Model output discussion - 7th January onwards

[ALL ABOARD]

2 minutes ago, ITSY said:

Just a dose of something sour to ensure we all don't get carried away into a narnia-induced coma. Zonal wind speeds in the Strat due to pick up and become mean westerly again by the last third of the month. As we know though, downwelling can take its time and the SPV will still be significantly weaker than normal, but worth noting as a note of caution while we look at charts showing amazing anomalies for months on end...

The plus side, taken from Marco Petangna's very interesting and insightful twitter feed, is that the SPV is currently at its weakest state on record for this time of year - which probably explains the ridiculous duration looming HLBs. Pick that one out! 

The zonal winds have to return to westerly eventually otherwise it wouldn't be classed as SSW and would indeed be a final warming. 

No need to worry about them returning to westerly anymore, they are at easterly for more than a substantial amount of time.

[Singularity]

I wish I could water-pistol every Twitter user that posts charts and makes simple statements without any useful elaboration. I know the character limit is tight but still...!

10 hPa zonal wind recovery and temp lowering at a steady pace is an indicator that the earlier negative anomalies are downwelling.

Based on the stratospheric signals and how the next tropical cycle is shaping up in the modelling, I think we've finally reached the point at which not seeing noteworthy winter weather affect a large portion of the UK at some point within the next few weeks would be downright unlucky (for those seeking such things).

[SMU]

5 minutes ago, ITSY said:

Just a dose of something sour to ensure we all don't get carried away into a narnia-induced coma. Zonal wind speeds in the Strat due to pick up and become mean westerly again by the last third of the month. As we know though, downwelling can take its time and the SPV will still be significantly weaker than normal, but worth noting for caution while we look at charts showing amazing anomalies for months on end...

Indeed, on the plus side, drawn from Marco Petangna's very interesting and insightful twitter feed, is that the SPV is currently at its weakest state on record for this time of year - which probably explains the ridiculous duration looming HLBs. Pick that one out! 

Just to add a bit to your post, recovery to westerly is almost inevitable - however recovery to the norm is extremely unlikely-

Other statistics that may be of use to put the current position into context-

As you mention the vortex is currently in its weakest ever position for todays timestamp-

Its -8.6M/S Easterly- which just pips 2004 as the lowest.

The Climo average for this date for the zonal wind is around +38 M/S westerly -

Today is also the day with the biggest differential between 2017-18 winter-

This point last year we were a whopping +57 M/S - A net difference of 65M/S zonal component...

We are also running circa 1 month ahead of 2017/18s SSW so net net if the downwelling is the same we have about 1 months more 'availability' for Winter weather over last year...

The last few days have been a bit of a drag with the GFS however the 06z has really come on strong- it feels simply that the only point lf contention is how far east the slider alligns & where the snow is along the boundry....

S

[fujita5]

4 minutes ago, ALL ABOARD said:

The zonal winds have to return to westerly eventually otherwise it wouldn't be classed as SSW and would indeed be a final warming. 

No need to worry about them returning to westerly anymore, they are at easterly for more than a substantial amount of time.

Exactly - it takes time generally for the stat to couple to the trop and vice versa.  Once established, the split trop pattern will imprint on the lower strat making it take a while for the reorganised PV to exert any influence on the surface weather.  And with further warmings in the long range forecast it seems the SPV is going to be in a bad way for a while.

We now just need everything to go our way to get some sustained and perhaps very severe cold, and for once the odds are stacked firmly in our favour.

[snowking]

Two things -

 

1. BBC website location forecasts (not that anybody should be paying any attention to these) are derived from the ECMWF now - presumably raw det.

2. @bluearmy that’s twice now you’ve mentioned  west based negative NAO in the last 18 hours...what are you trying to do to me?!

