Model Output Discussion - The Run In To Christmas

[SMU]

not strictly true Steve, the upper air pattern wil ldecide what happens to the low level system?

but best I go and look what all this is about, if I can discover what time frame is causing so much interest?

 

Hi John- Yes, however its the track that's 'visible' & easier to decipher for people looking for what pattern is going to develop.

 

S

Edited December 18, 2014 by Steve Murr

[Paul]

For those who'd like to put some xmas decorations up on the forum, the Christmas skin is now available

 

https://forum.netweather.tv/topic/82054-christmas-skin-now-available/

[Jason M]

Regardless of whether GFS or GFSP is better in the overall scheme of things, the important point here is that GFSP stays in high res out to 240 hours (I think that's correct). It is the 180 to 240 bit that's important at the moment, so between 192 and 240 hours I'd be paying more heed to the GFSP (whilst still just noting the old GFS).

[Eskimo]

Wouldn't the programmers incorporate the old GFS verification stats within the new model plus incorporating an advancement of technology?

[JoeShmoe]

All models are notoriously difficult at predicting shortwaves which by their very nature can pop up at very short range and affect a general pattern. I've lost count of the times a shortwave at sub t96 has derailed a 'nailed on' cold spell

If any route to cold is dependent on a shortwave its a bit like buying a llottery ticket

[No Balls Like Snow Balls]

Are you sure , I saw something from Brian on TWO saying the current GFS was verifying much better up to x hours

Consistent as in run to run the charts haven't chopped and changed to much.

[johnholmes]

But John, years of GFS at standard resolution, vs what, a month of GFS Parallel? Quantifiable evidence to currently use the GFS OP over the parallel, despite the higher resolution, surely?

 

you may be right but I tend to doubt that the new version will not be a better model than the older version, it certainly shows a better performance in the statistics for the northern hemisphere if you look at the link below

ha ha-keep your big mouth shut jh - latest stats show GFS in front again, link below I just look at the 6 day version

http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz6.html

[marksiwnc]

Didnt Tamara say that there would.be different scenarios been thrown at us due to the change?? We all need to calm down and see how tonight and tomorrow s runs look

[TonyH]

For those who'd like to put some xmas decorations up on the forum, the Christmas skin is now available

 

https://forum.netweather.tv/topic/82054-christmas-skin-now-available/

They were delivered late this year Paul

Ah all put up now - thats better feel a bit more Seasonal now in spite of the weather!

Edited December 18, 2014 by TonyH

[Cheshire Freeze]

Didnt Tamara say that there would.be different scenarios been thrown at us due to the change?? We all need to calm down and see how tonight and tomorrow s runs look

I can remember plenty of times where 'model rot' has been terminal but only a handful of times when a deterioration in trends has reversed. A lot of us experienced model watchers will tell you the same!

December 2012 being a recent case.

Edited December 18, 2014 by CreweCold

[IDO]

You can see the flatter upstream on the GFS P compared to the GEM:  

 

The GEM gets a chance to pump up the Ridge. Then it is reinforce by the second wave of WAA: 

 

And we get at D10: 

 

See what the GEFS make of this.

[Hocus Pocus]

I've been viewing this forum for a number of years and it seems we always have the same argument regarding the GFS and the ECM, surely there are no biases inbuilt or otherwise as their primary job is to number crunch the available data inputted into them, which computers being computers will each come up with different variations at different times of the day due to the most upto date data available at any given time. Or I'm I missing something?

[Banbury]

Consistent as in run to run the charts haven't chopped and changed to much.

Until now you mean?

 

Understanding you now

[The Weather Dragon]

Looks like Darren Bett could be spot on with his 'milder boxing day' suggestion !

[Banbury]

http://www.meteociel.fr/ukmo/runs/2014121812/UN144-21.GIF?18-17

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014121812/gfsnh-0-144.png?12

 

This is really about as far as anyone of can look and at this point we could end up on the cold side of things,

 

Patience

[karyo]

Does it matter whether the GFS Operational or P got the pattern right? They have both downgraded the potential cold spell. That's all that matters until we see what the ECM has to offer.

[TonyH]

I've been viewing this forum for a number of years and it seems we always have the same argument regarding the GFS and the ECM, surely there are no biases inbuilt or otherwise as their primary job is to number crunch the available data inputted into them, which computers being computers will each come up with different variations at different times of the day due to the most upto date data available at any given time. Or I'm I missing something?

Thats what I had assumed but apparently they are biased?

[Backtrack]

you may be right but I tend to doubt that the new version will not be a better model than the older version, it certainly shows a better performance in the statistics for the northern hemisphere if you look at the link below

ha ha-keep your big mouth shut jh - latest stats show GFS in front again, link below I just look at the 6 day version

http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz6.html

 

It'll be a fantastic upgrade when they fully get it up and running, I assume like all new things, there will be niggles and things which need tweeking before it's on top-form, but I can't wait for the official release. A great addition to the already groundbreaking data we have available to us

[Banbury]

Does it matter whether the GFS Operational or P got the pattern right? They have both downgraded the potential cold spell. That's all that matters until we see what the ECM has to offer.

Yes it does if people are having a discussion about it...................its good to talk and discuss certain model performances

[Cheshire Freeze]

Does it matter whether the GFS Operational or P got the pattern right? They have both downgraded the potential cold spell. That's all that matters until we see what the ECM has to offer.

Exactly. I always use the notion that they have 6 hours of new data....what went before is history and holds less weight than the most recent model runs. We can't brush these things under the table but equally we can't draw firm conclusions.

[mushymanrob]

gfs 12z?

 

take that how you will, but it highlights the fact that no one should believe the hype delivered from bias perspectives. and no, id be highly surprised if the gfs 12z has picked up on a new trend and verifies. until the noaa 500mb anomaly charts change to ones that support mildness then i still believe a colder snap post crimbo is most likely.

but  today there does appear to be some delaying of the cooler crimbo weather, and even the gfs 12z although mild for the rest of the year (more or less) still has the potential for much colder weather...

but then again, since early november theres been several cold spells promised on the horizon, they didnt become reality so maybe this one wont either. the point being that theres a huge amount of uncertainty beyond day 5 and theres nothing certain.

[bluearmy]

People - as the runs tick by, so the higher res of the ops should begin to decipher the solution. However, the ens mean will still be a better guide to the Atlantic shortwave for the moment. (Statistically). By Saturday 00z, the general op concensus should be clear.

I think one can appreciate the tone and content of Exeter's forecasts now.

[winterof79]

I am on my phone so excuse me if I am reading this incorrectly.

GFS and GFSP 12z have no n/westerly or cold for exmas day or boxing day.METO outlook says cold Xmas and Boxing day with snow to low levels ooop north.

Summary....bin....Next

[Bullseye]

There we go one run with downgrades and this topic goes downhill in a matter of hours predictable really (not the runs but the uproar in here this afternoon), wait until ECM has finished and then make conclusions. Anyway, still looking good for Christmas and on wards in my opinion, we are in fantastic position compared to last year and also we still have ongoing wave activity and increased chance of SSW/Wave 2 Activity by turn of the year. So no complaining from me today. 

[East_England_Stormchaser91]

This is just part of the roller coaster we are experiencing! This is model watching at its best.

It's not until 90 hours out when we can get a realistic idea on what is going to happen. In the past it's not been unknown for a cold solution to disappear completely at 24 hours out, only to reappear again 6 hours later. This happened on Boxing Day 2005 I believe!