Model Output Discussion - Into 2024

[BarnetBlizzard]

 

Example of what I was saying earlier

[Lukesluckybunch]

There is a clear shift now..for cold arriving 13/14th onwards it's pretty clear in the ensembles..the risk of something milder seems to be diminishing every run..quite a big cluster now in the -8 range

[SussexSnow]

15 minutes ago, Mcconnor8 said:

Looks pretty chilly by the 14th!

Control also brings in the cold on the 14th/15th.

P23 has a pretty decent snow event for the South on 15/16 Jan.

2 minutes ago, BarnetBlizzard said:

 

Example of what I was saying earlier

Just what caught my eye too!

Edited January 5 by SussexSnow

[Jason M]

So, just had a quick run through each of the GEFS at 228. I don't normally pay much if any heed to them that far out as 192 hours is normally my limit.

They look very good and nearly all are cold or going that way. My main observation though is be very wary of these runs and opps at that range. The solutions on offer all look 'clean' with no shortwaves or other complications. Anything that shows a screaming easterly / northerly where everything goes perfectly should be treated as suspect IMHO. As we get nearer complications will almost certainly arise!!!!

[The Northern Ramper]

In my mind nothing has changed from my stance of being optimistic but cautious 24 hours ago, with a couple of points to add.

1. It is said often that the GFS is strongest in that particular area where the shortwave appears and the other models don’t show it. So don’t be surprised if that is correct.

That being said it is also poor in modelling these features against a block so it’s doubtful to have got its track correct, if it even exists.

2. The gems snowfall charts have always been woefully over exaggerated.

 

Plenty of water to go under the bridge still but for me we are 24 hours closer tonight.

[AO-]

What I miss the recent runs (particularly GFS as other models do not go that far yet), is a southerly jet with shortwaves moving into Europ to suck the cold air from the north. That is kind of the ideal situation. I suppose by Sunday this has to be in the charts of the EC. Then we are in the game. 

[claret047]

1 hour ago, Midlands Ice Age said:

A very good question and one that I have thought about myself after watching one of the American forecasters (on X) over there give his outlook  for the USA (using all the available models), for the next 7 days....

For interest only,  they are fore-seeing freezing conditions spreading in during the weekend and then across to all but the extreme east and north east by next weekend, with the possibilities of record lows.. So a massive change for them.

However interestingly, for all but the short term prognosis (where he used the GFS mainly, but for some precipitation charts he used  a 'blend' of the others) ,  he used the GEM and ECMWF models for most of his outlook after 3 days. Sometimes he would state that he had used a blended forecast (GFS 40, ECM 40, GEM 20), etc..  but mainly ECMWF. 

I have noticed this before when watching US forecasts that they frequently state that they are using ECM and GEM rather than GFS,  almost as if they do not think the GFS is accurate, in their corner of the globe..

As Paul  says above they use more or less the same starting data, but I am beginning to suspect that the GFS  is quite weak on any stratospheric medium outlook influences, when it gets to the 10-12 days ahead outlook,  They seem to be able to pick up at a way out timescale, but then seem to wander away from it again for a while,  until it comes back into more the reliable.....    

This 'feeling' is  shown by the way in which the GFS suddenly 'veered away' from the rest  at the start of this chase over a week ago now.  And we know from the ECMWF blogg (on SEVERE weather EU),  that  the GFS were not seeing any strat changes, when it was being shown that all other models had picked them up back in late December..

HOWEVER , could it have been that actually the rest left the GFS behind,(?? -likely in my opinion),   as they factored in the warming of the Stratosphere, and moved it into its tropospheric effects - even though it did not actually cause an SSW, it has certainly weakened the jet flows around the world. Perhaps GFS at the shorter range only use the tropospheric data and  then will slowly come back onside again.

It would also explain why the GFS was so good on the last cold spell - where it was totally tropospherically based, - and it seemed to wind it down to zero better than the other models..

Back to here and now again...We now see that ECMWF are seeing another rapid warming occuring at the  same time as GFS apparently veers away from the rest again.

\Will it be correct this time or will it come back into the fold as the effects of the latest warming actually become apparent at lower levels (possibly in 10 days time).

Last week the GFS  took quite a while to gradually come back 'in fold', (3days?) - maybe as they started picking up on the actual tropospheric influence of the partial and minor SSW which occured at the same time as the charts merged together again. 

Do they use different programs for their longer range compared to their more immediate  forecasts? Certainly we have seen sometimes how their 13- 15 days forecasts suddenly go totally haywire. (as shown up by the pub run?)

This would explain the type of behaviour of the models that many of the more experienced of the guys have observed on here....

