Model Output Discussion - the cold has arrived

[LRD]

Similarities between ECM and GFS at 144 but the Atlantic low on the GFS is better aligned and shaped. ECM top, GFS 2nd

ECM from 168 might not be great

[tight isobar]

I’m gonna say it ecm playing catch-up here it’s been 2nd best when dealing with both troghing and Atlantic spawners!!

[Drifter]

2 minutes ago, Kasim Awan said:

Localized zonality is definitely a valid concept

Yes, it’s normally called ‘unsettled’. 

[MATTWOLVES 3]

4 minutes ago, Kasim Awan said:

Localized zonality is definitely a valid concept

Loco zonal chaps! A new word for all the weather gurus on here..Make reference to it when your feeling unsure or want to sound a little bit more important.

Or if there's a long fetched swtly from Acapulco.

I think many of us will want to stick with mild zonality or cool zonality though.The Americans always say things the wrong way...ie...math instead of maths.

Edited December 18, 2022 by MATTWOLVES

[Don]

1 minute ago, tight isobar said:

I’m gonna say it ecm playing catch-up here it’s been 2nd best when dealing with both troghing and Atlantic spawners!!

But it isn't without support?

[Drifter]

Appalling ECM at 168. Literally the polar opposite of GFS. Chaos!

[January Snowstorm]

Ecm says no!

Different evolution as mild southerlys move up Christmas day.

Uncertain outlook, but if any model looks isolated it's the gfs

[Snowmadsam]

Op EC at t+168 again showing the chaos that models find themselves in, intriguing to see never the less. I wonder how it will perform in its ensembles later...given its been at the top end as of late....

[Day 10]

5 minutes ago, MATTWOLVES said:

Yeh just googled it and the closest I got was a firm called Zonal Hospitality

For all your wet & windy needs, catering for bbq's that are a real washout!

[Kasim Awan]

3 minutes ago, MATTWOLVES said:

Loco zonal chaps! A new word for all the weather gurus on here..Make reference to it when your feeling unsure or want to sound a little bit more important.

Or if there's a long fetched swtly from Acapulco.

I think many of us will want to stick with mild zonality or cool zonality though.The Americans always say things the wrong way...ie...math instead of maths.

Localized zonality can occur when waves are very amplified like in this chart. Zonal only for a short longitudinal plane. Very common in synoptically deviant patterns.

[The PIT]

UKMO says no as well with a very similar positioning of the low. However the Atlantic doesn't look very powerful either.

[Don]

2 minutes ago, January Snowstorm said:

Ecm says no!

Different evolution as mild southerlys move up Christmas day.

Uncertain outlook, but if any model looks isolated it's the gfs

Indeed but cannot discount the GFS yet, especially as it has support from its ensembles.

[LRD]

Yep, as suspected, ECM 168 is poor for cold

You have to back ECM and UKMO over GFS I'm afraid but let's see what the ensembles say as well as MOGREPS

[Stuie]

That LP in the US `could` strengthen the ridge up to Greenland.  Ok from the ECM on this run.

 

[MATTWOLVES 3]

Poor ECM and UKMO...I await the ens from ecm and mogreps with anticipation...I've got a feeling outlier will spring to mind.

Not only that since the word loco zonal was brandished,everything's gone wrong.

[Mike Poole]

1 minute ago, Kasim Awan said:

Localized zonality can occur when waves are very amplified like in this chart. Zonal only for a short longitudinal plane. Very common in synoptically deviant patterns.

Synoptically deviant - now there’s a term I do like!  Describes the current setup very well.  Meanwhile, small differences early on lead to ECM going for a Spanish plume by Christmas Day, while GFS had a freezing northerly.  

Chalk and cheese, folks, chalk and cheese!  The uncertainty continues…

[MattH]

The situation for next week and into the Christmas weekend, in particular, is, simply put an asbolutely forecasters nightmare...

The better agreement within the GEFS for a fall through the 23rd/24th onwards is interesting, but as we are now all seeing the ECMWF once again continues to be a distinct 'scrooge' and just doesn't help the cause at all later this coming week - There is nothing fancy about this outlook, there is no hidden answers, it is simply about waiting for models to resolve what is a very (very) tricky evolution and those hoping for a potential White Christmas or, at a minimum, seasonal Christmas has to hope that on this occasion the GFS/GEFS are firmly more right than the ECMWF.

The phasing of lows within what is a clear baroclinic environment (an area of conflicting air masses) is what is causing the problems, as is the European higher pressure areas as well, again, which model has this correct is still not yet known and won't be for another few days - If someone was putting me on the spot and from what I've seen over the weekend, then my money is with the GFS, I think the likes of the ECMWF and the UKMO are complicating matters with the development of the low, to the point where a S or SW'ly remains possible, but clearly confidence in all this remains low, either way.

If and, for now, that is a big IF the GEFS is correct then for many it will be a cold and seasonal Christmas and for some the transitional phase, through Christmas Eve, especially across parts of Ireland, N England, perhaps Wales and the Midlands could also be a snowy one as well. There may well be a perfect 'sweet spot' with this evolution because any sort of frontal system or frontal wave sliding eastwards as cold air tries to come down from the north could, as the GEFS show, bring a White Christmas to some areas.

However, I remind all of the huge flip that both the GEFS and the EPS did a number of days ago after they both suggested that the fall in temperatures would occur on Tue or Wed of this week, let alone next weekend. Short and sharp changes in this setup can and will still occur, there is no clear 'form horse' here yet, but I do believe and think that the GEFS has this one, but time will tell next few days.

Cheers, Matt.

Edited December 18, 2022 by MattH

[london-snow]

3 minutes ago, tight isobar said:

I’m gonna say it ecm playing catch-up here it’s been 2nd best when dealing with both troghing and Atlantic spawners!!

I don’t see why their is so much interest, yes at best the Christmas period can deliver a two day transitional northerly but post that their is no clear signals to anything sustained. Typically winter fare apart from possible landing on the dates it could come to fruition. I must also laugh at a comment earlier stating we have over half the winter left for snow and cold, I wish i had a pound for every time I’ve heard that and fast forward to spring and all looking at what’s gone wrong lol. 

[LRD]

Differences between GFS and ECM at 192 are extreme!

I think a backward step has been taken today (for a cold Xmas) despite the encouraging GFS runs and ensembles. If GFS wins this battle I'd be surprised, though

[Spah1]

What time do the ECM ens come out? 

[Kasim Awan]

1 minute ago, Spah1 said:

What time do the ECM ens come out? 

About 7.50. Need to see a weaker low to have a decent chance of pulling cold air in. Too large and it shifts everything north.

[Tim Bland]

Am I the only one who doesn’t give 2 hoots what ‘loco zonal’ is

Could still see a wedge around Greenland ? 

[Methuselah]

Well, I don't know how the weather will pan out (if I did, I'd be the Man Upstairs!). So, who knows: will it be snowy? I don't have a clue... Que serra, serra?

[Jason M]

Well, place your bets. GFS or ECM?

I'm going for ECM simply because of the heights to our south. It just makes more sense that we will be mild in my honest opinion. ECM won't be exact of course but odds wise I'd say 90% on ECM in very broad terms.   

[I remember Atlantic 252]

Just now, Ed Stone said:

Well, I don't know how the weather will pan out (if I did, I'd be the Man Upstairs!). So, who knows: will it be snowy? I don't have a clue... Que serra, serra?

My guess, poor for south, snow fest for north, could be looking at 11 degrees SW'lys here, NE'lys Manchester northwards