Model Output Discussion - Christmas and New Year

[Mike Poole]

GEM looks like another classic, it’s rolled out a few recently, here T162:

[Kasim Awan]

GEM is more favoured over gfs atm ❄❄❄

Send sufficienr energy south to prevent toppiling as the gfs tried to do but failed..

[Mucka]

Plenty of interesting weather and marginal snow events to come over the next week and then the early part of Jan looks to be very interesting (potentially very snowy)

It does now look as though we will see the repeating pattern set up I mentioned was a possibility a few days ago with Atlantic ridge being eroded from the NW and then rebuilding.

As these LP systems must attack from the NW on a SE trajectory they offer far more interest than the normal W to E track and associated wind and rain of our normal Winter pattern.

The first of these is pushing through today but with a large warm sector ahead so will be rain except perhaps far N and hills but thereafter the systems should be less vigorous and coming into colder air although they will still throw warm sectors ahead - how much they slide will determine how much the cold air gets mixed out but because they are coming into established cold air as well snow chances will be much greater and heavy snow at that.

Here we are GFS 12z 192 with a renewed attack from the NW, not much sliding but still the warm sector is held mainly W and being chilled by colder ahead which could give heavy widespread snow and while rain is possible snow looks the favourite unless we get unlucky with a more E tracking and blown up low.

The lows should though disrupt and head on a more S track and with that the Atlantic reamplify behind

From there we will would either continue the pattern or perhaps bring in a more NE/E flow perhaps bringing colder and somewhat more settled weather though with snow chances especially for the E.

The only way beck in for the Atlantic within 2 weeks appears to be by the jet slowly heading on a more N track and the pattern eventually flattening out but even then we would have had a protracted cold spell with snow chances.

From here is just a case of hoping the marginal setups favour us for some snowfall as different locations are favoured as we get into the cold spell proper.

NW England looks like it could have a chance of heavy snow showers tomorrow but we will see how that develops.

Perhaps no deep cold is programmed but exciting times ahead for snow fans.

 

EDIT

I should add ensembles are currently offering many different solutions past 144 including cut off high to our NW but just about all offer good wintry potential.

I expect the high would offer deeper cold but a more settled pattern, not sure what I want to root for, just bring the snow.

Edited December 26, 2020 by Mucka

[Eagle Eye]

GFS at T+102 Just wow an incredible Upper feeding through bringing Scandanavian air with it as well. 

[sheikhy]

Gota say looks like the gfs has had its victory in terms of gettin this current pattern right with the slight amplification but i think its back to normality now and ecm/ukmo will show the damn model whose boss!!

[Cuban Zebra]

3 minutes ago, TSNWK said:

Yep.. colder uppers over uk brushed aside from the east......

I was just about to say the same, although wouldn’t need much cold from the North to cool it down!!

[Daniel*]

GFS sister is in another world to it... an actual cold easterly. 

[sheikhy]

Control looks more likw ukmo at 150 hours and the mean looks the same!!!over to ecm to kill this off!!

[winterof79]

That depression is tilted towards you know who although i think the jet is buckling

Edited December 26, 2020 by winterof79

[Scott Ingham]

27 minutes ago, Daniel* said:

GFS clearly has lost its consistency and it is reversing to old habits. Old habits die hard.

Lets not forget the GFS nailed the very first amplification into greenland the first time and is generally better in that area so as to not let confirmation bias set in things may flatten out just a touch. 

It wouldnt be for long tho as the over riding atmosoheric set up will only reamplify once more

As long as we stay on the right side of the jet we will hang on to the cold either way and stay in a holding pattern until the next round

[Chesil View]

1 minute ago, Scott Ingham said:

Lets not forget the GFS nailed the very first amplification into greenland the first time and is generally better in that area so as to not let confirmation bias set in things may flatten out just a touch. 

It wouldnt be for long tho as the over riding atmosoheric set up will only reamplify once more

As long as we stay on the right side of the jet we will hang on to the cold either way and stay in a holding pattern until the next round

Quite so Scott. Ebb and flow and all that.

[Kasim Awan]

GEFS is certainly far from totally supporting the Polar Maritime evolution to cold

Confirmed by the deviation charts, slightly technical but shows uncertainty around Greenland and therefore some support for less flattening...

