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

[SussexSnow]

12 minutes ago, sheikhy said:

Ecm 06z looking juicy at just 90 hours!better block and colder air further south!!!

Hopefully this GIF shows the difference.  A wedge of 1025hpa has been lost to our south 

[Cold Winter Night]

51 minutes ago, Jason M said:

Many of the GEFS raise heights over Iberia towards the back end. That's a death sentence for cold weather.

Way to far out to worry about though!!!

 

Maybe, maybe not.

Both teleconnections and NWP point towards a waning of heights in the North, and a somewhat less blocked period following the coming week. If this is to be followed by Scandinavian height rises end of the month/into February, then a sequence of amplification, with height rises starting near the Azores, moving through Iberia, over the UK towards Scandinavia is a logical path.

Take these for example, Jan 1947, Dec 1962, Jan 1987: heights to the South, no HLB, flow from the West. Poor as standalone charts, but they're part of a sequence.

(Disclaimer: No, I'm not promising 1947, 1963 or 1987 events at this point; illustration purposes only)

However, if heights do manage to hold their ground in the mid term, a potential move to Scandi heights could develop in a completely different way.

Edited January 10 by Cold Winter Night

[Spah1]

What’s the ECM 06z? 

[Mcconnor8]

1 minute ago, Spah1 said:

What’s the ECM 06z? 

Meteociel - Cartes Ensemble CEP/ECMWF ENS

WWW.METEOCIEL.FR

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meteociel propose des rubriques météo temps réel, forums, modeles...

ECM run that goes out to +144 Hours with an ensemble set as well, has an 18z run as well that is the same.

Edited January 10 by Mcconnor8

[SussexSnow]

2 minutes ago, Mcconnor8 said:

Meteociel - Cartes Ensemble CEP/ECMWF ENS

WWW.METEOCIEL.FR

---

meteociel propose des rubriques météo temps réel, forums, modeles...

ECM run that goes out to +144 Hours with an ensemble set as well, has an 18z run as well that is the same.

The Op run is here I think 

 

WWW.METEOCIEL.FR

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Meteociel propose le modèle deterministe de ECMWF CEP en Open-Data avec une résolution de 0.4°

 

[MattStoke]

C3S seasonal model update for February looks OK.

[steveinsussex]

1 hour ago, Frigid said:

What a run from the GFS, possibly the best we've seen yet this winter. Both OP and control keep the faith. Huge upgrades all round!

Majority of places don't exceed freezing for a whole week, incredible. CET could be near or below 0C if it came off. 

The ENS are not good, its a right outlier 

[Catacol]

21 minutes ago, Tamara said:

Bom dia e todos

I make no apologies for yet again re-pasting this sequence originally posted just prior to New Year, because it has become an even more focused roadmap. Not just for the upcoming 10 day period, but indeed confidence increasing as a blue-print for well into the second half of the winter:

....................................................................................................................................................................................

With the Nino attractor phases fully engaged, the amount of westerlies propagated into the atmospheric circulation between tropics & extra tropics do, as you suggest, indicate a higher floor to the angular momentum budget in the 'lull' ahead of the next upswing as the MJO traverses the tropics during January. GWO Phase 4 is a good medium base floor level I would think.

If we were to take a diagnostic template of GWO Phase 4 (and account for a likely return shallow orbit through phases 0,8 & back to 4) during an intermediate 'lull', then that very intermediate lull phase you describe will likely feature the return of a flat upper flow extending towards Europe.

The difference to recently though with the Atlantic forcing will be the jet suppressed further south - and with a cold pool established then attritional forcing of lows against the blocking likely to be a feature. (This accounts for some of the thinking as expressed within my previous posts in respect of the sub tropical jet)

With a cold pool established, any erosion from the south/west into NW Europe is likely to be attritional and not likely to displace cold pooling totally.

