Model Output Discussion - Colder spell ending, what's to follow?

[SqueakheartLW]

We are doing better now with the 06z GFS runs and members compared to what I showed earlier. These are for Christmas Eve however as Christmas Day isn't in standard range till tomorrow. As before the least cold option is first through to what looks to be the coldest

GFS 06z Member 3

Although this option is the least cold above the UK itself the cold is lurking there just over the continent and could easily move in in time for the big day itself

GFS 06z Member 27

This run is more interesting in terms of a battleground situation. The remains of a low that has just filled is sat over the UK itself and cold air is in place in the east of the UK. This looks like a failed attempt to push milder air in as the low came up against the block. Colder air is lurking to the east and could push in, especially if the next low is deflected to the south of the block. Could have been a possible 23rd December snow event, especially in the N and E of the UK

GFS 06z Member 28

This option looks very much like a standard cold and dry continental situation with very low minimums likely with little or no precipitation what so ever. However there is deeper cold to the east of the block and if the high moves a bit further north it is game on

GFS 06z Member 12

Although not particularly cold uppers this gentle easterly will no doubt contain a lot of surface cold and will be a cold and frosty Christmas Eve option. Much colder uppers are lurking away to the NE and if the pattern sticks will very likely end up in the UK in a few more days time

GFS 06z Member 4

This option has colder uppers just pushing into the E of the UK and looks like the start of a cold spell. A trough is close by and no doubt wintry showers are a real possibility here, probably turning more to snow throughout the day ready for Christmas Day

GFS 06z Member 24

Another quite anticyclonic option here with frost and cold. However the coldest uppers are behind the low over Scandinavia and if that low dives SW on this run then this will unleash a beast from the east behind it

GFS 06z Member 9

A very anticyclonic option with cold uppers too. This option will most likely have the most severe cold nights of all the options I have picked out. A lack of very deep cold over Europe but overall general cold away from S Europe at least. Would make for a seasonable Christmas period at least even if there is no snow

GFS 06z Member 10

This one looks like a potential snow maker. An area of low pressure smack bang over the UK with cold uppers really nationwide. Very slack winds to prevent any mixing of the air along with evaporative cooling could be a potential snow fest in any precipitation

GFS 06z Member 1

The final and coldest option looks the most odds on for a snow fest away from SE England that is which sticks out into less cold air on this chart. SW England, Wales, C and N and E England look to be on a frontal boundary with uppers down below -5 and getting into -10 territory further N. This looks like a potential blizzard for some. Scotland and N Ireland look to be in brighter weather with snow showers coming in from the NE

Summary

My previous chart update had 7 out of 31 options showing easterlies

This latest one, although for Christmas Eve rather than for Christmas Day has 9 out of 32 colder options or patterns that could potentially deliver cold at the right time so the fraction of cold or very cold options has increased slightly on before. Lets see what the 18z GFS and its members show

[blizzard81]

1 hour ago, Catacol said:

Let's put this one to bed. A single C class flare does not constitute a major uptick in solar activity. The sunspot number remains low - though yes: we are on the way back up now as we head into cycle 25. The reports are of "very low" and "low" activity with only a single sunspot currently visible. There is no issue here. The best place to get a quick summary of the current position is here:

StackPath

WWW.SPACEWEATHERLIVE.COM

 

 

Thank you . That first post of mine was maybe looking on the pessimistic side of things as I stated in subsequent posts. I was looking for some input from much more experienced forum members. You kindly obliged, along with others and I really appreciate it . Thank you for that link as well. Love this forum . 

[ITSY]

UKMO officials indicating, as per Catacol's note, the interim likelihood of slow moving atlantic systems in the context of so much blocking everywhere. No comment on longer term prospects but see med-long term outlook by ECM below and the full tweet here. As catacol says, need these ratios to start showing more later-stage green in coming week or so...

https://twitter.com/Petagna/status/1336293553056739328?s=19

Edited December 8, 2020 by ITSY

[Frosty.]

