Model output discussion - January cold spell ending, what next?

[Uncertainty]

Just now, Bricriu said:

The only problem is the GFS ends the cold spell quickly. Given, as you say, it  has done well up to this point, we can't ignore the possibility that the latest runs are correct, as oppose to it just displaying the old GFS zonal bias in a complicated setup.

Yes you’re right both GEFS/GEPS go stormy towards the end but neither of them picked the amplitude at day 9( if it happens). People have their preferences but for trends  recently I look at the EPS, the extended para and strat dynamics which indicate that the reversion to wet and windy is possible as is an extended cold spell with big time N blocking as do Exeter fwiw.

Not seeing a BFTE with a giant Scandi high yet despite the papers and It’s  been covered in this forum that the 2018 event was seen 15days away by the ensembles so we haven’t got nearly that much confidence yet.

[Catacol]

So - I think we are still in the doldrums, no different to several days ago. The pattern is still amplified, the vortex is displacing and stretching as I type - end product unknown in terms of split or no split - and we are about to see a short westerly phase which very temporarily will overcome the amplified pattern in our locale.

And still the 240 EPS mean looks like this - have we been staring at a Greenland anomaly and a U.K. trough with a definite easterly element for a long time now? Feels like eons. 

The big question that isn’t going to go away any time soon is - will the deep cold out to the east back far enough west to engulf to U.K.? At present the BFTE style strat split and shattered vortex from Feb 18 has faded as an option. It may resurface later as the vortex is going to keep being bashed around a bit....but for now we have a displacement that looks to enhance the Euro trough over the next couple of weeks and keep that cold backing west on the table as a serious option.

 

One factor in this that has taken me a bit by surprise is the lack of momentum via an EAMT in recent days. A near flat line like this catches the eye, illustrating perhaps one element that contributed to the model reversal for next week.

Had torque behaved as might have been expected the pacific jet momentum I still think would have overcome the modest downwelling impacts of strat westerlies over the Atlantic. Anyway- that’s old news now.

So - where next? The GWO graph, a pretty technical tool, shows that we have dropped out of the stagnant holding pattern of December, with the current setup now sitting on the cusp of a new direction. If torques reengage we could see a similar move to the one we saw way back in October, with more of an amplified Nino pattern favoured long term rather than a flat Niña one.

What would be the source of any such increased momentum? For this I think our best bet is the MJO, not talked about much recently. I still have a mini project on the back burner to make better sense of this key driver of the hemispheric wave pattern, but using the common tool of an RMM plot we can see that the forcing has left the stagnant “circle of death” and looks primed to push on towards the maritime continent. The last move never got into 7/8/1, hitting that Niña cold wall brick wall....but Niña is  moderating, and a more coherent emergence towards phase 6/7 by mid month could be the trigger that helps connect trop driven amplification with strat driven downwelling support for westerlies. 

All in all though these are fine lines. My hope for a historic month was always hung on the hope of a shattered vortex. Without that we are back into more traditional driver combinations, and once the short lived Atlantic reemergence cold lovers (like me!) must hope for the factors mentioned above lining up to do a better job than last week at sourcing some deep cold.

Having said that - some parts have seen good snow this month so far. I know it’s true - I’ve seen the photos! Enjoy it if you’ve got it...! Nothing where I am here in Lincs....but I am optimistic we get a good bite at the cherry shortly and that the rewards could/should be better than the last 10 days or so. The cold is building to our east under the influence of the SSW and the arctic high. We now need an extra push in the pattern to get it to our shores. NWP is certainly flagging what might happen in the 7-14 day time frame. The next few days will be interesting watching. The whole season has been great from an analytical point of view so far and we aren’t half way through yet...

 

Edited January 9, 2021 by Catacol

[Mike Poole]

ECM clusters T264-T360

Actually reduced uncertainty here, and clusters 1 and 2 look excellent, between them 35/51.  I expect the outlook to become even better as the next few days runs come out...

[bluearmy]

10 minutes ago, SnowSalah said:

I’m due to move back to Barcelona office on the 19th, if I was there at the minute I could have travelled to Madrid for some record snowfalls . Judging by the ECM mean tonight I may have to delay my return as I could stand missing out on two major snow events. The real cold (if it ever shows it’s face) looks likely to come round 20th.. allowing for a few blips!! Let’s keep the fingers, toes and wives crossed that the trend keeps going  

If you delay your return awaiting a snow event for the U.K. predicted on the nwp you may as well retire here .......

