But surely what you want is not high pressure in itself, but high pressure linked to the Arctic rather than to the Azores as it is at the moment?

But ECM is offering some straws with the HP retrogressing westwards, allowing space to be filled by a northerly.

The main issue with ridging North from the Azores high is that there's no path for the jet to dive south, which means pressure on the mid-Atlantic ridge. The only way out of that is if the jet goes over the Pole and drops energy south into Scandi, then possibly you have an opening for heights to rise further north in its wake.  In my experience high pressure extending south from the Arctic is extraordinarily rare.

Could be gone in 6 hours.

Could be! Enjoy it while it lasts nice to see a change is on the way though

True, even FI eye candy has been in short supply recently!

Yes this is my only concern - ill perhaps bank this as the best GFS operational this winter thus far 1075 over Greenland @ +240 looks like the lights have been switched on: It could be gone but, it's @ 240z and not in FI range and (for now) at least it is of interest and something different for us cold weather enthusiasts to discuss for a change!! Just keeping fingers crossed! I wonder how the 12z ensembles will come out?

GFS operational has support from Control, ECM and GEM but high pressure position varies! But all are in agreement for HIGH pressure to build over Greenland @ and by 240z:

GEM @ 240z

GFS @ 240z:

ECM @ 240z:

GFS control run @ 240z:

All eyes on the 12z ECM :)

12z ensembles for London - a few submarine like ENS turning up - sub -10c @ 850hpa:

Not seen this in a while - but who knows what could happen this evening when the 18z will come out? Short term there is exceptionally mild weather around the 19th if you compared that with yesterdays 18z and todays 00z ENS - it has flipped.

I wonder if we are on to something ?

Tally the 19th is an inversion a small layer of warm air at height (850hpa) Temperatures at the surface are somewhat different often seen in winter months in the uk under strong areas of high pressure.

Note pressure and not particularly mild at the surface across 20 members.

http://www.meteociel.fr/modeles/gefs_table.php?x=0&y=0&lat=51.5085&lon=-0.12574&run=12&ext=fr&mode=2&sort=0
http://www.meteociel.fr/modeles/gefs_table.php?x=0&y=0&lat=51.5085&lon=-0.12574&run=12&ext=fr&mode=7&sort=0

Big shift in ENS thou latter on nice to see very cold members cluster.

http://www.meteociel.fr/modeles/gefs_table.php?x=0&y=0&lat=51.5085&lon=-0.12574&run=12&ext=fr&mode=0&sort=0

Finally a cold Op run seems like weeks since the last one hopefully it's onto something . Quite a few ensembles go with it as well.

The 12Z ECMWF operational run seems to be showing something at T+240 not dissimilar to the GFS.

not sure, given upstream drivers I would expect the jet to flatten the ridge. Still with some form of cross model agreement nothing can be ruled out at present. Perhaps this is when winter finally begins to unfold ?

Ther is a lot of water to pass under the bridge before the time period in question but I don’t think the Jet flattening any ridge would actually be that probable a situation in synoptics like these

ECM https://www.wetterzentrale.de/maps/ECMOPNH12_240_1.png

GFS https://www.wetterzentrale.de/maps/GFSOPNH12_240_1.png

GEM https://www.wetterzentrale.de/maps/GEMOPNH12_240_1.png

Having said that, based in experience, there is still quite some time to wait before we should even consider these to be a probable outcome.

At the very least we seem to have the possibility of a change from the mild and unsettled pattern that has dominated the last 5-6 weeks or so. It is still far from certain of course and what is indicated by GFS and ECM around day 10 needs to come into the more reliable timeframe, but as I say at least the possibility of a change is there.

Well at least it's got its ability back to "go into one". It's the first time it's managed that this year and so at least can provoke some discussion/hope for the coldies.

18Z Ens for London:

A growing signal for milder conditions between 19th and 21st January then a trend towards colder conditions - thankfully the operational isnt an outlier and if anything a at least 5 ensembles bring in the -10c  or below isotherm in earlier around the 23rd Jan with some going down to -12c@ 850hpa.

Storm Brendan well telegraphed for Mon/Tue 13/14th, spawns a few secondaries and then decays in situ off NW Scotland. High Pressure over the SE back by Mon 20th with southerly winds for all, slackening later iwn the week with possibility of fog and frost. Then by Mon 27th HP has moved off into the Atlantic allowing a northerly to run down from near Iceland (that'll be a shock!) but hints that t won't last and the mobile pattern will resume.

ECM similar but moves the HP into the Atlantic sooner with northerlies present from Wed 22nd, but in this case round the top of the high, not from the far north, Bartlett style.

GEFS temps up and down either side of normal until approx 22nd, then generally a bit below normal especially towards the end (28th) Rain generally in week 1, and again sporadically from 25th especially in the west.

Postage stamps in FI are now more green than yellow, but still not many with the deep blues which people are hoping for.

A little encouragement on http://www.wxmaps.org/pix/temp4 with cold air making some progress west in week 2, and keeping to the north instead of going off to Greece.

wow?! Only one comment on here since the 18z model - silence speaks volumes as they say! Just looking at the O6z run.

Quite a difference in the position of the high between the ECM at 240 to the GFS Op:

GFS Op: