Model Output Discussion 29th December - Into mid-Winter.

[Nick F]

As expected, a backtrack from GFS toward EC and EPS, even squeezes in a brief and subtle easterly at t+162

[SMU]

11 minutes ago, Mucka said:

 

Yeah makes a big difference over just a few hours in prolonging cold. I really mean the actual amplification though if we want an Easterly. 

I do see the significance of the changes you are outlining and same corrections we would have a nice ridge by tomorrorws 12z.

Do you fancy a continuation of slow corrections or a complete flip tomorrow?

00z to 06z to 12z would be fine--

@radiohead its not totally about the left end of the block its the right end - note the GFS trying to carve out a low to come back SW- The 12z had nothing of the sorts..

[Geordiesnow]

To be fair, barring some minor detail changes which is expected, the 18Z is not all that much different to the 12Z Euro runs although in fairness, I rather see a chance of a frontal snow event if this cold blast is to end early rather than go out on a damp squib.

All in all, not too bad of a day for coldies, hopefully we see some sort of trend towards this afternoon's UKMO output but I do feel such a ridge like that is the outside bet with something more like the ECM offering more likely. The GFS is not that bad and with any shortwaves like on the 18Z your more likely too see frontal snow but on the flip side, its more likely to end any colder snap quicker so I guess how things play out will depend on what people will prefer.

[sawan]

Winter wonderland in central England @t144 according to  GFS 18Z, long way away but a significant change from what was being proposed in 12Z. 

Sorry, don't know how to insert the url as an image

Edited January 8, 2017 by sawan

[damianslaw]

Key changes in GFS 18z, much more influence of the ridge building into the country, with possible slider low territory, a backtrack from the quick westerly influence, which to my eyes looks far too swift anyway, so not surprised to see such changes this evening, given the direction of ECM/UKMO. 

[radiohead]

1 minute ago, sawan said:

Winter wonderland in central England @t144 according to  GFS 18Z, long way away but a significant change from what was being proposed in 12Z. 

A proper nowcast if that happened. Real knife-edge stuff there. Some happy people, some soaking wet people!

[Mucka]

9 minutes ago, Steve Murr said:

00z to 06z to 12z would be fine--

 

LOL it would be better than fine.  I was just curious if you felt that now it has the signal whether it would flip or go the slow correction route?

I have a feeling we may well see the 00z move all the way to ECM 12z and even better but it is JFF - same as you, I don't care as long as we get there.

Edited January 8, 2017 by Mucka

[snowbob]

1 hour ago, snowbob said:

Like I said in a post earlier gfs to my knowledge has always dropped the idea of cold, then backtracks in a true up and coming cold spell.

it nearly always over does the default Atlantic driven weather in this country, then realises the cold to the east is to strong.

if the ecm and ukmo had the Atlantic piling through I would be concerned but. there is no way the gfs is correct.

no science to back it up I'm afraid just age and experience.

the gfs will fall in line with ecm tonight or tomorrow's 0z

 

[Doctor96]

snowbob 

 

wise comments  and agree 

[FreezingFog]

24 minutes ago, Steve Murr said:

Anyone notice the difference yet!!!

I can see it, you charged your battery!!! 

Colder air further east and south. 

[nick sussex]

Nice to see the GFS 18hrs run edging towards a colder solution and the ECM ensembles are showing more support for an easterly so not a bad way to round off the evening. I think what most members would like to see though is an easterly which can come with some convection off the North Sea and that's still not really being signalled.

I think a cold easterly if its dry would be more acceptable if it was preserving already fallen snow, dry is fine if you've got snow to play in already!

[tight isobar]

Although pleasant pleasing to view..

I would refrain from being suckered in via precipitation charts.. (especially gfs)..

With a fair few more twists/turns yet.

There's lots and lots to evolve. And geographical exactions in order of precipitation type/amounts will most likely be of nowcast pin-pointing especially with a northerly flow!

Edited January 8, 2017 by tight isobar

[stewfox]

26 minutes ago, radiohead said:

18Z is not very different from the 12Z by T180 really...but small steps in the right way.

Massive differences in the 2M temps over a number of days

18z next sunday 9pm..... 9c drop for some

12 Z next Sunday 9pm

18z 17/1 9c degree drop for some cf 12z. Loads more examples, its going the right way, Free drinks for all (20 mins)

 

12 Z 17/1 same time mid day 10c in places

Edited January 8, 2017 by stewfox

[swfc]

out into fi but look at the heights exiting the esb!!!!.Tbh tho prob be feb before it had any effect on the uk!!!

