Early run up to Winter 2021/2022 discussion

[Summer8906]

On 28/10/2021 at 19:33, HafrenLMP1 said:

I actually preferred the 2009/10 winter to the following one. Sunny, dry and cold is my ideal 'winter' weather, with the odd fall of snow. Anything that isn't grey, mild, wet & windy......

Feb 2010 was a bit desperate though: coldish but very dull and wet.

@damianslawsorry for OT comment - just seen your post. Feel free to delete this one.

Edited October 30, 2021 by Summer8906

[Catacol]

Looking still at the building blocks - worth a brief look at the current cycle of the MJO. 

Broadly speaking, therefore, we have the MJO entering 7/8/1 in the middle of November approx. One driver alone does not a forecast make....but this might suggest greater chance of blocking in the latter half of November and the MetO long ranger suggests so. However of greater interest for snow hunters is the likely periodicity of the next 7/8/1 phase. The MJO is described as a cycle that repeats every 30 - 60 days. Observationally it seems to me that it comes in more frequently closer to the 30 days than the 60. So in terms of our weather ahead we can make a gently educated guess that we will see 7/8/1 phases at the end of December and then again in early February. If you are a believer in the power of the MJO then this suggests greatest chance of cold weather occuring in the New Year and in early to mid February.

But....only one piece of a big jigsaw and it assumes the MJO cycle sticks to script.

Edited October 30, 2021 by Catacol

[E17boy]

Hi peeps

Hope you are all well. I have not posted on here yet this season but here I am and my chase for snow is on.

Just had a read of Gav’s seasonal model 2nd round up which was done today and I must admit it has put me into a downbeat mode. Most of the seasonal models he mentioned today are going for a mild to milder than average winter, except for a few which have got some northern blocking ie the Beijing  climate centre model is going for some northern blocking but only slightly.

However I suspect this needs to be taken with a pinch of salt, and there may be a swing to colder when the next roundup is done at the end of November.

I really hope the pieces of the jigsaw fall in place and we at least get a weeks worth of snow and cold this season.

There is a long ride ahead .

THE SEARCH FOR OUR WINTER WONDERLAND HAS STARTED

Stay safe all

regards

[I remember Atlantic 252]

5 minutes ago, E17boy said:

Hi peeps

Hope you are all well. I have not posted on here yet this season but here I am and my chase for snow is on.

Just had a read of Gav’s seasonal model 2nd round up which was done today and I must admit it has put me into a downbeat mode. Most of the seasonal models he mentioned today are going for a mild to milder than average winter, except for a few which have got some northern blocking ie the Beijing  climate centre model is going for some northern blocking but only slightly.

However I suspect this needs to be taken with a pinch of salt, and there may be a swing to colder when the next roundup is done at the end of November.

I really hope the pieces of the jigsaw fall in place and we at least get a weeks worth of snow and cold this season.

There is a long ride ahead .

THE SEARCH FOR OUR WINTER WONDERLAND HAS STARTED

Stay safe all

regards

Ya can stay another day! where you been all summer then?

[E17boy]

3 minutes ago, I remember Atlantic 252 said:

Ya can stay another day! where you been all summer then?

Hi Atlantic 252 I did post now and then when I was storm chasing, but winter is my main season.  Fingers crossed for this chase.

hope you are keeping well 

regards 

[Froze were the Days]

58 minutes ago, E17boy said:

Just had a read of Gav’s seasonal model 2nd round up which was done today and I must admit it has put me into a downbeat mode. Most of the seasonal models he mentioned today are going for a mild to milder than average winter, except for a few which have got some northern blocking ie the Beijing  climate centre model is going for some northern blocking but only slightly.

I shouldn't worry too much fella...LRF's and to a degree global seasonal models I wouldn't take as gospel. I remember I believe in the run up to 2018/19 winter (correct me if I'm wrong) a reasonable amount of models (EC/Glosea and a number of foreign ones) were showing some form of Northern blocking through DJF other than the DWD (German) and think Canadian (GEM)...guess which were closer to the mark?

Gav uses analogue pattern matching from previous years and as much as I admire his enthusiasm and the effort put in it feels a bit outdated with the earth heating up so significantly of recent years with warmer SST's, less sea ice and warmer continents and matching teleconnections from then (I'm talking 20/30+ odd years ago) to now seems a tad fruitless in my opinion - but as said full credit for the effort put in.

