Hunt For Cold: Model Discussion - Heading Into Christmas

[snowfish1]

I don't know why but I still think it's too early to get a proper handle on what is going to happen. The models do not have a clue since they are all over the shop and that is apparent with each one and it's consecutive runs. We are also still in December..... 

[Methuselah]

Here's Gavin's latest video: 

You can see that (as 2001-2 clearly demonstrates) SSWs do not always give us what we want; and, you can also see that Steve Murr's contention, that the GFS's rampaging zonality will almost certainly be kicked into touch, looks spot-on!

[Blessed Weather]

I've removed a few posts this evening as they drifted too far off topic. Can we please try to stick to discussions around what the models are showing. There is another thread for banter, moans or speculation. Many thanks.

[nick sussex]

Large differences upstream between the ECM and the other models .

It phases the northern and southern streams of the jet towards the ne USA , developing a stronger shortwave and more amplitude ahead .

If there’s favourable phasing with the PV lobe at day 7 this might help keep the energy back from spilling too far east over the high .

Edited December 29, 2018 by nick sussex

[Ladyofthestorm]

GFS long way off Fl , zonality cut off and Easterly ensues. 

 

One to define watch. 

[Dancerwithwings]

Some lovely cold pooling showing itself in the ECM at 144h over Central Europe, why can’t the HP over the UK be sitting a little further North

[SLEETY]

boring ecm,miss out on the cold AGAIN and high just meanders around,doing nothing.Pass

[Froze were the Days]

216z seems a bit flatter than the 0z (I know we should be comparing like to like) but feel like we're getting nowhere quick with the ops...

[Methuselah]

And an iffy northerly @T+384???

[booferking]

EC is boring nothing happening whatsoever infact the period with the most potential is 72hr-96hr then just flappy high sitting over the UK.. 

[Frosty.]

Casting the netweather net further out to mid Jan..the GEFS 12z postage stamps look interesting with some snow potential!..in the meantime, the next 7-9 days look dominated by high pressure and then beyond that the uk based anticyclone declines and low pressure becomes more influential...fingers crossed things will become more exciting as we head further into January..I got my prayer mat out!

[Seasonality]

28 minutes ago, Dancerwithwings said:

Some lovely cold pooling showing itself in the ECM at 144h over Central Europe, why can’t the HP over the UK be sitting a little further North

As much as I like seeing cold for my location this ECM run just seems a little implausible to me. Odd looking evolution over Central and Eastern Europe, especially compared to its previous run. 

 

[Seasonality]

56 minutes ago, Blessed Weather said:

I've removed a few posts this evening as they drifted too far off topic. Can we please try to stick to discussions around what the models are showing. There is another thread for banter, moans or speculation. Many thanks.

Can we have some sort of function where your posts get read out in Brian Blessed's voice? 

[cheeky_monkey]

the GFS parallel seems to evolve the best solution to cold spilling out across the whole NH..esp at the end big height rises across the pole forcing cold out into Europe and America and the eventual pull of heights into Greenland soon after.

[Dancerwithwings]

1 minute ago, Seasonality said:

As much as I like seeing cold for my location this ECM run just seems a little implausible to me. Odd looking evolution over Central and Eastern Europe, especially compared to its previous run. 

 

My personal thoughts are all the models are struggling with the SSW and until they get a grip with the down dwelling, these runs will look odd/implausible.

[nick sussex]

On the face of it a very uninspiring ECM run.

It is different upstream at day 6 with more amplification ahead of the more developed shortwave in the ne USA.

It makes several attempts to cut some shortwave energy south to the east and the day 6 to 7 timeframe might develop more interest .

Look out for the ECM spreads to see if that shows a ne sw orientation between day 6 and 7 running towards Denmark and the Low Countries .

PS no joy in the spreads , on to plan B ! Start praying ! 

Edited December 29, 2018 by nick sussex

[Sir Mim]

43 minutes ago, Seasonality said:

Can we have some sort of function where your posts get read out in Brian Blessed's voice? 

That's what caps lock is for...  

 

Pretty uninspired output from ECM it seems, but the GFS maybe a little more hope for us coldies.  However with the SSW apparently in full swing now we should start to see the models reflect that.  If it's going to happen it should happen soon.

Edited December 29, 2018 by SJ NM

[GeordieX9v]

One of the points of negotiation must have been that we have to take our fair share of the cold continental weather #Potentially2InARow

[Mapantz]

OK - Back to the models.. if you have any complaints, please contact a member of the team rather than airing it in this thread.

