Model output discussion - Jan 3rd onwards

[Geordiesnow]

31 minutes ago, General Cluster said:

A nice push of warm Uppers, into SE Europe. Again... Something which, I think, has gotten more common during our winters -- especially since 2019?

    

Now back to SSW watch!

It's not unusual if Spain and North Africa go cold(for their standards) quite warm air gets pushed up towards Italy/Greece and Turkey etc but it's quite something when you see  uppers of 20C on the charts at the start of January. Sadly another sign of a warming climate. 

Does look more likely we will go into a less cold set up, may not last long, may last weeks, far too early to call though. 

[sebastiaan1973]

17 minutes ago, feb1991blizzard said:

Together with the displacement of the vortex in the Atlantic Ocean in EC. Without a split, it's not going to work.

[Frostbite1980]

6 minutes ago, sebastiaan1973 said:

Together with the displacement of the vortex in the Atlantic Ocean in EC. Without a split, it's not going to work.

As said many a time if it can go wrong for coldies in the UK it will go wrong! Let's just hope we get that split which ends up in a favourable position for us but at present I'm not feeling as positive about this SSW as I was a week ago!

[bluearmy]

4 minutes ago, sebastiaan1973 said:

Together with the displacement of the vortex in the Atlantic Ocean in EC. Without a split, it's not going to work.

Ec looks like it will broadly follow gfs ....the 06z run not leaving a vortex behind but is continuing to pivot ....time for a comment on the strat thread ....

[East_England_Stormchaser91]

We need to see how that shortwave develops pushing off Greenland over the next few days. That is what is preventing the cold travelling down. If that fails to develop as modelled, it could be a game changer, even more so if that developing low over Iberia manages to become significant. 

Lots to keep our eye on at the moment. 

[Anthony Burden]

GFS 06z high pressure going nowhere,interesting Synoptics,not sure about milder spell 

ie 7c /9c . Frost fog will keep temperatures low if high sticks around as ECM was hinting 

earlier.

[Scott Ingham]

27 minutes ago, wellington boot said:

Hey get off that fence! You have been emphatically in the cold camp, rejected models suggesting a warm up, insisted it would stay blocked and cold.

And I for one hope you are right.

I cant. Realistically models atm show more chance of a brief warm up. The likes of Feb etc at the minute should be given credit as a warm up is more favourable as it stands but on the flip side my own reasons to suggest this may be models not having a full grasp of things yet still stand so the fence is the right place to be. Charts back up a warm up (onoy brief) logic and back ground factors around my own forecast are still there though.

So for me. Being balanced and not biased its the best place to be 

Its worth noting a middle ground wont warm us up. 

It will back up the forecast of it staying below average all month and us just be us in a holding pattern till the next push of high lat blocking.

Whatever side of the argument your on you cant proclaim to be right as tye clusters and ensembles are starting to retract back to saying the warm was models being in disaray.

The morning clusters have increased chance of cold winning out

Edited January 4, 2021 by Scott Ingham

[Methuselah]

At least there are clear signs (or are there?) of deep cold becoming established, on our side of the globe, by Day 16... But, as that's precisely what we'd expect, or hope, the SSW to produce, confirmation bias cannot be ruled out!

    

Warning: FANTASY ISLAND!

 

[Howie]

40 minutes ago, Cavehill Snow said:

I am mystified by this also - i acknowledge that many are looking for a cold / snowy outcome for our neck of the woods, but what i am perplexed by is that there will be much less high latitude blocking anywhere in the northern hemisphere @240 hrs compared to what we have seen over the last week.

It just dissappeared, how!?

[sebastiaan1973]

15 minutes ago, Frostbite1980 said:

As said many a time if it can go wrong for coldies in the UK it will go wrong! Let's just hope we get that split which ends up in a favourable position for us but at present I'm not feeling as positive about this SSW as I was a week ago!

Haha. It's the same over here in the Netherlands. So close to sea and just above sealevel we really need winds from the east to get some cold weather.

