Model output discussion - Winter has arrived

[Cheshire Freeze]

3 minutes ago, mountain shadow said:

Well personally I prefer a seasonal Christmas than unseasonable Spring.

There's always the risk that something else occurs weather wise which overrides any strat influence.

Well there's nothing at present to say we won't get a seasonal Christmas?

Christmas is day 21, UKMO goes out to day 6...

Edited December 4, 2020 by CreweCold

[mountain shadow]

20 minutes ago, Kentish Snowman said:

Absolutely nowhere for the Atlantic to go though other than SE.  That Russian high is like a brick wall and is probably being underestimated at 6 days out?  I would suggest the status quo will be maintained for a good while yet until either the high retreats or flexes its muscles.

The Atlantic can go NE with us on the milder side. 

[northwestsnow]

3 minutes ago, mountain shadow said:

The Atlantic is not taking over on the UKMO. It's still blocked, but we're on the wrong side.

Blocked where? Its heading right for us .

[Skullzrulerz]

22 minutes ago, Faronstream said:

Still the pv will be weaker than average so for how long time is the question.

It won't matter if we can't get the other blocks in place 

We could still have a strong pv and have a decent cold spell

7 minutes ago, CreweCold said:

Well it may be a case of kissing a few frogs to find the prince.

I'll put up with any amount of rain if we can secure a January SSW

Could very well be but then we have the issue of time and a ssw isn't guarantee to work in our favour if it happens 

 

[Tim Bland]

Here’s another slider opportunity. Just wish she had some colder air to tap into as it looks like more cold rain at the moment ...

[Bricriu]

The CFS, that most reliable of models, indicates we are in for a seasonal Christmas

[Kentish Snowman in Yorks]

8 minutes ago, northwestsnow said:

Blocked where? Its heading right for us .

Heading right for us but won't get any further East than the UK so yes it might be nothing other than cool and wet for us but the Atlantic is not taking over from there given the strength of that high to our East?

[nick sussex]

So far this evening the UKMO and GEM have a shortwave calamity .

The ICON goes into the semi calamity pile as it phases that but much further north and tries desperately to recover the situation.

The GFS phases that but more favourably so avoids that calamity .

 

[dragan]

1 minute ago, Kentish Snowman said:

Heading right for us but won't get any further East than the UK so yes it might be nothing other than cool and wet for us but the Atlantic is not taking over from there given the strength of that high to our East?

yeh, but the weather is still coming off the atlantic, just as rubbish IF ITS COLD you want

[northwestsnow]

Just now, Kentish Snowman said:

Heading right for us but won't get any further East than the UK so yes it might be nothing other than cool and wet for us but the Atlantic is not taking over from there given the strength of that high to our East?

I beg to differ but thats OK.

UKMO is going to lead to a Euro high and Pos NAO ,in my opinion, very quickly.

[sebastiaan1973]

4 hours ago, Catacol said:

But the atmosphere refuses to couple with Nina (assisted by ongoing MJO forcing) and it would appear that the vortex is not going to couple any time soon. Let's be clear on this - these are HUGE changes to the context that was seen only 4 weeks ago....and if tropospheric forcing continues to rule the roost, the vortex spins down and potentially splits, and the Nina signal fades away (and add on low solar, high snow cover levels now across Asia, impact of low sea ice, QBO moving ever closer to aggregate neutral) then this winter could provide something of real interest - and for once possibly in the heart of winter!!

 

Not according to Michael Ventrice

 

[Catacol]

Remember that 06z GFS that someone posted that I talked to - forget who posted it now and cant be bothered to check back through....but it should the change of the Ural ridge that doesnt seem to want to go anywhere linking up with the enhanced north pacific ridge emerging. Those not liking the ECM do need to get a bit of perspective. The 240h EPS shows a distinctly chilly pattern for the UK as we head towards mid month, and we are not a million miles away from a cross polar link here with associated cold air leakage out of the arctic.

