T+192.. Milder air poised to move in from the SW with some snow possible depending on the positioning of the low. 

On this run the Greenland High is just that bit too weak, and there's also an unhelpful ridge setting in across mainland Europe.

A bit of a dog's dinner! 

Not the best compared to the eye candy of the past few runs. 

You can see the warmer air with the LP into the UK, It could well be quickly eaten up by the cold air

hmmm

Yes fair to say it's a poor run. 

Hopefully it has gone off on one. :) 

A poorer run though the GFS 18z is generally, from what I can see, pressure over the Greenland region doesn't look like falling that much, if at all.

Not so good for those in the south though, admittedly.

Tonight's 18z is following last night's, with the handling of the LP near the Azores completely different to the other output.  By drawing it north it seems to get picked up by the jet and at the same time draws WAA north, again just like last night.

Clearly it's a possible evolution but unless the ensembles and other models start to support that evolution I'll treat this as I did last night's run, which was unsupported by subsequent runs.

I don't agree David.. The Greenland High is much much weaker on this run compared with others, and is a big part of the problem. 

Either GFS has gone off on one or it has picked up a new trend.

Hopefully the Euros have this nailed. 

From Liam Dutton a couple of hours ago

Liam Dutton ‏@liamdutton 2h2 hours ago

Colder and, more importantly, drier weather still coming next week. Snowfall detail elusive, but some 'interesting' possibilities! #uksnow

As poor as we think the GFS run is , it throws some cold over us

GFS may be wobbling but in  the short term METO faxes at 96h and 120h bring in the colder air.

http://www.meteociel.fr/modeles/ukmo2.php?ech=96&carte=2000

http://www.meteociel.fr/modeles/ukmo2.php?ech=120&carte=2000

The rest of the output looks absolutely stunning, just re-looked at the MetO, ECM, JMA, GEM.. All exceptionally good with a robust Greenland/Atlantic block. 

Hopefully tomorrow we'll see the trigger low shifting east at a more reliable timeframe (a la MetO) and we'll get a clean, Arctic flow developing by t+96. 

Hopefully the 18z GFS can be binned. 

That's spooky, I have just done the same thing and it seems that the GFS18z is out on its own .

It is known as the pub run.

GFS in particular is having major issues with the Bermazores low/greeny block combo. I'm not sure why the 18Z suffers from these aberrations more than the others but I expect this OP to go as wildly against it's ENS set as the last 18Z.

We're in unusual territory here with regard modelling anomalous sub-tropical energy, a deeply looped jet and an unprecedented surge of WAA high up towards the pole. The algorithms are being stretched to the limit it seems.

When it don't show what they want it to yes 

Id guess there is very little difference in verification stats from the 4 daily runs.

Looks cold until next Monday:

But to contrast this with this - a slight shift - I guess it will all depend on the positioning of the HP and LP's. - But either way it will stay cold, because this chart shows the HP right over the UK!?

That's very eloquent Neil.     It's an interesting hypothesis; maybe some very minor change drives the subsequent evolution, akin to the proverbial butterfly flapping its wings.

It's weird because it's the same model as for the other runs. I guess it's just chance that it's two 18z runs in a row.  

ECM 12z op very well supported by its ensemble, with what looks like at least half the runs even colder throughout.

And the cold cluster is heavily dominant right out to day 15.

The blue GFS 12z op line is on the mild side throughout.

Very pleasing imo: