Model Output Discussion - Into the new year

[winterof79]

8 minutes ago, MATTWOLVES said:

Anyone questioning cold pools...go check some overnight temps in Finland and Siberia...trust me there is some serious cold out there..let things just align for those colder temps to manifest...and like others state we are on the cusp of magnifying our very own home grown cold pool...Thus smacks of 2018 to me,but with added oomph...whatever comes now will be at the heart of Winter,rather than the scrag  end...all systems go...let the fun and games begin gang....fantastic ens by the way...merwahhhh

[bluearmy]

2 minutes ago, Gael_Force said:

Is there such a thing as a displacement split?

This is expected to be a displacement followed by a split of some kind. How long that split sustains is currently the question ...could be a double dip on the reversed zonal winds ....

[Jason M]

From the GEFS by day 10 there is some evidence that we might access some colder 850s with the source of the flow becoming more E or NE (at last!!!). An easterly of sorts is now pretty much inevitable I'd have thought. The question that is yet to be answered though is whether the source of our easterly is from a long way south or not.

Steve's no 29 leads the way but its certainly not alone in bringing some polar / arctic air into the mix. 

As expected in such a set up there is a cluster that look a bit like a westerly based solution. Too far out to worry about that though.  

[alexisj9]

40 minutes ago, Stu_London said:

Has the Western Hemisphere ever been so devoid of upper level cold in the deep midwinter ever before. 

Maybe the earth has dropped on its axis several degrees and no one noticed.

Winter has only just started, let's see what happens.

[nick sussex]

GEFS 29 shows a more favourable track of shortwave energy . The best solution is se then south and then a small sw shift but once the shortwave is sufficiently to the se of the UK.

The GFS 12 hrs is too amplified ironically at the wrong time . We chase amplification all winter but sometimes too much is a bad thing .

Also some of the best looking charts don’t always deliver in that on a NH scale they show blocking all over the place to the north but it’s pointless if you’re the wrong side of those blocks .

A western based negative NAO is like the dog chewing up your winning lottery ticket ! 

[kold weather]

11 minutes ago, bluearmy said:

This is expected to be a displacement followed by a split of some kind. How long that split sustains is currently the question ...could be a double dip on the reversed zonal winds ....

Yeah, some of the runs on the ECM ensembles are going super low, of course going that low doesn't automatically mean we are cold, especially if we end up with a really overly rampant southern arm of the jet, could end up in a very wet wave train.

However, thinking positively for the moment. If things pull off for us, this could well be a very memorable spell. Any ease up will allow an attempt at a SW attack some point between the 5-10th Jan which could end up with a battleground somewhere near our shores. Any re-strengthening of the blocking leads us fairly close to the holy grail of snow set-ups with a 10 day colder spell to prime the situation.

However that really is a rare beast and would need alot of things to come together neatly. But the fact its even on the table as an option says we are in a good place for the first half of Jan.

[Beanz]

Caution is still the word with this, we only just get to the solution we want on the GFS and each run is a different solution.  Its pretty knife edge, we could easily see our block head west and allow the SW back in off the back of an Atlantic trough.  

@kold weather is right that, so often in the past we've seen a N'ly like this disappear at the last moment, completely cut off by a rogue shortwave.  

I'm cautiously optimistic at this point, but prepared for a return to around average temps by day 12.  

[snowy weather]

34 minutes ago, Met4Cast said:

I don't buy into this. The cold hasn't just suddenly vanished, it's still there in the Arctic. The reason Europe hasn't got deep cold established is due to the persistent nature of the Russian & Siberian high preventing a route for deep cold to move into Europe. That same HP is part of the reason we have an up-coming SSW, too. Short term pain = long term gain in this case.

We're seeing an increasingly stagnant cold pool developing in situ across the UK and Europe as we go through into January, marginal events will slowly become less marginal. Once we see the high retrogress towards Greenland and a trough drop down into Scandi, deep cold isn't a million miles away. Exceptional, exceptional ensemble mean! 

Thank you for this. I understand. Hopefully it comes off

[BLAST FROM THE PAST]

18 minutes ago, winterof79 said:

That backs up what I’ve been saying, incredible Siberian ‘December’ cold spreading west.  
 

BFTP

[SLEETY]

1 hour ago, Harsh Climate said:

Am I right in thinking that the met office 'no indications of exceptionally cold conditions occurring anywhere' in their long range forecast will be dropped tomorrow? 

From looking at the latest output we are on the cusp of something very big!

Hope so,their credibility has already taken a hit with  that 10 day trend forecast last wednesday  of high pressure sitting over uk at start of new year,with no mention it was only one of several possibilties at that timeframe,which now is looking WRONG.