All of this hits the vortex - driving warm air up where it doesnt like it.....and setting us up for 2 subsequent possibilities: a continental/atlantic battle ongoing into the second half of December but also the opportunity for significant vortex stress. The first precursor pattern that setup around 12 Jan 2018 when the most unbelievable vortex split occured (the date that reanalysis has traced the first signs of significant vortex stress) looks like this.

Rotate the EPS anomaly chart 90 degrees clockwise in your head. Notice anything? 

Edited December 4, 2020 by Catacol

[Cheshire Freeze]

1 minute ago, Catacol said:

Remember that 06z GFS that someone posted that I talked to - forget who posted it now and cant be bothered to check back through....but it should the change of the Ural ridge that doesnt seem to want to go anywhere linking up with the enhanced north pacific ridge emerging. Those not liking the ECM do need to get a bit of perspective. The 240h EPS shows a distinctly chilly pattern for the UK as we head towards mid month, and we are not a million miles away from a cross polar link here with associated cold air leakage out of the arctic.

 

All of this hits the vortex - driving warm air up where it doesnt like it.....and setting us up for 2 subsequent possibilities: a continental/atlantic battle ongoing into the second half of December but also the opportunity for significant vortex stress. The first precursor pattern that setup around 12 Jan (that date that reanalysis has traced the first signs of significant vortex stress) looks like this.

Rotate the EPS anomaly chart 90 degrees clockwise in your head. Notice anything? 

Glad I'm not the only one seeing it 

[Beanz]

2 minutes ago, Catacol said:

Remember that 06z GFS that someone posted that I talked to - forget who posted it now and cant be bothered to check back through....but it should the change of the Ural ridge that doesnt seem to want to go anywhere linking up with the enhanced north pacific ridge emerging. Those not liking the ECM do need to get a bit of perspective. The 240h EPS shows a distinctly chilly pattern for the UK as we head towards mid month, and we are not a million miles away from a cross polar link here with associated cold air leakage out of the arctic.

 

All of this hits the vortex - driving warm air up where it doesnt like it.....and setting us up for 2 subsequent possibilities: a continental/atlantic battle ongoing into the second half of December but also the opportunity for significant vortex stress. The first precursor pattern that setup around 12 Jan (that date that reanalysis has traced the first signs of significant vortex stress) looks like this.

Rotate the EPS anomaly chart 90 degrees clockwise in your head. Notice anything? 

A small dog...?

[snefnug]

2 minutes ago, Beanz said:

A small dog...?

The ghost of Christmas Snow Past?

[Tim Bland]

3rd time lucky for the sliders..for the far north at least. Plenty of time for this to all trend south though...

 

Edited December 4, 2020 by Tim Bland

[Beanz]

Just now, snefnug said:

The ghost of Christmas Snow Past?

Even he’s forgotten what his job is! 
 

In all seriousness, what should I be seeing?  I’m genuinely too much of an amateur to know.. 

[BlueHedgehog074]

10 minutes ago, Catacol said:

Remember that 06z GFS that someone posted that I talked to - forget who posted it now and cant be bothered to check back through....but it should the change of the Ural ridge that doesnt seem to want to go anywhere linking up with the enhanced north pacific ridge emerging. Those not liking the ECM do need to get a bit of perspective. The 240h EPS shows a distinctly chilly pattern for the UK as we head towards mid month, and we are not a million miles away from a cross polar link here with associated cold air leakage out of the arctic.

 

All of this hits the vortex - driving warm air up where it doesnt like it.....and setting us up for 2 subsequent possibilities: a continental/atlantic battle ongoing into the second half of December but also the opportunity for significant vortex stress. The first precursor pattern that setup around 12 Jan 2018 when the most unbelievable vortex split occured (the date that reanalysis has traced the first signs of significant vortex stress) looks like this.

Rotate the EPS anomaly chart 90 degrees clockwise in your head. Notice anything? 

Just a bit of a guess, but possible wave 2 activity between both the Pacific and Russian/Northern Scandinavian ridges?

 

Does look like the Vortex is being put under a lot of strain on that chart.