[E17boy]

6 minutes ago, Froze were the Days said:

I shouldn't worry too much fella...LRF's and to a degree global seasonal models I wouldn't take as gospel. I remember I believe in the run up to 2018/19 winter (correct me if I'm wrong) a reasonable amount of models (EC/Glosea and a number of foreign ones) were showing some form of Northern blocking through DJF other than the DWD (German) and think Canadian (GEM)...guess which were closer to the mark?

Gav uses analogue pattern matching from previous years and as much as I admire his enthusiasm and the effort put in it feels a bit outdated with the earth heating up so significantly of recent years with warmer SST's, less sea ice and warmer continents and matching teleconnections from then (I'm talking 20/30+ odd years ago) to now seems a tad fruitless in my opinion - but as said full credit for the effort put in.

Hi 

I remember 2018/19 as well there was much excitement that quite a few of the models were going for northern blocking, but it did not materialise.

it is really impossible to predict a month or a few months ahead. Even the short term daily forecasts sometimes don’t go according to plan. The weather will keep changing.and no matter how much technology and skill we may have it’s something that will always be a guess game trying to predict it for the longer term.

Anyway Let’s see what happens in November and what appears above our island in terms of any blocking signals. I am also keeping an eye out on how temperature will be doing across Eastern and Northern  Europe and if there is any dramatic drop.  Also will be looking at the pressure patterns to see if any signs of high pressure building over scandi or north of us, and if the Atlantic slows down. Dips in the jet stream with weather systems pushing further south than us is another sign the it’s not a normal west to east pattern.

take care

kine regards

[Wold Topper]

On 30/10/2021 at 19:03, I remember Atlantic 252 said:

Ya can stay another day! where you been all summer then?

You are a miserable sod, can't people have different weather preferences and perhaps refrain in summer and rejoice in winter? 

[SqueakheartLW]

Take a look at these BOOM!!! charts from today's CFS 00z run for early part of January 2022

Tuesday 4th January 2022

Will winter strike or not?

Already signs here of a brewing battleground between the Atlantic and the Scandi block. Guess which one is going to win out on the next few charts. Already a very cold day over a good part of the UK with daytime maxes below 0C. The surface wind pattern is clearly drawing in that lower level cold from the SE on this day with that cold blue blob over central Europe.

Wednesday 5th January 2022

Another cold day but will we get the "Beast"?

The high is starting to pull up a bit further to the north here and this is turning the winds more from the S or SE into the E. Despite similar 850hpa temps to the previous day the change in wind direction from SE to E means more of a track over the North Sea so temperatures not quite as low in the north as the previous day but the shorter sea track in the south means more sub zero daytime maxes in the south.

Thursday 6th January 2022

The Beast is beginning to stir

The high pressure is pushing further up to the north now and we are now into a more of a direct easterly over England and Wales at least but this isn't the beast just yet. Look at all those cold uppers waiting over eastern Europe and Western Russia to move over towards the UK. With even more of a North Sea influence now and winds beginning to pick up we achieve daytime maxes above freezing here but not by very much.

Friday 7th January 2022

Here it comes, the beast is coming

The high is now even further north and the winds have gone due easterly and this is now pushing all that cold air to the east towards us. Snow showers are a real threat, especially the further east you are in the UK but some could even make their way over to the west. Another cold day but maxes do get above freezing on this day but even colder conditions are still to come.

Saturday 8th January 2022

Beast from the east unleashed, especially in the S and E

Here comes the full blown beast to the UK. The south and east are hardest hit and get the full force of the cold sub zero daytime maxes and look at those cold uppers too. Snow showers in the east and even more persistent snow a possibility in the south. Significant wind chill too.

Sunday 9th January 2022

The beast continues for a second day, wrap up warm and enjoy the snow

Day 2 of the full blown beast sees the continuation of heavy snow showers and even more organized snow showers too. Even colder than yesterday with sub zero maxes again in southern parts. However things are about to warm up quite a bit for those who would want this to end quickly

Monday 10th January 2022

Snowmageddon - Not really. Just a transitional snow event

The coldest of the uppers have finally blown away and milder air is beginning to push in from the south. This isn't without a fight by the cold air though and as this mild air hits all of that beast air it turns to a band of snow which pushes north throughout the day. Daytime maxes just scraping above freezing ahead of the warm front.

