Model output discussion - into Christmas

[Duane S.]

OK, as we stare down the barrel, time to inject a bit of optimism. Blind or otherwise... 

Tonight’s straw clutcher is the latest JMA MJO forecast.

 

[Nick F]

Tough model watching at the moment for those wanting to see some snow, particularly with the AO forecast to go strongly positive combined with a +NAO, probably because a strengthening stratospheric PV is coupling with the troposphere. 18z GFS no exception to the continued horror show output for snow lovers.

This very cold upper air vortex tightening up over the arctic can take a while to shift and can last through much of the winter (hopefully not the rest of this winter though). 

However, there's a few glimmers of hope, carrying on from s4lancia's mention of the MJO above. Aswell as the Indian Ocean Dipole beginning to weaken, the SOI is tanking through -ve (ENSO neutral towards El Nino-esque tropical Pacific pressure pattern), and also it appears the models have been struggling to predict the MJO progression and are playing catch up, latest GFS and EC RMM plots seem to increasingly be trying to orbit through colder phases of 7-8, when previously the orbit has gone from the current warm phase of 6 back into COD then back out into warm phases. So we could see more coherent progress through 7-8-1, so after the usual lag we could see some sort of pattern change favouring blocking as we head through Jan. 

however, it's just a glimmer of hope for pattern change, remains to be seen if tropical Pacific forcing will have any impact on the pattern becoming deeply entrenched over the N Atlantic and Europe caused by the strengthening tPV over the arctic.

Edited December 26, 2019 by Nick F

[mountain shadow]

2 hours ago, s4lancia said:

OK, as we stare down the barrel, time to inject a bit of optimism. Blind or otherwise... 

Tonight’s straw clutcher is the latest JMA MJO forecast.

 

Even though the MJO is forecast to move into more favourable 7-8-1 sectors, it is at very low amplitude and unlikely to provide any meaningful benefit in my opinion. 

 

[Newberryone]

Again, overnight model runs do not make for happy viewing with euro heights looking as relentless as ever out to day 10 and beyond. What looked like a possible breakdown of sorts around the turn of the year a few days ago now looking more typically like a minor blip with fronts barely making inroads against those stationary heights over Central Europe.

Edited December 27, 2019 by Newberryone

[IDO]

The mean at D16 showing the core vortex edging NE more towards the Arctic than previous runs:

That should push the flow further north than recently modelled, so again height rises in the UK vicinity assuming no other interference. My region highlights this:

Cool or warm high and the op and control highlight those two clusters:

Another cluster not following this HP scenario for D16. The height rise occurs around T300 and is common amongst the GEFS:

Shall see how this develops with further runs?

Around D10 we see a nascent Pacific ridge, more wedge like than a strong WAA pushing wave. However this appears mostly transient though some members push a wedge into higher-lats.

For the rest of the 2019, HP dominant, with mild uppers and dry. Maybe more cloud but that should keep night time temps high:

Mean to D6:

N/S split after that...

[Nick F]

7 hours ago, mountain shadow said:

Even though the MJO is forecast to move into more favourable 7-8-1 sectors, it is at very low amplitude and unlikely to provide any meaningful benefit in my opinion. 

 

The models could be underestimating the amplitude, given they seem to be playing catch up on the MJO's progress. Clutching straws I know, but a possibility. 

However, given the lag of 10 days or so of the impacts of more favourable 7-8-1 for HLB, we are unlikely to see the models showing anything for a week at least.

In the meantime, not a good look from the operationals if it's snow you want.

[SLEETY]

Think patience is the key this winter,but it is unbelievable how we are going to start another New Year with very mild weather and not much sign of a change from any model at the moment..

[Djdazzle]

30 minutes ago, SLEETY said:

Think patience is the key this winter,but it is unbelievable how we are going to start another New Year with very mild weather and not much sign of a change from any model at the moment..

Not really unbelievable. It’s just the form horse during most winters.

Let’s just hope that the models, teleconnections etc are as spectacularly wrong as they were last year. However, as they are showing a poor outcome for cold fans, they probably will be correct.

[Methuselah]

Good morning peeps, hope y'all had a good-un?!

A wee glimmer of hope, mehopes:

    

Wel it could develop nicely, for us never-say-die snow-lovers, I guess. But I fear (and my SAD really kicks in around now, anyway) anticyclonic gloom might be the form horse...

Hope for the best, and prepare for the worst?

Edited December 27, 2019 by General Cluster

[SqueakheartLW]

That AO is going almost off the scale. Don't think I've ever seen the GFS ensembles so confident of a +5 AO index

At least the NAO is a more realistic positive figure forecast of around +1 NAO index

 

No wonder we are expecting some very mild days in the next week.

[Methuselah]

It's sure looking like the January Fog Index might be getting off to a cracking start!

   

[mushymanrob]

wow... just look at that!... low pressure covering the whole polar region , extending over most of America.. High pressure to our south though holding off the colder air to our north, but just look how windy itll be towards mid January.

 

[Ali1977]

A PV shift to Russian side of the pole or just a variation of the theme? Atleast a chilly looking PM flow inbound, a long way off though so could be gone by the 12z

Edited December 27, 2019 by Ali1977

[Methuselah]

Where there is despair, let there be hope...Jam tomorrow? Well, at T+384, on the GFS 06Z, anywho!

    

[lassie23]

1 hour ago, General Cluster said:

It's sure looking like the January Fog Index might be getting off to a cracking start!

   

There can only be one and that index said NO to snow and cold this winter

[KTtom]

To be fair, looking at the current set up and taking the pattern of the winter as a whole, I really don't see anything out of the ordinary from a typical, traditional UK winter. A strong Polor Vortex with the pole dominated by low pressure along with  a rampant jet to greet the turn of the year isn't anything shocking or out the ordinary IMO. February tends to be the best time for cold in the UK under these set ups as the jet finally weakens and the PV breaks up...currently, looks like this year will be no different. If you want a silver lining, the dense cold bottled up over the pole will certainly help the deteriorating Ice fields!      

[Jeremy Shockey]

GEM points to a small window of hope around the 4th Jan perhaps ?

[Ali1977]

9 minutes ago, Jeremy Shockey said:

GEM points to a small window of hope around the 4th Jan perhaps ?

There has been a few models/ENS toying with this, I think this is the next window of opportunity,  it may help introduce a colder Hp rather than a snowy set up but people like severe frosts as much as snow sometimes!! 
 

JMA similar for the same day, as was last nights GFS I think. 

Edited December 27, 2019 by Ali1977

[tight isobar]

Well some crumbs as we move into the new year!!!   And navgem (lol) geo pick of the bunch moving forward with aligned heights favoured and a reasonable polar field profile!    Although all in all a certain step (although small) in a better direction. With hfs even glimmering a "perhaps " step in the right direction with a noted eastern/western ridge with a desired want of our own hp cell showing baby steps for a desired move into the Scandinavian/Russian sectors!  And with the madden julienne oscillating part also showing signs of, more favourable synoptic. So all certainly not lost as we now evolve into winter 'proper ' and with given gains perhaps some more favourable Synoptics coming into view via even the raw/operationals.  So some hope again and things to watch evolve as we move toward new year!!!!

[That ECM]

It’s fair to say there is not a lot happening. I’ve just looked through the met for Bournemouth and during the next 7 days including today there is a 3 degrees variance. No lower than 7 no higher than 10 day or night 

[Ali1977]

Potent if it verified, shame it’s 11 days out. Snow for most bar far south possible with those uppers, toppler obviously!! or is it!! 

[Dorsetbred]

10 minutes ago, Ali1977 said:

Potent if it verified, shame it’s 11 days out. Snow for most bar far south possible with those uppers, toppler obviously!! or is it!! 

Looking at that, it might suggest some of the oranges in Florida might be in for a shock!

[Allseasons-Si]

4 minutes ago, Dorsetbred said:

Looking at that, it might suggest some of the oranges in Florida might be in for a shock!

And a merry Christmas to you

looking at the 12z,they do seem more amplified to me

and the UKMO at 144 is the best of the bunch with the pv moving away from the NW with a potent NW'ly incoming.

 

[Ali1977]

7 minutes ago, Allseasons-si said:

And a merry Christmas to you

looking at the 12z,they do seem more amplified to me

and the UKMO at 144 is the best of the bunch with the pv moving away from the NW with a potent NW'ly incoming.

 

Just seen that UKMO, that’s a bit of a flip with the PV on the move away from Canada - just need the push of heights up through Eastern Greeny and we’d have a very Very potent northerly , doubt that’ll happen looking at the 120-144 transition though as it’s pretty flat 

The day 10 GEFS mean however, isn’t good!! It’s like someone has got the ruler out !! 

Edited December 27, 2019 by Ali1977

[The PIT]

Not really all that potent from T144 basically a temporary feed of colder air before the high reasserts itself. The high then continues to hang around in a generally unwelcome manner for sometime. The coming weeks are going to show a large rainfall contrast north to south.