[SLEETY]

Could be mega fl if that high retrogresses to greenland  and trough drops down.......maybe..

[Mike Poole]

The GFS parallel is looking very good for cold and snow at T192:

I think this is about the best of what’s on offer at the moment.  But GFS // also very consistent re the strat warming, here T228, and very similar to the 6z:

As I mentioned in the strat thread, one of the major enhancements of the new parallel GFS is in the vertical resolution, so this could be good news, because that looks a favourable split (caveat that this only shows temperature). 

[Allseasons-Si]

All three at day ten

gfs/gfs/p and GEM

i think the models are trying to latch onto the eps/cpc anomalies here with Atlantic/Scandi heights combo with trough underneath .

[Eagle Eye]

ECMWF Amplified showing a Strong Low coming through from Greenland with High Blocking being quite Strong With A Weakening Low Over time. 

 

[Scott Ingham]

4 minutes ago, Broadmayne blizzard said:

Quite so Scott. Ebb and flow and all that.

Yeah in my opinion this is what we are seeing.

On the flip side when thought about in more depth.

Although its better in greenland it is super poor in split energy scenarios.

Taking that into account i would suggest a middle ground.

Lower heights around greenland compared to the euros but more energy headed south i.e its sister parallel model??

The parallel could be nearer the mark.

The upcoming ecm will help in this regards as its the king of split energy

[Man With Beard]

Still an awful lot of toing and froing with regards this little low for Monday morning, but the ARPEGE seems a middle ground, and along with ECM would be my first model to check now - It shows the low moving from the Irish Sea, down to Devon, then swinging up the channel. Precipitation on Monday (and possible snow) therefore seems a Welsh and South West England affair, with the chance of rain/snow also brushing channel coasts.

Wouldn't get to hung up on charts beyond that - anyone remember the January 2010 snow that covered the whole country? The low that caused it was only picked up at T48, on a northerly flow.

[winterof79]

 

No point in thinking one run has nailed the evolution 12z v 6z

Goodness me that is some chart from the //V16

Edited December 26, 2020 by winterof79

[Allseasons-Si]

Just for fun but what's the gfs/p up to here!

and it has been quite consistent with a split spv for the past few runs.

 

[SLEETY]

Better cold pool on gfs at the end,but worth nothing as the consistency of this model is back to utter rubbish again.Nailed this cold spell coming but awful since then for some reason.

[Daniel*]

15 minutes ago, Scott Ingham said:

Lets not forget the GFS nailed the very first amplification into greenland the first time and is generally better in that area so as to not let confirmation bias set in things may flatten out just a touch. 

It wouldnt be for long tho as the over riding atmosoheric set up will only reamplify once more

As long as we stay on the right side of the jet we will hang on to the cold either way and stay in a holding pattern until the next round

Not the point here Scott inconsistency as now does not yield confidence. It’s completely alone in stratosphere as well.... I don’t have much confidence in the model at the moment. Until EPS shows it seriously flatter which it wasn’t screaming from rooftops with initial amplification, I don’t think anything drastically has changed. 

[Scott Ingham]

2 minutes ago, Allseasons-si said:

Just for fun but what's the gfs/p up to here!

and it has been quite consistent with a split spv for the past few runs.

 

Whats left of the vortex showing over europe?

Yeah ill take it! Hahaha!

[sheikhy]

Mean is good at 204 hours and control slides that low further west compared to the op!!you can clearly see whats happening here gfs op is struggling and will probably do one of those typical slow crawl back round to reality lol!!what a day for me got a clean sheet from my fantasy football players as well!!cmon ecm dont let me down

[Scott Ingham]

1 minute ago, Daniel* said:

Not the point here Scott inconsistency as now does not yield confidence. It’s completely alone in stratosphere as well.... I don’t have much confidence in the model at the moment. Until EPS shows it seriously flatter which it wasn’t screaming from rooftops with initial amplification, I don’t think anything drastically has changed. 

As i stated gfs parallel is the one on the money. I said i think its splitting too much energy north but it did nail heaights over Greenland so an objective way of thinking is needed.

I never said we will end up flat and warmer i just said i dont think heights will be what they were 4 days ago shown.