[Model Output Discussion - Spring Has Sprung]

The EC 12z solution has been marching through the ensembles (EPS and GEFS) and now finally appears as an Operational solution, backed up by UKMO 12z at 168h.
And no lack of cold to the NE this time:

Although I'm not sure about the 'squeeze'  between Arctic High and Siberian High. But so far, so good.

[Model Output Discussion - Spring Has Sprung]

 Mike Poole

Glad to see operational runs finally coming to their senses at reasonable lead times, and showing what was the ensemble majority direction for days, instead of making us ensemble/cluster watchers look like complete fools.

[Model discussion highlights]

 Lukesluckybunch

Let's see, here's EC46 from two weeks ago:

NAO+ until February 10, then a few transition days to an attributed Scandinavian Blocking regime February 16 onwards.

Now watch EC 12z again, that's exactly what it shows.
EC 240h anomaly fits the Scandinavian Blocking regime:

The problem is thinking that "Blocking = Immediately Very Cold and Snowy IMBY," like 1+1=2, but that's not the way it works.

Original post: https://community.netweather.tv/topic/99814-model-output-discussion-22nd-jan-2024-onwards/?do=findComment&comment=5032052

[Model Output Discussion - Spring Has Sprung]

 Lukesluckybunch

Let's see, here's EC46 from two weeks ago:

NAO+ until February 10, then a few transition days to an attributed Scandinavian Blocking regime February 16 onwards.

Now watch EC 12z again, that's exactly what it shows.
EC 240h anomaly fits the Scandinavian Blocking regime:

The problem is thinking that "Blocking = Immediately Very Cold and Snowy IMBY," like 1+1=2, but that's not the way it works.

[Model Output Discussion - Spring Has Sprung]

 Ice Day

Exactly.

They have in common that around 168h they show simulatneously developing heights over the UK and over Western Russia, which then connect towards 240h to form a larger NE High.
GEM 240h really is a massive 1060 hPa beast.

GFS -of course- the odd one out, but to me it looks strange again with the distribution of ridges and troughs around 240h.

[Model Output Discussion - Spring Has Sprung]

 Froze were the Days

Like I say in that quote, the development on UKMO is represented in the 0z EPS set, with the Low moving away NE through Scandinavia, and that Atlantic Low pushing up heights through the UK towards Scandinavia after that. EPS 0z P6, P40 for example.

And yes, some preceding Iberian height rises may be involved as part of that, but that's not strange in the setup of Scandi Highs.

Nothing is guaranteed, but I see no reason for despair. Let's see what EC/EPS makes of it tonight.

[Model Output Discussion - Spring Has Sprung]

 nick sussex

It's steadily coming closer in time.
Take the 360h GEFS mean 4 days ago vs GFS Op today for the same lead time:

Fits nicely.

There is strong forcing towards Northern blocking going on. That is not depending on a Low passing the UK 100 miles further North or South.
Of course exact location, orientation etc will matter eventually, but we're not in that phase yet.

And all the complaining is mainly about a GFS run that has, say, 80% of the British isles with a snow cover at one time, with room for upgrades left. Beggars can't be choosers, isn't that the saying?

There are times for complaining about "winter", today isn't one of those times.

[Model Output Discussion - Spring Has Sprung]

UKMO 168h preparing for Scandi height rise, similar to many EPS members at that lead time.

Really strange emo-posting this afternoon .

Based on previous runs and ensembles, we were expecting Northern heights developing Day 8-15, not before.
You still see GFS and GEM doing that!

So I don't get the 'throwing of toys' at all.
Giving up on the rest of winter, because the models don't suddenly show at Day 5 what was not expected before Day 10? Come on.

[Model Output Discussion - Spring Has Sprung]

 johncam

EC46 (yesterday's, the most recent) has positive height anomalies NW of the UK from beginning to end.

On EPS 0z, 49 out of 51 members in the extended have pos. height anomalies to the NW. One, maybe two, could be described as "normal default winter weather."

