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Model output discussion - into 2018

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The GEFS 6z mean shows a battle developing next week between atlantic lows trying to push in against high pressure blocking to the east with winds generally from a  SEly direction and feeling cold, especially as the isobars occasionally tighten (winds strengthen) with maxima  in the low to mid single digits celsius range from north to south..there is a risk of wintry ppn, more likely on hills and further north. Beyond next week low pressure to the northwest becomes the more dominant feature with a zonal broadly westerly flow bringing spells of wet and windy weather across the uk, sometimes cold enough for snow, mainly further north and higher up and some overnight frosts / ice during any short-lived quieter interludes.:)

Edited by Frosty.

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“The next 12Z will be crucial” is a bit irksome the same has been said day on day, surely if it was so crucial we would have firmed up by now, if you see GFS it’s been correcting a lot more than ECM.

I’ve not had a look at GEFS but that’s good to hear^ 

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20 minutes ago, Catacol said:

Any idea what's going on with this? The cache issue is bizarre - @Singularity - sorry - you are correct - my WDT graphic is NOT the one that then appears after the save. Only work around seems to be to save and then upload the saved image. I'll try and adjust my initial post....

 

EDIT: Grrr - cant edit my original cos time has gone. GP has posted the proper one I had meant to show above. I'm off to have another moan at WDT....

Ah the fun of science :laugh:

I have been under the impression that a bit of a drop in GLAAM was always expected as the MJO moved through the western IO, with the hope being that trends would reverse again as the MJO propagated east. Last I could see before the H-W plots went AWOL (they do pick their moments don't they?), GEFS was still not going with that, hence the renewed downward tendency it produces, but ECM was taking it nicely east with scope for the GWO 3-4 to follow relatively quickly.

All that seems particularly clear right now is that the situation is unusually complex. Good luck everyone :D.

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2 minutes ago, Daniel* said:

“The next 12Z will be crucial” is a bit irksome the same has been said day on day, surely if it was so crucial we would have firmed up by now, if you see GFS it’s been correcting a lot more than ECM.

I’ve not had a look at GEFS but that’s good to hear^ 

After a few runs easing the cold spell I’m fully expecting a step back colder again , hoping yes but there’s still a good chance looking at some ENS.

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3 hours ago, Glacier Point said:

Yesterday I was sceptical. Even more so now.

GFS drop in angular momentum is now inching forward day by day sufficient to be taken notice of.

tropics.thumb.jpg.1cf98a34d96eae28dda07c734b88eba1.jpg

That ensures us in a GWO Phase 2 type scenario, cyclonic but still with the ridge tantilisingly to the north-east. The lack of any real depth of cold the crucial thing here.

5a4df50426923_gwophase2jan.thumb.jpg.25409643acf8e4b3bfca54889d262861.jpg5a4df50a95732_GWOphase2janeuro.thumb.jpg.92758068ab24ecfd8256612fbc66e1f1.jpg

After day 10, the lowering AAM trend should abate and steadily reverse. With the eastward progression of the tropical wave, westerly inertia should pick up signalling a movement in the GWO towards phases 3 and 4. Phase 4 being the phase in which a proper easterly could take root - but stress, that is some way off yet.

5a4df55579944_gwophase4janfilternina.thumb.gif.95b81138f09bba15f2a7d08bf04b88cb.gif5a4df528a611b_GWOphase4janeuro.thumb.jpg.f638b56114cf783071a2a18c4ead62d3.jpg

Hi GP - Hopefully a silly question!! You mention the GFS tendencies for angular momentum - does the ECM (/other models) show the same? 

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Just now, johnholmes said:

It's also the wrong thread!

Ho John appreciate your last two posts but how about giving your ex pro's view on possible developments next week

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I think the crucial runs depend on the timeframe of model divergence and what happens to make them diverge. As that time gets nearer into the reliable, then obviously what the models start to show get more crucial.

Of course it depends on what you regard the reliable to be.

And even then, with cross model agreement, no guarantees are involved beyond T-6 I'd say!  Even the development of today's system bringing strong winds to the southern half of the country was subject to a revision by Meto within 24 hours of arrival

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Just flicking through the GEFS 6z perturbations, P5 grabbed my attention..:cold::)

5_198_850tmp.png

5_222_850tmp.png

5_222_2mtmpmax.png

5_246_850tmp.png

5_246_2mtmpmax.png

5_366_850tmp.png

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44 minutes ago, Man With Beard said:

Hi GP - Hopefully a silly question!! You mention the GFS tendencies for angular momentum - does the ECM (/other models) show the same? 

I know WSI provide a GEFS based AAM / GWO product, and also provide EC based Hovmollers for zonal wind analysis and forecast, although I've not seen a GWO ECM product. It would be doable if you had the right data to work off. EC will show the same negative anomaly across 20N-30N as GEFS.

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43 minutes ago, ShortWaveHell said:

This is what Iv been doing myself @johnholmes without getting embroyeled in the thread , been comparing GFS 12z with 12z and likewise for ECM , the GFS updating every six hours seems more of a hindrance if you follow it every update rather than benefit ! Especially for a complete novice trying to learn like me ! 

I have never unsterstood that?  Why can’t we compare each and every run?  Seems truly bizarre.

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4 minutes ago, mulzy said:

I have never unsterstood that?  Why can’t we compare each and every run?  Seems truly bizarre.

I have a job and family. Dunno about anyone else...

 

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1 minute ago, jvenge said:

I have a job and family. Dunno about anyone else...

 

Exactly! I may do what John says when I retire...

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& were off ( IKON )

1-2 runs of sharpening should see some of the pessimists withdraw their negativity...

 

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20 minutes ago, mulzy said:

I have never unsterstood that?  Why can’t we compare each and every run?  Seems truly bizarre.

I agree - Comparing a run to something that's 24 hours out of date has never made sense to me either. Perhaps in the olden days when models were in their infancy it made sense but certainly not anymore. 

There's been a definitely shift towards the GFS but not completely. We've still got the block but it's definitely leaning more towards battleground snow (yet again, great if you live up North, rubbish for us snow starved Southerners) rather than a cold, convective Easterly which many of us were hoping for.

Still, it's only January.. 

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10 minutes ago, Danny* said:

I agree - Comparing a run to something that's 24 hours out of date has never made sense to me either. Perhaps in the olden days when models were in their infancy it made sense but certainly not anymore. 

There's been a definitely shift towards the GFS but not completely. We've still got the block but it's definitely leaning more towards battleground snow (yet again, great if you live up North, rubbish for us snow starved Southerners) rather than a cold, convective Easterly which many of us were hoping for.

Still, it's only January.. 


I also agree. I have always found it strange, without really questioning it properly.

I understand there is different types of data fed in, depending on which run it is (06z 12z 18z 00z), but at the end of the day the most (IMO) important thing (for eventual accuracy) is for the starting data to be as accurate as possible? Therefore, surely, it is more accurate to do a run to run comparison, as opposed to matching a run that, yes has the same set of data fed in, but has starting data 24 hours out of date.

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4 minutes ago, ShortWaveHell said:

This is what Iv been doing but is it beneficial to a beginner ? If there’s a consensus another way im all ears and eyes 👀 

Sorry but I think that's a nonsense way of viewing models (just my opinion)!

Any benefit of comparing against a 24 hr old run are nullified by the fact that the newer runs have more recent data. It's surely better to compare to the preceding run when looking at model trends.

Edit - or basically what s4lancia said 👍

Edited by Johnp

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I for one am looking forward to battleground snow followed by a prolonged spell of cold from the east. Unfortunately though I don't think the pessimists will withdraw their negativity, they will just move it on to something else to be pessimistic and negative about !

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