Model output discussion - winter proper underway

[frosty ground]

Hmmmm Atlantic is quieting down a bit here, probably a reflection of the height getting further over the pole form the alaskan ridge.

[frosty ground]

2 minutes ago, bluearmy said:

A very interesting set of 12z suites emerging with the anti PVTL in full swing day 5 !!!!

 

Anti PVTL?

[Longtimelurker]

Big difference in GEM this run, from this

 

To this

Edited December 20, 2017 by Longtimelurker

[Weathizard]

Not looking past day 5 at this point, but this looks a very interesting and unusual chart from the UKM at day 5

[Seasonality]

Big changes relatively early on from the GFS. Comparing run to run, stronger high pressure towards the pole squeezing out the vortex in Greenland, very different pressure profile over Greenland, Iceland and the North Atlantic and this only five days out.

 

 

[frosty ground]

Vs

You can see the difference over the pole

[Singularity]

GFS aligning the Arctic High very similar to the 00z ECM... now that’s an interesting development!

[Seasonality]

By t+144 the UK is comfortably back in cooler uppers.

[bluearmy]

10 minutes ago, frosty ground said:

Anti PVTL?

Nick’s acronym 

polar vortex transfer lobe

 

[joggs]

5 minutes ago, frosty ground said:

Vs

You can see the difference over the pole

And the jet slightly further south.......interesting.

I can only see upgrades over the next few days.

Edited December 20, 2017 by joggs

[frosty ground]

The slider that we was told earlier was impossible looks to be a bit further south.

[Seasonality]

4 minutes ago, joggs said:

And the jet slightly further south.......interesting.

I can only see upgrades over the next few days.

I think further upgrades are a real possibility. Next week could turn out to be a slightly delayed wintry Xmas gift.

Edited December 20, 2017 by Seasonality

[northwestsnow]

GFS is pretty good for the period between xmas and new year-much better run than the earlier ones..

Still quite a big difference at 144 tho and ukmo nowhere near as cold  i would suggest.

Wonder which way EC will go?

[shaky]

Really surprises by the ukmo and gfs 12zs!!did not expect a split like that across greenland!!bar navgem and ecm no other model has shown it consistently enough!!so we could be staring at another cold and snowy spell from christmas evening next week!!

[Chesil View]

I posted a reminder this morning about GP's thoughts backalong that he suggested a date around the 21st /22nd December to start seeing interesting developments in the Nwp irrespective of any transitional phase. Well its the 20th today and developments are getting interesting.

[West is Best]

That's a 12z GFS run which is distinctly more flavoursome for cold lovers. It may not yet deliver the full monty, but it's certainly not flat, zonal and mild. 

I love the way this is progressing. We need to see if this has more support in the ensembles but this could be the harbinger of something really exciting. Or not, of course  I'm encouraged.

[Daniel*]

A snowy Boxing Day for Scotland on UKMO:

[northwestsnow]

ukmo 144 is quite fascinating- will the jet continue to dig south allowing all that freezing arctic air over northern scandy to be pulled towards the UK- or will the energy spilling out of the ESB flatten everything out (ala METO update earlier)..

 

Edited December 20, 2017 by northwestsnow

[West is Best]

31 minutes ago, joggs said:

And the jet slightly further south.......interesting.

I can only see upgrades over the next few days.

Yep agreed. I have no problems with a powerful jet: providing it splits and disappears south of us. It's often the prelude to a fantastic spell of cold and subsequent block.

[bluearmy]

2 minutes ago, northwestsnow said:

ukmo 144 is quite fascinating- will the jet continue to dig south allowing all that freezing arctic air over northern scandy to be pulled towards the UK- or will the energy spilling out of the ESB flatten everything out (ala METO update earlier)..

 

Given the updates we know where the clever money is - the ecm later will be notable for having a view post day 6, assuming it gets to day 6 like it’s previous run over the polar field. 

With a polar high there is always the chance that the nwp in general could be ‘caught on the hop’ 

Unlikely but possible 

[mulzy]

Ban me for posting an ICON chart if you must but this is close to a very good chart.

[Ali1977]

3 minutes ago, mulzy said:

Ban me for posting an ICON chart if you must but this is close to a very good chart.

Looks great, just a mass of cold air over in the USA that normally ramps up a big lump of PV that flattens any attempted splits or Greeny highs

Edited December 20, 2017 by Ali1977

[nick sussex]

What drama!

Christmas week has gone from a dull underwhelming affair for coldies to now  a range of options on offer including some snow.

Both the GFS and UKMO support the ECM 00hrs view of the Pacific Ridge extending south into Greenland.

The high lobe effectively gets forced south into Greenland as low pressure runs towards the Aleutians , boxing the high in.

Where the pattern goes afterwards is a lot more uncertain re the track of energy spilling east. Given the ECM seems to have been the first to model the Pacific side correctly then one would expect it to have a better idea of how much ridging heads south and so I'll leave the deciding vote to that later on.

 

[Longtimelurker]

12 minutes ago, northwestsnow said:

ukmo 144 is quite fascinating- will the jet continue to dig south allowing all that freezing arctic air over northern scandy to be pulled towards the UK- or will the energy spilling out of the ESB flatten everything out (ala METO update earlier)..

 

Wouldn't the cold air be coming down from the North rather than via Scandinavia in this set up? Looks like its coming from the direct North to me but I'm just a noob

Edited December 20, 2017 by Longtimelurker

[Seasonality]

5 minutes ago, mulzy said:

Ban me for posting an ICON chart if you must but this is close to a very good chart.

Go on, get out the Navgem or the Chinese or Brazilian models.