Model Output Discussion - 05/01/2016 18z onwards

[IDO]

3 minutes ago, Catacol said:

Model verification stats generally do not back this up, so I am curious as to why you think this.

Hi

Read the initial post containing the tweet from Ryan Maue and it will become clearer.

[Met4Cast]

Okay, so a few things we've learnt in this entire model debacle. 

1. Even when you have full cross model & ensemble support, everything can and will go pear shaped

2. The UKMO model is consistently last to pick out any new trends, for future reference if the GFS "wobbles" and says something different to the UKMO/ECM, we should probably pay attention and not discard it for being "silly"

TWO was the one to Tweet about MOGREPS support with Matt Hugo confirming the ECM EN support for longer cold

 

 

[Spah1]

14 minutes ago, bobbydog said:

here you go- and the NAO

Thanks

 

[Nick F]

Comparing the GFS and EC high res, the mslp differences are actually more stark on the 12z as early as t+144 than they were for the same timeframe on the 00z, more particularly the area between the UK and the Azores:

12z EC has low pressure pushing NE from the Azores merging with the cyclonic circulation near the UK dragging cold air around it from the north, whilst GFS op keeps a ridge between LP over the Azores and near the UK.

I suppose the pros for GFS is it's quicker getting the cold air south across the UK, -5C T850 line north coast of France by 06z Thursday, whilst EC takes an internity to get the -5C line to the south of England, not until Thursday night, thanks to that low coming up from the SW. There is a chance for wintry mix from any ppn almost anywhere on the 12z GFS from Wednesday, though settling snow most likely in the north.

ECM shows a low moving across Scotland on Weds night, wxbell charts (which can't post for the license on them) show snow from northern England northwards, perhaps to sea-level in Scotland. Here the ppn chart anyway:

Then Thursday night, EC has that low grazing southern England as it moves NE along E Channel/N France. wxbell snow charts even show snow for the SE as the northern edge of ppn encounters colder air moving down from the N, you can see the -5C line into the SE at 00z Friday:

Obviously low confidence in that low coming up from the SW on the EC later next week and likely that track wont verify, but shows the potential for wintriness even in the far south later next week. OK, its marginal, but it's far better position to be in than we were back in December!

Beyond next week, probably not worth backing any model atm, though the 12z EC high res certainly has much more cold and wintry potential beyond than GFS!

But the 12z EPS mean shifts Atlantic ridge east across the UK as a lobe of the trop PV pushes out of NE Canada, so certainly backing the potential for the Scandi high through the empirical route as per high res EC, not the route of the failed easterly earlier this month!

Edited January 8, 2016 by Nick F

[Catacol]

2 minutes ago, IDO said:

Hi

Read the initial post containing the tweet from Ryan Maue and it will become clearer.

He stated NWP predictability is higher when the AO is negative. Nothing in there about GFS being the one to follow. I would never trust GFS out beyond 120 - it overblows the atlantic nearly every time.

[Cleeve Hill]

15 minutes ago, bobbydog said:

here you go- and the NAO

Up & down - It's like following the FTSE although on this one it's great to see it keep sliding ! 

[IDO]

The De Bilt Control and Op look to be at the extreme range of what is likely:

  

[Methuselah]

18 minutes ago, Catacol said:

He stated NWP predictability is higher when the AO is negative. Nothing in there about GFS being the one to follow. I would never trust GFS out beyond 120 - it overblows the atlantic nearly every time.

Then again, others have accused it of being too eager to build Scandi highs?

Edited January 8, 2016 by Ed Stone

[Nick F]

The 12z EPS 500mb mean/anomaly to day 15 are actually a big change to the extended 00z EPS mean. 

The 00z EPS H500 mean was all about retrogressing the +height anomaly over Greenland down into NE Canada while -height anomalies/troughing energy pushes NE toward the UK.

Now, the 12z EPS H500 has a +height anomaly ridge pushing east over Iceland/NE Atlantic and UK towards d15.

Oh, and the EPS control builds a Scandi high at d10-12 too.

Very interesting for coldies ...

Edited January 8, 2016 by Nick F

[Kentish Snowman in Yorks]

Well having now had a chance to digest all of the model output from today it is undeniable that we have been led up the garden path regarding the Greenland High.

However...I see absolutely no reason for despondency if you are a coldie particularly if you live Midlands Northwards.  The less cold messier scenario only serves to increase the snow risk over the next week or so surely?!

What I certainly don't see in the model output at present is a return to any sustained mild weather!  With the Northern Hemisphere profile setup as it is - it is surely only a matter of time before we are locked in the freezer?

I have a feeling that the output will start to swing back in coldies favour tomorrow anyway...no more than a hunch but maybe the ECM12z is the start of a sustained fightback?!

