Bit snowy !

The 12Zs show a much more impressive cold pool. Majority now are below -6C at T+192h for most of the UK with a few -10Cs showing up.

(wxcharts is up to around 180h atm)

I knew you'd be pleased with some of the current output 🤣

A small swing towards the Scandi/continental HP having more influence this evening when viewed against this mornings efforts but may of course swing back. I don't think the latter would help with the gray/cool/dank thing for you and many eastern coast locations though, other than making it a touch less cool, that's unless the models decide the atlantic is going to power through after all which currently seems unlikely.

From an IMBY POV I'm encouraged the 12zs have so far maintained the GEFS 6z improvement and there seems a reasonable chance of getting cold enough uppers for some snow. It's not a massive/deep cold pool though so wouldn't surprise me if raw and damp don't feature at least some of the time assuming the pattern verified roughly as shown. 

Still get the cold in and all that and worry about the specifics later. The GFS op does show what can happen once the air over the UK has cooled, with little features wandering through and bringing more organised snow for some. Who knows, if something like this run does verify we might be looking at 2 out of 3 colder than average winter months, which would be a bit of a surprise. (That should put the mockers on the whole thing...). 

The cold spell that is quite obvious to see has most of the uppers at -5 average and many nearing -10, pressure is obviously high at ~1030, but on the ground there is hardly anything lower than a -2c min for us down here.

For whatever reason it doesn't seen to be translating into anything that I would call particularly cold given many of the factors.

The dive just down to -5C at the moment for Nuneaton ensembles while Nicosia ensembles show more amazing dive to near -4C which translate far much better effect than here, if -4C there we should be seeing -14 to -15C uppers here if USA able to get so low uppers despite global warming then we should see some of it too.  Not asking too much for -10 to -15C to give us much needed ice days.  Darren so far quiet about this 12z runs but early days and need more runs for uppers to be much lower than -5C with snowfall chances.  Better get this happening now and not in Spring months.

One of the Buchan cold spells , though these are now believed to be random events, and even Buchan only applied them to Scotland

Buchan cold spells [Wiki]:

7-14 February, 11-14 April, 9-14 May, 29 June - 4 July, 6-11 August, 6-13 November

The AI model is also a stonker tonight 🙂

Darrens explanation here is incredibly helpful. I have noticed the phenomenon of cold pools just manifesting in static or blocked situations over the years, and have always been perplexed by how this occurs, and I see now, how this sometimes led to snow events in my childhood (in Mid Sussex), which I couldn’t explain from the broad charts. Of course back then, south coast snow was still less common than the more frequent and regular east coast snow shower events, and which now that I live in Norfolk, have all but Vamoosed! The Council used to provide snow fencing all along the A140, to drift the snow before it blocked the road. This drifting snow was so frequent from the 1940s to 80s. From 1996 onwards, this was cut, because the frequency had dropped so low compared to the annual cost. I cant imagine that Cost and precaution being suggested today, it would seem absurd. I think it was 2018  the last drifting snow was seen in EA and before that - 2010, and before that 1991.

PV shows cold strat temps pushing into N America and another into E Europe:

Again may not verify but these are consistent signs now...

No Sign of a reversal looking at mean zonal winds @ 10hpa but they are showing quite a weakening and compared with last night's ECM run, the ENS mean has plummeted and there is a lot more scatter now:

The models are struggling to pick up the detail which they tend to do in those scenarios. Slack low pressure below the block suggests a cool dry spell,  but plenty time for that to change.

Interesting times.

Also the airmass over eastern seaboard of USA/Canada are not as cold as last week so maybe there is more chance of a Scandinavian block or any other HLB to develop. Looking at 18z ENS the GFS Op run is one of the colder runs but not an outlier however it does show that there is now colder weather /uppers from roughly 4th - 14th? So 10 days of colder weather according to tonight's 18z ENS's? But will it intensify or not? Time will tell...?

https://www.meteociel.fr/modeles/ecmwf_hres.php?&ech=360&mode=0 

I don't really think that's been the case so much in recent decades. Oddly, my 21st birthday coincided with a foot of snow (1991) and prior to that I would often expect cold weather around it. However, since then proper cold spells have been few and far between. 

GFS Op 0z: ridge of HP currently just to the east of Britain, with S/SW-ly winds and a weak trough running N-wards on Sunday; this ridge collapsing on Tue 4th with trough more extensive than shown yesterday covering Britain but giving way quickly to HP 1045mb England Thu 6th. This moves on again to NW Russia Sat 8th and sits thereabouts 1050/1055mb through to Mon 17th with cool SE-lies for Britain, cold at times with cold pools appearing esp near N Sea areas from time to time, and a full-on cold SE-ly gale Fri 14th.

ECM : similar to gfs - less of a trough on Tue 4th, and then later (Tue 11th) the HP over Russia extends a ridge to Scotland which has the effect of turning winds from the SE into the E.

GEFS - in the S, temps dipping to cool after Tue 4th and persisting through to Thu 13th when the mean regains norm; but quite a long period in the middle of this when most ens members agree on 3 or 4C below norm. In the N, temps are up and down, with quite large swings until Sat 8th after which cold as for the S. Chance of rain or snow increases generally from Tue 11th. 

Better if was at tomorrow date line.  Just hope we get someting cold this month to save from attacking Spring with unecessary cold and wet.