[Stratosphere and Polar Vortex Watch]

Some stratospheric pornography now, courtesy of a rogue Ensemble member...

[Scotland/Alba Weather Discussion 2019]

5 minutes ago, shuggee said:

What a disgusting evening.

Coal fire lit!

I concur, sadly no coal fire, but a proper MINGER of a day !

 

[Stratosphere and Polar Vortex Watch]

November certainly seems to be the most exciting Winter month these days given our further knowledge of the vortex influence. Vis a vis above post around Vortex Intensification phases, a good illustration of things we just couldn't see with any clarity with the material available vs. the amazing data on offer now.

Robust cold vortex on the T Plot first off, then the zonal wind profile showing the disconnect advertised previously and expressed in AO outlooks. Following this the vT Heat Flux plot, some crude annotation on there on possible route forward. The 100hPa layer also show from stratobserve, note the GFS progressive here vs. ENS so one to watch in terms of how this may write into other data.

Much wave breaking ongoing right now, the MJO kicking up - and watch the JMA NWP output here for some tasty charts, as it is definitely more progressive than GFS / ECM. An ECM which pivots to P8 on today's update. Also we have an AAM boost going on. Loads of mechanics to unfold in next 7-10 days.

Been here before though in the last couple of Novembers is the caveat though, all that glitters / torches , aint gold as we know...  Solar and eQBO could still prove interesting wildcards here.. 

 

 

 

[Upcoming winter speculation and chat - October edition]

Ye olde eQBO looking meaningful... No signs of stalling, or blips... Always a welcome driver to chuck in the mix. 

Strat Trop interaction clearly the key variable now Vs will it or won't it SSW .. good to read the conversation evolving again.

Last year downwelling hit a brick wall, would be nice if that brick wall was still in place and that rampant vortex decided to remain locked at altitude.. 

November taking on early significance in terms of direction of travel further into winter. 

[Stratosphere and Polar Vortex Watch]

Here's hoping the disruption plays out as you see it Steve... even at 100hPa we see scatter in the top medians.

Lower down the strat the CFS longer view shows a healthy spin up of the vortex..

[Model Output Discussion - Into Autumn 2019.]

I seem to be causing forecasting problems.

[Tour 2 chase day 5 Oklahoma potential High risk]

Bewildering evening ahead.. the SPC advisory and replies are sobering.

Radar link here http://catalog.eol.ucar.edu/torus_2019/radar

[Cold hunt - models and chat]

Thread title is 

Cold hunt - models and banter

Not...

Cold hunt - models and bickering 

It's easy to hide the poor additions to the thread , so don't waste your time adding them.

[Cold hunt - models and chat]

Just now, pureasthedriven said:

That’s a cluster and a half! 

Well actually it isn't, and that's kinda the point. 

But metaphorically speaking - I hear you.

[Focussed Model Discussion]

http://brunnur.vedur.is/kort/ec-ens/2019/

[Cold hunt - models and chat]

4 minutes ago, AWD said:

How can you possibly have 100% agreement on an evolution 264 hours away, especially in the current atmospheric volatility we are experiencing?

I think in as much as the same way as the last 48 hours threw out solutions with 1 or 2 clusters, which then moved to 4,5 or 6 clusters as the NWP programmed in the various impacts of the US storm and resulting pattern on the Canadian Lobe of Vortex and Jet profiles. At this point in time this morning the output isn't seeing such entropy and has dialled in on something else... In retrospect it may be the case we look back on the disappointment of losing the initial quick route to cold charts as a bump in the road.

As noted above, the encouragement arrives from this being the direction of travel and also has good synergy with with weekly forecasts EC has produced.

[Focussed Model Discussion]

00z Iceland look... massive signal there...

[Cold hunt - models and chat]

[Cold hunt - models and chat]

Alice was told that there wasn't much Jam left in the Jam Jar, and when she wanted her Jam today was disappointed to find out this was all that was left..

Thankfully Alice was patient and found this hiding down the back of the ECM.

[Cold hunt - models and chat]

Hopefully someone will pop them up when the Icelandic site updates.. sorry nor sure what time that is at.

[Cold hunt - models and chat]

Would normally not put a one liner on without charts - however given the paywall status of the EC Ens and clusters, all I can say is think - weeklies. Today will be a good day

The roller coaster is firmly back on the tracks and heading for the winter theme park.

