Model output discussion - The run up to Christmas

[sheikhy]

1 minute ago, bluearmy said:

I don’t think they necessarily show a displacement- gfs doesn’t go far enough to split on its 00z run. it would probably split by day 18.  However, the gfs op is no longer consistent on the upcoming warming.  Until we get consistency back then guessing where any vortices end up is a bit pointless 

What do you mean by not consistent blue?do you mean gfs is showing the warming 1 minute and then gone the next?its been pretty solid from what i have seen so far!!

[BLAST FROM THE PAST]

20 minutes ago, northwestsnow said:

gfs Yes...

Ec kind of

Uk absolutely not 

 

You need to explain to me what’s wrong with the UKMO and to some extent the ECM .

BFTP

[NewEra21]

11 minutes ago, jethro said:

Morning all, I rarely post in here because frankly my contribution of 'ooo, look at the pretty blobs and squiggly lines' adds little to the conversation. But even my baffled brain can see the potential on offer this time and I'm looking forward to seeing snowmen and sledging on the news, a bit of light relief that's much needed.

Let's be fair, the news will only report the broken ankles and broken bones. Because it's always doom and gloom

[Frosty.]

Loving  the ECM 0z operational trend again this morning..and the GFS 0z op to!..I’m starting to get a very good feeling about the next few weeks..plus!  

Edited December 23, 2020 by Jon Snow

[Winterdarkness]

Guys we need to talk about the sSW the models have dropped the split?!! Only displacement I’m gonna cry!! 

[bluearmy]

1 minute ago, sheikhy said:

What do you mean by not consistent blue?do you mean gfs is showing the warming 1 minute and then gone the next?its been pretty solid from what i have seen so far!!

the 0z was furthest away yet from a reversal .....prior to that the previous few runs had almost/just  got there. Prior to that we had a couple days where reversals came almost on every run.  I don’t recall any reversal yet shown which wasn’t a split. 
 

Ec suite currently seems keener on a reversal than the gfs and its ens ....

 

[bluearmy]

Just now, Winterdarkness said:

Guys we need to talk about the sSW the models have dropped the split?!! Only displacement I’m gonna cry!! 

INCORRECT !!!!!!!!!!!!

please don’t mislead the forum ......

[Northern Sky]

1 hour ago, sheikhy said:

Guys its done man!!we heading for what could be a notable cold and snowy period!!all 3 models look amazing!!!

For reference folks. This is the exact moment the wheels began to fall off...

[sheikhy]

2 minutes ago, bluearmy said:

the 0z was furthest away yet from a reversal .....prior to that the previous few runs had almost/just  got there. Prior to that we had a couple days where reversals came almost on every run.  I don’t recall any reversal yet shown which wasn’t a split. 
 

Ec suite currently seems keener on a reversal than the gfs and its ens ....

 

Ahh got you!!hopefully improves again today!!! But what a position we are in at the moment!!could not have hoped for any better!!glosea joined in last night as well!!!big times coming up❄

[Winterdarkness]

5 minutes ago, bluearmy said:

INCORRECT !!!!!!!!!!!!

please don’t mislead the forum ......

Oh that’s what someone said on Twitter. It got me scared

[Battleground Snow]

A little adjustment south east of the deep trough at 120 v the 00z on the icon, helps a little with colder air circulation

[Tim Bland]

I suspect if truth be told some members don’t understand the differences between a Reversal, split & displacement. Key here is that there is more than likely going to be a SSW and the above are the possible outcomes of that warming. Some people panic when they hear a line from someone suggesting that one of the above isn’t going to happen ...it still (probably) means the SSW is on.  No need to sell the kids sledges..

if anyone has time over the Christmas period who fully understands the nuances and likely effects on the Uk weather of a Reversal, split & displacement it would be great if they could write a post as it would assist conversations and understanding going forward. 

p.s great to see media forecasts now showing the widespread snow potential next week. Looks similar to the ECM path...

Edited December 23, 2020 by Tim Bland

[Skullzrulerz]

23 minutes ago, bluearmy said:

INCORRECT !!!!!!!!!!!!

please don’t mislead the forum ......

So what is exactly happening then ? I heard that in terms of the SSW was downgraded? Or the amount of pressure was 

[Nick F]

By the looks from the 00z GEFS 10 hPa zonal wind at 65'N , the mean still going for a reversal, just the op isn't

Back to the nearer future, great deal of uncertainty over the positioning of the upper vortex in relation to the UK early next week - which will determine where surface features will be, the 00z EC had the core of the upper vortex close to the NE, while the 00z GFS had the upper vortex centred over the SW. Secondary surface lows likely to form on the N and W side of this vortex, so it's position important to what the sensible weather will be. EC runs a secondary low south down the west then swings it SE across the south around the vortex on Monday, bringing potential for disruptive snow, even in the south. Because the GFS has different position of the upper vortex, it doesn't have this feature - instead has showers around coast but getting inland across the north where it has a surface low.

Slack conditions at the surface will be crucial to snow potential at lower levels next week, hopefully with low pressure slap bang over UK and filling, isobars will slacken and winds will fall light, allowing for boundary layer to keep cold - with help of short daylight hours and long frosty nights. The low heights / freezing level will help initially too, but surface cold building may lessen need for heights being low as rise later.

Edited December 23, 2020 by Nick F

[Methuselah]

Slim pickings for Friday... but a few places might be lucky. Sure beats mowing the lawn!

    

[IanT]

23 minutes ago, Winterdarkness said:

Oh that’s what someone said on Twitter. It got me scared

Did they post any charts to support their assertion? Did you at least look at them?

If not then please accept that unsubstantiated stuff from Twitter isn’t really what people here are looking for...

[tight isobar]

Jeez check the shallowing.. @greenland into the pole... check the 6z... ridiculous run coming up !!!

[bluearmy]

21 minutes ago, Winterdarkness said:

Oh that’s what someone said on Twitter. It got me scared

Twitter is a scary place .........

2 minutes ago, Skullzrulerz said:

So what is exactly happening then ? I heard that in terms of the SSW was downgraded? Or the amount of pressure was 

Gfs ops showed a split of the spv but we’re never consistent with post warming placement of the vortices. The split caused by a push across from the strat ridge the pacific side of the NH. We can expect one vortex to end up in n America and one Asian side. That could be as far to the east as e Canada/newfound and as far to the west as scandi. The envelope on that too far away to pin down. 
recent gfs ops have backed off from a split with most showing a stretched vortex at 10hpa by the end of the runs. But they would likely split beyond the end of the run. 
 

we don’t get to see eps extended strat data but some of the stuff on Twitter seems to show a similar picture to the more progressive gfs runs from a couple days ago with split across the pole within two weeks 

[SLEETY]

this look better than 00 run,low pressure further east in the reliable timefrme

[Speedbird]

1 minute ago, SLEETY said:

this look better than 00 run,low pressure further east in the reliable timefrme

Yeah, this has got the makings of stunning run 

[tight isobar]

144 cold air gushing south .. the door is open!!!!!!

[Kasim Awan]

The GFS 06Z has moved towards the ECM in producing a greater northerly component here at 150h. Euro model is favored in bias terms when dealing with low modifications.

 

 

[Skullzrulerz]

1 minute ago, tight isobar said:

144 cold air gushing south .. the door is open!!!!!!

Purple Temperature look like a jellyfish

Good to see cold air coming into the reliable timeframe

[Mike Poole]

GFS 06z is a cracker!  And at just T150:

 

[Yarmy]

Obviously attention is focused further out, but there still could be a few little bonus surprises at selected spots in the east on xmas morning: