Model output discussion - January cold spell ending, what next?

[Battleground Snow]

2 minutes ago, IDO said:

GFS op is outperforming the gfsP on both 0z and 12z stats:

ATM we are looking at this upgrade making gfs reliability even worse in setups like this. I understand that the gfsP has been tuned by ecm so no surprise it is more amplified in FI and as it goes out to d16 that is exaggerated even further! 

Fantastic in Winter when we get d10 ecm and gfsP charts showing phantom heights that are always out of reach!

Link  >here<

Thanks for this.. I know the OP did well with current cold spell we are just about to exit, which will explain why it's ahead now, but I am interested to see what it looks like in 2 weeks, after the SSW has flushed through the data.

[ALL ABOARD]

All academic of course.. 

But - 20 uppers passing over a relatively warm North sea? 

Sea affect snow to rival the Great lakes of America. 

[Met4Cast]

As some have already pointed out, the GEFS 06z show a huge shift towards a colder outlook compared with previous runs. Not sure when the last time such a dramatic shift occurred, but 2010 stands out in my mind.

GFS Op is a clear outlier now. I would also put more weight in the GFS(P) simply because it has more vertical layers so should resolve any SSW downwelling more accurately. 

After a tricky few days, things are steadily improving towards a colder outlook for the UK. EPS means/clusters are strengthening the signal with each model run. 

We're reaching the "tipping point" where we start to see increasingly cold and blocked runs appearing in the mid-extended. Buckle up!

[Bartlett High]

This is all so confusing!!!! What is it to be? The Op the parallel the mean the tea leaves!!!! I need to lie down.

[winterof79]

3 minutes ago, IDO said:

GFS op is outperforming the gfsP on both 0z and 12z stats:

ATM we are looking at this upgrade making gfs reliability even worse in setups like this. I understand that the gfsP has been tuned by ecm so no surprise it is more amplified in FI and as it goes out to d16 that is exaggerated even further! 

Fantastic in Winter when we get d10 ecm and gfsP charts showing phantom heights that are always out of reach!

Link  >here<

Shame this will not be happening then

But hang on are they all wrong

 

 

 

[wellington boot]

11 minutes ago, IDO said:

GFS op is outperforming the gfsP on both 0z and 12z stats:

ATM we are looking at this upgrade making gfs reliability even worse in setups like this. I understand that the gfsP has been tuned by ecm so no surprise it is more amplified in FI and as it goes out to d16 that is exaggerated even further! 

Fantastic in Winter when we get d10 ecm and gfsP charts showing phantom heights that are always out of reach!

Link  >here<

I really know nothing about this, but I think it is very very unlikely they would switch to using that model, as it currently is, if it's verification stats are so much worse. Hardly have to think about it to reach that conclusion. 

If that is indeed the beta and will soon be taking over, I would imagine the public version that we currently see is running at lower resolution, or data is being withheld, or something else will change before they'll let that become the OP... 

A more interesting comparison, therefore, might be too compare v16 vs all other ensemble verification...

 

Edited January 10, 2021 by wellington boot

[AFCBSNOW]

19 minutes ago, Battleground Snow said:

Does anyone have the link to the NH verification stats and how often they get updated? If will be interesting to monitor how much the para pulls ahead of the GFS op once this period passes. I have a feeling it might even take a run at the ECM

I think it was on here yesterday. I think it was well ahead, but don't quote me on that lol

[IDO]

1 minute ago, winterof79 said:

Shame this will not be happening then

But hang on are they all wrong

 

 

 

I have called it a while back; Greenland block, Scandi trough and cold potential. I am onboard that train and though I suggested that the new gfs will be more amplified on average, I am not saying it is wrong on this occasion as clearly this is an SSWE so we are expecting amplification!

[Battleground Snow]

5 minutes ago, AFCBSNOW said:

I think it was on here yesterday. I think it was well ahead, but don't quote me on that lol

I'm going to put a positive slant on its and say because it verifying better than the OP at 120, it has the cut off Low nailed 

Edited January 10, 2021 by Battleground Snow

[bluearmy]

4 minutes ago, Battleground Snow said:

I'm going to put a positive slant on its and say because it verifying better than the OP at 120, it has the cut off Low nailed 

This is the point @wellington boot 

NOAA won’t judge the v16 on the basis of its stats at day 10. Ops aren’t generally meant to be used beyond day 7/8 for forecast reliability.  That’s what ens are for.  

