Agreed. The ECM ENS 12z London precip chart has the greatest probability for snow at 10% on 6th Jan. If the probabilities start getting up to 30% or above I might get interested.

https://www.theweatheroutlook.com/twodata/ecmhrens.aspx?chartname=ecmwfenspreciprate&chartlocation=london  

?? Not in my part of the S.E.  45mm for December is not high nor 44 in November or 57mm in October. Yes it helped a bit but nowhere near enough to compensate for an annual total of just 438mm. I've yet to check but that is possibly my lowest in almost 20 years of recording. Ground is dry here and cracks in lawn only just vanishing. Will need a lot of rain in late winter to make up the deficit. Just shows what a massive area the S.E is and how much variation there is across the region.

Here In the east - NW Norfolk, the drought is over, because the winter springs and watercourses have now become wet and running. However, more rain is needed to top these up and keep them running in the spring.

Tonight’s ECM is a peach, with low pressure, -10 uppers and  all of the ingredients to the 1979 snow event, that stranded my brother-in-law in Bury t Edmunds Guildhall for 3 days and nights when on his way home to Hadleigh from a conference in the midlsnds

Morning Mooms, a merry Christmas to you and all on TWO!

The lack of data issue isn't "mythical", I showed over the course of several years that the amount of aeroplane data drops significantly on Christmas and Boxing Days, and again on New Year's Day. I also showed (via the verification correlation charts) that there's a corresponding drop in accuracy for charts produced on Christmas Day especially. Since the Ukraine war started it's less of an issue, because there's virtually no data from Russian airspace - and that's year round. It means the loss of data over Christmas isn't as much of an issue as it used to be and indeed though there's still usually a slight drop in accuracy it's no longer statistically significant. 

Ironically I was keeping an eye on things this year, as I always do, but the ECM site is having trouble with its charts showing data coverage - "data unavailable"!

https://ukwct.org.uk/weather/data.jpg 

I'll not be paying too much attention to the charts today, not because I'll be busy, because I won't - Christmas on your own is just another day - but because of the potential drop in accuracy (old habits die hard). 

Yesterday saw a gradual decline during the day in terms of the GEFS delivering deep cold in London, going from a roughly 55% chance in the 0z run down to a 30% chance in last night's 18z output - and the ECM ensembles, if you can get the ECM site to display them, show that yesterday's 12z output was the 4th coldest in terms of its 850s. Taken together it means I'm remaining somewhat cautious regarding the new year potential - the Christmas easterly's cold pool ended up too far south, I'm wary that the new year plunge will end up too far east. We'll see over the next three days or so!

A reminder that you can see the ECM "plumes", which show 850s, here:

https://charts.ecmwf.int/products/opencharts_meteogram?base_time=202512240000&epsgram=classical_plume&lat=51.5085&lon=-0.12574&station_name=London 

FWIW the lack of data manifested in producing more blocked patterns in our part of the world, it was quite common in the midst of a zonal spell for some truly cracking charts to appear over Christmas (in the mid- to long-range), only to revert back tout de suite when more data became available. It seems that assumptions were made about the jet which meant our usual "spoiler lows" weren't resolved - perhaps due to reverting to climatological norms as a fallback. And, of course, planes provide a good deal of data about the jet as they fly at that altitude.

It would have, and still would, make for a fascinating research project for a student. 

And Happy Christmas from our robot overlords AIFS. A beauty.

https://www.wetterzentrale.de/en/topkarten.php?map=1&model=aifs&var=2&run=0&time=216&lid=OP&h=0&mv=0&tr=6#mapref 

FAX has the forecast E-ly in place for England, HP 1042 mb Scotland (also driving Sw-lies to N Norway where temp is +5C) #. By Mon 29th the HP has drifted up to SW Iceland 1037mb and winds are lighter but beginning to draw in air from the N rather than the E.