 

Sensational gfs run,snow for many soon with very cold weather not far away.

 

 

 

[bobbydog]

I haven't woken up to a magical winter wonderland for nearly 8 years....

Extended cold, snowy weather or not. The 12z has something for everyone.

 

Just once... this time... please.... 

[Mapantz]

Stick to model discussion please?!

[kold weather]

2 minutes ago, BLAST FROM THE PAST said:

That backs up what I’ve been saying, incredible Siberian ‘December’ cold spreading west.  
 

BFTP

I'm not overly concerned in this set-up with regards to deep cold. I think the surface is cooling off nicely and I'd b very surprised if we do end up with the type of evolution currently being pegged if we don't at some point end up with a proper shot of arctic air. Now whether it sustains for long, I've not got a clue. 

Besides, we have several marginal evolution that will give snow for some over the next few days in a ever slightly cooling pattern at the surface. That ever so slightly cooling set-up makes the world of difference in marginal events.

[Decemberof2010]

Just look at the cold to the North on P15

Insane

 

[blizzard81]

3 minutes ago, nick sussex said:

GEFS 29 shows a more favourable track of shortwave energy . The best solution is se then south and then a small sw shift but once the shortwave is sufficiently to the se of the UK.

The GFS 12 hrs is too amplified ironically at the wrong time . We chase amplification all winter but sometimes too much is a bad thing .

Also some of the best looking charts don’t always deliver in that on a NH scale they show blocking all over the place to the north but it’s pointless if you’re the wrong side of those blocks .

A western based negative NAO is like the dog chewing up your winning lottery ticket ! 

Ha ha . Indeed. I feel like the west based neg nao is the elephant in the room at the moment. The gfs control run is a classic example which is why nobody has mentioned it lol. The gfs op and control have moved away from the 'quite' prolonged easterly feed this coming weekend and into next week and shot straight into retrogression into Greenland instead. We don't want this to happen as this increases the likelyhood of a west based neg nao. We want this morning's easterly runs to come back as this will help negate the risks of that dreaded west based neg nao. 

 

[bluearmy]

Ec op is further south with Wednesday - along the m4 and n Home Counties ..... a long way to go on pinning this one down ! 
 

tomorrows less intense snowfall is more consistent across the models  

[Harsh Climate]

ECM out to 72h, steady as she goes.

[SMU]

ECM 72 > must be a snow event for the south >>>> SE there in -5c air!!

Similar to GEM

[Tim Bland]

Chances of significant snow from Wales across the south to the south east still showing on the ECM for Weds. starts Wales and exits here..

[Harsh Climate]

1 minute ago, bluearmy said:

Ec op is further south with Wednesday - along the m4 and n Home Counties ..... a long way to go on pinning this one down ! 
 

tomorrows less intense snowfall is more consistent across the models  

-6 uppers and an open low from looks of 48-72, would almost certainly be all snow on northern side.

[Mike Poole]

Well, just as the ECM starts rolling, it has become clearer to me that a) a cold spell is incoming and b) the op runs are struggling to get to grips with the details of the evolution.  Actually, they all looked more on the same page 24 hrs ago to be honest.  

So we should go with the ensembles for now, GEFS T192, T240:

Interest short term for snow, here’s the EURO4 cumulative snow into Wednesday evening which doesn’t cover the whole of the MO warning period.  Looks a bit like a Jackson Pollock...

Finally, ECM now has a technical SSW, and a split too, in  9 days time, 5 Jan:

There’s a lot going on, isn’t there?

 

[kold weather]

By the way, just to note that if we see an extreme burst of cold coming through the Greenland/Iceland area, it runs a very high risk of developing an area of LP in a place that may very rapidly help us to switch back into a SW pattern, especially should the upper high migrate westwards.

For example:

You can very easily end up on the wrong side of that sort of pattern and default back into an Atlantic set-up even if the AO remains negative.

Just a word of cuation for those that see deep cold coming out of that area and think we are in the money, its REALLY rare for that cold to make it down to our neck of the woods, I've seen it literally a handful of times looking back at the last 100 years of charts on the archives. 

[I remember Atlantic 252]

2 minutes ago, Harsh Climate said:

-6 uppers and an open low from looks of 48-72, would almost certainly be all snow on northern side.

been following this last few runs, as a guess south of M4 event, that 'dreaded' M4 some may say

[SMU]

EC 96 -

Low still stuck in the SE in -5c air

[Daniel*]

4 minutes ago, Steve Murr said:

ECM 72 > must be a snow event for the south >>>> SE there in -5c air!!

Similar to GEM

Much further south to 00z south of the dreaded M4 in fact.