[knocker]

Question is will we get snow of the front edge before the drier air kicks in ?

[snowbob]

3 minutes ago, stewfox said:

Massive differences in the 2M temps over a number of days

18z next sunday 9pm..... 9c drop for some

12 Z next Sunday 9pm

18z 17/1 9c degree drop for some cf 12z mid day still some 0

 

12 Z 17/1 same time mid day 10c in places

That's a huge difference in temps

what a significant difference in one run

really hoping gfs has smelt the coffee now

Edited January 8, 2017 by snowbob

[snowbunting]

That looks like the beginnings of an Easterly. It will be interesting to see what the 0Z brings tomorrow. As the run progresses it is definitely less Atlantic driven.

NAO forecast to be positive during our cold spell.

This forum is great and a great place to learn about the fast paced world of meteorology. It would be nice to think that all members can feel encouraged to make a contribution. Everyone has to start off from somewhere. People learn best when they are actively learning and processing information in their own way, so they should be encouraged to make comments. And yes like bumbling clumsy bafoons we will make mistakes or not understand something completely but, that should be ok as mistakes is how we all learn.  

 

[radiohead]

3 minutes ago, stewfox said:

Massive differences in the 2M temps over a number of days

18z next sunday 9pm..... 9c drop for some

12 Z next Sunday 9pm

18z 17/1 9c degree drop for some cf 12z. Loads more

 

12 Z 17/1 same time mid day 10c in places

I mean in terms of the wider pattern, as you can see they are broadly similar. I wasn't referring to UK temperatures. Those will obviously vary a lot depending on whether there is a covering of snow or not etc. and that depends on what precip the run throws out each time...

[nick sussex]

The best fax charts of the winter so far, the T120hrs shows the 510 dam on its way south and the flow looks unstable and full of fun!

 

[bluearmy]

London temps reflect the anticyclonic nature of the latest eps with more than a a hint of continental flow I reckon

 

And note that exeter haven't seen fit to change the fax too much from raw ukmo at day 5

Edited January 8, 2017 by bluearmy

[snowbunting]

1 minute ago, nick sussex said:

The best fax charts of the winter so far, the T120hrs shows the 510 dam on its way south and the flow looks unstable and full of fun!

 

It has been a very long time since we talked about the 510 dam heading south towards the UK. I don't think it will make it though.

[Mucka]

4 minutes ago, bluearmy said:

London temps reflect the anticyclonic nature of the latest eps with more than a a hint of continental flow I reckon

They are superb BA, much better than this mornings which had a bit of a wobble and I think the best set of the winter - though last failed cold spell may have been a tad better for a run or two?

Edited January 8, 2017 by Mucka

[Catacol]

9 minutes ago, nick sussex said:

Nice to see the GFS 18hrs run edging towards a colder solution and the ECM ensembles are showing more support for an easterly so not a bad way to round off the evening. I think what most members would like to see though is an easterly which can come with some convection off the North Sea and that's still not really being signalled.

I think a cold easterly if its dry would be more acceptable if it was preserving already fallen snow, dry is fine if you've got snow to play in already!

An easterly is what I crave - and today we saw progress in the models. Yesterday the only Wheeler plot showing an active MJO phase was BOMM. Today you can add to that the GFS and to a lesser extent ECM. Something may be stirring at long last in the Pacific though the Ventrice charts I use have conked out for now... so Wheeler is all there is... but it's a good sign.

GLAAM also gently on the up according to the Schiraldi plots, and GEFS also has positive GLAAM for the first time since the end of December - also good news.

End result is in increase today in chances of higher lat blocking, though baby steps rather than a dramatic acceleration in amplification potential. Model watching this week might become interesting...

 

 

[nick sussex]

Just now, snowbunting said:

It has been a very long time since we talked about the 510 dam heading south towards the UK. I don't think it will make it though.

If the T144hrs output verified it would but that's a long way off. The fax charts are likely to change though with troughs being modelled more accurately closer to the time.

[Duane S.]

Great 18z to round off a very positive day all in all. The GFS hardly ever does a dramatic flip / backtrack, more edging towards / baby steps.