Tuesday 11th January 2022

The big thaw

The beast has moved on now and the mild air from the south has pushed right up over the UK now. Temperatures are in high single digits in the south and around mid single in the north so the snow is now melting to a degree. The rest of January 2022 on this particular run is generally milder than average so despite the very cold start the month actually ended up averaging just a tiny bit above the 1991-2020 mean. An anomaly of something around +0.13C or there about.

Hope you enjoyed this fantasy cold scenario the CFS generated on this run. Really for fun but it may happen yet.

[damianslaw]

6 hours ago, E17boy said:

Hi peeps

Hope you are all well. I have not posted on here yet this season but here I am and my chase for snow is on.

Just had a read of Gav’s seasonal model 2nd round up which was done today and I must admit it has put me into a downbeat mode. Most of the seasonal models he mentioned today are going for a mild to milder than average winter, except for a few which have got some northern blocking ie the Beijing  climate centre model is going for some northern blocking but only slightly.

However I suspect this needs to be taken with a pinch of salt, and there may be a swing to colder when the next roundup is done at the end of November.

I really hope the pieces of the jigsaw fall in place and we at least get a weeks worth of snow and cold this season.

There is a long ride ahead .

THE SEARCH FOR OUR WINTER WONDERLAND HAS STARTED

Stay safe all

regards

Seen to recall Beijing climate centre was the only one we went with an average or slightly below average winter this time last year.. and was right!

[jules216]

20 hours ago, Catacol said:

Looking still at the building blocks - worth a brief look at the current cycle of the MJO. 

Broadly speaking, therefore, we have the MJO entering 7/8/1 in the middle of November approx. One driver alone does not a forecast make....but this might suggest greater chance of blocking in the latter half of November and the MetO long ranger suggests so. However of greater interest for snow hunters is the likely periodicity of the next 7/8/1 phase. The MJO is described as a cycle that repeats every 30 - 60 days. Observationally it seems to me that it comes in more frequently closer to the 30 days than the 60. So in terms of our weather ahead we can make a gently educated guess that we will see 7/8/1 phases at the end of December and then again in early February. If you are a believer in the power of the MJO then this suggests greatest chance of cold weather occuring in the New Year and in early to mid February.

But....only one piece of a big jigsaw and it assumes the MJO cycle sticks to script.

Week 2 has a Nina like forcing around MC,phases 4-5 maybe 6 that is not bad timing at all

[jules216]

Look how important is for this MJO to get its thing going, velocity potential does look like phase 4 come week 2, also as equally important is for the destructive Pacific subsidence to move through South America to resemble phase 5 forcing as only then can the Rossby wave train influence our Atlantic sector, the longer it takes and the weaker the event is the advection of blocking high will be more southerly in nature - flat westerly. The timing of MJO is perfect,but the amplitude and propagation will decide, too long phase 4 does look worse and worse by the seasonal wavelenghts.

[sebastiaan1973]

Interesting contribution from Gav, especially on the comparison of seawater temperature

http://Winter 2021/22 Forecast: Ninth Update (Part One) - YouTube

[SqueakheartLW]

Saw a nice cold January run on yesterday's CFS 18z 9 monthly. It's CET mean came in at a more or less match for January 2010 at 1.37C.

First here are the min and max figures I got from the 2m temp charts.

Lowest Min during this January 2022 run = -5.0C on both Jan 14th and Jan 25th

Lowest Max during this January 2022 run = -2C on Jan 16th

Highest Min during this January 2022 run = 4C on Jan 11th

Highest Max during this January 2022 run =5C on Jan 4th, 11th and 12th

Date         Min          Max                    Date         Min          Max                    Date          Min          Max

Jan 1st      2.0           4.0                      Jan 12th   3.0           5.0                       Jan 22nd  -2.0         0.0

Jan 2nd     2.0           4.0                      Jan 13th   2.0           3.0                       Jan 23rd   0.0          1.0

Jan 3rd      3.0           4.0                      Jan 14th   -5.0          0.0                       Jan 24th  -3.0         1.0

Jan 4th      3.0           5.0                      Jan 15th   -2.0          0.0                       Jan 25th  -5.0         -1.0

Jan 5th      3.0           4.0                      Jan 16th   -3.0         -2.0                       Jan 26th  -3.0         1.0

Jan 6th      2.0           3.0                      Jan 17th   -2.0          1.0                       Jan 27th   0.0          2.0

Jan 7th      1.0           4.0                      Jan 18th   1.0           2.0                       Jan 28th   0.0          3.0