In the meantime, shall we have a little game of 'play your models right' in advance of the Pub Run?!  Will pressure be higher or lower over Greenland?  Good Game Good Game!!

 

[winterof79]

10 minutes ago, Nick F said:

The 12z EPS 500mb mean/anomaly to day 15 are actually a big change to the extended 00z EPS mean. 

The 00z EPS H500 mean was all about retrogressing the +height anomaly over Greenland down into NE Canada while -height anomalies/troughing energy pushes NE toward the UK.

Now, the 12z EPS H500 has a +height anomaly ridge pushing east over Iceland/NE Atlantic and UK towards d15.

Very interesting for coldies ...

Thanks Nick,i have read a lot of "interesting" debate this evening and only in the last few moments have my ears pricked up. Your post and Tom Cs from Two have  restored some sanity .Not that the quality of posting has been substandard,but the complicated situation has led many to become confused along with the models.

Edited January 8, 2016 by winterof79

[shaky]

All i can say to gfs is you little beauty for picking that little kink to the northwest and sending it westwards creating this west based nao!!!ecm was late and the ukmo well its all at sea!!!what makes this even worse for cold lovers is everything else barr that pesky little showrtwave to the northwest was all set for a long cold spell!!might change back but my money is on what the gfs is showing at the moment!!any improvements on the 18z?

[Nick F]

7 minutes ago, winterof79 said:

Thanks Nick,i have read a lot of "interesting" debate this evening and only in the last few moments have my ears pricked up. Your post and Tom Cs from Two have  restored some sanity .Not that the quality of posting has been substandard,but the complicated situation has led many to become confused along with the models.

Indeed, it's difficult to jump on any bandwagon at the moment, prefer to sit on the fence, even if the 12z EPS sways to prolonging the cold! 

Going to be more twist and turns from the models for sure over the coming days, so don't worry too much about the 12z GFS op horror show in FI ...

[bobbydog]

bearing in mind the snippets of info from the professionals regarding the ECM ensembles, would anyone care to have a little wager that the 18z GFS is at the very least 'hinting' at a scandi high by day 10?

i'd bet my house on it...

[bluearmy]

12z GFSP fairly consistent with general gfs solution. In week 2, establishes nw European high with brief easterly which then retrogresses to Greenland at the end of the run. That's a more reliable way of getting a greeny ridge and the timing ..........

[snowice]

8 minutes ago, shaky said:

All i can say to gfs is you little beauty for picking that little kink to the northwest and sending it westwards creating this west based nao!!!ecm was late and the ukmo well its all at sea!!!what makes this even worse for cold lovers is everything else barr that pesky little showrtwave to the northwest was all set for a long cold spell!!might change back but my money is on what the gfs is showing at the moment!!any improvements on the 18z?

Looks like upgrade on way that low over UK moving east quicker so far!

Edited January 8, 2016 by snowice

[northwestsnow]

Goodness me a look at 18z 120 shows just how complicated this setup is, for the models to guess where every bit of energy goes must be incredibly difficult.

I'd say this is a lonnnnnnnng way from being resolved.

[Mucka]

Some improvement in amplification upstream compared to 12z so should be a fair bit better but we would be much better off with that Icelandic shortwave either sodding off altogether or forming further South and/or East.

The Greenland shortwave will hinder the Northerly flow but also aid the ridging behind.

Edited January 8, 2016 by Mucka

[northwestsnow]

2 minutes ago, Mucka said:

Some improvement in amplification upstream compared to 12z so should be a fair bit better but we would be much better off with that Icelandic shortwave either sodding off altogether or forming further South and/or East.

18z Would produce snow for scotland NEngland next week mucka.

 

[radiohead]

Hmmm. Very messy and complex, highly likely to change again on the next run. But this is a slight improvement on the 12Z at this point.

 

[Harsh Climate]

Gfs 18z so far

126h we have heavy bands of snow pushing in from the west, with colder uppers filtering through, very nice

 

Would be a bit borderline at first but would likely turn to snow for many. Yes speculative but not bad at under 130h.

[Hull snow]

Looking better then the 12z tho which is small steps I guess 

[TEITS]

43 minutes ago, IDO said:

The De Bilt Control and Op look to be at the extreme range of what is likely:

  

Considering we have seen very mild S,lys, Cold N,lys, Bitter E,ly in the past 12 hrs from the operational outputs then in my opinion the ensembles are a waste of time especially the ensemble mean.  This is a time to only follow the Op and control run from the ensembles.

[northwestsnow]

Just now, Hull snow said:

Looking better then the 12z tho which is small steps I guess 

Maybe the reversal has begun

Ever so slight improvement imo, certainly for the north chances of snow shwers through the week .

[Carlrg]

What's that 1005 pressure ridge building over Scandi.