Taking into account we are still now in the lag period for the effect of +ve momentum from FT/MT mechanisms c/o the recent tropical>extra tropical cycle, we are seeing the new convective signal come into the Indian Ocean. Sea temp anomalies are supportive of deep thunderstorm convection. This, allied to convection in the western Pacific, will generate further mean zonal west wind anomalies to propagate across the tropics into the sub-tropics. With the westerly wind additions generated in December still in the atmospheric circulation, total and relative angular momentum will increase sending the GWO back into a (potential high amplitude) phase 5 orbit.

This progression & evolution suggests a strong -ve NAO with positive height anomalies shuffling between Greenland > Iceland and Scandinavia. Meantime southern Europe wet & mild under the sub tropical jetstream.

Muito obrigada. Melhores Cumprimentos

......................................................................................

To update the template of this analysis:

A very starkly high octane angular momentum budget is emerging and prolific within the global-wind-flow budgets. This translates to stockpile ammunition supply levels for deeply sustained poleward amplification eddies taking on veritable tanker sized reserves.

Based on how much tropospheric led influence there has been on the NH pattern in recent weeks since the starting pistol was fired to destabilise the polar profile, these further poleward swathes of +ve momentum transport take on especially egregiously gargantuan proportions for future wholesale instability and implosion across the polar field. In this respect it is not hard to comprehend the latest sentiments of Amy Butler and how she sees the synoptic pattern imprinted

The copied post referred to a baseline phase landing place for the Global Wind Oscillation. This baseline, ahead of the strongest wind-additions yet c/o eastward progressing high amplitude MJO wave back to the Pacific has remained higher than intermediate phase 4 (as discussed in the copied post)

The latest GWO phasing, even under present lull stopgap at very low amplitude 5/6, reflects the remaining considerably high levels of +AAM anomalies within the atmospheric circulation as aggregate total AAM. (Phase 4 GWO would be more suggestive of flatter return of the jet and greater attrition from the Atlantic against blocking. (Though even this sharpens somewhat against late Jan/early Feb wavelengths)

This GSDM wind flow budget situation is significant. More on this shortly.

The GWO is a phase plot depiction of aggregate wind-flow within both the tropics (MJO related) and the extra tropics as a measure of how efficiently propagation of wind-flow is proceeding between the tropics & extra tropics. This matters, because it is a barometer for synoptic pattern (poleward) amplification potential and provides a diagnostic towards directional flux of wind-flow eddies.

Poleward flux has now become quite supercharged

What of the significance of this?

As the intraseasonally driven MJO crosses the Maritimes at high amplitude, then very strong +ve torque mechanisms will be re-engaged to over top a system already awash with +AAM anomalies. The GWO likely to drill upwards into very high amplitude Phase 5/6. Taking into account maximum winter wavelengths, then this teleconnects ever more strongly to entrenched -ve NAO (under chaotic stratospheric diminution to spotweld a deeply -ve Annular Mode).

How can this be visualised?

The upcoming next cascade of westerly wind burst propagation into the extra tropics creates white water rafting within the sub tropical jet from the Equatorial Pacific downstream to the Atlantic -at the same time as the polar profile becomes riven with -ve mean zonal -ve wind anomalies. Defining solid roadblocks for southward directive of a deeply unstable thermal boundary.

How can this in turn be visualised?

With deeper upper cold air ensconced north of the polar boundary, this leads to feedbacks of entrenched surface cold with time to feed an ever starker thermal boundary, This encourages and emboldens larger progressions of numbers of kayaks slipstreaming below it. This translates to trains of low pressure undercuts - and it is not difficult to envisage the potential for high impact weather events to unfold in such a scenario. 

The kayak posse delivers an "atmospheric river" of saturated sub tropical air and a large jump of temperature into the upper teens for my part of the world well below the thermal boundary at the same time as in contrast...

.... that is better left to the mercurial imaginations of any members who might be looking in from NW Europe.

Putting all this diagnostic analysis together, it is hard to see anything other than a tanked -ve Annular Mode relationship dominating much of the rest of the winter. However, and as ever, further analysis is wholly prudent to document how proceedings unfold.

Muito obrigada. Feliz quarta-feira

 

 

 

Quite excellent. I was going to post something later of a similar but much less well explained and detailed nature. I won't bother now. 

