The Annual Mumsnet Christmas Weather Thread.

[OhYouBadBadKitten]

Its that time of year again, when amateur meteorologists, weather enthusiasts, the generally interested and those that hate the concept of weather forecasting all gather to guess, ahem, forecast the weather for the Christmas week.

Now given that at the moment we don't know what the weather will be like in two weeks time, this is clearly rather a tall order at present! But we can give it a go.

At the moment looking at the GEFS 35 day ensembles, which is the only weather model I can view out to that time period, it looks chilly, but not snowy, nor wet, just generally settled conditions.

That is a lovely photo Wags!

Boosey www.mumsnet.com/talk/weather/4626193-winter-weather-outlook for the general discussion.

OYBK thank you for the link.

Wags that reminds me of the first time we had thick snow when I was a child in the 70s and my dog ran outside and galloped around in it biting at the snow like a demented thing! I can still see her face now, the look of joy and surprise.

Morning all! Just a quick one at the moment. You might see on media much noise being made today about the potential of a cold snowy Christmas. The latest GFS model does show this, but a strong note of caution. This is an outlier run when you place it among the ensembles.

To illustrate this, see this chart. GFS is the green line. Most ensemble members lie above this line.

Another day closer to Christmas!
GFS grants a snowy Christmas Eve to much of Scotland, having really never got rid of the snow signal throughout next week. Once again, this is not reflected in the ensembles though.

In England, it looks milder.

Booo! I want crisp, sunny frost for Christmas (in England)

Thank you OYBK.

I have to admit I feel relieved it's going to be milder. It's just too cold and I'm so worried about the energy bills. But I do love looking at the sun on frosty trees and landscapes. I'll miss that.

The 06z run removes snow for Scotland for Christmas even and brings in festive wind and rain instead. Oh dear!

This mornings GFS* shows:

Christmas Eve: A fair bit of rain or snow depending on where you are - the more north and hillier the likely it is to be snow, with rain in the south. NE Scotland below freezing.

Christmas Day: Colder, with a risk of ice in the evening. A sub zero day in parts of Scotland.

Boxing Day: A cold day, with widespread ice possible where things haven't dried up from Christmas Eve.

*Remember GFS is just one model and this is one scenario. Although it lies to the warm side of the ensembles to start with, by Christmas it lies on the cold side of the ensembles.

ECM ensembles show a huge variety of solutions, with no clear clustering towards cold or warm, so frankly they are useless to help us resolve what Christmas weather might be like.

You may have noticed a distinct lack of updates on this thread. It's simply because I have little inkling as to what the weather will be over Christmas. I could just make it up for something to write, but I hate knowingly writing bollocks, its bad enough when I do it unwittingly.

My current thinking is that we have a much warmer couple of days, with wind and rain next week as we transition on Sunday and into Monday, but then after things probably will turn colder. Not as cold as it has been and the more north you are, there colder it is likely to be.

It might be a rather wet and windy week in the south throughout though. There might be snow further north. It might get cold everywhere by Christmas or it might be mild in the south and cold 'up north'.

Ill do a detailed model analysis after I've had my lunch in a bit and try and demonstrate the issue as best I can.

All forecasts are for around 12pm to try and show the range of model solutions.

GFS 06z run

Christmas Eve: Too mild for snow apart from perhaps NE and central Scotland. Perhaps rain for much of England. Feeling very mild in the south.

Christmas day: Deeply cold upper air temperatures move into Scotland, bringing in sub zero temperatures for northern Scotland and a more widespread risk of snow here. Mild in the south.

Boxing Day: Southern coastal counties hold onto mild air still by this point, but cold temperatures elsewhere. A widespread risk of snow across the Midlands, northern England and Wales.

GEFS ensembles

GFS above lies roughly middle of pack, to a colder than the average ensemble members for Aberdeenshire . It certainly isn't an outlier. Further south out becomes more of a cold leaning member. Ensembles as usual show a wide range of outcomes. Nothing is outrageously cold or warm

ECM 00Z run

Christmas Eve: Mild in the south. Colder further north, with a risk of snow in Scotland.

Christmas day: Cold air continues to sink southwards across Scotland. A continued risk of snow here. Mild in the south. Some risk of snow across northern England where the boundary lies.

ECM Ensembles

Most runs are not looking snowy or cold in the south. But most looking cold up in Scotland

Boxing Day: The model doesn't reach this far.

GEM 00Z A model I rarely use.

Christmas Eve: Very cold everywhere, largely dry.

Christmas Day: Deep cold continues, again generally dry but with a risk of snow over parts of northern Scotland and possibly down eastern coastal counties.

To summarise: The further north you are, the more likely you are to have a cold and snowy Christmas. At the moment I'd suggest a 30% chance of cold in the south and a very hand wavy (aka guess) of 70% chance of cold up up north, especially in Scotland. because we have this disparity, an increased chance of snow along that cold/warm boundary.

Thank you for keeping us updated OYBBK! Much appreciated.

OYBK Thank-you and merry Christmas to you! 🌲

You're very welcome, another update a little later on I need to find some time to sit down and focus.

All forecasts are for around 12pm to try and show the range of model solutions. I've done a bit of a cut and paste job from above where things are similar, which may explain any deja vu feelings you get reading the update!