Edited December 4, 2020 by DiagonalRedLine
Typos

[MarkM]

10 minutes ago, Catacol said:

Remember that 06z GFS that someone posted that I talked to - forget who posted it now and cant be bothered to check back through....but it should the change of the Ural ridge that doesnt seem to want to go anywhere linking up with the enhanced north pacific ridge emerging. Those not liking the ECM do need to get a bit of perspective. The 240h EPS shows a distinctly chilly pattern for the UK as we head towards mid month, and we are not a million miles away from a cross polar link here with associated cold air leakage out of the arctic.

All of this hits the vortex - driving warm air up where it doesnt like it.....and setting us up for 2 subsequent possibilities: a continental/atlantic battle ongoing into the second half of December but also the opportunity for significant vortex stress. The first precursor pattern that setup around 12 Jan 2018 when the most unbelievable vortex split occured (the date that reanalysis has traced the first signs of significant vortex stress) looks like this.

Rotate the EPS anomaly chart 90 degrees clockwise in your head. Notice anything? 

Snoopy !

[Uncertainty]

Good afternoon everyone.

Just a snapshot from the GEM

Not dissimilar from the GFS

Icon also looked to be trending in a similar direction 

Wet for the south yes but still seasonal with slider potential.

If it wasn’t for the UKMO then we’d have had a reasonable set of medium term charts this afternoon although as @CreweCold and @Catacol point out, if we do get the Atlantic tilting positively against the trough to the east of the UK (which would of course manifest in a wet and windy pattern here at the surface) that may well intensify the pressure on the SPV which, clearly, is under some pressure already from that monster Urals high. We can see this from the Strat projections.

(Though notice a couple of bias corrected CFS members go AWOL later on and enter apocalypse mode, which shows the importance of the following...)

For me, the longer that Urals high sticks around the better, the more wave breaks we see against it the better. We don’t want a half baked reflective event / displacement spilling over the cold into the US, we want a full on absorbtion event leading to a favourable split down the line. It looks right now to be 50/50 which makes sense in a WQBO/moderate Nina winter. If it fails then Glosea will be right as it usually is and we’re looking at Feb 2020 pt2. If it lands then we’re in the game.

 

Edited December 4, 2020 by Uncertainy

[Catacol]

11 minutes ago, Beanz said:

A small dog...?

 - the same approximate precursor pattern. Not saying of course that the end product will be exactly identical - that would be daft - but there is definitely the potential for something to develop into January that might get interesting indeed.

Back in 2018 the second tropospheric pattern that set the vortex up for its hammer blow was this

Significant north pacific ridge while the Ural high drifted SE and the UK looked at an unremarkable set of local conditions. The point that is worth making is that unremarkable conditions here can set up impacts that are far more significant later. Our current position is pretty good. Can we get a big north pacific ridge as we head into January?  Hmmmmmm

Edited December 4, 2020 by Catacol

[Zak M]

Bonkers CFS run as usual this evening.

This chart is for Christmas Day - would almost certainly be a white Christmas for the majority.

   

And then the day after...

         

You can see the -18c isotherm clipping Kent!

Edited December 4, 2020 by Zak M

[Tim Bland]

That CFS looks a marginal to me ...altitude will be key...

[Skullzrulerz]

7 minutes ago, Zak M said:

Bonkers CFS run as usual this evening.

This chart is for Christmas Day - would almost certainly be a white Christmas for the majority.

   

And then the day after...

         

You can see the -18c isotherm clipping Kent!

Reminds me of The day after tomorrow film besides all the flooding 

[Daniel*]

55 minutes ago, northwestsnow said:

Typically the least appealing run from the 00z suite ( EC det) looks like it will verify now UKMO has flipped to the  Atlantic taking over...

UKMO isn’t a particularly great model imo which is sad as it is one of our best at our disposal, I think over the years it’s reputation has gone down, I remember in winters gone and it was a leading model, but now we don’t see that often when it has different ideas often ends up giving in. It requires an upgrade, have you seen how erratic it has been at day 5-6? Thank god we don’t see it go further. And yes, I know people like to share UKMO is second best performing model but if you focused on Europe I bet GFS at day 5-6 would be very close. 

Edited December 4, 2020 by Daniel*