Model Output Discussion 29th December - Into mid-Winter.

[Ali1977]

1 minute ago, Mucka said:

Fairly big differences with UKMO and GFS by 120 this morning both in how deep and fast the rough is and upstream. So UKMO colder initially at least.

Yeah although potent the GFS is a 2 day cold snap, the UKMO looks a much better set up - poss ECM like later on !!

[Mucka]

21 minutes ago, Ali1977 said:

Yeah although potent the GFS is a 2 day cold snap, the UKMO looks a much better set up - poss ECM like later on !!

It is a stunner at 144 Ali, the forum will be busy this morning  

Think my forecast of the other day is going in the bin but I don't want to jinx any cold potentially snowy spell just yet

(Anyway even if GFS is right it still gives snow chances - would love UKMO to be onto something though. Would likely go on to ridge toward Iceland with those heights trapped between closed low and neg tilted trough. Certainly a chance of maintaining cold uppers and some form of Easterly flow down the line I would think so long as the trough and low didn't phase. Not sure it will be repeated but nice to see it trying to amplify.)

Edited January 8, 2017 by Mucka

[knocker]

The GFS this morning is very much a mixed bag caused mainly it would appear with the problems it's having with the energy and lobe of the vortes which swings east and drops SE over Greenland and the subsequent interaction with high pressure and amplification of the latter. During this process it does pay lip service to the ecm interpretation of last evening. Suffice it to say the evolution is long way from a done deal  A quick chart just to illustrate this not because it's necessarily going to verify and then a glance at the closer time table

Thursday see the upper trough tracking SE over Scandinavia which plunges the UK into a strong NW Pm airstream portending frequent wintry showers. As it veers northerly perturbations are liable to form  in the circulation but this will be more of interest in the next couple of days.

The northerly doesn't hang around very long and by 00 Saturday the low that has been spawned by the ubiquitous upper low to the south swings around the HP that has been relegated to the SW and arrives west of southern Ireland. The question will be, if it gets anywhere near verifying, will it produce snow from the leading edge as the lower regions of the UK will now be quite cold from the recent northerly incursion?

After that it's all about what has already been briefly discussed and the UK gets into a rather mild south westerly. Confidence in this is low.although the GEFS anomaly does support an Atlantic trough

Edited January 8, 2017 by knocker

[Cheshire Freeze]

Wow, the 0z GEFS are brutal...not brutally cold but brutal as in how many of the individual perts raise pressure again to our S after the cold snap

Almost unanimous on a warm up (at the 850hpa level anyway)

About 2 (poss 3) perts go on to produce a Scandi high at day 10. Pretty slim odds that the ECM will maintain its output of previous runs on the 0z I would think.

I'm going to keep my fingers crossed the end of the week snow window doesn't shorten any more and go out and make the most of any snow that does fall from the sky. It may be the last this winter...you never know.

Edited January 8, 2017 by CreweCold

[That ECM]

26 minutes ago, CreweCold said:

Wow, the 0z GEFS are brutal...not brutally cold but brutal as in how many of the individual perts raise pressure again to our S after the cold snap

Almost unanimous on a warm up (at the 850hpa level anyway)

About 2 (poss 3) perts go on to produce a Scandi high at day 10. Pretty slim odds that the ECM will maintain its output of previous runs on the 0z I would think.

I'm going to keep my fingers crossed the end of the week snow window doesn't shorten any more and go out and make the most of any snow that does fall from the sky. It may be the last this winter...you never know.

Yes, get out and enjoy. This will feel bitter.

[Cheshire Freeze]

GFS looks to be out on a limb at 120 hrs...ECM, like the UKMO, has the troughing pushing further S&W

Different profile around the Greenland area to GFS too

ECM and GFS chalk and cheese at 144hrs

ECM closer to UKMO. If GFS is wrong going forward, pretty much the whole 0z GEFS suite is going to be wrong too based on the ensemble graph I posted earlier. Guess we'll have to wait and see where the rest of the ECM run takes us.

Edited January 8, 2017 by CreweCold

[That ECM]

6 minutes ago, northwestsnow said:

WOW!!!fabtastic.ec..

You could see the ukmo following this.

[Cheshire Freeze]

5 minutes ago, That ECM said:

You could see the ukmo following this.

The continuity between the 12z and 0z to day 7 is excellent...though that doesn't make the output correct. I'm wary of the GFS output.

Will view day 8 ECM then off to bed!

EDIT: it's cold

Night!