Thank you!

[Singularity]

The decaying MJO that ECM/EPS continue to go with is likely holding back the amplification across the N. Atlantic a bit D7+. Having said that - it does look a bit excessively 'messy' to the NW and N of the UK on the ECM 12z - something cleaner probably would have led to more of a split vortex appearance by D10; you can see the Canadian, Siberian and Pacific centres of action (mirroring the stratospheric setup) but they lack clear boundaries.

Funnily enough, should GFS/GEFS manage to lock onto a downward propagating stratospheric split, then with their more amplified MJO solution, I'd actually consider them to be the better guide for D7+ until ECM & EPS caught up MJO-wise... believe me, it's extremely rare for me to even contemplate that! 

Important to take note of the major assumption here; that the MJO will remain active due to a colder upper tropical troposphere related to the processes associated with the SSW.

[stodge]

1 hour ago, cheeky_monkey said:

the GFS parallel seems to evolve the best solution to cold spilling out across the whole NH..esp at the end big height rises across the pole forcing cold out into Europe and America and the eventual pull of heights into Greenland soon after.

This was, as I recall, one of the possibilities from the SSW and something mentioned by Judah Cohen as a possible outcome. If you get a strong anticyclone over the Pole the possibilities for cold at lower latitudes increase considerably because, as you rightly say, the cold gets chased south. 

One evolution touted last week on a number of GFS OP and Parallel runs was dropping the trough into NW Europe or Scandinavia with a mid Atlantic ridge behind it - the 12Z Parallel ends with a sharp N'ly.

Other evolutions today have returned to the possibility of the mid-latitude block creeping into southern Scandinavia. - you can see the kick of WAA between T+288 and T+300 over eastern Greenland on the 12Z GFS OP that allows an HP to build over Scandinavia and re-enforce the mid-latitude block. 

Developments in the stratosphere continue to intrigue and perplex in equal measure and as others have said may constitute to make the model output even less unreliable than usual. We seem to have stepped back from an Atlantic breakdown in the New Year to a continuation of the quiet anticyclonic theme but it's by no means assured and a number of the GEFS keep the signal of a revived stronger jet.

Oddly enough, as the cold does draw out of the Polar region I could see a brief return of a more active regime before more amplification takes hold. 

The onset of much colder conditions took two and a half weeks in February from the initial PV split so if the split is due Jan 1 that takes us to Jan 18-19 or thereabouts and as I recall there was plenty of wailing and gnashing of teeth earlier tin the year when some output seemed to suggest the SSW having no real effect in our area. 

[stodge]

4 minutes ago, Singularity said:

The decaying MJO that ECM/EPS continue to go with is likely holding back the amplification across the N. Atlantic a bit D7+. Having said that - it does look a bit excessively 'messy' to the NW and N of the UK on the ECM 12z - something cleaner probably would have led to more of a split vortex appearance by D10; you can see the Canadian, Siberian and Pacific centres of action (mirroring the stratospheric setup) but they lack clear boundaries.

Funnily enough, should GFS/GEFS manage to lock onto a downward propagating stratospheric split, then with their more amplified MJO solution, I'd actually consider them to be the better guide for D7+ until ECM & EPS caught up MJO-wise... believe me, it's extremely rare for me to even contemplate that! 

Important to take note of the major assumption here; that the MJO will remain active due to a colder upper tropical troposphere related to the processes associated with the SSW.

Thanks as always my friend for the cogent comment.

As I recall, back in March, the MJO was at record-breaking levels of amplitude and we saw the HP move west across the northern hemisphere from Scandinavia to Canada. That did for our initial cold spell and I've never seen anything like that.

I suppose we can never catch a break of getting a reasonable level of amplification to prevent the west-based negative NAO setting up quickly - that also killed the December 2010 spell.

[Summer Sun]

The ECM mean suggests next week will be a very short snap it only just about makes it to -2 on the 850's as a peak low

[summer blizzard]

Ensemble means from GEFS and GEFS(P) still good for -AO from 11th/12th. The question then is whether events between Canada and the uk allow us to benefit.

[feb1991blizzard]

2 minutes ago, summer blizzard said:

Ensemble means from GEFS and GEFS(P) still good for -AO from 11th/12th. The question then is whether events between Canada and the uk allow us to benefit.

That could be all down to how wide the split is in the stratosphere.

-AO all but guaranteed, -NAO far from......

Edited December 29, 2018 by feb1991blizzard