Model output discussion - The Hunt For Cold

[BlueHedgehog074]

7 minutes ago, Summer Sun said:

Found this from the ECM seasonal for winter

Source: https://twitter.com/CopernicusECMWF/status/1062678724615774209

 

I’m guessing that chart suggests temperatures over the U.K would be around average with the lack of positive and negative temperature anomalies over that area. Just the fact it has the whole U.K covered in white. (Or us being buried in snow ) 

[feb1991blizzard]

2 minutes ago, DiagonalRedLine said:

I’m guessing that chart suggests temperatures over the U.K would be around average with the lack of positive and negative temperature anomalies over that area. Just the fact it has the whole U.K covered in white. (Or us being buried in snow ) 

Unfortunately not - it has us being buried in no strong signal for below or above temperatures.

[bluearmy]

3 minutes ago, DiagonalRedLine said:

I’m guessing that chart suggests temperatures over the U.K would be around average with the lack of positive and negative temperature anomalies over that area. Just the fact it has the whole U.K covered in white. (Or us being buried in snow ) 

 a three month seasonal mean chart is quite useless at the best of times ……….. one which takes several seasonal  models into account is in the realms of chocolate fireguards …...

[BlueHedgehog074]

5 minutes ago, bluearmy said:

 a three month seasonal mean chart is quite useless at the best of times ……….. one which takes several seasonal  models into account is in the realms of chocolate fireguards …...

Yeah, guess that’s true lol!

[Chesil View]

7 minutes ago, bluearmy said:

 a three month seasonal mean chart is quite useless at the best of times ……….. one which takes several seasonal  models into account is in the realms of chocolate fireguards …...

Indeed so Blue. We could have a month long cold and snowy spell which would keep us all happy on here and still end up with seasonal chart like that.  

[Methuselah]

10 minutes ago, bluearmy said:

 a three month seasonal mean chart is quite useless at the best of times ……….. one which takes several seasonal  models into account is in the realms of chocolate fireguards …...

Not only that, Blue: an 'average' month (temperature wise) could be made up of two weeks' -12C uppers, and a fortnight dominated by uppers of +10...and, given the current propensity for meridional flow, such a scenario mightn't be entirely out of the question...?

[bluearmy]

4 minutes ago, Broadmayne blizzard said:

Indeed so Blue. We could have a month long cold and snowy spell which would keep us all happy on here and still end up with seasonal chart like that.  

We could have two if month three was very warm ...... even the months broken down can be misleading if one model sees a cold month when another sees warm ...

[Cheshire Freeze]

I'm more struck by the anomalous warmth to our N & W on that chart. Gives us an idea where mean HP may set up...

[bluearmy]

Two things to take from that chart are

1) warm eastern med indicates plenty of central med low pressure systems over the period 

2) warmth to our north possibly reflects where upper ridges look to become centred - but then why no cool anomaly over ne Europe ???

nah - still don’t see the point !

[BLAST FROM THE PAST]

2 hours ago, Quicksilver1989 said:

I think they were comparing next weeks large Scandi high to the beast and explaining the lack of really cold uppers. Anyway not to worry its the retrogression to Greenland we need to keep an eye on  

That makes more sense as the air initially isn’t beast from east source, cheers.  Retrogression possibly likely to be slower and it may take until turn of month before we get a stable GHP set up....but as long as we head towards sustainable cold pattern...but I’m very happy with how developments are coming along....

 

BFTP

Edited November 14, 2018 by BLAST FROM THE PAST

[Connor Bailey Degnan]

NAO and AO still looking like tanking...

[Met4Cast]

6 minutes ago, Connor Bailey Degnan said:

NAO and AO still looking like tanking...

No kidding!

 

[Chesil View]

We await the 12z GFS with interest. Will it be an upgrade on yesterday's. Lol

[SMU]

3 hours ago, Seasonality said:

Hey Big Steve! What is your take on the GFS 06z evolution? 

Hi Mate here is my take inlne with my NH thread & my opinion of what 'usually happens....

I certainly expected this to be occuring right now - forecast for 2nd week of Nov was for record breaking high pressures beginning to retrograde towards High Lattitudes ( see NH thead )

 

As for actual evolution-  Even though the run ups are messy there are in my eyes 2 very clear trends

- When we throw messy 'light' ridges to greenland or Scandi despite the initial prognosis by the models we always seem to downgrade nearer the time with borderline scenarios- ( occasional transitory snow & cold )

- Also vice versa - The few times we have thrown genuine blocking highs into Greenland & Scandi the resultant model outputs have all converged to a clean cold scenario with relative upgrades felt along the way- ( Normally removing the messy obsticles )

In this current outlook I expect the latter to be the form horse- I see no reason to suggest these are temporary blocks as the initial set up has a HP circa 588 Thickness indicating a substantial high pressures ( towards record strength ) & the iceland > GH progression is natural-

I therefor forecast that its a repeat of 2010 ( which I have maintained for 2-3 days & also indicated in the NH thread in October )

This will hopefully knock the stratosphere for December...