GFS 12z run

Christmas Eve: Too mild for snow in the south, marginal in the north, cold in Scotland. Some dampness around potentially.

Christmas day: Potential for a very cold day in Scotland with sub zero temperatures. Mild in the south and midlands. Perhaps some snow along that boundary, somewhere in northern England/southern Scotland.

Boxing Day: mild for much of England and Wales, perhaps with the exception of northern England. This is in marked contrast with the 06Z run which showed a very cold pool of air over us, so don't despair.

GEFS ensembles

GFS above lies roughly middle to the upper part of the pack for these days.

ECM 00Z run

Christmas Eve: Pretty mild in the south. Colder further north, with a risk of snow in Scotland.

Christmas day: A bit chilly in Scotland, otherwise - meh.

Boxing Day: Mild everywhere.

ECM Ensembles
Very few runs show cold in England. Ensemble members are low to high single digit temperatures in general . Chillier in Scotland

GEM 00Z

Christmas Eve: Cold in Scotland and northern England. Snow showers possible there, rain showers elsewhere

Christmas Day: cold away from the SW. Snow showers in the northern half of the UK possible.

Boxing Day: A band of rain sweeps northward, interacting with cold air across northern England and Scotland to bring snow in these areas.

To summarise: The further north you are, the more likely you are to have a cold and snowy Christmas. It feels as though today the models are trending away from a cold set up though.

We should be able to include the UKMO model tomorrow when it covers Christmas Eve. Next update, tomorrow night.

Thank you very much. Disappointing in some ways but it must be a a relief for those traveling, especially with strike related things to contend with too.

It's not over yet.
Ill update tomorrow. It's been a very busy day, so I'm only fit for wine and netflix.

Thanks OYBBK, I only lurk in your threads and only usually in extreme weather but find them really useful.

Enjoy your wine and Netflix

You're welcome Littlebelina!

All forecasts are for daytime to try and show the range of model solutions. I've done a bit of a cut and paste job from above where things are similar, which may explain any deja vu deja vu feelings you get reading the update!

GFS 00z run

Christmas Eve: Very much a north south split, with Scotland, especially seeing cold temperatures and a battle ground somewhere between southern Scotland to northern England between cold and milder air - giving rise to the potential for snowfall here.

Christmas day: Potential for a very cold day in Scotland with sub zero temperatures. Mild in the south and midlands. Once more a battle ground area between cold and milder air, giving rise to the potential for snow along that boundary. Mild in southern England.

Boxing Day: Colder air creeps down, while southern England holds onto milder air. very cold in Scotland and northern England. The chance of snow for parts of Ireland and perhaps Wales. Northern Scotland continues to see a risk of snow.

GEFS ensembles

GFS above lies around the ensemble mean in the north, moving to the colder side of the ensembles for Boxing Day, but is warmer for more southern areas.

ECM 00Z run
Christmas Eve: Very much a north south split, with Scotland, especially seeing cold temperatures and a battle ground somewhere between southern Scotland to northern England between cold and milder air - giving rise to the potential for snowfall here. (Does this sound familiar?

Christmas day: A N/S split, with mild air in the south and midlands, cold in Scotland. Continued risk for snow showers in northern Scotland and showers or rain elsewhere.

Boxing Day: Cooling down across England

Christmas week: A trend towards cold with high pressure taking charge.

UK Met

Christmas Eve: Very much echoes the cold in Scotland, more mild as you go further south.

Christmas Day: Doesn't pull cold down in the same way as the other models and cold relinquishes its grip somewhat across Scotland.

I don't feel that we are much closer to a forecast for Christmas yet! UK Met really throws a spanner in the worls.

Netweather's Christmas forecast (with the all-important Santa Shaker!) is being updated several times a week. And like OYBBK, they feel that there isn't a 'nailed on' forecast yet!

The met office also highlight uncertainty and the likely N/S divide in their Christmas outlook. www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2022/christmas-week

Still some uncertainty according to TheWeatherOutlook....

It's waaaaaay into the future but the few days after New Year......

Which model were you looking at Gloria? I missed the model runs this morning!

without summarising all the model differences over Christmas, It does still look most lively that we will have a north/south split, with potential for snow in many parts of central and northern scotland from Friday onwards, perhaps moving southwards into northern England. GFS in a fit of overexcitement moves it right cross the Midlands on Boxing Day (see below). So do plan travel carefully and stay tuned to local forecasts.

This is all GFS 06z run below, read it with a glass of rum, spiced with a good deal of skepticism:

Christmas eve
Potentially snowy across the northern Penines upwards (take this boundary very, very loosely!)

Christmas Day GFS limits snow to the central belt upwards.

Boxing Day An area of precipitation is shown to move in that awards buckets and buckets of snow right across Wales and parts of the Midlands through into the 27th!

It isn't well supported at all, once again, most ensemble members are warmer than this. But it is interesting that it keeps going for snow.

The UK Met global does not support this scenario at all. So don't get too excited!

It was the GFS run overnight, OYBBK. It looked like from the Midlands southwards were going to get a good dumping of snow around the 1st/2nd January and the cold was going to last for the whole country, in the days afterwards as well. It's all gone now though in the later runs