Jan 8th      3.0           4.0                      Jan 19th   1.0           3.0                       Jan 29th   2.0          4.0

Jan 9th      2.0           4.0                      Jan 20th   0.0           2.0                       Jan 30th   1.0          2.0

Jan 10th    3.0           4.0                      Jan 21st   -3.0         1.0                        Jan 31st    0.0          2.0

Jan 11th    4.0           5.0                                                                                                                               

 

Now feast your eyes upon these selected cold charts for January 2022 based on the 18z CFS 9 monthly run dated 30/10/2021

1st Jan 2022

5th Jan 2022

9th Jan 2022

12th Jan 2022

14th Jan 2022

16th Jan 2022

18th Jan 2022

21st Jan 2022

26th Jan 2022

28th Jan 2022

30th Jan 2022

[Cambrian]

I find that I can’t put too much stock in the winter seasonal forecasts, they make for interesting reading, but they often span too wide a range of potential outcomes, presumably depending on a wide range of modelling methodologies, different starting parameters and weightings etc., to be that credible. In any case, all they often do is end up with a “default” output that has a slightly higher chance of being realised than not, which is fine if that is the expectation.

They also can’t by their nature pick up on the impacts of single events on the rest of the season, for example a seemingly innocuous plunge of cold air into mainland Europe that contributes to a blocking pattern thereafter, and eventually brings us into the fray for some wintry weather. Nor can these models account for SSW’s, their likelihood or effects if they do occur.

The analogue approach is tremendously interesting, but of course is flawed in terms of reliable prediction of our most wintry weather as soon as we accept that no two years can possibly be the same, no two synopses can be exactly the same, and the importance of the raft of local effects at play in our winter weather, particularly in the UK and Ireland; and again, SSW’s.

I regularly read Judah Cohen’s updates and learn of all the factors considered to be determinant in the Arctic oscillation, establishment, maintenance and disruption of the polar vortex. These appear to be successfully applied in broad terms. However, determining the consequences for our weather in the UK and Ireland of these hemispheric PV events is not so tractable, and the outlook for specific regions is always restricted to only two weeks ahead. 

What we’re left with is interpreting the likely effects on our weather of propagation of repeated long wave patterns already observed in a given year as we approach winter, accepting of course that the pattern can change abruptly at any time. With this, we can endeavour to venture forward firstly to the more reliably modelled period of the next 1-2 weeks, then if there’s a fit with the pattern of recent months, extrapolating to looking at the probable patterns over the next 6-8 weeks. 

Winter 2021-22 : So for this coming winter, as ever we are being teased, essentially on this occasion, being in a notably slow moving pattern, we face the conundrum of judging the relative amounts of time we are to spend under the Azores ridge to the east of the North Atlantic trough (mild and dry), how long it takes to get the trough back over us (mild and wet), how long we spend under the trough (wet and cold, potentially wintry), how long we spend to the west of the trough (cold and wintry), and then how long under a high coming in from the west (dry and cold). We also have to keep an eye out for a pattern change in the form of trends towards the establishment of a firm European, Scandinavian or Greenland high. 

The current periodicity is for roughly 50 / 50 under the trough vs. not under the trough, and also for northerly or northwesterly vs. high pressure or milder directions. The 9-panel of the 0z ECM operational run from today shows this nicely. Counting 2 days at the start under the trough in a northwesterly, there are five out of eleven. The toppling high following the trough will also give cold night temperatures, meaning that we’re only in a properly mild feed about 30% of the time, which fits with the slightly below average overall temperatures in the extended forecast from the Met Office.

The current safest bet for the first part of the winter has to be on a continuation of the slow pattern, no real trends towards emergence of a European or Scandinavian high, or towards the polar vortex being located towards Greenland, with a North Atlantic diving trough being driven amongst other things by pulses of warm air advection out of Canada to Greenland, so some potential for formation of a Greenland high. If this pattern is maintained, the seasonal cooling of the Arctic should ultimately drive deeper troughs running along a more southerly tracking jet stream, frequently NW-SE aligned to our shores. In the absence of a signal for a Scandinavian high, cold trough formation / extension there also becomes more likely.

