes because it would get even better as that SW tracks S.

So overall im pleased with the model output but im refraining from ramping until we get +144 sorted out.

[nick sussex]

Oh the UKMO.......

Yes this model never progs a colder set up at 144hrs which verifies but you can bet your life it always verifies when it has an annoying cold delaying output.

The GFS IMO looks cleanest and therefore safest , the ECM promises much at the end but decides to go the UKMO route, not good if you're of the nervous disposition.

It's hard to see the GFS holding out against the ECM/UKMO but you live in hope. I know some might wonder why I'm so anti the long drawn out route to what at first hand seems a good end point but been there done it and got the no sledge t-shirt to prove it.

To assume good synoptics will appear well past 168hrs when the earlier output has a weaker foundation is asking for trouble, but hey thats just me being pessimistic.

The overall NH pattern is still good and hopefully the ECM/UKMO do get over the line but its going to be a fraught couple of days waiting to see if they do.

[Iceberg]

i do think your being a little too pessimistic nick, the ecm if you follow the 850s is pretty good really and has more than a few days that will delivery snow for some between 0Z and 240Z. It starts well at T0 and ends well at T244.

It might not give country wide snow, but its still pretty good for the first 2 weeks of winter and ends full or promise.!

Cheers

[weather eater]

GFS looks broadly similar to its last nine outputs even out beyond 144hrs, I'm going to stick my neck out and suggest the others will eventually fall into line with it.

Edited December 3, 2012 by weather eater

[IDO]

Oh the UKMO.......

Yes this model never progs a colder set up at 144hrs which verifies but you can bet your life it always verifies when it has an annoying cold delaying output.

The GFS IMO looks cleanest and therefore safest , the ECM promises much at the end but decides to go the UKMO route, not good if you're of the nervous disposition.

It's hard to see the GFS holding out against the ECM/UKMO but you live in hope. I know some might wonder why I'm so anti the long drawn out route to what at first hand seems a good end point but been there done it and got the no sledge t-shirt to prove it.

To assume good synoptics will appear well past 168hrs when the earlier output has a weaker foundation is asking for trouble, but hey thats just me being pessimistic.

The overall NH pattern is still good and hopefully the ECM/UKMO do get over the line but its going to be a fraught couple of days waiting to see if they do.

Yes it's experience rather than charts that tell us the UK will get to the clear synoptic pattern via a drawn out convoluted route. The good news it is almost certain to get there and any delay, especially with the potential cold pool developing in Europe, may indeed mean an even harsher cold spell. So win win (hopefully, fingers crossed).

[chris55]

ECM much better than GFS at 192 with the Low undercutting the building ridge, GFS pushes some energy over the top,

http://www.wetterzen...cs/Recm1921.gif

http://www.wetterzen...s/Rtavn1921.png

Resulting in a good Greenland block on ECM versus an Atlantic high on the GFS

http://www.wetterzen...cs/Recm2401.gif

http://www.wetterzen...s/Rtavn2401.png

But as others have said a long way to go yet, but it's encouraging ECM is following it's longer term outlook (ec 32) and the trend for height rises to the north and east remain.

Edited December 3, 2012 by chris55

[Bristawl Si]

Yes it's experience rather than charts that tell us the UK will get to the clear synoptic pattern via a drawn out convoluted route. The good news it is almost certain to get there and any delay, especially with the potential cold pool developing in Europe, may indeed mean an even harsher cold spell. So win win (hopefully, fingers crossed).

Just because there's a cold pool developing in Europe during Winter doesn't guarantee that the UK will tap into it - a cold pool in much of mainland Europe is pretty much the default position in Winter after all.

I sincerely hope that we do eventually but is anyone else out there getting the feeling we could be chasing widespread deep cold (and maybe countrywide snow events) for all the period leading up to Xmas?

[Dexter29]

Just because there's a cold pool developing in Europe during Winter doesn't guarantee that the UK will tap into it - a cold pool in much of mainland Europe is pretty much the default position in Winter after all.

I sincerely hope that we do eventually but is anyone else out there getting the feeling we could be chasing widespread deep cold (and maybe countrywide snow events) for all the period leading up to Xmas?

Absolutely, we have some great members in this thread with very good knowledgable posts. However - bottom line - we are ALWAYS chasing real cold that is 144hrs away.

[Frosty.]

A wintry week ahead, especially further northeast, and there is no doubt the Ecm run would be much better for long term very cold prospects with high pressure retrogression, strong height rises to the nw sector, really wonderful synoptically with arctic air flooding south over the uk, a really strong looking cold block in place. On the other hand, the Gfs 00z op run rather fails towards the T+240 hour mark and never really recovers with high pressure in the atlantic poorly positioned and orientated and gradually feeds less cold air/milder over the top of it and then down across the uk, this high is even a spoiler for a massive arctic surge towards the end of FI which is shunted further east due to that high to the nw being too close, the ecm has the high further northwest out of harms way and just allows the floodgates to open. As for this week, ironically the gfs 00z looks better in the short term with lows pushing southeast from iceland and colder air digging in behind, this happens 3 times, late tuesday, friday and then later in the weekend with arctic air then pushing south each time with wintry showers and sharp frosts, the ecm 00z looks a little bit flatter this week, the gfs rather more amplified but longer term it's the ecm which brings the uk a much colder further outlook.

[weather eater]

Just because there's a cold pool developing in Europe during Winter doesn't guarantee that the UK will tap into it - a cold pool in much of mainland Europe is pretty much the default position in Winter after all.