That is the GFS picking up way in advance a pattern change, only to drop it ., and then come back to it again after the other models (about 10 days) have picked up on it and then the GFS  returns to the fold very slowly at days 10 to 5,

I am sorry if this post is difficult to follow, but it is quite difficult to describe the fluctuations of the GFS. - Sorry mods 

Note you GFS fans, I am  not decrying the GFS,,, but it is these highly visible times that it seems it sometimes behaves strangely - but in a consistent manner. 

We will see  whether the above is 'tosh' or indeed correct.

MIA

Hello David- Many thanks for your very detailed reply. Also thanks to @Paul for his informative earlier response.

[Jason M]

34 minutes ago, Kentspur said:

In this example though would you class Gravesend/Dartford as Coastal even though they're estuary towns, As normally I think of East Kent etc  and Southend as "coastal" but due to.the likely E/ENE wind flow wouldn't my area be in the firing line it seems like the charts show precip heading here also

Yes, but actually the northern side of the estuary looks better placed this time (unusually). I think here I'll see a bit of light snow but even right in the sweet spot it will amount to very little. We are not going to see much snow with pressure that high.

[Kentspur]

Just now, Jason M said:

Yes, but actually the northern side of the estuary looks better placed this time (unusually). I think here I'll see a bit of light snow but even right in the sweet spot it will amount to very little. We are not going to see much snow with pressure that high.

Surprised by that! Don't think I've ever seen a ENEly wind flow forecast bring more of the white stuff north of the Thames only a Direct Ely or a ESEly like during the Feb 2018 Beast most the models I just looked at show a line from the far east coast of East Anglias through here to West Kent- Sussex with others towards the Isle of Wight etc

[Jason M]

Agree its a bit unusual. On the modelling it looks like a streamer through the Thames that moves inland across South Essex and dies very quickly. 

To be honest it will be a complete non event IMHO so you won't be missing much (if anything).

[Ali1977]

We need a good ECM here, ideally nailed on cold pattern by 168 - hitting us around 204 we don’t want it meeting the Gfs In the middle 

[Mark wheeler]

Have posted in regional but for one last time will do here too as it's been spoken about for some time . Nmm backs aprege . With uppers not to different to the 12z Ecm coming out .

[snowblind]

43 minutes ago, sundog said:

Don't give up on us GFS

RIP David.

[BLAST FROM THE PAST]

I think the GFS is on fact finding mission.  Tbh, on a long term scale I quite like the 12z…..it’s not binning a longerterm cold set up….indeed it’s struggling, with the cold still very much in the thro

 

BFTP

Edited January 5 by BLAST FROM THE PAST

[Anthony Burden]

Evening all,not much to add tonight except enjoy this long wintery spell that seems to be excepted by ECM/GFS and met office extended outlook,dry to begin first phase,then phase two hopefully involving some white stuff.That of course is possibley nine to ten days away still so fingers crossed ECM will follow that scenario this evening so all eyes on the charts in this exceptional period coming up,fingers crossed.

[Harsh Climate]

Good ECM 120

Can't see anything wrong with it 

[KTtom]

Just now, Harsh Climate said:

Good ECM 120

Can't see anything wrong with it 

Apart from the fact Spain is colder than the UK

[Ali1977]

Very nice 144, look how weak the PV over the pole is. Great runs looks likely again 

[Mike Poole]

ECM T144 v GFS and GEM:

Note the ridge from the pacific side.  On GFS, this feature is gone in a load of crud to the north.  ECM should go OK from here, as it looks to be finding a way north.

[Snowman.]

Today  Yesterday 

 

Defo been a push back against the northern extent, but within the envelope. Low by Greenland further East however, might benefit us later.

Edited January 5 by Snowman.

[Kentspur]

17 minutes ago, Mark wheeler said:

Have posted in regional but for one last time will do here too as it's been spoken about for some time . Nmm backs aprege . With uppers not to different to the 12z Ecm coming out .

Seems a light streamer from the far E/S of Essex increasing a little as it crosses the Thames through my area down to the North Downs of East Surrey and NW Kent &Weald of Sevenoaks and surrounds and down to the Sussex  South Downs even a light dusting id take I had my snow fix in Sweden in November

Edited January 5 by Kentspur

[booferking]

Ecm & gfs 144hr very similar tense.

[Ali1977]

Crazy 168, NH is in bits - I just can’t decipher what happens next - anyone?? 

[Harsh Climate]

168h pretty nice

Just now, Ali1977 said:

Crazy 168, NH is in bits - I just can’t decipher what happens next - anyone?? 

The deep cold is coming into Europe, just hope as far west as us.

[booferking]

2 minutes ago, Ali1977 said:

Crazy 168, NH is in bits - I just can’t decipher what happens next - anyone?? 

Either can i to be honest but it looks good.