[Timmytour]

Regarding the SSW, is there any memory out here among the members of how dramatically the models shift in the event of one?   Or is it more a drip feed effect?  I can  imagine 10 day modelling changing quite a bit but then again it tends to do that on a frequent basis without any SSW  (especially when Narnia is in sight!). But has there been for example an instance of a Day Five view, with a broad agreement across all models, being shifted to such a degree that, by the day before it materialized, the models were in agreement of a completely different outcome for the same day ?

[IDO]

Solid trend for HP close to the UK after the cold spell. The d9 mean and ens are as solid as they could be, and we know that is far easier to model than Atlantic ridges:

d9 mean 06z>

From then, the main lobe of the tPV moves through Siberia and the question is where it goes from there? Does it split to Europe and US, or stalls (due to residue Russian high and nascent Arctic high)? The 06z op stalled it for a few days whilst it cleared the residue Russian high.

For me, up to about d12 is within reliability, but afterwards I am unsure. I do not make no presumptions as to the trop and the effect from the strat, as this year it seems the trop is driving the strat. If there is a qtr then the models will start showing it, but atm I see no conclusive proof that something is afoot; we have Arctic highs without warmings, and from the 06z gfs op it seems the arctic highs are injected from wedges generated by transient ridges in the flow? This is course the gfs and we will see how it handles the SSWE assuming that it is a clean predictable coupling.

[sebastiaan1973]

Just now, IDO said:

Solid trend for HP close to the UK after the cold spell. The d9 mean and ens are as solid as they could be, and we know that is far easier to model than Atlantic ridges:

d9 mean 06z>

From then, the main lobe of the tPV moves through Siberia and the question is where it goes from there? Does it split to Europe and US, or stalls (due to residue Russian high and nascent Arctic high)? The 06z op stalled it for a few days whilst it cleared the residue Russian high.

For me, up to about d12 is within reliability, but afterwards I am unsure. I do not make no presumptions as to the trop and the effect from the strat, as this year it seems the trop is driving the strat. If there is a qtr then the models will start showing it, but atm I see no conclusive proof that something is afoot; we have Arctic highs without warmings, and from the 06z gfs op it seems the arctic highs are injected from wedges generated by transient ridges in the flow? This is course the gfs and we will see how it handles the SSWE assuming that it is a clean predictable coupling.

It's quite logical, because GFS shows no downwelling into the troposphere. That's one of the problems.

[Gael_Force]

5 minutes ago, sebastiaan1973 said:

It's quite logical, because GFS shows no downwelling into the troposphere. That's one of the problems.

I have in memory a recent SSW that did not downwell at the time but it did have an effect on early Spring. Anybody remember which year that was?

[ALL ABOARD]

9 minutes ago, sebastiaan1973 said:

It's quite logical, because GFS shows no downwelling into the troposphere. That's one of the problems.

Its quite confusing.. 

Because if the GFS is showing no downwelling.. 

What's causing the sudden change to more of a westerly influence? 

[jayb1989]

Further disappointing output this morning after we get through the current chilly spell. Those of us who are after noteable cold are forced again to be patient and look ahead. We really need to see changes to the jet over the Pacific.

In terms of the SSW, hopefully this also has a positive effect, however it’s far from certain it will lead to a notable cold outcome for the UK.

[Paul T]

2 minutes ago, Gael_Force said:

I have in memory a recent SSW that did not downwell at the time but it did have an effect on early Spring. Anybody remember which year that was?

2013 had a similarly timed SSW event to this year that could have contributed to the very cold March (it was colder than both Jan and Feb).  

 

 

[bluearmy]

8 minutes ago, sebastiaan1973 said:

It's quite logical, because GFS shows no downwelling into the troposphere. That's one of the problems.

Maybe at 10hpa (marked 1) 

bit the reversal clear downwells into the polar field though the area marked 2 shows a small area of positive flow around 12/15 m/s 75N which persists right out until the end of the run 
 

 

[Brocken Spectre]

29 minutes ago, Timmytour said:

Regarding the SSW, is there any memory out here among the members of how dramatically the models shift in the event of one?   Or is it more a drip feed effect?  I can  imagine 10 day modelling changing quite a bit but then again it tends to do that on a frequent basis without any SSW  (especially when Narnia is in sight!). But has there been for example an instance of a Day Five view, with a broad agreement across all models, being shifted to such a degree that, by the day before it materialized, the models were in agreement of a completely different outcome for the same day ?