GFS Op 0Z - agrees with FAX, continues the set up but weakens the HP enough for the SE to get a brief wintry blast from the NE  on Fri 2nd. The HP continues S to the Azores and winds become a general W-ly from Mon 5th, turning cold NW-ly by Sat 10th when LP 980mb moves to Norwegian Sea. Prospect of a dump of snow in the SE Fri 2nd and in the Highlands a week later.

ECM - like GFS to Fri 2nd but then a weaker HP allows the LP (in GFS over the Low Countries) to move directly S-ward 995mb N England, but not quite as cold. Snow for the hills. cold rain elsewhere? Then W-lies as per GFS but Sat 10th the HP has moved to C Europe and Britain gets very mild SW-lies, any LP staying well to the north of Iceland.

AIFS - London, maxima around 5c to Fri 2nd then 😮a week with temps below 0C day and night, and perhaps a little snow at first. Edinburgh, also near 5C at first, but up and down a bit; and then the cold spell but hovering either side of 0C. Quite a bit of Rain/snow from Sat 3rd onwards.

GEFS - in the S mild (mean up to 5C above norm) until Wed 31st then into the freezer 5C below norm Jan 1st, slowly recovering but ens increasingly spread, not a few very cold runs. Small amounts of pptn from New Year's day but snow row figures only significant on the E coast esp E Anglia. In the N, In the N, similar but less of a dip at New Year, though cold enough for snow in the Highlands.

Something go wrong with the green lines but i can make out it a slowly lowering down the uppers than yesterday so need more runs to bring down to -10C to below to get a subzero maxes I am very after. Same green lines problems over London and Nicosia ensembles, the colder shot for Nicosia had been slightly downgraded so it mean the cold pool had moved west a bit.  Also need to watch the date line when this cold air arrive NOT to be pushed back, so far it staying at 1st Jan.

Merry Christmas everyone.

Though the 0Z ECM is a lot milder than yesterday's 12Z, unless my memory is at fault the ensemble mean is a good bit colder and is now showing a comparable degree of cold to what the GEFS has been showing for a while.

Same here mate.  

Yes, always the concern the high will do what UKMO is showing and not even build up to greenland.  Again, the curse of the modern winter and power of the jet.  30 years ago I'm sure today would have been white as our high would have been a few hundred miles further north. 

Sad, but life mostly a series of disappointments, interspersed with some moments of happiness (usually involving drugs, porn or alcohol)

GFS control and a lot of the runs are very good.  But probably lack of data.  

A very Merry Christmas to everyone.

Yes, a fair summary.  I find it interesting to watch the models trying to work out the next pattern change.  The build of pressure to our north and north east this week was well signalled but there have been quite a few variations on what comes next, centred around whether the high retrogresses or is forced south, both largely a function of the behaviour of the jet stream.  It does now look like a hybrid solution is possible, with still uncertainty about whether we get a cold northerly or a less cold north-westerly, ahead of the next potential change.

Merry Christmas to all. 🙂

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49068&model=gfs&var=201&run=6&lid=ENS&bw=1 

lack of data most likely as Darren explained earlier. Not picking up those spoiler shortwaves that always scupper northern blocking

Argh. Always something 🙄 so a false call 📞 🙄 I thought lack of data. (Which we see every year) means models reverting to milder and wet. So when will there be more data? And i will assume the cold ENS will trend back to average or above soon then? Or is it not worth even following the models at this stage as there is lack of data?

Should be a little better tomorrow and back to normal by Saturday.  But a lack of data means just that, there’s no bias one way or another, just less accuracy as you get further ahead.

Yes, it's clear that the models are finding a flatter solution in the New Year.  The long range search continues. 12z ECM depicts a classic lee northerly with wintry showers on Eastern coasts exposed the the NW (some cheer for those high on the NYM). 

 The JMA is a bit exaggerated and somewhat isolated this evening, though cold if you want to see an  alternative reality for a few hours.