Model Output Discussion - New Year and Beyond

[Paul_1978]

57 minutes ago, frosty ground said:

What you have written and what the tweet states are not the same.

have you missed a tweet?

It’s the second tweet down - for some reason copying the link has quoted both the first and the second. 

[mushymanrob]

15 hours ago, Don said:

I'm starting to fear that February could be similar to last year now!

I think your fears are well founded, these predictive charts certainly suggest it becoming more unsettled and stormy into Feb, and that TPV is deeper/stronger than ever.

 

[Bricriu]

 

2 minutes ago, mushymanrob said:

I think your fears are well founded, these predictive charts certainly suggest it becoming more unsettled and stormy into Feb, and that TPV is deeper/stronger than ever.

 

Yes, it looks windy to the north west around the 5th of February. A couple of GFS runs have now shown this. 

Edited January 23, 2023 by Bricriu

[Bricriu]

I think it's a bust for positive impacts from the weakening of zonal winds, unless wave 2 warming starts showing up to kill off the pv. With a strong TPV will the mjo going to phase 6 or 7 be enough to produce a block in a favourable position? That's probably our only chance for a snowy outlook more widely, but we could well get further polar maritime shots over the next month if the jet plays ball. 

Edited January 23, 2023 by Bricriu

[bluearmy]

1 hour ago, Paul_1978 said:

This may have already been mentioned, apologies if it has. Marco from the Met Office tweeted that if a warming does occur then it is expected to have no impact on our weather as the strat and trop are not coupled. 

 

They said the same about the non coupling ahead of the northern arm awakening once the upper strat winds went into overdrive - it could just be co incidence that we saw the trop flow go strong zonal thereafter (it wasn’t though).  I can accept that the upper strat and trop are decoupled when the upper strat is fairly benign but when bigger things happen high up I don’t accept that they won’t affect further down in time. 

[Eagle Eye]

Despite the warming best attempts, the Vortex still keeps a lot of its baratropic stability with an especially inertial Vortex on its southern most extent as the Wave-1 dominant mode displaces the initial Northern baratropic stability. So that does create an unstable inertial pattern over Eurasia-North America but I don't think it's a strong enough baroclinic Wave to be able to cause a split. This is probable the big reason why displacements can be recovered from. The thermal dampening of Wave-1 with a baratropic pressure gradient of the main Vortex though displaced will allow the zonal-mean to ramp up as the Vortex rapidly balances itself back up towards the initial inertial pattern. Things like to be stable and without a sudden reversal through a split, it's unlikely that the recovery process won't happen quite quickly. Of course we have the warming Wave displacing the thermal-pressure stability so some attempt at a baroclinic instability induced split is attempted via the outer riding Wave but without Wave-2 its simply a fairly weak attempt without much of a steep angled gradient of attack and therefore nothing to really split the thermal-pressure gradient. This meaning that a split is looking very unlikely and a recovery likely once the vertical Eddy's stop being driven so unless we can get a secondary Wave somehow push in like near Scandinavia very quickly which none of the models are really showing, then the Vortex is likely to recover.

[Bricriu]

2 minutes ago, bluearmy said:

They said the same about the non coupling ahead of the northern arm awakening once the upper strat winds went into overdrive - it could just be co incidence that we saw the trop flow go strong zonal thereafter (it wasn’t though).  I can accept that the upper strat and trop are decoupled when the upper strat is fairly benign but when bigger things happen high up I don’t accept that they won’t affect further down in time

So if they do couple, will this lead to a reinforcing of the mobile pattern in the trop? 

[minus10]

Where do we go from here?....

.....edit...to here..

 

Edited January 23, 2023 by minus10

[Drifter]

Just now, minus10 said:

Where do we go from here?....

We seem to be sleepwalking towards a cold period again, where ‘lee’ northerlies are now getting upgraded and longer lasting. Interesting times. 

23 minutes ago, bluearmy said:

They said the same about the non coupling ahead of the northern arm awakening once the upper strat winds went into overdrive - it could just be co incidence that we saw the trop flow go strong zonal thereafter (it wasn’t though).  I can accept that the upper strat and trop are decoupled when the upper strat is fairly benign but when bigger things happen high up I don’t accept that they won’t affect further down in time. 

He’s also posting from his personal account , not the met office views. He may therefore be letting his mild persuasion influence his thoughts. 