Edited January 8, 2017 by CreweCold

[cheshire snow]

Correct me if I am wrong but at T168 on the ECM are those -14 uppers in Northern

Scotland?

C.S

[That ECM]

2 minutes ago, CreweCold said:

The continuity between the 12z and 0z to day 7 is excellent...though that doesn't make the output correct. I'm wary of the GFS output.

Gfs is ok of course we should be wary but if you take the flat bias argument, a little more of a shift of the high and every thing would look very different. About time something went right for a change.

[Cheshire Freeze]

1 minute ago, cheshire snow said:

Correct me if I am wrong but at T168 on the ECM are those -14 uppers in Northern

Scotland?

C.S

-10 just clips the N coast

[cheshire snow]

1 minute ago, CreweCold said:

-10 just clips the N coast

My error Crewe was looking at the thickness charts

C.S

[Cheshire Freeze]

@Steve Murr will love the last frame ECM...

Snow piling into Kent on that chart.

Edited January 8, 2017 by CreweCold

[Radiating Dendrite]

Thought there would be a few more people in for the ECM.

It's an absolute cracker and continues the easterly theme towards the end of the run. It has good support from the UKMO and seems pretty keen on this evolution given the past few runs. Cold air never leaves the south once it sets in so any snow that does fall could stick around for a few days. 

ECM is the best run of the winter for me - cold and snow now coming into reliable and no breakdown out to day 10.

[knocker]

Te ecm, predictable is totally different to the GFS post T144 and repeats the amplification of the Azores ridging NE wth the trough swinging SW thus again introducing north easterlies and some very cold air.

If you look at the ecm for T216 for 12 and 00 they are almost identical which is fairly remarkable in itself.

Edited January 8, 2017 by knocker

[northwestsnow]

Well ecm brings a pretty classic cold spell but we really need the gfs to join the party, sharpish,as the pm cold plunge is only 96 hours away now..

A fascinating meto update today beckons, will they go with EC/UKMO or the GFS..

Edited January 8, 2017 by northwestsnow

[Radiating Dendrite]

3 minutes ago, knocker said:

Te ecm, predictable is totally different to the GFS post T144 and repeats the amplification of the Azores ridging NE wth the trough swinging SW thus again introducing north easterlies and some very cold air.

Almost a mini ramp there knocker

GFS still makes me nervous though. It is often derided but does have a habit of picking up a nuisance shortwave before the ECM and UKMO. 

The ECM looks very clean in its progression which is great but I still expect a few bumps in the road and a possible crash!

[knocker]

Just now, Radiating Dendrite said:

Almost a mini ramp there knocker

GFS still makes me nervous though. It is often derided but does have a habit of picking up a nuisance shortwave before the ECM and UKMO. 

The ECM looks very clean in its progression which is great but I still expect a few bumps in the road and a possible crash!

Yes I must get a grip for Sidney's sake.

[Radiating Dendrite]

Completely agree northwestsnow - might still take a few runs for the GFS to come on board if it is wrong.

It is struggling to resolve the energy at the tip of Greenland and goes a bit trigger happy with the shortwaves. It looks a little unlikely but could end up being right. Shortwaves in the local do tend to crop up. 

Edited January 8, 2017 by Radiating Dendrite

[Ali1977]

Well if the ECM is correct, snow falling and lying in the south on Thurs/Fri will still be there the following Wed. What a run, the GFS is so different though so we best not get carried away.

[knocker]

[ArHu3]

12 minutes ago, knocker said:

Te ecm, predictable is totally different to the GFS post T144 and repeats the amplification of the Azores ridging NE wth the trough swinging SW thus again introducing north easterlies and some very cold air.

If you look at the ecm for T216 for 12 and 00 they are almost identical which is fairly remarkable in itself.

Last night I posted a plume for DeBilt from yesterday's 12z and there was virtually no spread of the members until post day 9 to 10

[snowice]

ECM looking great for cold spell UKmo on right track, is Gfs over doing the energy South of Greenland it does love the shortwaves

[Skyraker]

 

Might get a polar low out of this one, worth checking the visible sat images while this is going on as they materialise out of thin air.

Edited January 8, 2017 by Paul

[marksiwnc]

Tbh you can almost laugh at these charts.  I'm hoping the ECM and UKMO is correct but I can't see the GFS being wrong when showing mild.  It almost guaranteed to be correct knowing our luck.  Here's to hoping...... Forecasters nightmare every week