Model Output Discussion - Snow for some, but what else is in store?

[Battleground Snow]

1 hour ago, Battleground Snow said:

Some folks have indicated on twitter that it is actually more active than these plots show.

The waiting goes on....

Just to add some evidence of this....

You can see where it was predicted to be on the 13th and where it actually is on the 13th on the 1st image.

 

Edited January 14, 2021 by Battleground Snow

[MJB]

8 minutes ago, WINTRY WALES said:

Hi...when we talk about about the possibility of a southerly tracking jet creating a snowy battleground....would this still favour more northern areas or bring say midlands south in to play? Sorry if it’s a dumb question 

It depends just how far inland it can push, 50 miles makes a huge difference and is impossible to call even 24 hours out from the event. I am in N Oxfordshire and done very well being in a sweet spot , I have also stayed bone dry when the system hasn't got as far North as predicted and I have had rain when the system has edged further North , I have had rain and Daventry ( 20 miles up the road ) has been a Winter Wonderland 

[chris55]

P21 on the (very scattered) 6z ensembles is what we want to see happen to the Atlantic Low next week. Modelling of this Low and how/where/if it phases with the Scandi trough and where it ends up has been changeable to say the least. 

Most runs spin it up and/or phase it to far north and west but p21 takes it much further south into Iberia, allowing the much colder air to force south via the Scandi trough.

Would be lovely to see the 12zs lean this way! Although I don't have much hope lol.

Sunday, Cut off Low in Atlantic

 

Wednesday, Headed much further south and doesn't really phase with Scandi trough.

 

Leading to colder feed, especially so by day 10

 

 

 

Edited January 14, 2021 by chris55

[chris55]

1 hour ago, Met4Cast said:

 Next week looks initially to be milder as low pressure phases across the UK bringing in some warmer air, especially across southern areas however as the low transfers eastwards into the N Sea colder air returns southwards. At the moment, there's no immediate sign of "deep cold".

Given the Clusters, blocking does seem likely to develop in the Scandi region, perhaps a little stronger than the Ops are currently suggesting 

However at the moment there doesn't seem to be anything to advect deeper cold down from the N/NE into the UK. So "cold and wintry" looks to be the continued theme with snow favoured for northern hills, as seems to be the story of this winter so far.

Hopefully we start to see something being modelled that'll bring deeper cold towards the UK towards the very end of this month/beginning of February, but at the moment I'm thinking that proper cold is becoming increasingly unlikely this month unfortunately. 

Look at the Spread Tuesday /Wednesday!

Thats the phasing/positioning of the Atlantic low that is still open to change. Both op and control right at the top of the pack, so they phase it quite far north. 

My post above re p21 on 6z ens would be sitting right at the bottom of the spread.

Will be interesting to see how it eventually verifies. If it were to stay south that 'uptick' would be much flatter, or non existent.

[mb018538]

@Met4Cast we must be looking at different ensembles? Just had a look out to 360 and I can’t see any promoting scandi blocking at all. Just looks like stronger heights persisting to the N/NW forcing a southerly tracking jet with low pressure headed our way.

[mb018538]

GFS pressure mean for Oslo is just above 1010mb

[Vikos]

A short explanation why models do you from very mild to cold

 

[pyrotech]

A Southerly  Direction Jet would imply a amplified jet stream where the Southern flow is close to or over the UK. That would have probability of High pressure to the West of the Jet and lower pressure to our East side of the Jet.

A Jet to the South of the Uk  would be a good boundary of Colder and milder air, the jet would steer  low pressure along its path with tendency to attempt to move North out of the jet. This is probably the option that would be best for snow chances. We would hope for a slider low to effect  the Southern Uk and the precipitation to become snow on its Northern Edge. In this scenario there would most likely be convective showers bringing snow showers to much of the UK possibly over a prolonged period. The risk here is that Snow can evolve towards rain if it moves too far North and can be quite marginal ( High reward V high Risk)

A north jet would bring rain to the UK, Either we would be most likely on wrong side of the Jet stream ( Warmer side)  or it would likely drive less cold zonal weather off the warm Atlantic.

So of two jet profiles we would benefit most from, one is the North to South trajectory West of / or over UK, or a Jet stream South of the UK. 

Hopefully these images help, but importance is Southerly Jet stream or Southern trajectory Jet Stream ( North too South)

 

Please pick this apart as you may wish

[Frosty.]

I’m not going to pretend that everything is rosy in the garden because it isn’t...but, the GEFS 6z does have some wintry potential, although the trend is clearly milder later according to the mean..however, these are volatile times with the ssw etc..so, things could work out ‍ quite well for netweather coldies compared to the garbage we have endured in recent winters..time will reveal all?..fingers crossed and all that!  

 

[feb1991blizzard]

We are going to have to be realistic now, we are well past the point where the wedge of heights can become a true high , in other words if the trough does set up over us or just East, the trough will be not far behind it in the Atlantic rather than left behind to pump up WAA up the Western side of Greenland, with the close proximity of the 2 areas of troughing they will engage each other at some point, its just how far South can the energy be ejected from the Atlantic trough, and how many if any, snowfalls can we sneak out of the setup and how far south we can get them.

[Djdazzle]

Pretty much last chance saloon on the 12z suite to pull this out of the fire.

Can we pull something out of the hat?

Edited January 14, 2021 by Djdazzle

[Paul_1978]

1 minute ago, Djdazzle said:

Pretty much last chance saloon on the 13z suite to pull this out of the fire.

Can we pull something out of the hat?

I don't think so. It's 14th Jan, we are only mereologically half way through winter with lots to play for next week, with short notice surprises to be expected.

[Djdazzle]

1 minute ago, Paul_1978 said:

I don't think so. It's 14th Jan, we are only mereologically half way through winter with lots to play for next week, with short notice surprises to be expected.

I was thinking more of the next 10 days or so, not the rest of winter.

[John Ronane]

2 minutes ago, feb1991blizzard said:

We are going to have to be realistic now, we are well past the point where the wedge of heights can become a true high , in other words if the trough does set up over us or just East, the trough will be not far behind it in the Atlantic rather than left behind to pump up WAA up the Western side of Greenland, with the close proximity of the 2 areas of troughing they will engage each other at some point, its just how far South can the energy be ejected from the Atlantic trough, and how many if any, snowfalls can we sneak out of the setup and how far south we can get them.

Its more or less evolving as Exeter envisaged. It could be good to very good for people in Northern England, but painful for those of us further to the west and south.

[Polar Maritime]

1 minute ago, Paul_1978 said:

I don't think so. It's 14th Jan, we are only mereologically half way through winter with lots to play for next week, with short notice surprises to be expected.

Absolutely, There's so much uncertainty over the next 2 weeks at least never mind the rest of winter. The models are still trying to find the up-coming pattern..

[Methuselah]

A snowy weekend coming up?  

And, what does Tasha say?  I guess that's a 'no' then!

Edited January 14, 2021 by General Cluster

[chris55]

Icon phases the low further south and east, keeping the milder boundary away from Scotland and Northern England. Euro high pressure looks to be diminishing somewhat.

Also disrupts the next incoming Atlantic system.

Im liking the trends. A few tweaks going forward and we could start to pull in a northeasterly with a blocked Atlantic/stalling slider territory (a bit like todays front, just backed west) We need that phasing energy mid week to head as far south and east as possible.

 

Edited January 14, 2021 by chris55

[phil nw.]

As the 12z are now on the way Just a gentle reminder guys to post only model discussion in here.

If you want to just chat please use that thread or maybe the regionals.Thanks.

Edited January 14, 2021 by phil nw.

[Singularity]

 

Worth noting that something has potentially improved a great deal since yesterday's 12z runs: The stall point of the trough near the UK is a good deal further south and west.

I say potentially because this only plays into our favour if the low from the southwest doesn't start phasing with it too far north and west - if that happens, you head the way of the ECM 00z with cold air transported down a long way west of the UK where it seeds further development of low heights, allowing the trough off the USA to extend eastward faster and more strongly.

Interestingly, UKMO has not only adjusted the phasing low even further south - having already been toward the southern end of the model run spectrum - but increased the strength of the ridge to our west. That's a two-fer of positives!

[KTtom]

Im guessing the usual suspects are in the regionals...so heres the ukmo day 6...not bad!? Gfs also 144, very similar.

Edited January 14, 2021 by KTtom

[TSNWK]

4 minutes ago, KTtom said:

Im guessing the usual suspects are in the regionals...so heres the ukmo day 6...not bad!? Gfs also 144, very similar.

Both look poised to drop but they just hang about on previous runs.  That's the change that we need

[Singularity]

 

GFS still phases slightly further northwest but there's not much in it. As a result the low sits a little further west at +144 with the ridge to the west a little narrower. Very similar to the 06z which then made a mess of the breakaway lows... I guess what this run does next is pretty much pot luck.

[mountain shadow]

6 minutes ago, KTtom said:

Im guessing the usual suspects are in the regionals...so heres the ukmo day 6...not bad!? Gfs also 144, very similar.

But look at the 850s. Awful. Another tepid Northerly.

[winterof79]

What's not to like

[Johnp]

1 minute ago, SLEETY said:

much improved model runs today,maybe even the South coast might see a flake soon,lol

In what way do you feel they have improved?

I'm still seeing no chance of snow for us in the south. Even at day seven, uppers struggling to even get down to -4