[East_England_Stormchaser91]

40 minutes ago, General Cluster said:

-11C Uppers will do me fine, feb... Why waste all that money, on extra heating bills, when maxes of -1C will still deliver the goods, just as well?!

May be a bit too marginal  lol. 

Things really starting to get exciting again now!! Norfolk and Suffolk have always been cracking places to be in the right setup. Living in Cambridgeshire, it’s always been a painful watch in the past when we’ve been stuck with nothing at all and watching East coast streamers give a dumping just 20 miles away. Living in Norfolk now should eradicate that problem! 

[Matt H]

Just now, East_England_Stormchaser91 said:

May be a bit too marginal  lol. 

Things really starting to get exciting again now!! Norfolk and Suffolk have always been cracking places to be in the right setup. Living in Cambridgeshire, it’s always been a painful watch in the past when we’ve been stuck with nothing at all and watching East coast streamers give a dumping just 20 miles away. Living in Norfolk now should eradicate that problem! 

Nothing like rubbing salt into the wound.

[Jordan S]

Milder weather next week looking occasional.. quite blocked with frontal systems bumping into some cold air that will be over us at times and just to the east and northeast of us..

A lot of rain for western scotland tomorrow and Monday with the northern portion of it falling as snow tomorrow night into Monday mostly over high ground as much colder air moves in here..

tomorrow evening..

3pm Monday..

Monday night and Tuesday night looking very cold in scotland -7 -8c possible and daytime temperature on Tuesday may rise to -2c at most in a few places.

Another area of rain moving east on Wednesday possibly precided by snow in the north particularly scotland before turning back to rain as milder air temporarily moves in..

Later next week and weekend quite complex but likely turns cold at times with more rain on Friday or Saturday possibly with snow into the mix at times..

Gfs chart for the early part of the following week 18th January plenty of interest may change somewhat but not looking mild atm.. the gem and ecm are different both quite cold too though.

 

Edited January 9, 2021 by jordan smith

[Mike Poole]

Quite a shift to a more blocked pattern on ICON 18z at T120, here with 12z at same time:

I’m expecting from here on in, the op runs will tend to the ECM ensemble mean position, over the next day or so.  I expect we will be able to give good go ahead for the Greenland block by 12z tomorrow, or at latest 0z Monday...

Edited January 9, 2021 by Mike Poole

[frosty ground]

a small shift west would be useful 

[LRD]

I ain't being a suck up here (or maybe I am, I dunno) but there is some first class model analysis on here tonight

Bravo chaps

[stodge]

43 minutes ago, Singularity said:

Worth considering just how much hasn't worked out well within the next 10 days in todays deterministic runs from ECM and GFS. Slider lows taking unfortunate paths and even a low becoming stuck due north of us on the 12z ECM, which really doesn't help with moving the very cold air toward and across the UK.

Judging by the ensembles, we may well have been seeing some of the most 'difficult' options. Best hope, then, that this is merely by chance, as opposed to the det. runs resolving the situation more effectively. For what it's worth, the situation is so complicated and downright unusual (in terms of combination of factors in play) that I'd be surprised if they were able to gain that much of an edge.

I do wonder if ECM could be onto something with the lack of Greenland height rises. After all, the (potential... still not nailed down!) vortex split location could feasibly support a blocking high over Scandinavia instead.

Yes, I noticed that. ECM OP went on a completely different path to GFS and GEM yet the end effect was much the same.

The thing with which I'm struggling is the GFS which continues in far FI to fire up the PV and the Atlantic as though the current SSW hadn't happened. My theory is the repeated wave 1 warmings from the Siberian side are sending the PV back over to Greenland/NE Canada where it is somehow able to re-strengthen in situ and, aided by a return of stronger zonal winds, energises the jet later this month.

Now, IF the PV has been as weakened as the 10HPA charts suggest, I can't reconcile that and the longer-range model output. Are we using the usual GFS "bias" toward an Atlantic reset (to be fair, Control goes down a different, much colder and less intense PV route) or are we expecting a more "traditional" second half of winter which would suggest the impact of an early SSW is much less than some have suggested?

[Ice Day]

Such a funny place here, especially when there's a good chance of a cold spell on the horizon.  The downbeat reaction to the ECM was so odd.  Many of the more experienced posters have been talking about 19th - 21st Jan being 'landing day' for some real cold to hit the UK.  So let's see where we are on the latest runs.

GFS - 19th January

 

GFSP 19th January

GFS Control 21 January

GEM 19th January

ECM 19th January

And people think this has been a poor day?  