The drivers that have lined up to produce this first amplification phase and are lined up to produce the second surge of amplification next week are going nowhere anytime soon. As I posted before, MJO progression is clear and well timed. I think week 22-29 January will be the least cold section of the next month or so but GLAAM has remained high with little damage caused by the ping back of relative AAM progression. We are shortly going to see another surge that will set us up beautifully, given lag, for the end of the month and on into February.

But this is a poor summary compared to the post above. Read that and wrestle with its contents.

As to next week - no change. Snow will be in the mix whether those who enjoy posting the least favourable interpretation of current signals and output like it or not. 

[nick sussex]

2 minutes ago, steveinsussex said:

The ENS are not good, its a right outlier 

There’s still a good cluster supporting the colder option upto day ten .

I really wouldn’t worry about post day ten . That’s miles away . 

The main initial hurdle is around day 6 into 7 . 

[Catacol]

6 minutes ago, MattStoke said:

C3S seasonal model update for February looks OK.

Just ok??  - it literally couldn't be any better though the gloss is taken off by the fact it is the CFS. I prefer the JMA monthly - that won't be too far away.

[MattStoke]

Just now, Catacol said:

Just ok??  - it literally couldn't be any better though the gloss is taken off by the fact it is the CFS. I prefer the JMA monthly - that won't be too far away.

Slight tongue in cheek

[That ECM]

29 minutes ago, Tamara said:

trains of low pressure undercuts

Adding to dictionary now. awesome as ever.

[Met4Cast]

1 minute ago, Catacol said:

Just ok??  - it literally couldn't be any better though the gloss is taken off by the fact it is the CFS. I prefer the JMA monthly - that won't be too far away.

How about this from GLOSEA then.. 

[MATTWOLVES 3]

Blocked February anyone! Nice signal to say the least and does fit in with El Nino EQBO and weak strat..long overdue a wintry February folks.

[northwestsnow]

Oh wow.

GLOSEA

Feb looks AMAZING 

[Andy8472]

2 minutes ago, Catacol said:

Just ok??  - it literally couldn't be any better though the gloss is taken off by the fact it is the CFS. I prefer the JMA monthly - that won't be too far away.

Yeah slightly the same 

[Mcconnor8]

ECM 06z Control is looking so much better than the 0z did, will update with pics when it finishes running!

[Catacol]

1 minute ago, Met4Cast said:

How about this from GLOSEA then.. 

Haha - now that I hadn't seen. That's even better than the CFS (which I said couldn't be any better....so scrap that comment.) Just look at the contrast mid atlantic between greeny and the jet directly to the south? If ever there was a sign of a southerly tracking jet, full of moisture, and a cold block in situ then this is it.

Gallas!

[SussexSnow]

Just now, Mcconnor8 said:

ECM 06z Control is looking so much better than the 0z did, will update with pics when it finishes running!

It is very much so.  Clean.

[booferking]

Cleanas a whistle EC control and mean boom

[TSNWK]

1 minute ago, Mcconnor8 said:

ECM 06z Control is looking so much better than the 0z did, will update with pics when it finishes running!

Thank you

[Derecho]

6 minutes ago, Met4Cast said:

How about this from GLOSEA then.. 

Very nice, El Nino winters are often backloaded so I'm leaning towards a cold February this year. That would bring the most blocked February since 2010.

I think the end of the month may briefly become milder as we go through the lagged effects of the MJO phase 5 but then there is the added complication of the stratosphere and the increasing impacts of El Nino on atmospheric circulation.

Edited January 10 by Derecho

[northwestsnow]

2 minutes ago, Mcconnor8 said:

ECM 06z Control is looking so much better than the 0z did, will update with pics when it finishes running!

The good news is FLOWING !!

1 minute ago, booferking said:

Cleanas a whistle EC control and mean boom

Oh yesssssssssss !!

Really looking forwards to 12z runs now..

[MattStoke]

7 minutes ago, Met4Cast said:

How about this from GLOSEA then.. 

Is there a Greeland High anomaly? It's hard to tell 

[Mcconnor8]

Much better blocking on the 06z ECM at T+144, colder run all the way through from Saturday.