[johnholmes]

Update for the 500 mb charts

Ec-gfs shows ec now flattish flow from e Canada to near Iceland then splitting, n’ern arm to jan meyen area then sharply se into marked trough over n’ern Russia with s’ern arm swing down over uk into European trough centred approx 15-20 e; gfs swings n from n America trough over Greenland, including atlantic part, then shows trough Iceland to n Scotland with then variable flow e, s’ern atlantic part flows into euro trough but way w of ec, more Iberia area; so overall both show ridging Greenland area with n of w flow over uk to some type of trough e of uk

Noaa shows some ridging towards Greenland, less so than recently then a flattish wnw flow into Scandinavia and n’er n Europe, flow over uk is a fairly gentle wnw flow; 8-14 is a bit more pronounced towards Greenland but similar then to east; far west then trough-ridge idea is similar to last few days charts

Overall then, the prediction for a more westerly flow seems the way we go, for how long is uncertain, with flows slack enough to allow either a more pronounced westerly or for development of ridging anywhere between NW and NE in the upper pattern. Wait and see is the best advice!

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

[Waterspout]

13 minutes ago, wellington boot said:

I really know nothing about this, but I think it is very very unlikely they would switch to using that model, as it currently is, if it's verification stats are so much worse. Hardly have to think about it to reach that conclusion. 

 

The v16 code was actually signed off and approved back in May 2020 by the Ops Director. This Parallel running October to the end of this month is purely “IT” related. The actual verification improvements were assessed by EMC based on the previous year’s initialisation data to evaluate performance compared to v15.

They won’t pull the code on a project that started back in 2019, on those Stats you published for the 3 week period you illustrated. This is the new and improved code, even if it’s an overall 1% increase, it’s still improved after extensive testing on long term previous starting data spanning a longer period than those weeks you highlighted.

[winterof79]

17 minutes ago, IDO said:

I have called it a while back; Greenland block, Scandi trough and cold potential. I am onboard that train and though I suggested that the new gfs will be more amplified on average, I am not saying it is wrong on this occasion as clearly this is an SSWE so we are expecting amplification!

Cheers IDO

[SMU]

Day 5 swing back to cold for the SE -5c the midpoint & -8c the top out > could be some snow

[Cold Winter Night]

Let's be honest, we have seen several great runs, not just on GFSp runs, but all of the models have shown similar developments, operational runs, ensembles and ensemble members. And it is counting down as well, a couple of days ago we were looking at the +300-384h charts with excitement, now it's much closer already.

The Operational runs that do not look that great do so in the later stages. There are massive changes in the output, and huge disagreement between models, at timeframes as near as +72h and that gives enough reason for at least 'synoptical excitement'. We cannot look at details yet, certainly not +144h and later.

I am particularly interested in the developments surrounding the Scandi High and the Arctic High at +72-144h.
In the past, models have underestimated those features, and I see them more developed on the output as it comes closer in time.

[damianslaw]

On 07/01/2021 at 21:31, Man Without Beard said:

 

 

Variance in the models this morning, all rather messy still, however, main trend includes:

-Developing Arctic High (this is the dominant force)

-PV stretched and moving to NW Russia, significant cold pool building to our NE

-A ragged weak atlantic

The arctic high working in tandem with the PV to our NE by law of averages should result in heights building to our NW.

Likely synoptical evolution - weak low pressure and fronts riding around the azores/mid atlantic ridge, by end of the coming week, forced SE under the trough to the NE, azores high surges to Greenland with a link up with arctic high. End result southerly weak tracking jet, UK on the polar side and exposed to the cold pool to our north and north east.

Models this morning showing more energy in the jet, but expect them to tone this down in future runs, allowing for the height rises to our NW. Need to keep an eye on developments upstream over NE USA seaboard, warm air advection through west greenland required to make it a smoother transition.

[wellington boot]

32 minutes ago, ThamesStreamer said:

Christ, look at the switch in the GEFS from the 00z (left) to the 06z (right). Must be something afoot to see such a pronounced movement in the ensembles from a crazy spread to a more confident outlook?