4 week CET from Mid Nov - Mid Dec could be below 2c...

S

 

Edited November 14, 2018 by Steve Murr

[Scandinavian High.]

I’m struck by gfs as we are mainly east north easterly from 102 hours right to end of run very unusual as we are normally being batted from the west .

[WINTRY WALES]

8 minutes ago, Steve Murr said:

Hi Mate here is my take inlne with my NH thread & my opinion of what 'usually happens....

I certainly expected this to be occuring right now - forecast for 2nd week of Nov was for record breaking high pressures beginning to retrograde towards High Lattitudes ( see NH thead )

 

As for actual evolution-  Even though the run ups are messy there are in my eyes 2 very clear trends

- When we throw messy 'light' ridges to greenland or Scandi despite the initial prognosis by the models we always seem to downgrade nearer the time with borderline scenarios- ( occasional transitory snow & cold )

- Also vice versa - The few times we have thrown genuine blocking highs into Greenland & Scandi the resultant model outputs have all converged to a clean cold scenario with relative upgrades felt along the way- ( Normally removing the messy obsticles )

In this current outlook I expect the latter to be the form horse- I see no reason to suggest these are temporary blocks as the initial set up has a HP circa 588 Thickness indicating a substantial high pressures ( towards record strength ) & the iceland > GH progression is natural-

I therefor forecast that its a repeat of 2010 ( which I have maintained for 2-3 days & also indicated in the NH thread in October )

This will hopefully knock the stratosphere for December...

4 week CET from Mid Nov - Mid Dec could be below 2c...

S

 

Hi Steve

Apologies but where is this NH Thread????

[Tamara]

3 hours ago, Ed Stone said:

Maybe the Met are just trying to inject a little calm into proceedings?

This quoted statement strikes quite a chord  - looking in as I am from the outside of the thick panelled window of this particular utopian world 

The METO are professionals and interpret numerical model data, as well as utilising the considerable investment they have in tropical modelling - and make their own conclusions. As such they are completely divorced from any hysteria attached to weather preferences.

One can of course dispute their own findings and conclusions based on other collective/ individual professional or amateur analysis and many rightly do this. Assuming that is, that such alternative offerings remain credible in themselves and designated such that the signals are derived from applied meteorological science, and so fit a realistic range of probabilistic solutions, and not merely as given lip service to try to fit an idealised one

Sensibly, the Met are quite right to state things as they see them - and not instead on a regular basis feel obliged to please (and equally reassure!) their public of any perceived preferences they may have through making extemporaneous interjections  in the interests of satisfying bias neurosis. Therefore as a consequence making a skewed mockery of probabilistic solutions (and making them redundant as a credible service provider at the same time!)

On that basis, the idea of them trying to inject a little calm into the proceedings takes on a highly absurd quality if one stops to consider that the "hunt for cold" thread world is a very different planet - objectivity and non pre-occupation with ice age synoptics being deemed boringly alien and kill-joy because it spoils the entertainment and threatens a tribally protected species.

So, with that in mind, some one-off attempted analysis before vanishing back to my own planet of Venus.

Process of +ve momentum transport c/o CCKW driven tropical convection has been progressing through I/O and has spiked frictional torque tendency +ve with associated westerly wind burst anomalies representative of this around 30N (orange shading)

 

The frictional torque response reflects the inflexion point of where additional westerly winds are added to the atmospheric circulation through progression of advancing organised MJO thunderstorm development  - and convergence of macro scale wind-flows creates a turning force on the Jetstream and changes the direction of travel of relative angular momentum.  

So this increased +ve momentum transport  and associated +ve frictional torque response registers immediately as a fairly significant spike in atmospheric angular momentum tendency -

 

- A mechanism that leads towards programming the highly amplified pattern as advertised by numerical models within the atmospheric circulation, as according to the spatial poleward propagation of those +AAM anomalies over time.

It is the lagged timescales according to this progression which provides the lead for further +ve mountain torque tendency in the extra tropics and sustains the amplified pattern through the majority of this momentum accounted for over the Himalayan ranges, setting up an extended Pacific jet and supporting phasing of energy into sub tropical flow (of which the models are presently balancing the equation over the medium term)

 

The 'however' that is coming is that the adage is "what goes up must come down".