The caveat is the oscillation of the Aleutian low, in recent times often where it should be, driving the downstream sequence that brings us into the cold part of the trough, but at other times, slipping over to the Southern Alaska / Canada coast, which flattens the pattern through Canada, preventing any WAA into Greenland. The result for us here is a mild high pushing up from the south with or without the conveyer belt of rain into the north and west, depending on how close we are to the polar front. It is however notable that we haven’t seen an Aleutian high for many weeks now, just the moving around, part filling and re-intensification of the low. At the end of the ECM run, the Aleutian low is neatly back in place, after its gander to the coast in the intervening period, and there is the beginnings of a central Canada trough. This is a repeated feature of day 10 at the moment and I’d like to think the models are picking up on the general forcing and trends.

So to my mind it’s likely to be from the middle part of the month that we see the colder pattern, that we have already seen develop intermittently in recent weeks, begin to become more firmly established, the cold spells lengthened by the diving troughs and jet stream being pushed further south as colder air amasses around the pole with the approach and passing of the winter solstice. 

For the remaining 9 weeks of 2021, my feeling is that our cold weather, when we get it, later in November and into December will come from the northwest and north, with weather from this direction being much more frequent than usual. Low pressure systems getting stuck at the base of the trough will provide opportunities for more general wintry events, particularly as it all cools down into December.

This is only a guess, half a clue based on not being able to see anything that suggests an end to the current pattern, and in that event, this pattern, if anything, becoming more entrenched with colder feeds from the Arctic. I think this is part of what others are seeing when they speak of a front-loaded winter. And we can all have a great laugh at this post when following a big pattern change next week, we have two months of mild, sunny weather, eating our Christmas pudding out in the garden! But it’s worth a punt.

After this period of the next couple of months, I haven’t even half a clue, but then in reality, I wonder if anyone has. 

[East_England_Stormchaser91]

Some absolutely awesome FI charts to be had at the moment! Of course, not to be taken too seriously. The lowering pressure in the Mediterranean is not a bad thing for the here and now, as that will prevent any deep eurotrash high from setting up. It will be interesting to see what will result from this benign high that is set to come in. If it retrogresses or amplifies to the N, then it could well open the gates to some early cold. 

Very notable how quickly the arctic is icing over this year, and the impressive amount of snowcover of the Siberian/Russian side of the arctic, and also lack of snow over the American/Canadian side. This may be promoting more cold pooling our side, and stopping the jet from powering up over the US. Definitely not your usual Autumn across the NH. 

[Catacol]

And MJO, discussed a few days ago, showing some potential for emerging into phase 7 by the second half of the month. ECM spaghetti forecast below:

[Catacol]

I think, all things considered, we are seeing a growing stack of evidence suggesting a blocked and cold pattern as we move into December. Personally I hope winter doesn't start and end there - and signals pointing to an SSW and something more substantial in mid winter can come together....but for favoured spots and areas of high ground the first half of December could bring some wintry cheer.

[damianslaw]

2 hours ago, Catacol said:

I think, all things considered, we are seeing a growing stack of evidence suggesting a blocked and cold pattern as we move into December. Personally I hope winter doesn't start and end there - and signals pointing to an SSW and something more substantial in mid winter can come together....but for favoured spots and areas of high ground the first half of December could bring some wintry cheer.

Remember the likes of 2008, 2012 and 2017 to lesser extent that brought cold wintry weather first half of Dec but then very mild wet weather build up to Christmas. Personally much prefer second half of Dec to be cold and wintry than first half. 2009 was excellent in this respect. Mind 2008 the cold quickly came back at Christmas. Not had a cold run in to Christmas since 2010.. overdue! 

[sundog]

36 minutes ago, damianslaw said:

Remember the likes of 2008, 2012 and 2017 to lesser extent that brought cold wintry weather first half of Dec but then very mild wet weather build up to Christmas. Personally much prefer second half of Dec to be cold and wintry than first half. 2009 was excellent in this respect. Mind 2008 the cold quickly came back at Christmas. Not had a cold run in to Christmas since 2010.. overdue! 

First half of December 2011 was chilly with a lot of pm air ,nothing too exciting but I did get light dustings of snow on a couple of nights. Second half of that December was much milder.

[Anthony Burden]

Morning all weather at present rather cold with the first frosts for some.Nice start for the beginning of November,but

as we all do looking for what’s next.temperatures look to return to average or slightly above,but a home grown

high pressure could change temperatures due to fog / frost so everything up in the air at present for mid November,

after that in the lap of the Gods.