Looking ? ? at the GEFS 6z longer term there is some wintry potential on the cusp of Christmas, whether it’s white from snow or frost is too early to say but as things stand, there’s a chance it could be a cold / very cold Christmas...fingers..toes..everything crossed!  

[Tim Bland]

Not much support from the GEFS...Yet..

[alexisj9]

1 hour ago, Bricriu said:

Speaking of Solar Flares, was it a Solar Flare that Stuart Rampling(GP) pointed to as scuppering an easterly he had envisaged back in 2013? It was all looking so good, then a few days out it all went pear shaped.

I doubt the solar wind caused a short wave low in the wrong place for us, it was just slack flow, and rather a common thing to happen, it fills the space. We ended up with a nice cold snowy northerly instead. May be less cold uppers perhaps, I never worked out what all the fuss was about. It was just a scuppered forecast, happens all the time.

[Paul]

I posted this in the Strat thread as it's got close links to that, but thought I'd post in here too, particularly as we're between runs right now. It's well worth a read:

Arctic Amplification and Winter Weather - What's the Connection?

WWW.NETWEATHER.TV

---

Samuel Hayes explores how Arctic Amplification impacts the UK's winter weather, and how it links into the stratosphere, sea ice, snow cover and more.

 

[Jeremy Shockey]

GFs 06 ensemble mean anomaly at t 240

Pretty strong signal for high pressure in the right place for cold at day 10 on the GFS 6z ens mean 

[bluearmy]

9 minutes ago, Jeremy Shockey said:

GFs 06 ensemble mean anomaly at t 240

Pretty strong signal for high pressure in the right place for cold at day 10 on the GFS 6z ens mean 

That e euro high anomoly is a possible fly in the ointment ..... where will the gaps be in those anoms ???

[mountain shadow]

8 minutes ago, Jeremy Shockey said:

GFs 06 ensemble mean anomaly at t 240

Pretty strong signal for high pressure in the right place for cold at day 10 on the GFS 6z ens mean 

I always query these charts as to whether the anomalies are anomalous enough. 

Unless the anomalies are off the scale I don't get too excited, this might just show low pressure of 1000mb as opposed to 980mb.

[winterof79]

2 hours ago, Ali1977 said:

-12/14c uppers covering most the country in 2018, -16/18c In 1987. Both Epic cold really but 87 in a diff league with daytime max nearer -6c . I’d love to see that again in my lifetime, I think

79 was in my school days. 

87 I was stationed in Germany

[TSNWK]

14 minutes ago, Jeremy Shockey said:

GFs 06 ensemble mean anomaly at t 240

Pretty strong signal for high pressure in the right place for cold at day 10 on the GFS 6z ens mean 

Umm. I'm seeing troughing to our south pumping up warm air and how will any cold air get to us if there is a signal for heights in eastern Europe.

I don't like that chart.. 

[Eagle Eye]

Personally the biggest christmas present i'm expecting is a - 2oc Sunny Day we all know we'd be happy if that happened most modles going for an average Christmas. 

[weirpig]

Just now, XanderP007 said:

Personally the biggest christmas present i'm expecting is a - 2oc Sunny Day we all know we'd be happy if that happened most modles going for an average Christmas. 

I think if that happened  most of us would be able to keep a leg of lamb down our underpants and keep it fresh for a month   much better at -2c

[Updated_Weather]

1 minute ago, XanderP007 said:

Personally the biggest christmas present i'm expecting is a - 2oc Sunny Day we all know we'd be happy if that happened most modles going for an average Christmas. 

Anything that far is in FI.. Can't say its looking average at the moment if models are to believed anyways.

[alexisj9]

10 minutes ago, bluearmy said:

That e euro high anomoly is a possible fly in the ointment ..... where will the gaps be in those anoms ???

Lost my geography lol, looks like North Africa and Asia.

Edited December 8, 2020 by alexisj9

[Kiwi]

3 minutes ago, winterof79 said:

79 was in my school days. 