I'll prob find someone has answered this now, but the key difference is that parameters are different. X axis goes to -20 on one and -30 on the other, and one goes out to 20th Jan while the other goes to 26th...

[Tim Bland]

22 minutes ago, Battleground Snow said:

I'm going to put a positive slant on its and say because it verifying better than the OP at 120, it has the cut off Low nailed 

GFS and JMA almost neck and neck with the GFSp a clear winner.

[Methuselah]

35 minutes ago, Bartlett High said:

This is all so confusing!!!! What is it to be? The Op the parallel the mean the tea leaves!!!! I need to lie down.

Sometimes makes you wonder why we listen to anything folks say, on here? I'm so confused by all the 'upgrades', 'downgrades', 'flatter', 'more amplified at Day X' missives, that I no longer pay any attention even to myself!

[Cold Winter Night]

36 minutes ago, IDO said:

GFS op is outperforming the gfsP on both 0z and 12z stats:

ATM we are looking at this upgrade making gfs reliability even worse in setups like this. I understand that the gfsP has been tuned by ecm so no surprise it is more amplified in FI and as it goes out to d16 that is exaggerated even further! 

Fantastic in Winter when we get d10 ecm and gfsP charts showing phantom heights that are always out of reach!

Link  >here<

The verification process of these models is a little bit more sophisticated than simply eyeballing a one month line graph of just one variable (500hPa heights). Tomorrow things might look different again.
Based on these data alone, the only thing you could say is that they are all extremely close.

Add to that the fact that we are currently in a situation with rare events and combinations of background signals and this might become a good test for the verification of all models in a complicated setup that includes both Troposhere and Stratosphere.

[Catacol]

As stated earlier fine lines for future development at the moment, but if this morning's GFS is anything to go by the signal for a backing west of significant Russian cold just acquired definite momentum........note the deepening and strengthening ensemble mean low pressure to our east. Much more likely to advect the cold more swiftly than the 10 days just gone by. And the op was none too shabby....and in January there is always a lot more cold to tap into than in December....

Temp anomaly has a good look to it

 

[Tim Bland]

48 minutes ago, ThamesStreamer said:

Christ, look at the switch in the GEFS from the 00z (left) to the 06z (right). Must be something afoot to see such a pronounced movement in the ensembles from a crazy spread to a more confident outlook?

Longer ensembles show a bit more scatter (as you would always expect) but it’s still a massive improvement!

[Guest]

2 hours ago, claret047 said:

Lovely charts. Thanks for posting them. 

Perhaps you could tell novices like me what draws you to the conclusion that the cold spell if it arrives is likely to be of only a short duration.

I had always believed that once strong areas of high pressure and the accompanied very cold air in winter time they are very difficult to shift. I am old enough to recall the winter of 1962/3 and the Met Office kept calling an end to the bitter weather, but again and again they were wrong and the very cold conditions remained.

Many thanks

Kind Regards

Dave

 

Im no expert. far from it but the reason me thinking it will be hard to get entrenched cold is the difficulties we seem to be having getting high pressure in the right areas to stick around long enough. Having Said that though depends on peoples own definition of a cold spell.  The 2018 BFTE was about a week long and for us on the East coast was amazing with 10ft+ snowdrifts!

Who knows though look at Madrid they have had huge snowfall and unbelievable low temps down to -15c! and that is from 850's of around -7! and looking at their outlook doesn't seem to be going anywhere fast! As you allude to, once you get snow and cold here it can take a lot of shifting, especially if we can keep the Atlantic out of the equation. 

 

Heres hoping 

Edited January 10, 2021 by Guest

[londonblizzard]

Full 0z vs 06z ensembles, side by side, same axes. Definite improvement on mean and spread, and a couple of sub -15 options in there. 

[SLEETY]

The gfs p run,if that verified then we would have an historic cold spell with deep snow for many,and uk record low temp in danger of being broken.Utterly insane run,with the end showing lake-effect snow hitting Northern Scotland, with MINUS 20 uppers and probably polar-lows forming in the bitterly cold Arctic air-stream.

Please verify..