[SqueakheartLW]

2 of the recent CFS runs caught my eye. The first was the 06z CFS 9 monthly run for a large part of December 2021 and the first half of January 2022. The second run was the 12z from yesterday as it contains a very cold Christmas 2021 episode.

Run 1 - CFS 06z 9 monthly run dated 01/11/2021     The 2 cold or very cold spells

December 1st 2021

This is how December 2021 starts with us under a cold high pressure area which has brought cold uppers over from the east. Nothing especially brutal in terms of cold but low single figure days and frosty nights.

December 5th 2021

We push an area of low pressure up into this cold air so there is potential here for a snow event in the S and E especially and a snow shower risk increases in general in exposed coastal regions in the NE. Look at all that increasingly cold air appearing to the east of Europe but does this pounce on the UK or not?

December 11th 2021

We just generally turn cold and unsettled with the risk of snow moving around the UK under that low pressure area but milder weather is on the way but only a brief warm up.

December 18th 2021

This is the mildest day of December 2021 in the relatively brief milder spell but a lot of colder air is pooling now to the east and this looks like it could be threatening to head in our direction

December 22nd 2021

Cold air is now making its way back into the UK from the north after the high pressure that was to our south retrogresses then pulls up towards Greenland. This is the start of what is going to be the most severe of the cold on this 06z run.

December 25th 2021

Anyone want a White Christmas? Looks like we could be having one here. A trough is moving down the UK within the cold flow and is no doubt taking a band of snow down from the N with it. Could be quite a widespread snow event if this comes off.

December 28th 2021

That low pressure was threatening to end the cold spell on the previous day's chart but this one is interesting as the low simply can't shift the cold block to the east and very cold uppers are waiting here to pounce. A west UK snow event is likely here as the milder air over N Ireland and the republic comes up against the Great Britain cold air.

December 29th 2021

The cold air has won out and a beasterly has developed here and brought very cold uppers and sub zero daytime maxes. This is the most brutal part of this colder spell and in general lasts now until mid January.

The change starts here when the SW winds come back but it takes some time to shift the cold

Only by this day does it finally turn much milder

After this on the 06z run it stays mild throughout February 2022 and March 2022

Run 2 - CFS 12z 9 monthly run dated 01/11/2021     The very cold Christmas spell

Two recent CFS runs that both feature cold around Christmas time but this very brief cold snap is much colder than the cold that comes at Christmas on the 06z. Read on and enjoy

December 23rd 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

I begin the summary of this very brief severe cold snap just a couple of days before it strikes. On this day there is no signs at least in the UK of what is about to happen. A very typical Atlantic driven day with wind and rain no doubt pushing in on the S to SW winds but take note of that big very cold blob there over eastern Europe on the 850hpa temps chart. That is going to play a part in the Christmas weather on this particular run. Minimum temps on this day range from around 8C in the south to 4C in the north whilst maximums are around 9C in the south to 7C in the north.

December 24th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Christmas Eve 2021 on this run is very much transition day from the relative mild weather to the arrival of the cold from the east. Notice the low pressure initially struggles against the block to the east and so this angles the winds so that the very cold blob at 850hpa starts heading in towards the UK and at this stage it looks like we are on for a direct hit from that brutal cold. This day is also bizarre in that temperatures just keep falling throughout the day and in fact the highest temperatures are at the very start of Christmas Eve and fall away right to the end of the day. Maximums are around 8C in the west to 4C in the north with 6C quite widespread in the east. By the end of Christmas Eve we get our minimums for the day ranging from 6C in the far SW to 0C in the north and -2C in the east.

December 25th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Christmas Day and a very cold one at that. We have lost the beasterly type pattern but under that high pressure a lot of cold air is now trapped there for the day. The brutal cold 850hpa temps look to be stalling and look like they are not going to reach us after all and if they had done these minimum and maximum 2m temps would have likely been even lower than they are. This run gives an ice day Christmas Day for really all inland regions of Great Britain at least. Minimums range from around -2C in the north to some localized -8C's in central England. Maximums range from 0C in the north to -4C in central England. A very cold Christmas Day on this run.

December 26th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Boxing Day. The cold relents a little but still a very cold night before a patchy ice day for Boxing Day. In general the coldest spots are higher ground in Scotland as well as central England. The brutal 850hpa temps are now pushing away in the other direction and the low pressures are now starting to queue up in the Atlantic once more, a sign of what is about to happen. Minimums on this day range from -4C to -6C whilst the maximums range from -2C in both Scotland and central England to 2C in northern England and N Ireland too.

