Model Output Discussion - Spring Has Sprung

[Dennis]

  @Mike Poole

Vortex position in start febr 

there is no W-E sign in the strato

[AO-]

So, what is the case with GFS? There are a lot of members that put a large part of the Vortex to move into Scandinavia/West Russia. But there are still some flat ones as well with a zonal flow. Then there are some interesting members with wintry or possibly wintry synoptics later on. A part of them showing ATR. there is still a lot of work to do, but it's a start. 

 

Edited January 25 by AO-

[Cold Winter Night]

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.

[Dennis]

  @Cold Winter Night

thnks for that here , this is a sudden act on the ideas about MJO event

 

[Lukesluckybunch]

34 minutes ago, AO- said:

Vortex to move into Scandinavia/West Russia. But their are still some flat ones as well with a zonal flow. Then there are some interesting members with wintry or possibly wintry synoptics later

Part 12 yes please!

[Dennis]

MJO 25-1

EC 

[Cambrian]

The devil will be in the detail as ever, but there is a consistent story emerging in the broad evolution in week 2, of a slow and steady fall in heights and pressure through Northern and Western Europe, the southwestward extent of which is important and to be firmed up over the coming days.

From the 0z and 6z GFS mean (note the inter-run variability) and 0z ECM mean…

  

0z ECM ensembles for Birmingham and Madrid. The ECM can be hawkish with respect to letting go of heights, so a universal 12mb drop in pressure on the mean during the first few days of February is significant…

 

…and particularly so in the context of those heights rises out west and the diminishing zonal flow - yesterday”s EC46 for 5-12 February, pressure and heights…

 

Very clear in all these is the establishment of the trough in and around Scandinavia and northwest Russia, and in some runs this is setting up further west over Denmark like here on the 0z ECM control, with some cold air and good wintry potential entrained for the UK and Ireland…

 

Though this doesn’t appear to have much scope for being deeply cold or long lasting, it is in keeping with the gaining trend by that stage for synoptics that are looking to actively entertain incursions from the northwest or north. 

[AO-]

  @Dennis

 

It looks like the MJO sticks around in phase 7 for a while. Could be promising. At least Scandinavia is getting back cold(er) soon. Hope the wintry options gain traction. 

[MJB]

  @Lukesluckybunch

It's a good one

[Rain All Night]

16 hours ago, RainAllNight said:

12z deterministic runs, Thu 25th to Wed 31st

In the last few frames here, we see that westward shift of the heights to the south that has been showing on the ensemble means for the past few days. Down south, we seem to be able to make a dry stretch last from Friday PM until Monday-ish. UKMO manages to get some modest high pressure to the north by the end of its run.

12z ensemble means, Thu 1st to Wed 7th

ECM seems especially confident about the PV paying a visit to northeast Europe on the weekend after next, but it is equally bullish about high pressure remaining strong to our south, hopefully at least meaning that we continue to get some decent stretches of dry weather further south.

0z deterministic runs, Thu 25th to Thu 1st

The end of the GEM is quite different to the others, with the low that forms over the Atlantic on Sunday flying upwards and kicking up a little high over Norway and Sweden.

0z ensemble means, Thu 1st to Thu 8th

We almost see some interest around days 10-12 (Sun 4th & Mon 5th) on the ECM, perhaps a hint that a brief ridge could build in from the west, after the PV clears back out of northeast Europe. It doesn't show so much on the other two models.

Edited January 25 by RainAllNight

[bluearmy]

1 hour ago, Mike Poole said:

The Strat profile has been very much in tandem with the trop profile all winter!

With a strong vortex that would be a bad thing.  But despite a very weak vortex, it has even so managed to thwart us at every turn.  Maybe our luck about to change?

As per dennis’ post above, the profile upcoming is surely not a bad thing even if the flow is stronger with a deeper centre and lack of strat ridges 

[Eagle Eye]

On 24/01/2024 at 12:48, Eagle Eye said:

Whereas a wetter than normal eastern Maritime and western Pacific that has been characterised poorly by the GFS(/most models but GFS most) so far. Theoretically leading to a larger response in phase 7.

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. 