[Focussed Model Discussion]

Interesting morning and really encouraging IMO in terms of the set of model suites we were looking at on Thursday and Friday being chipped away at then collapsing into something else late Friday into Saturday morning. Given the up close review of each run, and I get that, it is a time where the deck remains stacked in our favour. However, given the long lead on the SSW, the count down to it happening, the displacement and then elongation in time of the SSW via the vortex split. I think this has generated fatigue, it's certainly been a long watch!

The AO profile overall, whilst an output vs. a driver shows the trend and this looks solid as Jan ends, this is supported by both the Strat Temp Anoms and NAM 'paint drip'. There have been hints of the AO dropping to -3 and 04 SD, without 'fully' getting there. I think it is an eventuality vs a jam tomorrow. Indeed that phrase is getting used a lot, to contextualise - the after effects of an SSW 'will be' jam tomorrow given the lead times for imprints on the atmosphere..

 

AAM and GWO dynamics illustrated below, relative AAM courtesy of torque activity, gives a steer on expecting to see blocking regimes manifest, as does the SSW, so a double ingredient here.

From this morning's GFS we can see from around Day 9 both the AO starting to drop again and also blocking coming online over Greenland, c 26th is where the trend commences to elevate heights here, and there is a lot of energy firing towards Nuuk to start causing the Arctic profile to shuffle.

ECM goes back to something akin to the earlier ENS and just needs some sharper inflection to do similar damage and mirror it's weeklies.

I would say the US Storm, impacts on the jet, careering into the NE Canadian portion of the vortex as we all have seen collapsing the nirvana charts on offer at the end of last week has played through the system now, models catching onto again the true sense of direction. That wave guide remains, the signals for HLB remains, the down welling remains, the AO tendency remains, the AAM increase is there. Whilst the hyperbole of no definitive easterly programming from 210 down to 0 hrs created despondency, there is a lot that remains bloody good for - the end of January with a ton of winter left.

[Cold hunt - models and chat]

The low hanging around the North East Coast retains the best of the coldest temps as the run moves along presumably making it harder to shift. will await a met explaining fully in a more articulate manner.

 

[Scotland/Alba Weather Discussion 2019]

What's that - 6 of them lined up at 60 hrs out..! that low sure is fond of the NE Coast line, churns away in there..

Ciel wrt to down welling.. 'paint drip' expression of the slow progression of the NAM, from below u can see the obstacles since the SSW and the eventual connection to the trop. I think the initial arctic outbreak impacting Austria was programmed before / during SSW.

[Scotland/Alba Weather Discussion 2019]

Cracking pics Ravelin - GFS 12z looking very good for NE Scotland..

[Scotland/Alba Weather Discussion 2019]

@edo Yep - head's still stuck there although it is slowly down welling to the troposphere, lovely photos going up on the thread, nice to see. Had naff all here ...yet.

Tuesday looks decent and into mesoscale so worth an up close look vs the nuances of the ECM backing down from it's quicker route to cold. Doesn't help temper expectations when the GFS is gung ho churning our Day After Tomorrow stuff.

12z tonight will be interesting - EC last night and this morning definitely on the move back to massive variance, given just how good this model is one would be remiss to dismiss the trend, that said looking at the Ensembles posted earlier in the model thread, the Op run does sit in a cluster with around 13/51 Ensemble members, so it is certainly not game over. And, importantly the UKMO last night was looking good, and remains good this morning. 

So, all told a proper model stand off and decent debate ahead - what we do have is something of an all or nothing, will UKMO revert to EC, GFS looks to be. Then either way what follows to start Feb looks equally spectacular as what was initially programmed, just moved back a few days. 

Given the lagged impacts of the SSW, time is on our side this Winter...

06z Arpege Gif for snow accumulations as of this morning.

[Model banter returns]

[Model output discussion - 7th January onwards]

Incredible. Just utterly insane effort from the GFS..Filthy.

[Model output discussion - 7th January onwards]

Well, this looks terrible..

[Model output discussion - 7th January onwards]

12z GFS did this when it split the vortex filaments on the ridge > early it leaves residual energy in NE Canada, then a filament juices and attracts the long lead TPV segment from central europe, by 192 we are at an unusual situation...

Later the break plays through and flattens, before eventually leading to the 'all roads lead to cold'.. this follows the jet flattening at 192hrs

Then the break..

This first carve out of energy on the first image means so much for the play through of the run and speak to why the 0-5 day time frame creates the dynamic and time stamps going forward.