Model output discussion - 5th December 2016 - Into Winter we go

[mcweather]

1 minute ago, CreweCold said:

The Atlantic isn't blocked though? It's roaring away 1000 miles N of us!

We need to be on the N side of the jet, not stuck on its southern side under a dome of warm uppers!

Yes Crewe we know that but Iceberg is talking about the potential to move on from that point as per some of the gefs

[Cheshire Freeze]

6 minutes ago, mcweather said:

Yes Crewe we know that but Iceberg is talking about the potential to move on from that point as per some of the gefs

There's potential at any given timeframe though. The day 10 ECM chart is the same chart we've been seeing day in and day out over the past 2 weeks or so. My point was why single that chart out and highlight potential? He was using that chart to make a point about the wider trend in the 14 day + period and he was wrong to do so because it does not fit that particular script. And neither should it do at day 10 (outside point of interest).

People do have the right to post what they want...completely agree. However if you're going to post (an opinion as THAT ECM put it) then you leave yourself open to scrutiny if we're to have a healthy debate- especially when what you post is spurious in the first instance.

Edited December 20, 2016 by CreweCold

[Scandinavian High.]

Cooling trend as move on in to January.

[Frosty.]

I don't think anyone should write January off with perturbations like these from the GEFS 12z..admittedly they are in FI but they show potential all the same, enough to keep coldies interested!

Edited December 20, 2016 by Frosty.

[That ECM]

10 minutes ago, CreweCold said:

There's potential at any given timeframe though. The day 10 ECM chart is the same chart we've been seeing day in and day out over the past 2 weeks or so. My point was why single that chart out and highlight potential? He was using that chart to make a point about the wider trend in the 14 day + period and he was wrong to do so because it does not fit that particular script. And neither should it do at day 10 (outside point of interest).

People do have the right to post what they want...completely agree. However if you're going to post (an opinion as THAT ECM put it) then you leave yourself open to scrutiny if we're to have a healthy debate- especially when what you post is spurious in the first instance.

CC I enjoy your posts on most occasions but your are abrasive which is an odd way to have a healthy debate. Disagree by all means but constructively helps all to learn. Season of goodwill and all that?

[Cheshire Freeze]

4 minutes ago, inghams85 said:

I think I'm not the only poster who thinks you need to get off your high horse and drop the attitude. I could understand it if you were a trained meteorologist. Your not your an amateur like 90% on this forum

Indeed I am. Never pretended to be anything else. I have also been corrected on plenty of occasions...

There is no high horse, just a desire for a touch of reality? I like a ramp as much as the next person but there is really nothing to even remotely raise a smile for at the minute- to suggest otherwise is just misleading. That's my point.

There's a reason why even the rampiest of the rampers like Steve Murr are quiet at the moment...as he said earlier, we're looking 2nd week in Jan now at the earliest for a decent shot at cold.

Edited December 20, 2016 by CreweCold

[tight isobar]

Cross output is speaking for itself here.

The pv have an 'anger' issue and is gaining in momentum in its comfort zone...and that isn't unfortunately on an eastern migration! Also I appreciate some are in learning form via modeling. ..However toughness is sometimes the better of gain!

Anyhow with current synoptics its looking-mid- January' before atm anything plausible in terms of noteworthy aspect! !! ...hard reality..Im afraid! !!

 

[Nick L]

I swear this was the model thread...can we move on please and stop ruining the thread for others?

[knocker]

The anomalies this evening are firming up on the pattern they have been indicating for a couple of days now and they are on the same page so confidence level is reasonable high that the day by day evolution will fit within this frame work.

Thus we have the retrogression of the Atlantic trough as the vortex becomes more centred over N. Canada although the ecm is keen to have a second lobe associated with the eastern European trough. The upshot of this is a flat upper flow across the United States with a fairly deep trough in the western Atlantic and continuing build up of heights south of the UK ridging north  Ergo quite an amplified pattern across the Atlantic and this amplification is entirely dependent on the orientation and intensity of the two main players. This is illustrated quite well by just comparing the GEFS and ecm. This will not make a huge difference to outcome but any systems tracking NE with associated fronts would be more likely to impact further south over the UK with the GEFS scenario. But that's being a bit picky on the whole we are looking at generally settled and dry weather in a warm airstream, relatively speaking.

Moving into the 10-15 time frame the main change possibly the weakening of the Atlantic trough (losing the negative anomaly) so less amplification but still positive anomalies adjacent to the UK. There is no total agreement on this pattern and everything is a tad nebulous so there is plenty of room for some adjustments over the next few days. Meanwhile things continue to look quite pleasant particularly for the southern half of the UK.

[Matthew.]

Can't believe the models are firming up on another settled spell. A short-lived zonal spell. It used to be the other way round. A dry December on the cards. It will be interesting to see at the end of the month just how dry

[Rocheydub]

30 minutes ago, CreweCold said:

Indeed I am. Never pretended to be anything else. I have also been corrected on plenty of occasions...

There is no high horse, just a desire for a touch of reality? I like a ramp as much as the next person but there is really nothing to even remotely raise a smile for at the minute- to suggest otherwise is just misleading. That's my point.

There's a reason why even the rampiest of the rampers like Steve Murr are quiet at the moment...as he said earlier, we're looking 2nd week in Jan now at the earliest for a decent shot at cold.

 

Heaven forbid you disagree with a ramper.

