Model Output Discussion - New Year and Beyond

[sebastiaan1973]

29 minutes ago, feb1991blizzard said:

EC46 looses SSW signal

Game over? So it seems. 

[Daniel*]

29 minutes ago, feb1991blizzard said:

EC46 looses SSW signal

Not sure it’s fair to say loses SSW signal, about 10% do a reversal. I think this was quite predictable to be honest based on what we’ve been seeing still mean goes 20 m/s that’s not a strong vortex, think at moment it is ~50 m/s. Also note signal not for strengthening following weakening as we sometimes see. Maybe Thursday will be more insightful.

[lassie23]

We don't need an SSW for it to snow in our backyards.

[Singularity]

EC42 support for a SSW hasn’t totally gone but has reduced from about 20% of the pack to near 12%.

I expect it’s highly sensitive to just how long high pressure remains across Barents/Kara with some coverage of adjacent lands to drive cross-mountain flow hence vertical wave activity flux.

The faster it gets pushed east, the sooner that flux subsided and the less likely the warming is to be sufficient for fully displacing the polar vortex and triggering a SSW.

Theres also uncertainty regarding the Aleutian low, just how long that persists for. The longer it continues the better the odds of a very large wave-1 (displacement) or even a wave-2 (split type) event.

There’s a reason why SSWs aren’t reliably picked up on at over two weeks lead time.

The possible one for early Feb seems a coin-toss to me, we can only guess which way it will actually go.

[Frigid]

Well.. there are still quite a few members going negative. Last update can't be thrown out yet. 

 

[bluearmy]

21 minutes ago, RainAllNight said:

Hang on a minute... if the ENS will have the same resolution as the operational, then that means the control member will essentially be a second 'parallel' operational... mmmmmmmm...

One would assume that there will be an op upgrade fairly soon. Also, the op has 137 vertical levels. Be surprised if the new eps have quite as many. 

2 minutes ago, Daniel* said:

Not sure it’s fair to say loses SSW signal, about 10% do a reversal. I think this was quite predictable to be honest based on what we’ve been seeing still mean goes 20 m/s that’s not a strong vortex, think at moment it is ~50 m/s. Also note signal not for strengthening following weakening as we sometimes see. Maybe Thursday will be more insightful.

The spread on todays output is so wide - wouldn’t shock me to see a re strengthening of the spv at the end of Jan/early feb as a cluster of runs are showing. toss of a coin job …..

[Maz]

43 minutes ago, Nick F said:

EC due an upgrade this year, increasing ens to 9km resolution (same as high res), extended ens members will be run daily and with 100 members! GFS got a lot of catching up to do. 

103rd AMS Annual Meeting

AMS.CONFEX.COM

---

In 2021 ECMWF successfully introduced two new operational cycles, 47r2 and 47r3...

The next science cycle, 48r1, will be implemented in 2023 on our new HPC system in Bologna. This will see an enhancement of the ENS horizontal resolution to the TCo1279 grid (approximately 9km), the same resolution currently used by the HRES. There will also be an increase of the data assimilation resolution, with a new soft-centred approach to the Ensemble of DA (EDA) used to calculate background error covariances for 4D-Var and to initialise the ENS forecast runs. Other important changes in 48r1 include running the extended range ensembles daily and with 100 members, a new multi-level snowpack model, and use a new object orientated approach to run the 4D-Var atmospheric data assimilation (OOPS).

Did the new GFS use the object oriented approach (OOPS) as well? !

[Don]

3 minutes ago, bluearmy said:

The spread on todays output is so wide - wouldn’t shock me to see a re strengthening of the spv at the end of Jan/early feb as a cluster of runs are showing. toss of a coin job …..

Probably more than likely!  Met Office outlook continues to be broadly mild in the extended, so I suspect that's what's expected?  After things looking more positive a few days ago, we seem to have gone back to a poor outlook again!! 

[Daniel*]

5 minutes ago, bluearmy said:

One would assume that there will be an op upgrade fairly soon. Also, the op has 137 vertical levels. Be surprised if the new eps have quite as many. 

The spread on todays output is so wide - wouldn’t shock me to see a re strengthening of the spv at the end of Jan/early feb as a cluster of runs are showing. toss of a coin job …..