I sincerely hope that we do eventually but is anyone else out there getting the feeling we could be chasing widespread deep cold (and maybe countrywide snow events) for all the period leading up to Xmas?

No because I don’t think the models have given the impression that deep cold is just around the corner. It’s one of the odd things about this thread, people want to see fantastic outputs that go deep into FI but then get bored waiting for them to come around or worry excessively over every run that doesn’t show those fantastic synoptics. There is no guarantee of deep cold for the UK but the models are being consistent at interpreting the broad long range signals at the moment.

[stainesbloke]

Well we are still chasing the possibility of cold in the next couple of weeks.....was doing that 2 weeks ago and so far there has been nothing more than normal early Winter weather, at least here in the SE. I like that the charts keep pointing to a blocked scenario but that's still quite a long way from snow/deep cold over the UK. The shorter term looks more interesting IMO, anything after 5 days is anyone's guess.

[snow drift]

Absolutely, we have some great members in this thread with very good knowledgable posts. However - bottom line - we are ALWAYS chasing real cold that is 144hrs away.

I think people need to look at the output. We need clarification of which way it might go at T144. However, we still end up with interesting weather at the end. IMBY is coming into some of the posts which will always have an influence in how the output is portrayed. We have had colder than normal temps. We are in what was described by the BBC as a "mild blip" and we are heading back into below av temps for the foreseeable. Enjoy where we are and see what develops from now. The detail will come in time. T144 from now is the point at which we need clarity and future runs will start to resolve this.

I look for deep cold due to my location but if many areas don’t see snow over the next three weeks then this will be a period of model watching that will be remembered for a long time. So much in our favour.

[Dexter29]

No because I don’t think the models have given the impression that deep cold is just around the corner. It’s one of the odd things about this thread, people want to see fantastic outputs that go deep into FI but then get bored waiting for them to come around or worry excessively over every run that doesn’t show those fantastic synoptics. There is no guarantee of deep cold for the UK but the models are being consistent at interpreting the broad long range signals at the moment.

You are kidding right? Only the other day were 70's style charts showing up, synoptically the best. Something I have never seen while following the models and reading the great posts on this thread.

2 weeks ago - charts were showing the UK to be in some proper cold by now.

Edited December 3, 2012 by Dexter29

[Weathizard]

Not sure regarding the output this morning, I like the fact there is still a consistent signal for blocking but it seems to get further away every time I look at the charts, perhaps I'm being negative but we have seen a fee ECM runs recently show a stunning 240, but the evolution before that worries me because as Nick as already said, it takes us down a more complicated route and we have a lot that could go wrong. I'm not negative(I hope) just think we may need a lot of patience and realism about how long this could take because as usual there are so many things that can go wrong, I still think we'll get a very cold spell at some point but I think it will be at least 15'th before we get the prolonged cold

[swfc]

Seems a couple of runs and its rutting season again!!Anyway its december 3rd outlook in generall looks cold for most with the chance of a bit of snow here and there.Nothing biblical or "2010"but things heading in the right direction for coldies.In my opinion still a lot of firming up to do between 96-144 hrs regarding the movement of areas of low pressure but as ever the change from run to run leaves that wide open.All in all interesting times and pretty good week coming up for early december

[EML Network]

For the first time this Winter I am actually beginning to get excited about the prospects of some decent cold and snow potential.

I tend not to get too excited about anything post + 144 unless there is model agreement about it being cold and snowy, but this morning I see a trend to something quite interesting (IF it varifies)

Starting with the NOCAPS , and a nice big Greeny high, chart loaded with potential

EMC for a 2nd run in a row offers up something very nice quite late in the run another nice big greeny high

Now the GEM at + 144 (notice the similarity to the UKMO at the same timeframe)

4

ukmo + 144

THE GEM goes onto show this >>>

And finally our friend the GFS with ...a Greeny High

The JEM doesn't offer us anything of interest but trends along a similar path, so all in all some positive signs, but I am in the Nick Sussex school of thought and it's probably only an age difference that gives him more T-Shirts than I ...I feel something brewing and it's not my morning cup of coffee

[Isolated Frost]

WRF-ARW higher res with a strong snow signal for north and east on Thursday- SW-NE upper low complex could lead to some caa into north sea as well-

[swfc]

Well we are still chasing the possibility of cold in the next couple of weeks.....was doing that 2 weeks ago and so far there has been nothing more than normal early Winter weather, at least here in the SE. I like that the charts keep pointing to a blocked scenario but that's still quite a long way from snow/deep cold over the UK. The shorter term looks more interesting IMO, anything after 5 days is anyone's guess.

Ithink you will find that anything more than a week away on the models will come the time be almost deff not in line with the original forecast.You will here folk forecast severe weather based on the strat,nao,no,mjo ete ete.The truth is if you stick around the 120-144 hour mark it will be close but that said the fax charts are at the moment swinging and changing!!!.Living on an island at our latitude makes the weather interesting but very difficult to forecast lol

[Stu_London]

Just a very general point.

I do think there is a tendancy for people to look at the charts on Metociel and get a bit carried away. This is because of their rather extreme dark colour scheme. I've often looked at a chart on Metociel which appears very interesting only to look again on the net weather version (or the german one, tbf) and see that what looked like a juicy winter chart was fairly ordinary.

Everything in the reliable time frame remains just on the wrong side of marginal for the vast majority, rather like the weather of the last couple of weeks.

Edited December 3, 2012 by Stu_London

[lorenzo]

Stewart, any take this morning on the NE NW blocking and how you see the mid range ?