Model Output Discussion - Into 2024

[Mike Poole]

ECM clusters T120-T168:

Very good agreement on Atlantic ridge into Greenland.  The op is in cluster 2.  Cluster 1 looks more like UKMO or ECM 6z control, with just that extra something in the block that keeps the plunging vortex elongated. Hence, looking at T240, cluster 1 has the attack from almost due north.  Clusters 2 and 4 have it more from the NW at same time.  Cluster 3 somewhere in the middle.  But these are variations within quite a small envelope at this timeframe (on the EPS anyway).

T192-T240:

Just one cluster, so will hide plenty of variation.  Key in this timeframe, is the Azores low must move east to quell the heights over Spain, it does on this run, and it is what you’d expect to happen.  

T264+ not yet out.

[Met4Cast]

In terms of where the polar boundary lies that is something that's going to shift north & south probably 100 times before we actually get to the period of interest, I wouldn't place too much focus on that. 

Returning momentum in the form of the jet stream edging back northwards seems a certain bet, it will happen at some point as the MJO continues it's progression eastwards and on the back of the recent (but brief) AAM tendency dip. How this looks synoptically will depend on how much blocking we retain to the north. It could be that the jet doesn't quite get into the UK and instead we remain cold for far longer (the 00z and 06z GFS det runs played with this scenario) or it could be, like the GEM we see a widespread, high impact snow event (perhaps multiple) as lows push up into the cold air across the UK. 

Current thinking is the 20th-25th for a potential Atlantic return (of sorts) and therefore increasing risk of high impact weather. Where? How? Who knows, that wont be resolved for a longgggg time.

In any case, we've already seen a return to +AAM tendency and frictional torque will soon return to +ve followed by another likely +EAMT event driving AAM tendency upwards, total GLAAM & GWO remain coupled with the El Nino base state. MJO progression likely through the Maritimes and back into phases 6 >7 around the end of January/beginning of February (MJO timing always difficult).

In essence, any waning of the block and Atlantic return will likely be temporary with renewed blocking likely into early February, perhaps Greenland/Scandinavia, more likely is we wont see the block to the north become completely eroded, cold air will never be far away. 

Very, very positive moving forward away from the chopping and changing of NWP outputs and attempting to nail down precise details 10+ days away.

[Hatewarmth]

1 hour ago, Harsh Climate said:

There's no getting away from the ECM looking great for the northern half of the UK and less so for the southern half. Not any bias here just the way I see this run

Totally agree. ECM looks great for the midlands north but looks like it’s will come again do only a brief milder spell before cold air moves back south. All proper wintry spells have milder interludes do in my eyes it’s the general pattern that looks locked in for the foreseeable future 

[Mike Poole]

ECM extended cluster T264+:

Clusters 1 and 4 maintain the block and it relinquishes control by day 15, which is as per the timetable set out above by @Met4Cast for something of a resurgence from the Atlantic.  Cluster 2 is more mobile than that from the start of the timeframe.  Cluster 5 (and to a lesser extent 3) hint - like this mornings cluster 3 - at building heights into Scandi as the next move.

[nick sussex]

IMBYISM is perfectly understandable given the lack of snow in the UK .

However the track of low pressure is a bellwether for the strength of any blocking to the north .

The ECM only dodges a bullet because it finds just enough forcing day 7 into 8. Without that the low to the sw would move ne phase with that shortwave and deepen . This would push high pressure into France and it won’t be just southern members reaching for the helpline .

Relying on an Arctic high to deliver that forcing when you need it does not have a good track record . 

Don’t be seduced by the ECM op , it’s not a good run regardless of what it delivers later .

There is no margin for error at all . 

 

Edited January 8 by nick sussex

[North Easterly Breeze]

If anything that brief milder interlude, once in, looks to bring a great snow chance and then sweep away down towards France and gives the UK almost a fresh crack of the whip with a clean slate. Not concerned about it in the slightest.

[Stav]

18 minutes ago, Alderc 2.0 said:

Battle ground snow is absolutely terrible for most in the south as it’s always rain.

Yes, it is disappointing when it happens. Oh for a 2010 scenario. Despite the excitement here, looking at the charts and the comments from respected contributors there is quite a lot of doubt as to what the south will get.

[feb1991blizzard]

The pseudo magic-roundabout isnt something we want repeated in the morning, the last thing we need is a split flow in Scotland, all energy into France please.

4 minutes ago, nick sussex said:

IMBYISM is perfectly understandable given the lack of snow in the UK .

However the track of low pressure is a bellwether for the strength of any blocking to the north .

The ECM only dodges a bullet because it finds just enough forcing day 7 into 8. Without that the low to the sw would move ne phase with that shortwave and deepen . This would push high pressure into France and it won’t be just southern members reaching for the helpline .

Relying on an Arctic high to deliver that forcing when you need it does not have a good track record . 

Don’t be seduced by the ECM op , it’s not a good run regardless of what it delivers later .

There is no margin for error at all . 

 

yes.

[LRD]

EC46 still looking pretty solid for potential cold right into mid-Feb

Apart from week of 22 Jan where it turns warmer (tying in with what Met4Cast says above)

[northwestsnow]

EC 46 15th to 22nd..

suggests to me the jet quite well south ,noticably colder for much of the North..

 

Edited January 8 by northwestsnow

[Andy8472]

MJO picking up the pace through, hopefully gets back around to 8/1/2/3

[Met4Cast]

46/51 of the 12z EPS had a technical SSW reversal.

