Put the optimism on hold! More straws to clutch at but cross-model agreement in a reliable time frame is still needed.

GFS as yesterday; brings a trough through tonight then big rise of pressure, 1040-1045mb Sun - Wed 22nd over UK with strong southerlies over Ireland, then moves off into Atlantic by Sat 25th with northerlies down the N Sea into Denmark and Germany but just missing us (and if my experience of GFS northerlies is anything to go by, more likely to shift to the east than not). Generally W or SW-ly flow then resumes through to Fri 1st Feb

ECM takes the high pressure westwards a little earlier and brings in a NW-ly on Sat 25th, cold for Scotland but not making it all the way south

GEFS ensembles stay together for cold 18-21 Jan, then mild to ca 25th Jan after which agreement breaks up - the mean is close to seasonal average but a few very cold runs, notably the Op  Run EDIT, sorry, Control Run at -10 for a few days. Dry after today until 25th, not much after that either. Pattern much the same UK-wide, though N Scotland has more rain/snow after 25th.

A quick scan of the T+300-384 postage stamps shows a less persistent mild pattern than so far this winter, but cold air usually W or E of us

Yesterday's kind remarks appreciated

In Copenhagen at the moment - yesterday, Denmark recorded its warmest January temperature on record - 11.2 degrees. It is unremittingly warm, grey and wet here - just continuous gloom and the Danes are sick of it - never known a winter like it.

This foulest of foul winters continues as expected. This winter does not disappoint in being the worst of the worst. As I stated at the end of December, once this pattern sets in at the start of January, it persists.

How I wish for a January to be a winter month for a change!

Whether it is down to a distorted view of the past or actually sound observation, but I find that March tends to be more of a 'winter month' in terms of cold and frost/snow potential than January. To observe snow in January seems an almost impossible task! 

Not seeing much to get excited by from a cold perspective. The GEFS control run is about the coldest on show this morning. Can be stepped through here:

https://www.theweatheroutlook.com/twodata/gefs.aspx?run=na&charthour=180&chartname=850tmp&chartregion=na-region&p=0&charttag=MSLP%20850hPa%20C

Good point. Every January in the past 50 years has been 3.9C above CET after the first 14 days.

https://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

The past 50 years? Are you sure about that, Brian?

I'd be amazed if the likes of the Januarys of 1979, 1985, 1987 and 2010 too were as much above CET in the first half of the month.

Makes sense. Our climate is determined by sea-surface temperatures. These are at their coldest in March. Therefore any weather coming from the north or east has a wider range of tracks on which it is still cold enough to deliver frost or snow by the time it reaches here. 

Synoptics which are marginal in December or January can deliver in February or March. That's why I've never agreed when snow in March has been accompanied by comments along the lines of "if only we'd had these synoptics in December or January". If we had, it would probably have been cold rain.

I was being sarcastic. This Jan is most definitely not par for the course so far!

OK, thanks. I did wonder at first it was perhaps a typo or something like that!

I'm fairly sure that the last below average January for temps was probably 2010 (although 2013 turned colder as the month went on but not as cold as 2010 IIRC). Someone please correct me if I'm wrong though!

Surprised its a low as that! I would have thought it could easily get to 13 or 14 in the right conditions. Wonder what comparable temps were like in 1989. 

Don't forget that Denmark is maritime with sea temperatures moderating the temperature in either direction. Also, it has no hills (let alone mountains) capable of delivering any Foehn effect - that is why in these conditions, there is little diurnal temperature range and it remains unremittingly grey - nothing to disrupt the westerly grunge.

I see, but looks like you will get something like normal winter later next week

Would prefer the block to sit over us, but as long as it stays dry I don't mind the chill

For me, Feb has been the worst of the 4 months for snow (at least since the turn of the century).

In terms of frequency, it's January - but most have been up to only a couple cms and only a small minority have lasted 3 or more days. December best for good falls (either 5cm+ or the snow remains on the ground for 3 days or more)

MBY seems to have missed any decent Feb falls.

P00 the thick blue - is this P00 the coldest ens? I can't get to this - it shows -12c@ 850hpa

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=gfs&var=2&run=0&lid=ENS&bw=1

Recent cold, or at least chilly, Januaries:

Jan 2009: 3.0

Jan 2010: 1.4

Jan 2011: 3.7

Jan 2013: 3.5

Jan 2017: 4.0 (which is probably just about below average, depending on which reference period you are using)

06z builds a strong block, but too far south. Dry and frosty though. 

Control run Tally, need to select it on the left rather than click on the 850 graph for some reason. FWIW, control run similarly chilly on the 6z.

The pert. 00 is the control run (thick dark blue). It’s run with no tweaks to initial input data (as per the OP) but at about half the resolution as the OP.

When there is a big difference between OP and control you know resolution is having an effect on outcome.

The suite (1-20) are also lower resolution but with small tweaks to input data - these illustrate how minor changes early on might cause big differences down the line. When control and OP are close together confidence increases.

I think the op and control currently have different physics too. 

Thought it was control but couldn't get the the chart when clicking on graph thanks anyway!

Meanwhile a lot of interest post 24th Jan - a flip to colder ENS in medium term when a day or so back they were milder and operational was colder outlier.

26th or 27th seem cold. Timing of cold and positioning of HP is crucial. But plenty of interest here AND GOOD SUPPORT FOR A NORTHERLY. - this has cropped up at short notice.

P04:

P08

P17:

P12:

P19:

control: - P00

Yes Operational is in the milder END of the runs at +2c when when it's ensembles are widely down to -4 or -5c @ 850hpa from 24th Jan.