I've given up searching the model output for snow or frost.

Now I just crave charts something like this one verifying during daylight hours.

I think GFS ha scompletely lost the plot - charts like this just look ludicrous to me, as thouhgh they have given the crayon to a chimp:

http://modeles.meteociel.fr/modeles/gfs/runs/2016011112/gfs-0-114.png?12

I think the low coming out of Newfoundland is too intense, a classic dartboard low:

http://www.wetterzentrale.de/pics/Rtavn1201.gif

GFS is still all over the place at the moment changing with every operational run.

Indeed! I think this run is one for the bin I'm afraid.

Indeed.

The British Isles chart shows a little LP system tracking down the east coast. 500-1,000 thickness values in the low 520s so definitely snow away from the coast if that verified

GFS has returned to being the bad boy. Clearly something has to give soon.

Hoping ECM will go with UKMO

Agreed. When you run the projection from 96-120-144 on the UKMO 12z, the High pressure cell over us is heading East/NE. Certainly doesn't look a sinker at that stage.

Well the 12z GFS op run is hardly what you call mild by Sunday either!

http://www.wetterzentrale.de/pics/Rtavn13817.gif

The difference between UKMO and GFS starts as early as T+96, with UKMO showing a more marked mid-Atlantic ridge and associated WAA than GFS. Not a vast difference but it evolves from there and the GFS's absence of strong WAA means the jetstream drives through 3 days later.  This is a recurring theme with GFS.

GEM also has a strong storm exiting the eastern seaboard. Probably go the same way as GFS.

http://modeles.meteociel.fr/modeles/gem/runs/2016011112/gem-0-144.png?12

Just about enough energy goes south to save us from a quick sinker

That and the whacking great low in the Med.

GEM12z 144 somewhere in between.

The sinker is delayed with GEM for a bit, but the jet is over us by t192:

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=192&mode=0&carte=0

So UKMO is the best run this evening - let's see what ECM can do.

I'm guessing 'disappoint'

Facepalm time!

At least the reason for the difference is clear to see on this occasion. So what causes it?

Simple actually - there's a shortwave between the Azores and U.S. troughs at +96 hours which does different things in each case;

UKMO merges it with the Azores low which amplifies that feature and enhances the ridge ahead as the poleward flow is enhanced.

GFS on the other hand merges it with the U.S. trough and amplifies that feature, which due to the presence of the Azores low ends up firing a strong jet E then NE.

GFS was closer to the UKMO 12z solution with its 00z run, in which it merged the 'middle shortwave' with both the U.S. and Azores features simultaneously. Then the 06z favoured the U.S. trough and the 12z has taken that idea further still. So the question is, whether UKMO is lagging behind or GFS is being misleading?

Looking a bit further ahead and checking the N. Hem profile, UKMO is consistent with its 00z run in terms of the high Arctic:

Notice that purple blob just off the N coast of Greenland - that's the remnants of the Svalbard low that I talked about this morning,a nd again it looks to be headed for the Pacific trough instead of the Canadian/U.S./Atlantic one.

That latter trough is a fair bit west of the 00z, though. A nice trend if it could be maintained!

So where's ECM going to go... it actually had the 'middle shortwave' as I call it merging with the Azores low on the 00z, which gave the impression that it might persist the cold, blocked theme beyond day 6... but then it had the Svalbard low merging with the Atlantic trough and the blocking was knocked down with fury.

With two key features that need to behave favourably to produce an ECM run that prolongs the cold, you could say we have a 1 in 4 chance tonight. Factor in the chaotic nature of the atmosphere though, and who knows what the true odds are for something like the UKMO 12z...!

Just thought that I would highlight the important word.

The GFS op run may have been rather inconsistent in recent days but the overall ensemble picture has been more reliable -  like the op run it stays chilly until at least Sunday. Beyond that who knows.

Not sure I agree that  something 'has to give'  if we each day compare the 144 charts. In my opinion GFS has already lost because a couple of days ago it's 144hr chart was showing a sw breakdown which looks almost certainly (even on the  GFS) as being proven to be overly progressive. 

12z GEFS stamps at 144 (click for fullsize). There are a few members there which evolve things similarly to MetO, but it's not a majority by any means!

120 stamps from ECM this morning - 5 clusters!