If we do see a reversal then I expect modelling to be even less reliable than it currently is in the med-extended. There is a lot going on at the moment so getting caught up in every individual deterministic run searching for precise desired outcomes makes even less sense than it usually does. 

EC46 comes frustratingly close too..

Edited January 8 by Met4Cast

[saintkip]

30 minutes ago, Alderc 2.0 said:

Battle ground snow is absolutely terrible for most in the south as it’s always rain.

Maybe in Bournemouth but 30/40 miles north we do quite well 

[The Northern Ramper]

8 minutes ago, Mike Poole said:

ECM extended cluster T264+:

Clusters 1 and 4 maintain the block and it relinquishes control by day 15, which is as per the timetable set out above by @Met4Cast for something of a resurgence from the Atlantic.  Cluster 2 is more mobile than that from the start of the timeframe.  Cluster 5 (and to a lesser extent 3) hint - like this mornings cluster 3 - at building heights into Scandi as the next move.

I may have dreamt this but wasn’t  this scenario referenced by one of our most knowledgeable posters? They stated that the models would blow through the uk but in reality there would be struggles with attempts to remove our imbedded cold. Before renewed attempts at northern blocking.

[Scott Ingham]

14 minutes ago, Mike Poole said:

ECM extended cluster T264+:

Clusters 1 and 4 maintain the block and it relinquishes control by day 15, which is as per the timetable set out above by @Met4Cast for something of a resurgence from the Atlantic.  Cluster 2 is more mobile than that from the start of the timeframe.  Cluster 5 (and to a lesser extent 3) hint - like this mornings cluster 3 - at building heights into Scandi as the next move.

Good to see the Scandi height options are on the table now to give me some more confidence in the methods I’ve used this past 9 months which has resulted in a winter forecast that couldn’t have gone a lot better as far as direction of travel is concerned! 
 

As ever if we don’t go to Scandi next the fun bit will be doing an autopsy and working out why to add into my scrap book of learnings these past 10 years!

Whats your call Mike? Where do you see us going next?

[MATTWOLVES 3]

Let's throw the cat amongst the pigeons here folks.

Mmmmm the suspense is getting more than a Hitchcock thriller.

Sorry @Met4Cast you had already posted it.

That's some serious numbers though..yes we've been here before,but with the pv in a weekend state it ain't gonna take much to knock it out.

Edited January 8 by MATTWOLVES 3

[Andy8472]

5 minutes ago, Met4Cast said:

46/51 of the 12z EPS had a technical SSW reversal.

If we do see a reversal then I expect modelling to be even less reliable than it currently is in the med-extended. There is a lot going on at the moment so getting caught up in every individual deterministic run searching for precise desired outcomes makes even less sense than it usually does. 

EC46 comes frustratingly close too..

GFS close too but not quite as bullish

[Harsh Climate]

27 minutes ago, Hatewarmth said:

Totally agree. ECM looks great for the midlands north but looks like it’s will come again do only a brief milder spell before cold air moves back south. All proper wintry spells have milder interludes do in my eyes it’s the general pattern that looks locked in for the foreseeable future 

Yes, there does seem some delays in getting the cold air south.

In the end the boundary of polar air on ECM reaches the middle of France, way past the south of England! 

I think it will happen, the devil is in the detail though.

[bluearmy]

7 minutes ago, Met4Cast said:

46/51 of the 12z EPS had a technical SSW reversal.

If we do see a reversal then I expect modelling to be even less reliable than it currently is in the med-extended. There is a lot going on at the moment so getting caught up in every individual deterministic run searching for precise desired outcomes makes even less sense than it usually does. 

I’m not sure it will make much difference as it’s displacement  - we’ve already got ongoing reversed flow above 70N predicted for the next ten days or so. Having it get another ten degrees south could help to supress the jet a bit further south but I’m expecting reversal waves to head down into the trop out to the end of feb anyway. 

[irish1]

 

ECMWF ensembles much better, less mild options to get rid of and op was near top between 14-16th

[Scott Ingham]

1 minute ago, bluearmy said:

I’m not sure it will make much difference as it’s displacement  - we’ve already got ongoing reversed flow above 70N predicted for the next ten days or so. Having it get another ten degrees south could help to supress the jet a bit further south but I’m expecting reversal waves to head down into the trop out to the end of feb anyway. 

Quick question Blue as the Strat is an area I struggle with. Why do you think we’ll see reversal waves for the next 6 weeks after these current round of warmings? Just trying to improve my knowledge 

[minus10]

Pretty good 12z eps so far ..flatlining op/ control and cluster below mean..

 

[Weather of Mass Disruption]

4 hours ago, Ali1977 said:

This would be best case scenario for many, huge  snow event  then cold again 

This really would be the dream and an a truly memorable event  

[Ali1977]

With all the amazing charts of the day, this one is up there - ENS clearly having a quicker transition to the cold - by this time tomorrow we should really start having a good idea of the initial transition to cold for Sunday/Monday - hopefully we can really stay sub -6c uppers (snow conducive) for at least a week from then.  

Edited January 8 by Ali1977

[TSNWK]

2 minutes ago, minus10 said:

Pretty good 12z eps so far ..flatlining op/ control and cluster below mean..

 

Of note is that op is one of the few milder options for next weekends complications the 12z ecm illustrated.. could be a clean route to cold for all.