December 27th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

The last of the really cold days before the transition back to mild starts once more. That low pressure in the Atlantic has wound itself up now and this is beginning to push milder air towards the UK. It doesn't arrive on this day however so we remain very much in the freezer still. Minimums range from -2C in central England to just above freezing really elsewhere away from Scottish mountains whilst maximums range from -2C to 2C.

December 28th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Transition back towards milder day 1. This is the big day in terms of a transitional snow event. Milder air gets into the SW of the UK during the day but the cold generally hangs on further N and E. A band of snow pushes NE across England and Wales during this day reaching the midlands and NW England by the end of the day. Minimum temps start out at around -1C in central England and around 0 to 1C in the north with temps already up to 10C in the far SW with the arrival of the milder air. Maximum temps range from a cold 2 to 4C in the N and E through to a very mild 11 to 12C along the south coast and in the SW of England.

December 29th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Transition to mild day 2. This is when the mild air finally pushes across the entire UK. The last of any transitional snow clears through overnight and temperatures continue to rise throughout. Rain becomes the main threat now as well as some quite strong winds. Minimum temps range from around 0C in the far north to 10C in the South and West. Temperatures continue to rise throughout the day so by the time we get to the end of the day and our maximum values for the day we range from 6C in central Scotland right up to the general range of 10 to 12C across England, Wales and N Ireland.

[syed2878]

On 02/11/2021 at 14:08, SqueakheartLW said:

2 of the recent CFS runs caught my eye. The first was the 06z CFS 9 monthly run for a large part of December 2021 and the first half of January 2022. The second run was the 12z from yesterday as it contains a very cold Christmas 2021 episode.

Run 1 - CFS 06z 9 monthly run dated 01/11/2021     The 2 cold or very cold spells

December 1st 2021

This is how December 2021 starts with us under a cold high pressure area which has brought cold uppers over from the east. Nothing especially brutal in terms of cold but low single figure days and frosty nights.

December 5th 2021

We push an area of low pressure up into this cold air so there is potential here for a snow event in the S and E especially and a snow shower risk increases in general in exposed coastal regions in the NE. Look at all that increasingly cold air appearing to the east of Europe but does this pounce on the UK or not?

December 11th 2021

We just generally turn cold and unsettled with the risk of snow moving around the UK under that low pressure area but milder weather is on the way but only a brief warm up.

December 18th 2021

This is the mildest day of December 2021 in the relatively brief milder spell but a lot of colder air is pooling now to the east and this looks like it could be threatening to head in our direction

December 22nd 2021

Cold air is now making its way back into the UK from the north after the high pressure that was to our south retrogresses then pulls up towards Greenland. This is the start of what is going to be the most severe of the cold on this 06z run.

December 25th 2021

Anyone want a White Christmas? Looks like we could be having one here. A trough is moving down the UK within the cold flow and is no doubt taking a band of snow down from the N with it. Could be quite a widespread snow event if this comes off.

December 28th 2021

That low pressure was threatening to end the cold spell on the previous day's chart but this one is interesting as the low simply can't shift the cold block to the east and very cold uppers are waiting here to pounce. A west UK snow event is likely here as the milder air over N Ireland and the republic comes up against the Great Britain cold air.

December 29th 2021

The cold air has won out and a beasterly has developed here and brought very cold uppers and sub zero daytime maxes. This is the most brutal part of this colder spell and in general lasts now until mid January.

The change starts here when the SW winds come back but it takes some time to shift the cold

Only by this day does it finally turn much milder

After this on the 06z run it stays mild throughout February 2022 and March 2022

Run 2 - CFS 12z 9 monthly run dated 01/11/2021     The very cold Christmas spell

Two recent CFS runs that both feature cold around Christmas time but this very brief cold snap is much colder than the cold that comes at Christmas on the 06z. Read on and enjoy

December 23rd 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

I begin the summary of this very brief severe cold snap just a couple of days before it strikes. On this day there is no signs at least in the UK of what is about to happen. A very typical Atlantic driven day with wind and rain no doubt pushing in on the S to SW winds but take note of that big very cold blob there over eastern Europe on the 850hpa temps chart. That is going to play a part in the Christmas weather on this particular run. Minimum temps on this day range from around 8C in the south to 4C in the north whilst maximums are around 9C in the south to 7C in the north.