I eluded to the 2018 SSW yesterday.  GFS had the BFTE modelled (to a fashion) from about 288hrs, it always seemed to be showing.  I don't remember it flip flopping too much, and don't recall seeing the temperatures at 240+ being modelled at norms (like the GFS in the last few runs) 
In my very unprofessional opinion...I'm not holding my breath on this one

Edited January 4, 2021 by Brocken Spectre

[sebastiaan1973]

4 minutes ago, ALL ABOARD said:

Its quite confusing.. 

Because if the GFS is showing no downwelling.. 

What's causing the sudden change to more of a westerly influence? 

Things happening in the troposphere. Perhaps the MJO.

Besides that. Winds from the west are our default setting. When I climb into a tree, it's rather difficult, when I jump out of a tree, it's quite easy (energy wise). Gravity. The same is for our atmosphere at the NH.

6 minutes ago, bluearmy said:

Maybe at 10hpa (marked 1) 

bit the reversal clear downwells into the polar field though the area marked 2 shows a small area of positive flow around 12/15 m/s 75N which persists right out until the end of the run 
 

 

two days later I see this picture, do I see something wrong?

 

[fromey]

SSW is likely to be declared sometime this afternoon, winds overnight fell to 3.2mts sec 

credit to Marco 

[bluearmy]

1 minute ago, sebastiaan1973 said:

Things happening in the troposphere. Perhaps the MJO.

Besides that. Winds from the west are our default setting. When I climb into a tree, it's rather difficult, when I jump out of a tree, it's quite easy (energy wise). Gravity. The same is for our atmosphere at the NH.

two days later I see this picture, do I see something wrong?

 

No you don’t - it’s a wave which doesn’t sustain in the trop on that run (although if you go to the end will see a fair size reflection from the trop) 

note that the gfs and para (more advanced) are both showing downwelling waves into the trop back end week 2. You will need to view NH plots to see these 

   

[Cavehill Snow]

30 minutes ago, IDO said:

I do not make no presumptions as to the trop and the effect from the strat, as this year it seems the trop is driving the strat. If there is a qtr then the models will start showing it, but atm I see no conclusive proof that something is afoot. This is course the gfs and we will see how it handles the SSWE assuming that it is a clean predictable coupling.

Just trying to learn, a few questions if I may:-

Has the trop been uncoupled from the strat so far this year, or has the trop been leading the strat?

If the stat is not leading the trop at time the time of SSW occurence, can the trop lead the response on this?

TIA

[MATTWOLVES 3]

Interesting early developments..could be some wintry showers focused towards the SE and the NE on Tuesday...some of these could get well inland also,so a few surprises in some areas for sure.. I would say areas to the far SW And West more likely to stay dry..But perhaps it would be best to focus on the Radar tomorrow.

Bit of an update regarding SSW..Temps have now increased a further 44C during the last couple of days..we now have the effects percolating downwards,we now await for wind reversal to percolate down. GFS 6Z seems to be hinting at a MAJOR warming event and it could be declared later today. And according to Judah Cohen it looks on a similar magnitude to the 2018 event....fingers crossed.

[bluearmy]

1 minute ago, Cavehill Snow said:

Just trying to learn, a few questions if I may:-

Has the trop been uncoupled from the strat so far this year, or has the trop been leading the strat?

If the stat is not leading the trop at time the time of SSW occurence, can the trop lead the response on this?

TIA

Answer to question 1 is ‘yes’

answer to question 2 is ‘mainly yes’

answer to question 3 is unknown but with a reversal ongoing and working its way down, the trop will do well do maintain its prevalence...... it could be that the downwelling does not affect the trop over the next six weeks but given the current set up, that looks unlikely