Model Output Discussion - the cold has arrived

[Skullzrulerz]

3 minutes ago, mulzy said:

Word of warning: Little support for the GFS from the GEM and UKMO det runs.

Yeah, I think the models are struggling big time at the moment, GFS is good/great for cold weather but unless there's more support for that scenario it's best to take it with a pinch of salt.

 

[keithlucky]

26 minutes ago, Johnp said:

The problem with GFS as a model, is I’m 99% sure this low would disrupt against the high pressure. 
I’m also 99% sure GFS won’t model it to happen on this run, rendering the rest of the run moot. 
 

Edit: I’ve been mugged off.

Very cold over Iceland for the next 7 days -8 c if we can tap into that air  I'll be  happy coldie.

Edited December 14, 2022 by keithlucky

[Snowmadsam]

Day 97 of me putting my head in my hands over this weather pattern and hoping for some consistency

12z's just go for cold again, again highlighting the unknowns of this pattern

Spoiler: There is none, other than a mild up over the weekend (not saying warm up in winter)

[Allseasons-Si]

The gefs mean is slightly better than the 06z with less phasing of the lows in the Atlantic and lower heights further south

12z 168 vs 06z 174.

that's as far out as i would go.

 

Edited December 14, 2022 by Allseasons-si
Added text

[Stuie]

Regarding some frontal interest for the South on Sunday, the Arome has this take on things...

[Mike Poole]

7 minutes ago, Allseasons-si said:

The gefs mean is slightly better than the 06z with less phasing and lower heights further south

12z 168 vs 06z 174.

that's as far out as i would go.

 

With this amount of uncertainty, that’s definitely worth banking!

So far, this whole 12z suite is better for cold.  Lowering of heights further south/southeast is one takeaway from most of the runs, and is good news in the short term (meaning more of the country affected by the cold reload) and the longer term in terms of what pattern might develop afterwards.

I know some have suggested the background signal for amplification has waned and awaiting a renewed push via the MJO, but the models are still seeking out amplified solutions (arctic high evidence of that) - no sign of at all of reverting to a zonal dirge.  It is just a question of whether the local UK synoptics can benefit again this time around.  On to the ECM…

Edited December 14, 2022 by Mike Poole

[Johnp]

Just now, Stuie W said:

Regarding some frontal interest for the South on Sunday, the Arome has this take on things...

Doesn’t that show rain for the south?

[Stuie]

Just now, Johnp said:

Doesn’t that show rain for the south?

Far South yep but a big shift from the Scottish borders...

[Mucka]

GFS ensembles at 192h have a much improved mean over the 06z. in line with the improved Op

Stronger Atlantic/Greenland blocking, more Southerly Atlantic, deeper Scandi trough and stronger Polar high.

[Frank Trough]

1 minute ago, Johnp said:

Doesn’t that show rain for the south?

definitely does for what i consider "the south". Anything above winchester is "the north" as far as i'm concerned.....:)

[bluearmy]

1 minute ago, Mucka said:

GFS ensembles at 192h have a much improved mean over the 06z. in line with the improved Op

Stronger Atlantic/Greenland blocking, more Southerly Atlantic, deeper Scandi trough and stronger Polar high.

Edge that Baffin wedge east 500 miles and that mean looks like last weeks mean (not the Arctic high)

Edited December 14, 2022 by bluearmy

[Allseasons-Si]

....But i couldn't resist

why!!!

becouse the mean still looks good out to 192

12z vs 06z.

and the gefs ens,the gfs looks like it was an outlier but there are some V cold members with it.

[Skullzrulerz]

4 minutes ago, Johnp said:

Doesn’t that show rain for the south?

Depends on what area you think the South is.

For the most part it looks like London and mostly northwards you get a chance of snowfall.

However, I wouldn't take these charts too seriously just yet.

[Bricriu]

47 minutes ago, IDO said:

GEM and GFS similar, but the GFS makes the most out of the messy setup, whilst the GEM is more in keeping with previous runs:

GFS: GEM: 

The subtle shifting sands of micro details can mean big differences in the UK outcome down the line.

The problem is of late I'd be more inclined to believe the GEM. What do you think about it all? 

[supernova]

GFS Op departs via the Polar Express on Dec 21 having necked all the Baileys whilst most of its ensembles are still stood on the platform looking slightly bewildered but that isn't to say it's wrong.

Edited December 14, 2022 by supernova

[Johnp]

An encouraging improvement tonight, let’s hope the ECM delivers the goods too…

[Skullzrulerz]

2 minutes ago, Bricriu said:

The problem is of late I'd be more inclined to believe the GEM. What do you think about it all? 

Considering the uncertainty, we need some other model support.

It would calm our nerves if we can get the others on board.

[feb1991blizzard]

1 minute ago, Bricriu said:

The problem is of late I'd be more inclined to believe the GEM. What do you think about it all? 

The way the models have been recently i would be more inclined to believe the Daily Express or The Sun than any model run!

[Stuie]

3 minutes ago, Skullzrulerz said:

Depends on what area you think the South is.

For the most part it looks like London and mostly northwards you get a chance of snowfall.

However, I wouldn't take these charts too seriously just yet.

Very true mate. I forget that not everybody sees what I post and should have said it was a correction South from just Scotland previously.

[Mcconnor8]

2 minutes ago, supernova said:

GFS Op departing via the Polar Express on Dec 21 whilst most of its ensembles are still stood on the platform looking slightly bewildered but that isn't to say it's wrong.

Surely the temp drop in that short a time on that super low perturbation (P30?) would be a record? It drops like a stone

Edited December 14, 2022 by Mcconnor8

[supernova]

1 minute ago, feb1991blizzard said:

The way the models have been recently i would be more inclined to believe the Daily Express or The Sun than any model run!

LOL Feb that's tantamount to Forum sacrilege. 

Edited December 14, 2022 by supernova

[londonblizzard]

1 minute ago, Mcconnor8 said:

Surely the temp drop in that short a time on that super low perturbation (P30?) would be a record? It drops like a stone

Pert 11

[TSNWK]

4 minutes ago, supernova said:

GFS Op departs via the Polar Express on Dec 21 having necked all the Baileys whilst most of its ensembles are still stood on the platform looking slightly bewildered but that isn't to say it's wrong.

There’s several members there that are more enthusiastic than the op in returning us into real cold.

[IDO]

3 minutes ago, Bricriu said:

The problem is of late I'd be more inclined to believe the GEM. What do you think about it all? 

GEM has been pretty good of late. So as that is close to the GFS mean, that is favoured. These occasional GFS super-cold-runs need to be backed up by two other runs before I will take them as legit, so we shall see what comes tonight. The mean has improved from the 06z so hopefully that will trend.

I still would not go outside D7 as this is an unusual setup and I cannot remember such a messy complicated NH profile. Way above my pay grade and I take it one run at a time and just have a stab at what I think will happening, JFF!

[Snowmadsam]

Just now, londonblizzard said:

Pert 11

 

No but in all seriousness, that would be bitter! 

60/40 on the ECM potentially coming out with a colder option this evening, its a hunch. No evidence backing it. I could be very wrong.