[Eagle Eye]

4 minutes ago, Bricriu said:

So if they do couple, will this lead to a reinforcing of the mobile pattern in the trop? 

Well Waves are either reflected back or they break and cause easterly momentum to cycle. These Waves initiate in the Troposphere however during strong Vortex events that is caused by the lack of Waves pushing into the Stratosphere. Sure there may be some to break into the Strat but most interference is weak unless the Trop can regain upwards Wave flux in some way. This suggests that the Trop leads the Strat but during SSW's the Strat leads the Trop so perhaps the same can happen during VI events. 

I suspect that it's possible that a baratropic Strat pattern will lead to some downward balancing of the pressure gradients in the Troposphere and that likely leads to the increasing of zonal anomalies and balancing out of Eddy's.

It's important to understand what leads what in this situation and I think its a bit of both to be honest.

[KTtom]

1 hour ago, mushymanrob said:

I think your fears are well founded, these predictive charts certainly suggest it becoming more unsettled and stormy into Feb, and that TPV is deeper/stronger than ever.

 

I was beginning to wonder what charts I was missing out on reading the previous page... That anomaly is not good going forewords, and considering most have previously said they are the most reliable, it must be taken seriously? It sounds like the Stat warming will be no good for any assistance so we are relying on home grown luck to get another cold spell, which worked fine in December.

Edited January 23, 2023 by KTtom

[andymusic]

gfs 00z/06z looking good for coldies starting around about a week today

Edited January 23, 2023 by andymusic

[Stuie]

1 hour ago, mushymanrob said:

I think your fears are well founded, these predictive charts certainly suggest it becoming more unsettled and stormy into Feb, and that TPV is deeper/stronger than ever.

 

Looks like an example of both the AO and NAO going positive which i posted a day or 2 ago.

[goosey007]

Yes its GFS at 220 but something to watch and hope for upgrades in the reliable ...looks short lived but if timed well could have a decent snow event.

 

[TSNWK]

4 minutes ago, andymusic said:

gfs 00z/06z looking good for coldies starting around about a week today

Agree. But against the anoymies..

[mushymanrob]

2 minutes ago, KTtom said:

I was beginning to wonder what charts I was missing out on reading the previous page... That anomaly is not good going forewords, and considering most have previously said they are the most reliable, it must be taken seriously?

Well ive not been using the EPS anomalies very long, so cannot say with much degree of certainty how accurate they are. So far they havnt been far off very often. These charts go out furthern than my favoured NOAA which i will defend as accurate or the most accurate for the timescale they represent. After John holmes research over ten years ago or so , ive been using them for something like 7. No predictive model suite is right all the time and differing people prefer differing predictive sources.

When the EPS matches a consistent NOAA, then the extended EPS charts are likely to be near to what we get.... when consistent.

The latest EPS attached goes out to the 7th. It suggests that a very strong TPV will dominate our weather pattern bringing, after a quieter spell, a return to normal february conditions from the West. As the contour lines are close together, that suggests mobile, unsettled, and even stormy. True we might get short spells of cold, 24/36 hour events, but these charts are a long way off delivering the decent Winters spell most here desire.

So yes, take them seriously as they have a realistic chance of becoming reality. Id be surprised if they were far off the mark, but nothing is set in stone, especially over 2 weeks away.

[tight isobar]

The 6z gfs carries on with my initial thoughts.. of colder air again making inroads to the uk! The preety reliable Norwegian service yr. no are also noting colder air spilling further west in nxt 7 days!! I think it’s time to pause looking for holy grail Synoptics via an SSW it’s getting clear it’s not gonna have much/ if any bounce for ourselves!... time to concentrate of are own micro adjustments me thinks.. and ones that could “ at least hold some fairly decent outcomes “!!!   Tbh the whole SSW thing is grating on me!!! Have a good day

Edited January 23, 2023 by tight isobar

[andymusic]

5 minutes ago, tight isobar said:

The 6z gfs carries on with my initial thoughts.. of colder air again making inroads to the uk! The preety reliable Norwegian service yr. no are also noting colder air spilling further west in nxt 7 days!! I think it’s time to pause looking for holy grail Synoptics via an SSW it’s getting clear it’s not gonna have much/ if any bounce for ourselves!... time to concentrate of are own micro adjustments me thinks.. and ones that could “ at least hold some fairly decent outcomes “!!!   Tbh the whole SSW thing is grating on me!!! Have a good day

to have or not to have an ssw - we could very well do better without one in the UK - who knows - but agreed we should put the subject to bed for the mo - say no more about it

[TEITS]

The affects of the heights across the arctic are having more of an effect on the UK on the 06Z GFS as I mentioned the other day.

