[Hunt For Cold: Model Discussion - Heading Into Christmas]

Everyone having fun yet  That's a peach from the ECM at 240..

Just been busy on the GMAO run - what a displacement of the Euro daughter vortice.. incredible.

[Hunt For Cold: Model Discussion - Heading Into Christmas]

Do they have a -7 on standby on the AO table ! Wow  1070hPa over the pole... Bosh !

[Hunt For Cold: Model Discussion - Heading Into Christmas]

Good ole Pub Run - sniffing out porno charts at 360... this time it may be onto something...looks entirely plausible  

Neat way for the ever maligned 18z to sign off 2018! Happy New Year folks  

Into 2019 and the Hunt for cold should not be as arduous as the last few weeks!

[Hunt For Cold: Model Discussion - Heading Into Christmas]

ECM hasn't woken up fully to the MJO projection yet either - it is still relatively low amplitude vs JMA and GFS, the latter has tempered itself from the wild 4SD plots earlier (result of it over representing an Equatorial Rossby Wave).

Still think the ECM has amplitude to gain here and therefore a stronger imprint on the subsequent artefacts generated via eastward Pacific transition.

What is of interest here and frantically digging through research on this is the impact of SSW on UTLS, and what will this do to the MJO as it moves through the phase space.. The image below shows OLR anomalies for SSW of both Displacement and Split event, then also a table of historical values. The paper identifies the conduits for displacement and split events - however does not telegraph the forward effects - still an area of interest.

What is clear is that the NWP will be in absolute carnage just now - SSW overnight, split within 48 hrs, 3 vortex lobes as a result, I would expect literally every available solution possible to present itself between now and 04 Jan. The continuation / secondary warming on the parent lobe is also cool, and looks robust assists delaying the daughter vortices coalescing again. Right now split, FNMOC aside continues for entire GEOS run... anyone like movies.. some historical splits below, they do take a minute to load but are neat when they do.

http://birner.atmos.colostate.edu/SSW-animations/anim-PV/1979_530K/loop.html

http://birner.atmos.colostate.edu/SSW-animations/anim-PV/2008-2009_530K/loop_short.html

http://birner.atmos.colostate.edu/SSW-animations/anim-PV/2012-2013_530K/loop.html

Polar High appears to be appreciating, another trend to keep across - suspect the NAO flip will be severe when it arrives.. Onwards and Downwellwards!

[Hunt For Cold: Model Discussion - Heading Into Christmas]

Yesterday or perhaps the day before there were maybe two or three runs flirting with High Pressure over Greenland..

Today it looks like this... definitely a trend developing..

[Hunt For Cold: Model Discussion - Heading Into Christmas]

This one Nick by any chance...

It's a series of tweets outlining the route to the NAO flip, great work from Anthony. Everyday is a school day on wxtwitter.

 

[Hunt For Cold: Model Discussion - Heading Into Christmas]

I don't think an SSW is a fad - I think it's a dynamic we are beginning to further understand.. little by little, QBO regime by QBO regime, ENSO - Nina Vs Nino Regime, vs. Solar Regimes, including the AAM and MJO impacts..

I fear that if you are looking to dismiss SSW as a fad - you may end up sorely disappointed in years to come.. unless you like SMW - Sudden Mesospheric Warmings  - I suspect that is where the science will eventually take us.

[Hunt For Cold: Model Discussion - Heading Into Christmas]

Couple of GIFS looking at the killer question of propagation. First is the u profile from the CPC site and next up the GFS view of NAM as it progressed from between 20-30th Dec. Appreciate these are equally suited to the strat. thread but it's becoming a case of the SSW and NWP intertwining in the hunt for cold right now..

Then from Zac's site the actual split activity itself, you can see the window into Greenland playing out in part on the modelling just now, and also toward Day 10 the further energy wrapping into the Canadian Vortex lobe as it shears across. 

In particular these two stills from the sequence, just wow for what can happen in 24 hrs...

This party ain;t over yet with this action either... 

Over to you ECM to unpick the bones out of that lot please...

[Stratosphere and Polar Vortex Watch]

Couple of GIFS grabbed from NASA site - more for posterity than anything else..( future re-visits to the thread etc). 

[Hunt For Cold: Model Discussion - Heading Into Christmas]

EC getting ready to amplify into the cavernous stratospheric void.. 

Always fun to see the black holes on meteociel... Usually the 00z is less extreme than the 12z , makes tonight's viewing interesting..

[Stratosphere and Polar Vortex Watch]

That's a split

Technical SSW for 01 Jan and continues until end of the run where we continue to see warming artefacts in play vs the parent vortex.

Can't recall seeing a W2 plot like this in terms of its progression to here on this run. Looks odd.

Interesting output ahead...especially with MJO about to join in the fun..

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I thought it was the 12z from tonight, apologies. 

Anyway on wards to Berlin in the morning !

 

[Stratosphere and Polar Vortex Watch]

Not on wetterzentrale, although by 19:00 tomorrow evening... who knows.. I was referring to viewing the 12z EC trend on the strat plots on Berlin site.

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/diag.php?alert=1&lng=eng

[Stratosphere and Polar Vortex Watch]

GEOS view from 00z of the vortices and split action across the levels, not got the 12z yet - but from Ventrice tweet hints of the split extending on EC tonight via run to run comparison. Berlin will be worth a look in the morning... 