Catalysts as they are for major pattern changes, there is no indication (to me at least) that the present tropical convection cycle matches those that have been a prequel to some of the classic early to mid winters. Meaning by this that the tropical signal aborting and losing amplitude sooner as seems currently likely than on those occasions implies a faster reverse scrubbing out of more sustained +ve momentum to follow that may, in turn, prevent the upscaling of the switch to an ever colder and colder pattern as some of the extended numerical model fantasy, filling the cracks of these pages, panders to.

So a complicated sequence in terms of the lagged +ve momentum propagation which impacts the tropospheric/stratospheric pathway in the second half of November and reverse sequence to follow reflecting loss of the tropical signal  which suggests greater polar jet flow in relative terms to the generally weak vortex and some relaxation, at least for a time, of  -ve AO.

This makes making any prediction moving forward sensibly erred towards caution this side of the glass window, and irrespective of any personal preference.

Unfortunately the link to the consolidated Global Wind Oscillation plot has been down for some time to confirm precise position, But taking into account the relationship existing between an atmosphere co-operating well with an establishing Nino standing wave in the Pacific, as reflected by GLAAM retaining generally around a +1SD to parity...

….is suggestive and supportive of the GWO  progressive into the El Nino attractor phase 5 (illustrative of +ve extra tropical momentum poleward propagation as discussed above) to be followed by an orbit through the Nino phases and depending on how far AAM falls thereafter, possibly returning to Phase 8/0.

These phases within the tropical>extra tropical "mini ENSO cycle" being in simplest terms indicative of a 'waning' sequence during the major long term evolving +ve ENSO phase

This forcing sequence roughly translates to the possibility of  Scandinavian ridge and euro trough morphing into mid latitude Atlantic /UK ridge as the Pacific pattern re-amplifies somewhat (GWO Phase 8/0) following the relaxing of the +ve momentum phasing, switching some energy back into polar jet flow

There is also a notion of argument to subscribe to, that the +ve QBO transition has already passed its optimum tropospheric/stratospheric disruption potential as it continues to downwell further, and moving ahead the onus becomes increasingly further on active amplitude tropical forcing resuming to re-stock +ve poleward +AAM transport processes and keep the tropospheric/stratospheric boundary unstable in the face of ever colder mid and upper stratospheric layers- and so manage to sustain blocking mechanisms at higher latitude.

This occurred during early/mid winter 2009/10 under an emerging El Nino, bottom rung of solar forcing and being within -ve QBO phase and away from advanced westerly transition - but, notwithstanding polar stratospheric ozone distribution and concentration is (presently)elevated indicating the Brewer Dobson circulation between tropical and polar stratosphere is at least (currently) buoyant, the variables are not aligned the same this year.

Any shortfall in all these respects renders the chances of a closer struggle between the upper and lower atmosphere, and a 'less warm' tropopause boundary which alters the complexion of the establishing Nino pattern evolving more towards a mid latitude European blocked one rather than one sustained long term between vectors at higher latitude to the NE and NW.

Following what for some off us, away from the sole priorities of this thread, is a very pleasant and highly welcomed mid November week of weather to help save unnecessary heating bills, its certainly a cold outlook with perhaps some equally cold rain to match it and possible marginal wet wintry mixes for a few

But whether it morphs into the freeze frenzy that is the utopian paradise the other side of the glass from where I am sitting, remains (at least in my humble opinion) yet to be seen.

 

Edited November 14, 2018 by Tamara

[SMU]

1 minute ago, WINTRY WALES said:

Hi Steve

Apologies but where is this NH Thread????

General weather > Autumn discussion > NH 2018 patterns

[SMU]

IKON 120 looks great !

These little nodules of HP are vitally important if you want a GH

Edited November 14, 2018 by Steve Murr

[weirpig]

3 hours ago, Ed Stone said:

Aye; I'd be surprised to see -16C uppers, this early in the season, anyhow...but a lot of folks automatically think Siberia (with added misdirection from the tabloid press?) whenever the wind comes in from the east?

Maybe the Met are just trying to inject a little calm into proceedings?

Yes thats what they are doing.  

[SMU]

5 minutes ago, weirpig said:

Yes thats what they are doing.  

They were but factually the link was wrong....

[Polar Maritime]

Just Model Discussion please, Thanks.

[bluearmy]

Looking at the latest icon and eps from earlier. - when was the last time we saw a sustained cut off upper ridge centred between Iceland and Scandi ????

[weatherguy]

8 minutes ago, bluearmy said:

Looking at the latest icon and eps from earlier. - when was the last time we saw a sustained cut off upper ridge centred between Iceland and Scandi ????

The classic period of March-April 2013?

[Methuselah]

What a fabulous example of warm air advection this is - all the way from the Azores to the Arctic Circle!