Just a shame that the modelling is predicting the PV to be ramping up and heading back towards Greenland. Potential for a very stormy period to develop at the start of Feb and might yet prove to be cold and unsettled rather than mild/unsettled.

Plenty to keep our eyes on.

[Don]

2 hours ago, mushymanrob said:

I think your fears are well founded, these predictive charts certainly suggest it becoming more unsettled and stormy into Feb, and that TPV is deeper/stronger than ever.

 

That’s cheered me up on a Monday morning!

I did fear at the beginning of January that after the December cold spell, this winter could go the same way as last year and that’s now looking realistic!!

Edited January 23, 2023 by Don

[Northern Sky]

41 minutes ago, mushymanrob said:

Well ive not been using the EPS anomalies very long, so cannot say with much degree of certainty how accurate they are. So far they havnt been far off very often. These charts go out furthern than my favoured NOAA which i will defend as accurate or the most accurate for the timescale they represent. After John holmes research over ten years ago or so , ive been using them for something like 7. No predictive model suite is right all the time and differing people prefer differing predictive sources.

When the EPS matches a consistent NOAA, then the extended EPS charts are likely to be near to what we get.... when consistent.

The latest EPS attached goes out to the 7th. It suggests that a very strong TPV will dominate our weather pattern bringing, after a quieter spell, a return to normal february conditions from the West. As the contour lines are close together, that suggests mobile, unsettled, and even stormy. True we might get short spells of cold, 24/36 hour events, but these charts are a long way off delivering the decent Winters spell most here desire.

So yes, take them seriously as they have a realistic chance of becoming reality. Id be surprised if they were far off the mark, but nothing is set in stone, especially over 2 weeks away.

Hi Mushy, am I right in thinking that chart indicates a rather cool Westerly rather than mild South Westerly's? If that were the case then I'd be happy to take it for a while at least. We've had lots of settled cold weather and a bit of windy even stormy weather would be a nice change. 

Was it Jan 84 when we had some true cold zonality? Almost always the cold air is watered down as it approaches the nearer timeframe but I live in hope that one day we'll see a repeat of that pattern.

[mushymanrob]

1 minute ago, Northern Sky said:

Hi Mushy, am I right in thinking that chart indicates a rather cool Westerly rather than mild South Westerly's? If that were the case then I'd be happy to take it for a while at least. We've had lots of settled cold weather and a bit of windy even stormy weather would be a nice change. 

Was it Jan 84 when we had some true cold zonality? Almost always the cold air is watered down as it approaches the nearer timeframe but I live in hope that one day we'll see a repeat of that pattern.

Id call it average from the West.... but of course there would be both milder and colder spells as frontal systems track over us. 84 had a run of PM air from the Northwest, produced some very heavy snow showers even inland. (experienced them).

[Eagle Eye]

The modulation of the MJO characteristics via Kelvin Wave signals suggest that eventually we should see a slow Nina evolution lag week 2 via the reaction of MJO linear time-series and exiting +VE EPO Wave. Though this may see a further snap of cold as the development of local relative cold pooling and some meridional Wave train help. I don't think it'll amount to much but at least its something probably more for the North and Scotland.

[nick sussex]

It’s best to be cautious when the models show any northerly whilst you still have a strong PV located in ne Canada .

What often happens is the models often underestimate this and as you tick down things get shunted eastwards .

On the reverse side here we’re seeing the Arctic high trying to keep troughing over Europe .

Its a case of eastwards energy v southwards energy and currently this meets near the UK .

If the Canadian PV can weaken , first signs is an elongation of that and some amplification upstream can aid in pulling this further nw .

If you can separate that from feeding Atlantic low pressure you have a better chance of some trough disruption sending energy se to the west of the UK .

[bluearmy]

2 hours ago, Bricriu said:

So if they do couple, will this lead to a reinforcing of the mobile pattern in the trop? 

It doesn’t surprise me to be seeing the scandi trough becoming more relevant on the output with the same feature high up having been consistently modelled. Still waiting to be confident about the predicted zonal flow post weakening, top to bottom.