Given the current 'downwell / not to downwell' query via GFS vs GEOS, interesting to see hints of the EC modelling the NE Canada split more aggressively than GFS -has GEOS taken the lead here with EC coming in line.. feels like a window of opportunity opening however tentative at present.

 

 

[Stratosphere and Polar Vortex Watch]

Granted, not for everyone @knocker, the main point I wanted to make was around the derogatory tone. Don't get why there is the need to attack 'weather forums' or folks interested or enthused about weather? Anyway.. GEOS view of the forthcoming split at Day 10 - 240 hrs, across the levels.

 

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And, what's wrong with being a fan of cold and snow I wonder? Don't understand why Liam Dutton is so derogatory to folks enthusiastic about weather ?

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For Berlin charts they really have made navigation tricky on a mobile now.

Try this old link >>

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/diag.php?alert=1&lng=eng

[Stratosphere and Polar Vortex Watch]

Hopefully some PSC pics incoming in the next 24-48 hrs looking at the above temp profiles.

FV3 this morning not as progressive on the split as last evening's 12z.. Always caveat the GFS 06z run, i.e. don't trust it. Wonder if the FV3 will be subject to the same 'randomness'..

Couple of other plots below - Temp vs Pressure, the u wind profile and also Heat Flux progression.

Then from the excellent link shared earlier by I, a few from the NASA site.

GMAO still advertising a split vortex, GFS thinking not, GFS FV3 flipping between spilt / no split, ECM retaining the split vortex. A proper model conundrum here...

Over to Zacs site to see the latest view there from around 15:00 today. Updates circa 1000 Eastern which is 1500 for us in the UK.

 

[Hunt For Cold: Model Discussion - Heading Into Christmas]

How is NWP meant to cope with this when even 4 models across the strat cannot agree... Peak Eddy Heat Flux anomalies inbound within the next 24-48 hrs.

Simply put - not a chance any output has a ghost of a chance on reconciling on the NWP basis.

The most we can hope for is some kind of continuity in the strat vis a vis the technical reversal - as for the trop - it's a crap shoot.

I believe the phrase FergieWeather coined was Shannon Entropy - this more than any other phrase is redolent now.

 

 

[Hunt For Cold: Model Discussion - Heading Into Christmas]

I agree with the above @Catacol - in terms of want does everyone what for 'Xmas Day' things have improved markedly in the last 12-18 hrs with the models 'cleaning out' what was original a pretty uninspiring high. Cleaner high, cleaner cold, chance to wake up on Xmas day with very seasonal temps , blue skies, a frost etc...( Stop Press - EC delivers junk).

As for other events, there is no way.... 100% no way this winter will be ordinary after 01 Jan... we have well programmed MJO artefacts to play through from both directions - 

1) the phase 3 imprint on the strat ( again ) will slowly downwell over 30-50 days to create a u wind wave driving event on a crippled vortex.

2 the current MJO phase space and thinking about the forthcoming MJO phases predicating Greenland blocking - well given the easterly QBO in lower atmosphere - this alone would make folks salivate.. http://www.meteonetwork.it/models/mjo/ regardless of any Strat Activity - the trop does what it wants too !

Check Nino January plots on that link for 5-6-7-8..

All of the above - PLUS a monster warming.

Not withstanding whether it meets the 'classic' definition this is still remarkable. i.e. even if at the advertised point we pull back from the C&P u wind reversal at 10hPa.

The level of heat flux, the loading of MJO trop blocking precursors almost makes the SSW a 'cherry on top' or indeed a moot point.

At this point we can see GFS go bonkers, FV3 really show it's hand as a model to take seriously into 2019..

I think what cements the above is the ever cautious Met Office and the contingency update, these are know for the poker faced slant and candour - they never hyperbole anything. Given that steer - today's update one could consider as a proper ramp...

Edit : See Strat thread for ECM

Second Edit : 'Normally - this is peak VI Vortex intensification period... now that will become a cool question.'.

 

 

[Stratosphere and Polar Vortex Watch]

Just now, Singularity said:

ECM might well be the tortoise in this modelling race.

Tortoise with the best shell ( Model Lid)..

[Stratosphere and Polar Vortex Watch]

Stop Press - EC remains solid... 

 

[Stratosphere and Polar Vortex Watch]

8 hours ago, Interitus said:

Those GEOS charts are a bit SD, for HD try the animations (up to 10mb, 240h on 00z 120h on 12z) here - https://fluid.nccs.nasa.gov/wxmaps/?region=nps

Update on minimum zonal winds from last 18z and 00z runs -

GFS -2.0, +3.7 m/s

Para +6.4, +10.8 m/s

Wow!

 

 

Excellent link @Interitus - tremendous discussions kicking off between the esteemed folks on twitter now as to why GFS at odds with it's ensemble, and importantly why GEOS has back tracked. Take it those are 10hPa values.. need Sam Lillo to do one of his cool graphs on this...

Good also to see yourself and @Bring Back1962-63 chewing the fat over plenty of stuff, I am not going to arbitrate here, not in a position of expertise to judge. Would only say perhaps a PM will help get you both on same page

 

[Stratosphere and Polar Vortex Watch]

10 hours ago, Allseasons-si said:

Blimey.

 

Great discussion, on this poleward shift. Only one person I know who could unravel it and he has now replied. Top work from Anthony as ever.

In short a sheared vortex filament wraps under the high..

[Stratosphere and Polar Vortex Watch]

Good Puzzle above ^^^ and interesting discussion in the replies..