87 I was stationed in Germany

Just need a good long easterly like that and some cold to tap into.

 

[Eagle Eye]

2 minutes ago, Updated_Weather said:

Anything that far is in FI.. Can't say its looking average at the moment if models are to believed anyways.

Exactly i'm going for the opposite of The Models. 

[LRD]

22 minutes ago, mountain shadow said:

I always query these charts as to whether the anomalies are anomalous enough. 

Unless the anomalies are off the scale I don't get too excited, this might just show low pressure of 1000mb as opposed to 980mb.

Totally agree

Pressure anomaly charts on their own are so misleading. The reds have to be really deep red in the northern latitudes because the average pressure readings in winter are fairly low over Greenland, Iceland and West Scandi in the winter

That tail of heights into E Europe actually indicate pretty strong high pressure there because pressure is usually fairly high anyway

It's not a great chart at all but the interest lies beyond anyway, I think

Temp anomaly charts are better for very obvious reasons

Edited December 8, 2020 by LRD

[BlueHedgehog074]

13 hours ago, Allseasons-si said:

Stop beating around the block and get it sorted 

with that Arctic high forecast to be in situ it's clear from the above to me that this will slow the trop pv from gaining a westerly momentum to an easterly,how strong this will be,no one knows yet but one to watch as as a Ural block is still in the game looking at the latest cpc/EPS height anomalies

 

Hi Allseasons, was working very hard last night and all throughout this morning. As an invisible block, I’ve not quite got their yet on the ECMWF, and at least some way their on the GEM. Have at least tried to hold up the Atlantic Lows so they mostly struggle to get too far past me to the East of the UK

ECMWF

Although some blocking is maintained to the North, just needed to use a bit of extra force from the East against the Atlantic Lows. Will try harder on the next run though, don’t ya worry

GEM

It was easier on the GEM to fight away the Atlantic Lows further West. They were much less of a match for the Greenland heights and I. Just as easy as trying to rip cardboard up in half. But was getting very tired and realised I still had some way to go to get the Lows to fizzle and/or disrupt heading South into mainland Europe. Didn’t know if I’d have to energy to take them down on the GFS. 

But surely enough...

GFS

 

Almost lost it at first. But... got some reinforcements further into the run resulting in a nice looking block forming to our North and cold 850 hPa temperatures spilling Westwards over the UK. The Greenland block did loose some of its power even deeper into the run, but the Atlantic Lows to our South-West still couldn’t take down both the invisible and Northern UK blocking 

Man, that was hard work. Worth it for you guys though. Want you to get a great cold and snowy spell out of this later into December. Will try also get get some blues appearing over mainland Europe on some future NOAA 500mb anomaly and extended EPS runs. Not gonna be easy though

[Jeremy Shockey]

50 minutes ago, bluearmy said:

That e euro high anomoly is a possible fly in the ointment ..... where will the gaps be in those anoms ???

 t 360

maybe better at Dec 23rd perhaps ?

[SMU]

ICON now looking rather like the UKMO now!

[Mucka]

We are definitely seeing hints of an Atlantic ridge developing in the mid term in the output but ECM not interested as yet.

If the Atlantic ridge does develop it will greatly increase the chances of cold before Christmas.

Let's see how the main models go this afternoon.

[SMU]

2 hours ago, ITSY said:

UKMO officials indicating, as per Catacol's note, the interim likelihood of slow moving atlantic systems in the context of so much blocking everywhere. No comment on longer term prospects but see med-long term outlook by ECM below and the full tweet here. As catacol says, need these ratios to start showing more later-stage green in coming week or so...

https://twitter.com/Petagna/status/1336293553056739328?s=19

Remember Scandi blocks can often be neutral or positive NAOs

[Tim Bland]

29 minutes ago, Steve Murr said:

ICON now looking rather like the UKMO now!

I might still be playing the Grinch here but I’m struggling to see the excitement? UKMO and Icon both have zero cold anywhere in site ? Even if there was a true undercut there is no cold to draw west?