It's not often a heavily diluted, long lead time 360h mean looks like this:

Keeping your feet on the ground is one thing, nothing wrong with a bit of caution, but let's not pretend that the extended output is not heavily leaning towards a very meridional pattern.
The very opposite of a default zonal setup.

 

[Model Output Discussion - Spring Has Sprung]

At the moment, I don’t see reason to be downbeat or concerned about the second half of February.
This morning’s extended output from EPS and GEFS is still very blocked, regardless of the emotions in this thread.

The large majority of members is good to excellent from a cold synoptic POV.
Here are the full EPS 0z and GEFS 6z panels at 336h, mid-extended:

There’s no denying that we have a great collection of Scandi and Greenland Highs there.

As MJO and stratosphere are incorporated in the models (after all, the strat and MJO plots are output from the same models), there is in my opinion no need to worry about phase and progression as long as the synoptics in the Euro-Atlantic end up as amplified as they do at this moment.

“But it’s FI and that can change quickly,” I hear the pessimist say. True, of course it can, but that’s not the output reality right now.

Interesting stuff, sit back, learn, relax and keep breathing.

[Model Output Discussion - Spring Has Sprung]

No EPS clusters out yet, but the De Bilt output shows the pattern shift in the extended in wind direction and 2m Temperatures.
Solid increase in probability of winds from the North and East, likely comparable to the promising NH patterns on the 0z.

It's only beginning after Day 10, so there need not be disappointment about the setup before that.

[Model Output Discussion - Spring Has Sprung]

 northwestsnow

Check the panels for GEFS 0z/6z and EPS 0z and you'll see that many members were very similar to UKMO 168h with their NH/Atlantic pattern.
Then look at the same members again in the extended and they develop a wide variety of blocking.
As I'm writing this GFS is doing that again as well.

There's a small chance of a more wintry sweep around 144/168h, but the big pattern shift is found deeper in the extended, and I expect that 12z GEFS and EPS will not really move away from that.

[Model Output Discussion - Spring Has Sprung]

 Harsh Climate

GEFS mean at 360h suggests a firm High setting up after the trough plunges into Europe, whether it's an 'Atlantic' or an 'Icelandic' High is up for debate.

The panel with individual members reveals that most Highs, if  they build in the Atlantic are not that flimsy IMO. Little to suggest the Atlantic moving back in.
Quite a few even go from Atlantic High to a High between UK and Iceland, some even extending over Scandinavia, with winds turning NE in NW-Europe and at least the Southeastern part of England.

Will be interesting to see if EPS agrees with GEFS on these developments in the extended.

[Model Output Discussion - Spring Has Sprung]

Small depression moving into cold T850s at UKMO +168h.

What do you call that white stuff from the sky again?

But I doubt if UKMO would send the trough as far South into Europe as GFS and EC 0z do.

[Model Output Discussion - Spring Has Sprung]

21 minutes ago, Eagle Eye said:

Looking at the ECM which probably has a better convective envelope characterisation, has it being active into phase 7 before potentially moving towards COD by phase 8. However, will the convective envelope response to falling IOD into phase 8 be favourable or is that another dry phase response. I couldn't really tell you for now because it's still a dynamical evolution, not a perfect composite response as with pretty much anything. Perhaps things looking a little better on the NWP and the teleconnections. 

Not only in this instance, but anytime when using EC Extended Wheeler-Hendon MJO diagrams, I think it's important to be aware of what ECMWF says about them:

"Note also that by construction, the amplitude of the forecast ensemble mean MJO on this diagram (as shown by black triangles) will tend to reduce, on average, at longer lead-times." (ECMWF Forecast User Guide, Section 8.2.6)

So, when looking at the diagram at longer lead times, it probably tells us more about the direction and speed than about the amplitude.

I don't know if the same caveat applies to the back end of Medium Range MJO output, or to GFS/GEFS output, I can't find anything on that, but it wouldn't surprise me either.

Section 8.2.6 Madden-Julian Oscillation Output - Forecast User Guide - ECMWF Confluence Wiki

CONFLUENCE.ECMWF.INT

[Model discussion highlights]

The EPS regime chart is helpful for showing overall regime tendencies in the EPS ensemble out to day 8.