CC is absolutely spot on with his assessment of that chart and the contradiction of Frosty's post. In the posted chart, there is still a large chunk of the PV over Greenland, and we are under a HP cell, but on the warm side of the jet. There is zero chance of cold in that chart at all, apart maybe from inversion. People jumping all over CC, because he disagreed with a ramper is just ridiculous.

I'm an amateur too, but I can read charts, and CC was spot on.

Edited December 20, 2016 by Rocheydub

[Timmytour]

I want cold and snow as much as anyone and fervently I still believe that something near 47 is afoot. Yet I agree with CC. And I find that Knockers posts on average deliver the most accurate long term forecast ....by which mean  T72 plus...

[phil nw.]

Ok guys keep it friendly.A few posts have  had to be pruned.

Now back on topic please. 

Ta.

[legritter]

Its looking increasingly likely that after the coming unsettled spell which is forecast by models charts etc  Will come a spell of high pressure dominated weather for the UK but where this high pressure is going to be situated come the turn of the new year is still yet open to many possible out comes .of course it could move away south allowing the atlantic train to come rushing in ,or it could even back west then migrate north , there seems to be many options on the table , but looking across the atlantic it does look like high pressure could be setting up shop around n east canada ,which could allow our weather to perhaps take on more of a wintry outlook as high pressure could set up further to our north ,but i,m hoping that all of us can see some wintry weather come next year ,A bit of snow on the ground hanging around for a while and a few ice days ,not asking for much ,i can see the headlines now ,5CM snow causes chaos ,transport paralysed  ,Net weather posters dragged away by men in white coats ,cheers gang 

[Nick F]

Nick Finnis weekly Medium-long range outlook - 20.12.16

With little signs of any sustained cold and wintry spells on the horizon, certainly for the remainder of 2016, it’s perhaps worth looking at what’s driving this pattern which is so hostile to high-latitude blocking and the UK getting anything more than just fleeting shots of cold zonality behind deep lows passing north of Scotland over the coming days.

The upper pattern in the northern hemisphere is rather unconducive to a -NAO and -AO. We are seeing the  NAO and AO reach high positive values. This partly down to rapid intensification of 10hpa zonal winds with forecast cooling of temperatures to near record levels in the upper levels of the stratosphere in similar fashion to Dec/Jan 2015.

Currently the strat PV is elongated as per ECMWF 10hPa chart below, but the same model forecasts a tight / symmetrical vortex circulation by day 10, almost as strong as last winter  and there doesn’t seem to be a piece of guidance keeping it elongated, or purturbed. Though there are hints that there may be some wave 1-2 attacks down in the next few weeks, particularly from Europe/Scandi area and EC ens is also hinting at strong Gulf of Alaska ridge on current guidance, though they may not be strong enough to induce anything more than another elongation /stretching of the sPV.

We are in a period of largely low AAM regime in which is also generally unfavorable for wave-1/2 amplification on the Pacific side, however, there is a Pacific wave train evident looking at 500mb guidance which some model forecasts maybe missing.

In the longer term what happens in the stratosphere is crucial to how the rest of the winter pans out. But in the shorter term, the best opportunity for a pattern shake-up is likely be reliant upon MJO forcing. As those who follow the daily MJO forecasts from all the models, GEFS has been keen to move the MJO out of the circle of death (COD) into 8/1 – which is conducive to blocking shifting to high latitudes and possibly a colder pattern for us.

Other models are less keen to come out of COD, EC notably, but good chance these models will offer a more favourable look into Jan. In fact you can see the progression of the wave eastward on the latest CHI-200hPa forecasts.

However, not everyone buys in the MJO driving the pattern. But with the strong PV not likely to break down easily anytime soon, this may be where we have to look for something to shake up the pattern.

For now, MLB returns on the seen in the medium range after a bout of stormy Atlantic zonality, so strong chance its back to anticyclonic in the New Year:

[Iceberg]

Well 12z gfs p has just come out and looks very much like the t240 ecm at t240. 

It goes on to show the Atlantic completely blocked come the begining of January. All in all at this range that's all you can hope for. Plenty of potential from a blocked atlantic. 

[A Frayed Knot]

[frosty ground]

A bit more ringing in the Atlantic 

[Iceberg]

good update from Matt, hoped the ecm would show those solutions as we go into Jan  

[Man With Beard]

GEFS mean and ECM means at D15 - not miles apart (and fairly consistent with the most recent EC32 too). Heights centred just to our SW with a hint of retrogression ESP on GEFS.

Of course, the individual members will vary around the theme, so quite likely the ECM will throw some blocks slightly further north as well as south. 

[stewfox]

18z big changes to the north east by 29 dec                                                         

 

 

 

[Grimsby Snow Lover]

3 minutes ago, stewfox said:

18z big changes to the north east by 29 dec                                                         

 

 

 

In what way Stewfox? Thanks

[Banbury]

5 minutes ago, Grimsby Snow Lover said:

In what way Stewfox? Thanks

Not anything spectacular but its a cold day and cold air never too far away

HP clinging on D10 but this is deep deep FI

[stewfox]

17 minutes ago, Grimsby Snow Lover said:

In what way Stewfox? Thanks

Far more cold air too our North East as there appears to be a change in the surface features prior to that. Its a observation. One chart attached from yesterday the other from today. This pushes -10c 850s into southern Italy a bit later !

Tonight 18z .. midnight xmas day

Yesterday

Impact 29 dec

Edited December 20, 2016 by stewfox

[Dennis]

some PV is coming down