Maybe but also the alternative could also happen with greater clustering to weakening. Climatologically speaking February is not the month the vortex usually goes rampant, although I think 2020 it was wants a word.

[Eagle Eye]

40 minutes ago, swfc said:

Must be good you said it twice

 

[damianslaw]

Variance between ECM and GFS mid range timescale 120 hrs onwards continues... ECM maintains the theme of a colder feed of air from the NW through the coming weekend, with a cleaner deeper dig of the trough into Europe and the azores high advected west, GFS less quick with the evolution but gets there as we move into the following week, whereas ECM shuts off the colder airstream quickly with the azores high nudging back eastwards and we revert back to a westerly flow.

UKMO trending with ECM again as it has for a number of days.

Usually its the ECM that shows a more amplified flow than the GFS, the latter tends to pick up on greater levels at the closer timescale.

Either way a colder shot looks more or less certain the question is how cold and sustained. Northern parts could see quite a snowy picture with sub 522 dam air moving into N England.

[Don]

2 minutes ago, damianslaw said:

Either way a colder shot looks more or less certain the question is how cold and sustained. Northern parts could see quite a snowy picture with sub 522 dam air moving into N England.

I doubt it will be anything to write home about away from northern areas?

[damianslaw]

1 hour ago, northwestsnow said:

Hmmmm

maybe 12z was onto something..

Hmmmm

maybe 12z was onto something..

That's a cold trough signal.

[feb1991blizzard]

1 minute ago, Don said:

I doubt it will be anything to write home about away from northern areas?

It won't be anything to write home about in this Northern area even, it will 100% be rain here.

[damianslaw]

3 minutes ago, feb1991blizzard said:

It won't be anything to write home about in this Northern area even, it will 100% be rain here.

As ever it comes down to lots of parameters, time of day, intensity of precipitation, lapse rates, thicknesses, uppers, strength of wind and its direction, dewpoints, any trough features... always a nowcast when it comes to wintry weather.

Edited January 9, 2023 by damianslaw

[northwestsnow]

2 minutes ago, damianslaw said:

That's a cold trough signal.

Indeed.

that is a week anomoly so bearing in mind a PM flow will usually last 3 to 4 days maximum there is scope for something wintry in the North..

[northwestsnow]

Truth be told next week is as good as it gets acc to EC46 ,right out to 20th of Feb..

Edit 16th to 23rd 

Edited January 9, 2023 by northwestsnow

[zubzero]

2 hours ago, RJBingham said:

Snow no go

That's a sad amount off snow in Europe for Mid-Winter

Opps that's snow fall probabilitie still is poor fir Western Europe  https://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=16

 

 

Edited January 9, 2023 by zubzero

[northwestsnow]

Just now, zubzero said:

That's a sad amount off snow in Europe for Mid-Winter

Believe me if EC46 is right Europe is well above average until late Feb.

 

[damianslaw]

9 minutes ago, northwestsnow said:

Believe me if EC46 is right Europe is well above average until late Feb.

 

EC46 changes so often, I take little if any notice of it. Stick to the 120 hr timeframe and spot trends in the 120-240 hr timeframe tops best advice.

Edited January 9, 2023 by damianslaw

[Don]

8 minutes ago, northwestsnow said:

Believe me if EC46 is right Europe is well above average until late Feb.

 

Yes, a dreadful update and little to lift the mood in here tonight!!

[bluearmy]

8 minutes ago, northwestsnow said:

Believe me if EC46 is right Europe is well above average until late Feb.

 

The primary cluster to end week 4 is the cool zonal with a se euro trough so I expect the alps could get away with it 

[damianslaw]

6 minutes ago, Don said:

Yes, a dreadful update and little to lift the mood in here tonight!!

Ah note my post above, wait for the next one and the one after and it will change again and again and again... sometimes better for those wanting something colder, sometimes not so. 

[frosty ground]

8 minutes ago, Don said:

Yes, a dreadful update and little to lift the mood in here tonight!!

lol all we need now is the eastEnders music and some rolling credits.

honestly lift the mood  lol

Edited January 9, 2023 by frosty ground

[Purga]

Scuppered again by the Azores High which is far to dominant at the moment and will screw any decent southward movement of cold.