Two days ago it showed us staying on the Pos. NAO side:

Yesterday a bit more spread appeared:

But today in the 0z, we see a firm signal for a move towards Neg.NAO (left side of the chart) / Atlantic Ridge (bottom half of the chart) in about 7-8 days time:

Some light at the tunnel, or so it seems, with a potential switch to a more promising pattern, well within the period when winter still can have teeth.

Original post: https://community.netweather.tv/topic/99814-model-output-discussion-22nd-jan-2024-onwards/?do=findComment&comment=5024219

[Model Output Discussion - Spring Has Sprung]

The EPS regime chart is helpful for showing overall regime tendencies in the EPS ensemble out to day 8.

Two days ago it showed us staying on the Pos. NAO side:

Yesterday a bit more spread appeared:

But today in the 0z, we see a firm signal for a move towards Neg.NAO (left side of the chart) / Atlantic Ridge (bottom half of the chart) in about 7-8 days time:

Some light at the tunnel, or so it seems, with a potential switch to a more promising pattern, well within the period when winter still can have teeth.

[Model Output Discussion - Spring Has Sprung]

UKMO 168h makes more of those lingering heights over Scandinavia as a new Atlantic wave approaches.
It may slowly get more difficult for the Atlantic to push through.

GEM also ends with a more amplified Atlantic and lower heights into Europe at 240h.

[Model Output Discussion - Cold spell ending - what next?]

8 minutes ago, feb1991blizzard said:

Is there really gonna be enough forcing on this pattern to get the Griceland now?, starting to have my doubts now about anything before 10th-15th feb, - scandi dead in the water before at least 7th now.

??

February 7 is Day 19 (!) from today. Far beyond even the extended.
We still see the 12z output trying to build all sorts of Scandi/Euro/Sceuro/Scrussian or what have you variants before it's even February 1.
GEM at 240h is really not far from being very good, missing just a little bit of latitude.
GFS, although struggling, seems to be going in the right direction in FI right now.

A potential Griceland option I would expect after the Scandi High, not as the first stop of the retrogression train.

[Model Output Discussion - Cold spell ending - what next?]

At 180h, GFS, ICON and GEM are surprisingly similar with a Siberian High, modest low heights over E-Europe and simultaneous heights over W-Europe. At 144h, UKMO seems to be going in that direction as well.

[Model Output Discussion - Cold spell ending - what next?]

A run like GFS is also a good illustration of how quickly cold can return, as long as you have a strong and well-aligned Scandi High setting up.
That should calm the minds of those who lament the Eastern cold being driven out by the Westerlies.

T850's to the East, over Southern Sweden and Poland go from about +6c at 192h to -12c or lower at 264h, that's 3 days.

[Model Output Discussion - Cold spell ending - what next?]

1 minute ago, Mike Poole said:

Yes, GEM very much on the same page at T240:

Good to see these sorts of charts in the 10 day range.  Can we reel this one in?

It's right around the time renewed amplification was expected. We have the AAM increase supporting this, contrary to FI Scandi High output in past years. Now let's hope the stratosphere will behave well for once.

[Model Output Discussion - Cold spell ending - what next?]

GFS Op, like GEM, now has a Scandi High in place at Day 10 and it is beginning to advect cold Westward.
Good to see this signal repeated.

[Model Output Discussion - Cold spell ending - what next?]

7 minutes ago, bluearmy said:

Some very interesting NH profiles into week 3 on the gefs 

Indeed.

Many feature an Arctic High, detached from the Pacific High.
P7 even with a remarkable (and unrealistic) 584+ hPa Arctic High at 360h. A synoptic collector's item, you don't see such a fat beast at those latititudes very often, even within the ensembles.

[Model Output Discussion - Colder but how cold and for how long?]

I have a feeling we're not in Kansas zonal territory anymore.

EC and GFS at 240h are really not that far apart.

These developments have been present in the extended ensembles, but now also on Operationals.
Indeed indications that the zonal phase might not at all be as long as many fear.