Still a very prominent risk I think given the location of troughing anomalies on seasonal modelling suites, and looking at the last couple of EC46 runs....but to put on my rose tinted aviators for a second, fortunately that risk looks to be out at week 5/6, and we still have weeks 2, 3 and 4 to get through before then - even then, it’s not impossible to get cold and snow with a west based -NAO, it just depends how much cold we could inject into any residual troughing before then

Anyway, all speculation on far away modelling for now

[bluearmy]

Just now, snowking said:

Two things -

 

1. BBC website location forecasts (not that anybody should be paying any attention to these) are derived from the ECMWF now - presumably raw det.

2. @bluearmy that’s twice now you’ve mentioned  west based negative NAO in the last 18 hours...what are you trying to do to me?!

Still a very prominent risk I think given the location of troughing anomalies on seasonal modelling suites, and looking at the last couple of EC46 runs....but to put on my rose tinted aviators for a second, fortunately that risk looks to be out at week 5/6, and we still have weeks 2, 3 and 4 to get through before then - even then, it’s not impossible to get cold and snow with a west based -NAO, it just depends how much cold we could inject into any residual troughing before then

Anyway, all speculation on far away modelling for now

Ah 00kriss ..... I’ve been waiting for you ....

i think the west based neg nao will be the eventual ending but that could be many weeks away although as with most things meteorological, it could take three or four bites at the cherry for it to stick - each attempt would be more than interesting for the uk !

[Methuselah]

Is it just me? Or are others getting excited about the upcoming 12Z too? It's like the 15 minutes just before kick-off, at White Hart Lane!

[Weathizard]

Just the small difference in that low out Nw at day 5 on the icon....

[Light Without Heat]

4 minutes ago, Ed Stone said:

Is it just me? Or are others getting excited about the upcoming 12Z too? It's like the 15 minutes just before kick-off, at White Hart Lane!

Just to add to the light relief before all eyes down 

[warrenb]

ICON has a small hurricane incoming at 120

[swfc]

5 minutes ago, warrenb said:

ICON has a small hurricane incoming at 120

Slider/ polar low alert at 150 hrs!!!!

Edited January 11, 2019 by swfc

[danm]

8 minutes ago, Ed Stone said:

Is it just me? Or are others getting excited about the upcoming 12Z too? It's like the 15 minutes just before kick-off, at White Hart Lane!

Can’t be that excited then! 

[Lloyds32]

2 minutes ago, swfc said:

Slider alert at 150 hrs!!!!

sorry, link to where the icon can be found...thanks

[Weathizard]

We have wedge development, but given the difference in that low at day 5 i’d take that with a pinch of salt.

[swfc]

1 minute ago, Lloyds32 said:

sorry, link to where the icon can be found...thanks

metiociel

[Ali1977]

2 minutes ago, Lloyds32 said:

sorry, link to where the icon can be found...thanks

Left hand side of metrociel site 

[Lloyds32]

1 minute ago, swfc said:

metiociel

great help...

Anyone else, thanks

 

[Summer Sun]

3 minutes ago, Lloyds32 said:

sorry, link to where the icon can be found...thanks

https://www.meteociel.fr/modeles/icone_cartes.php

[Johnp]

4 minutes ago, Lloyds32 said:

sorry, link to where the icon can be found...thanks

http://www.meteociel.fr/modeles/icone_cartes.php?ech=6&code=0&mode=0&map=3&archive=0

[warrenb]

A tip for people, look at the Northern Hemisphere view of the charts, as this shows the lobe interaction.

"Carte Nord Hem"

[Lloyds32]

Just now, Summer Sun said:

https://www.meteociel.fr/modeles/icone_cartes.php

thanks very much

[Johnp]

3 minutes ago, swfc said:

metiociel

 

1 minute ago, Ali1977 said:

Left hand side of metrociel site 

Help a newbie - at least spell the site correctly

[bluearmy]

What’s the maximum number of trigger lows you can have within a five day period  ??????

[Johnp]

3 minutes ago, warrenb said:

A tip for people, look at the Northern Hemisphere view of the charts, as this shows the lobe interaction.

"Carte Nord Hem"

A tip for thirsty people, stressed by the models.

"Carte Noir"

[Ali1977]

Icon starts the 12z ball rolling , all good in the hood