Winter Model Discussion 18Z 3/2/13 onwards.

[weather eater]

Another one of those interesting different perceptions As I've seen it, it has consistently suggested the type that Phil mentions with a slack cyclonic trough close by in Europe rather than any classic reverse zonality look about it and straight NE'erly tramlines of isobars. The issue once again is the close proximity of the Azores High as these potential continental flows set up - much as has been the story for much of the winter. We have had trough disruption into Europe, but no classic -NAO. I guess on that basis we have done relatively well out of modest synoptics when they have presented thmselves

As an example Tamara

[Summer Sun]

Ian Fergusson has wrote this in the SW thread this evening

Longer term, MOGREPS stays consistent in ushering-in a broadly W'rly regime into 10-15d period or indeed earlier, as the block gets shunted-away further east. Weekend into early next week still uncertain re transition and longevity of the block, but signal in MOGREPS and EC EPS (which goes for an unbiased southerly into trend 10-15d period) all aid with broad notion of colder block being superceded after a few days. Anyway, much uncertainty for now - watch this space.

Looks like the Met office remain unconvinced with ECM at the moment although uncertainty remains a break down to a westerly flow is possible now its just how quickly it may happen

Edited February 4, 2013 by Gavin.

[chris55]

Absolutely, I remember a couple of days ago "BOOM" posts as the ECM churned out a good Easterly flow!!

Look how watered down it has become

Not exactly true, if you have a westerly showing, then the models turn it to an easterly (ECM) then that's a boom chart. It was the changes from dull westerlies to dropping Shortwaves and cold and snow potential that got the interest. At no point has the ECM shown a raging easterly.

[Frosty.]

I find it amazing that we have a cold northerly with snow showers and frosty nights in the coming days and it's been completely overlooked, quite ridiculous.

[weather eater]

I think generally speaking all models struggle towards the latter part of their runs and often the forecast solution is somewhat oversimplified, moreso with the ECM perhaps overdoing easterlies and the GFS certainly struggling to pick up on trough weakening and disruption and overdoing the jet. In this instance I tend to favour a solution not dissimilar to the outcome of the the two main undercut attempts in January, with most of the energy going under the block and a relatively cold but messy and potentially quite snowy solution for some.

Yes that wouldn’t surprise me either, usually though not always we end up with a blend or compromise situation, pretty standard stuff.

[Mucka]

GEM is looking good but I temper that welcome news with the fact the model has been abysmal of late.

[Dexter29]

Not exactly true, if you have a westerly showing, then the models turn it to an easterly (ECM) then that's a boom chart. It was the changes from dull westerlies to dropping Shortwaves and cold and snow potential that got the interest. At no point has the ECM shown a raging easterly.

I never said a raging easterly. I said a "good easterly flow" - that's exactly what the ECM on Saturday was showing.

From memory I think it was more of a NE flow actually.

[Tamara]

As an example Tamara

I see what you mean but I guess it still remains a subjective view as what constitutes a 'strong easterly' at any snapshot of time. one. It is true that is a better hybrid of the Euro trough/ NE atlantic to Scandinavian ridge - with more amplification perhaps than what is suggested now with the Azores ridge pulled further north - but it is still based on exactly the same pattern as now and not downgraded from any suggested classic HLB and -NAO

Furthermore as has been pointed out already (bluearmy,,,maybe or someone the ECM up to this morning had not downgraded the depth of cold advected westwards with the slack flow. So again it is subjective as what 'gets the job done' Anyway, the new one is coming out now and we will see if it does finally downgrade in this instance..or not, as the case may be

Edited February 4, 2013 by Tamara Road

[snowking]

Ens mean height anomalies continue to look impressive days 6-10:

That gives you the general idea of where we are headed. Of course, as ever, shortwave detail around the UK Locale will be key, and it should be noted that even on those anomaly images the UK is on the western periphery of what is, essentially, a Siberian/Scandi based omega block, and being on that periphery always leaves you a little open to the west potentially.

Of course the hope is that the pattern retrogresses (as per the thoughts of RJS/BFTP) and the GFS 12z Ens certainly suggest that in the extended timeframe:

GEM is a little muted on the later signal:

Though overall still a mean step west.

0z NAEFS depicts this too:

If people prefer to see things visualised more in terms of AO/NAO for the retrogression signal, here we go:

You can see from those that the GFS op remains out of touch with even its own ENS suite, along with those of the GEM, and whilst we don't get to see the extended ECM projection, it largely follows the progression of the GEM/GFS ENS suite up until 240.

Positive signs from todays output for me. Even if we see temporarily less cold conditions for a time, signs that the pattern continues to back west over time.

SK

Edited February 4, 2013 by snowking

[chris55]

I never said a raging easterly. I said a "good easterly flow" - that's exactly what the ECM on Saturday was showing.

