topple-tastic IMO and apart from a couple of foggy and damp days nothing too much to write home about. A familiar theme at the moment is the persistence of the HP cells to the South, though I am not calling a Bartlett ATM 

Looking out to 240h with GEFS the ENS are dominated by either Atlantic flow or HP to the south or south west.There is but a single ENS with an easterly flow.Can't see much sign of any real cold at present and frankly not expecting anything in December  asa whole -and nor is the METO monthly.

Get the next day or so out of the way and temps tumble down quite well, a much more seasonal feel coming up

As far as U.S. pattern amplification goes, the stand-off actually continues this morning, but the differences are smaller:

ECM (left) still digs the trough down just a little more and separates it from the Atlantic trough over Greenland more effectively by 144 hours:

ECM has hardly shifted on that regard from last night, while GFS has increased the amplification just a little.

The key difference between the 00z ECM today and yesterday's 12z is the low pressure in the Atlantic, which moves more slowly on this morning's run and doesn't drop south until further east. This is nicely in line with the spread of solutions in the ECM 12z ensembles yesterday.

Interestingly, UKMO is much more like yesterdays ECM 12z op run, and GEM is quite similar, leaving the door open on such a path.

The flatter situation in the GFS and GFSP runs then leads to some serious divergence from the ECM output. GFSP almost manages to achieve something similar to ECM anyway, but the Atlantic jet suddenly powers NE and shatters that prospect. The late stages of the run do recover the situation though - that theme is consistent from previous GFSP runs.

GFS seems to be off exploring a whole other route, in which the Greenland polar vortex steadily organises but also becomes more compact, which allows a large block to form to the east and northeast of the UK. There's little sign of the Atlantic jet trying to undercut that block as needed to get anywhere from that position. This run diverges from all other output, even the GFSP run, in just 8 days time so hopefully it's a lone dog barking up the wrong tree.

GEM's up to its old tricks again, amplifying the flow so much that rather than flattening the mid-Atlantic ridge of 5th-7th December, the jet splits and an undercut leads to a notable Scandi High. Both before and after the recent update, the model's tendency to throw out extreme options one way or the other makes it seem like peering into a parallel world in which the atmosphere is just a bit more crazy!

Well I like the drier output, but personally I'd like to see it turn quite a bit colder. 2014 has been ludicrously mild overall.

Couldn't agree more.

on one of Gav's videos he showed some charts for the start of next year below average ( 2-3 months) long may that continue

LRF of course

Am I the only one that is gobsmaked by this chart?

no Q, that temperature gradient over the States is insane LOL

Is it the North American gradients?.

Would that produce some rough weather on the boundaries, although the 2m discrepancy looks more gentle.

http://www.wetterzentrale.de/pics/Rhavn063.gif

Yeh the 2m is rather dissapointing; but I have never in my entire life seen such a huge upper gradient. Its amazing enough to see -20 and +20 on the same map, let alone 500miles apart!

A 40C difference over such a short distance is very interesting.

Although, it could be found on the same map with greater distances on a regular basis.

UKMO goes for a northerly toppler:

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=384

Unfortunately the strog ridge pretty soon topples.

Decent northerly blast on the GFS. Big difference on the GFSP at the same time. 

http://www.theweatheroutlook.com/twodata/datmdlout.aspx

What that chart doesn't show so well is a little HP cell lurking North of Norway:-

http://www.theweatheroutlook.com/charts/gfs/12_384_mslp850.png

Probably wouldn't matter but would be a small possibility of that developing in to a scandi HP as the ridge is toppling that way.

Will be totally different on the next run though

The repeating signal for a brief but coldish Northerly aside the HP domination in the 12z run is fairly impressive - haven't really checked the 850's to see how they are but chilly where skies clear and the air stagnates would almost be a given. I'd imagine there's going to be a fair bit of fog about at times too.

It might do but not before it gives me a day that is colder than any I saw last Winter

http://www.wetterzentrale.de/pics/Rtavn38417.gif

OK I'm going to look at whether the models are showing Amplification in the mid-Atlantic. Weak is defined as any non-trivial amplification of the north Atlantic high, generally speaking it has to be orientated north-south rather than slug shaped. Strong is defined as all of that plus the 552 500hpa isopleth reaching any coast of Greenland. Below are the models and when they first arrive at weak or strong amplification. Amplification is only for the mid or west atlantic, NOT Scandinavian highs or anything close to the UK. The dates do not necessarily correlate to cold spells and it is possible to get cold spells in other way, however mid-Atlantic amplification is a very good sign. 

GFS12Z

Weak: 312hr

Strong: 336hr

GFSP12Z

Weak:384hr

UKMO12z

Weak: 120hr 

NAVGEM12Z

Weak: 114hr

ECM0Z

Weak: 144hr

Strong (barely): 240hr

1065mb over Greenland:

http://www.wetterzentrale.de/pics/Rtavn3481.gif

GEM similar to UKMO, but the best we can hope for is brief colder spell. Nothing really to perk the interest

Really>

This Autumn is much more interesting than last years    D J and F put together

nothing to really get excited about i heard today by a guy who is a manager of the council who gets the long range forecast cos and for the gritters, say its going to be ok thru december evan upto january,  maybe a bit of cold but mild [ ish ] dry  [ ish ] no freeze or snow tho, and im taking my neck of the wood,  suits me fine, if i can save money on heating im happy, just mean more pub money lol

PS  we was not caught out in 2010 cos MR BRIAN here on TWO called it well before it happened in fact he was the first here is were i heard it, so was not caught out for 2010.,i think story went he even went to the daliy star news paper, and annouced it, dont know and cant remember the full story, so OVER TO YOU MR BRIAN, ?????  

As useful as any other LRF and better reserved for the winter thread please