I understand 'but they are at day 10' comments, but there's enough consistency to be positive, surely?  I would be unhappy if the models were showing a flat Atlantic pattern in FI, but none of them are currently.  

Time will tell, but no reason to be anything other than optimistic for my money!

[SMU]

Evening

My comments earlier were directly aimed at the slighter poorer medium term trend from UKMO today as it didnt follow yesterdays move to the wedge > infact it moved away from it.

The spirits have been somewhat lifted by the ECM Mean though > lets hope those crazy values are still there come day 3/4 

[Mike Poole]

1 minute ago, Ice Day said:

Such a funny place here, especially when there's a good chance of a cold spell on the horizon.  The downbeat reaction to the ECM was so odd.  Many of the more experienced posters have been talking about 19th - 21st Jan being 'landing day' for some real cold to hit the UK.  So let's see where we are on the latest runs.

GFS - 19th January

 

GFSP 19th January

GFS Control 21 January

GEM 19th January

ECM 19th January

And people think this has been a poor day?  

I understand 'but they are at day 10' comments, but there's enough consistency to be positive, surely?  I would be unhappy if the models were showing a flat Atlantic pattern in FI, but none of them are currently.  

Time will tell, but no reason to be anything other than optimistic for my money!

You are absolutely right about this, the whole episode has been driven by things that are happening on a longer timescale than the individual model runs, just like 2018.  We are one step ahead of the models in this scenario, usually we are one step behind (all seasons not just winter). Still, yet, doesn’t mean we will ‘win’.  65% chance now, up from 60% earlier.  

[XtremeUKWeather]

Pub run do your thing and make us all happy

[danm]

2 hours ago, CreweCold said:

The 20th has been the date of interest for days and days, not sure what people are expecting before then?

ECM looks bang on date wise- 

Look at the amplification upstream and secondary ridge off the ESB. Only one way that's heading (hint: not mild)

Agree. Don’t think anyone has been seriously expecting deep cold in the next week or so. The real opportunity still lies in the final third of the month. 

[Uncertainty]

7 minutes ago, Steve Murr said:

Evening

My comments earlier were directly aimed at the slighter poorer medium term trend from UKMO today as it didnt follow yesterdays move to the wedge > infact it moved away from it.

The spirits have been somewhat lifted by the ECM Mean though > lets hope those crazy values are still there come day 3/4 

Glad to hear this Steve, the wedge was a beautiful but unlikely option but the day 8-9 trend was a day 14/15 day trend 6 days ago so it’s still counting down...

Also, that ECM op has 1030mb surface high over Scandi and it wouldn’t take much for that link up with the AR and the crazy 850s to advert westwards: that’s the key to the puzzle we’ve been missing so far this winter...

Your thoughts on the GLOSEA 3monthly run on Monday? The others have flipped, will the UKMO make it a full house?

[SMU]

57 minutes ago, Day_9 said:

Wasn’t winter declared over in the first week of December?

No it wasnt.

It was just time to take a break - chasing the charts in early December rarely bares fruit so good to take a 2 week or so break

[SMU]

1 minute ago, Uncertainy said:

Glad to hear this Steve, the wedge was a beautiful but unlikely option but the day 8-9 trend was a day 14/15 day trend 6 days ago so it’s still counting down...

Also, that ECM op has 1030mb surface high over Scandi and it wouldn’t take much for that link up with the AR and the crazy 850s to advert westwards: that’s the key to the puzzle we’ve been missing so far this winter...

Your thoughts on the GLOSEA 3monthly run on Monday? The others have flipped, will the UKMO make it a full house?

I didnt see it - have you got an image -

S

[Mike Poole]

GFS 18z T126, stuff to keep your eye on:

[Griff]

Just now, Mike Poole said:

GFS 18z T126, stuff to keep your eye on:

I'm watching this from behind the sofa, thanks for the guidance, will have to take your word and a leap of faith

[Uncertainty]

7 minutes ago, Steve Murr said:

I didnt see it - have you got an image -

S

Of the Glosea run no, was just asking for your prediction as to whether it might flip From it’s Dec +NAM forecast, given the rest of the seasonals appear to have...

[Battleground Snow]

That's some cold over Central USA and Canada.. stronger system too, low cutting off in Atlantic as early as 150... Should be another stellar run from here on.

 

Edited January 9, 2021 by Battleground Snow

[Griff]

Para as you were so far up to 126

[Eskimo]

Pressure-wise, a chart that looks more like mid-Spring than mid-Winter - remarkable in its own right

Edited January 9, 2021 by Eskimo