Edited January 25 by Eagle Eye

[Cold Winter Night]

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

[AO-]

  @Eagle Eye this is the analysis of the 24th. Dennis had posted the one from the 25th. 

[Eagle Eye]

7 minutes ago, Cold Winter Night said:

"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."

Yes however I suspect that that's the amplitude of both the suppressed (dry) and active (wetter) phases because of the mix in the ensembles. So it depends whether the phase 8 of a combined falling +VE IOD and El Nino is a suppressed or active phase. 

  @AO- thank you, was wondering why today's wasn't showing up for me but anyway, still a similar strength and direction of travel. 

[northwestsnow]

So EC has mjo phase 7 for a wee while..that's got to be good news ..

I'm sure something else will go wrong somewhere , it nearly always does.

[AO-]

  @Eagle Eye

I think I know what the case is. You have shown the extended whereas Dennis has shown the two week analysis. 

Edited January 25 by AO-

[bluearmy]

Are we using non bias corrected MJO forecasts because they tend to look better ???

[StretfordEnd1996]

Bit late but these set of 6z ensembles don't look particularly pleasing from a cold perspective and to me show a reduction in colder members compared to recent runs

Big amount of scatter though yes. The period from around 3rd-6th February looks to have the most colder members, I suspect the majority of this is from some temporary NW type incursion (lacking any sort of blocking). Thankfully this above doesn't have any relevance to further longer range models mid-end of Feb which is still a good 3-4+ weeks away widely.

[Battleground Snow]

Gem interesting at 240, probably some pm shots coming in early February, but I'm watching that next wave of high pressure moving across Canada, which may give us a more robust HLB in 2 weeks time.

 

[nick sussex]

It’s a slow process to remove the limpet high or at least have it edging nw .

At least the MJO has finally left phase 5 , now into 6 and hopefully it keeps moving .

Its always frustrating seeing weeks of prime winter eaten up by some poor synoptics but we’ve had to endure this more often than not since I joined NW back in 2004 .

 

[AO-]

GFS day 10. A shot of Polar air, but not a long lasting one I guess. The vortex has moved towards the European side of the Atlantic, but CAA to the West leaves us in a Westerly flow. 

Edited January 25 by AO-

[AO-]

  @Battleground Snow

To be honest, when taking the WZ version, I like that chart. There is WAA to the West which might eventually lead to the Greenland block. 

(I prefer the presentation of WZ over meteociel) 

[jules216]

  @nick sussex yes, there is always something isnt it? The change is being pushed back and back until the sun is so strong IT will have exeptional synoptics late February. Its just Been a slice of luck that we had a rather good spell of winter here in Slovakia since 8.1 but even that it has been pure luck that mild westerlies did not break through the Carpathian ARCH and we kept a quasi inversion cold with uppers of -2 suffient enough to bring 5cm of Snow Yesterday but even that has Been melting like crazy today under Sunny north westerly with -4 uppers. The highlight of this January Has probably occured Yesterday morning and quite shockingly I have to admit it has Been the best January here since 2018! Its that Bad how shocking the recent Januaries have been.

[carinthian]

Evening all. Gave the model viewing a 5 day break as I felt deflated after viewing last weeks runs .  The models, especially GFS spot on to flush away the European cold at great speed. Sad that the hint of an Easterly failed again. Just trying to analyse the winter so far, not surprised to see a record January low recorded in Northern Sweden of -47c. Sad to see 27c recorded today in Eastern Spain. Sad to see a new January high recorded yesterday in West Tirol. Sad to see Northern Britain battered by recent run of storms. Where is it all heading ? Well looking at the latest models a prolonged  continuation of mild conditions to prevail for most . Wish I never looked !  Spoke to the team over here and they offer little prospect of proper cold or snowfall for the next 10 days. However, their longer term charts from second week of Feb show a change back to winter across much of Europe , especially the British Isles( so that must indicate some sort of Northerly incursion) Scandni-land keeps good winter charts for most of the period. Not a good 10 days prospect for the ski-ing resorts with plenty of warm sunshine in the offering.

All very trying at the moment this model watching for us many lovers of cold synoptics to emerge. Just like the words from a famous Kinks song " Tired of waiting...."