From memory I think it was more of a NE flow actually.

00z ECM - "good easterly flow", cold, -10 850s into the east. Nothing "watered down" there.

Edited February 4, 2013 by chris55

[weather eater]

I find it amazing that we have a cold northerly with snow showers and frosty nights in the coming days and it's been completely overlooked, quite ridiculous.

That’s because a northerly with snow showers and night frosts is not the Holy Grail, in winter we all know this is not the model thread it’s the search for 63 thread. Let’s hope the ECM stays bullish, the MO may not be going for it but they have been wrong before.

[bluearmy]

as far as exeter's opinion is concerned (the 10-15 day period), there is no real disagreement - as ian states the southerly period with the atlantic v the block around the 8/12 day period is signalled but mogreps isnt keen to hold that very long and as we can see from the extended ecm ens, the cluster that holds the atlantic back in the se of the uk is significant but not the majority view. for the cold to be sustained, we can only hope that the reamplification via the GWO becomes more apparent. it may not and we may well go more mobile again. the gefs are a curates egg with a whole selection of solutions on offer in week 2.

[Dexter29]

00z ECM - easterly flow, cold, -10 850s into the east. Nothing "watered down" there.

Slack easterly, -10 850s further East, a lower convection probability.

It has been watered down, but that's to be expected. After all it was 7 days away! FI

Praying the ECM 12z continues and doesn't not push even further to the GFS

[Mucka]

On ECM. The last 3 runs clearly moved away from advecting the cold much further East with the strength and longevity of HLB lessened- it has just kept us on the cold side to this point but to say it hasn't watered down the overall synoptic for a long lived deep cold spell is incorrect. Doesn't mean it can't move back to some of the blinding charts we saw through Friday , Saturday but seems unlikely.

Edited February 4, 2013 by Mucka

[bluearmy]

not looking so good is it.

indeed peter - its very gfs 12z like at day 4 and will be interesting to see how/where the model progs the undercut with the starting point at T96. perhaps we are coming together with the output at last. something i have learnt form the past few days is not to pre empt the ecm run as it comes out as you will likely look foolish.

[Continental Climate]

Well nobody is posting the ecmwf charts must be crap!

Why dont you post some mate, http://www.meteociel.fr/modeles/ecmwf/runs/2013020412/ECH1-96.GIF?04-0!! Just for you

[Mucka]

indeed peter - its very gfs 12z like at day 4 and will be interesting to see how/where the model progs the undercut with the starting point at T96. perhaps we are coming together with the output at last. something i have learnt form the past few days is not to pre empt the ecm run as it comes out as you will likely look foolish.

It is nothing like GFS, closer to UKMO.

[Dexter29]

On ECM. The last 3 runs clearly moved away from advecting the cold much further East with the strength and longevity of HLB lessened- it has just kept us on the cold side to this point but to say it hasn't watered down the overall synoptic for a long lived deep cold spell is incorrect. Doesn't mean it can't move back to some of the blinding charts we saw through Friday , Saturday but seems unlikely.

Thank you. I find it bizarre how some members can think the ECM is just as good as what was shown two days ago!

I'm still learning and even I can see the ECM has been watered down.

Anyway let's see if the ECM 12z can stick two fingers up to the GFS

Edited February 4, 2013 by Dexter29

[chris55]

120, things further east. Undercut should still be good though, snowline on the eastern edge.

Edited February 4, 2013 by chris55

[Gowon]

not looking so good is it.

Still looking good at 120h

[Frosty.]

This is the model thread, not the IMBY whats happening now thread.

my post was model related for the next 3 days, not what might or might not happen next week and beyond. Some areas will see some accumulations in the next 3 days or so and there is nothing IMBY about it : )

[bluearmy]

It is nothing like GFS, closer to UKMO.

at day 4 it was closer to gfs than ukmo - use the compare feature on meteociel - very handy. anyway, its irrelevant as by day 5 its closer to ukmo than gfs (and i'm still not going to second guess thats its undercut will be further west than ukmo - doh!)

[TEITS]

Some of the posts amaze me at times.

ECM is fine at +120 and is nothing like the GFS. The slider will be further W than the UKMO.

[london-snow]

Slack easterly, -10 850s further East, a lower convection probability.

It has been watered down, but that's to be expected. After all it was 7 days away! FI

Praying the ECM 12z continues and doesn't not push even further to the GFS

You find me a chart from the ecm where it has CONSISTENTLY toned down the potential & i will say i am wrong.

Each run will show a diffrence however the fact is the ecm thus far has been solid with a cold e~ne pattern to happen in the coming days.

[weather eater]

Interesting from the BBC today, start appears to have no sound

http://www.bbc.co.uk/weather/features/21328896