December 24th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Christmas Eve 2021 on this run is very much transition day from the relative mild weather to the arrival of the cold from the east. Notice the low pressure initially struggles against the block to the east and so this angles the winds so that the very cold blob at 850hpa starts heading in towards the UK and at this stage it looks like we are on for a direct hit from that brutal cold. This day is also bizarre in that temperatures just keep falling throughout the day and in fact the highest temperatures are at the very start of Christmas Eve and fall away right to the end of the day. Maximums are around 8C in the west to 4C in the north with 6C quite widespread in the east. By the end of Christmas Eve we get our minimums for the day ranging from 6C in the far SW to 0C in the north and -2C in the east.

December 25th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Christmas Day and a very cold one at that. We have lost the beasterly type pattern but under that high pressure a lot of cold air is now trapped there for the day. The brutal cold 850hpa temps look to be stalling and look like they are not going to reach us after all and if they had done these minimum and maximum 2m temps would have likely been even lower than they are. This run gives an ice day Christmas Day for really all inland regions of Great Britain at least. Minimums range from around -2C in the north to some localized -8C's in central England. Maximums range from 0C in the north to -4C in central England. A very cold Christmas Day on this run.

December 26th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Boxing Day. The cold relents a little but still a very cold night before a patchy ice day for Boxing Day. In general the coldest spots are higher ground in Scotland as well as central England. The brutal 850hpa temps are now pushing away in the other direction and the low pressures are now starting to queue up in the Atlantic once more, a sign of what is about to happen. Minimums on this day range from -4C to -6C whilst the maximums range from -2C in both Scotland and central England to 2C in northern England and N Ireland too.

December 27th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

The last of the really cold days before the transition back to mild starts once more. That low pressure in the Atlantic has wound itself up now and this is beginning to push milder air towards the UK. It doesn't arrive on this day however so we remain very much in the freezer still. Minimums range from -2C in central England to just above freezing really elsewhere away from Scottish mountains whilst maximums range from -2C to 2C.

December 28th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Transition back towards milder day 1. This is the big day in terms of a transitional snow event. Milder air gets into the SW of the UK during the day but the cold generally hangs on further N and E. A band of snow pushes NE across England and Wales during this day reaching the midlands and NW England by the end of the day. Minimum temps start out at around -1C in central England and around 0 to 1C in the north with temps already up to 10C in the far SW with the arrival of the milder air. Maximum temps range from a cold 2 to 4C in the N and E through to a very mild 11 to 12C along the south coast and in the SW of England.

December 29th 2021

500hpa                                                      850hpa

2m temp Min                                          2m temp max

Transition to mild day 2. This is when the mild air finally pushes across the entire UK. The last of any transitional snow clears through overnight and temperatures continue to rise throughout. Rain becomes the main threat now as well as some quite strong winds. Minimum temps range from around 0C in the far north to 10C in the South and West. Temperatures continue to rise throughout the day so by the time we get to the end of the day and our maximum values for the day we range from 6C in central Scotland right up to the general range of 10 to 12C across England, Wales and N Ireland.

 This does look rather exciting how ever this is the CFS secondly I would be extremely excited if this was 144 hours away however this is a month away yet if only this came to fruition then I think netweather would have to order a new server because of the melt down.

[Don]

On 31/10/2021 at 01:44, damianslaw said:

Seen to recall Beijing climate centre was the only one we went with an average or slightly below average winter this time last year.. and was right!

Yes, I think that's correct.  I believe it was the only model going for a very hot and blocked summer in 2018, too.  

[SqueakheartLW]

Christmas 2021 Update Number 5

Christmas update number 5 is now upon us as I have collected another weeks worth of 2m temperature data from the CFS 9 monthly runs so here we go. Time to present the data I have gathered so far in the image below

As we can see here just like with all other weeks we have a whole range of outcomes again from mild to cold. The big thing this week is how we set record highs and lows in all categories except highest daily minimum and there was a very cold Christmas run during the last week which I have featured as a separate post here just to show for fun.

How does week 5 compare with all of the others and will it be milder or colder than update 4 or sit somewhere in the middle or can be set mildest or coldest update so far, here are the numbers.

Week 1 came out like this                                                         Week 2 came out like this

              Average Min     Average Max     Average Mean                      Average Min       Average Max      Average Mean

Temp          3.61                      5.79                    4.70                  Temp          4.21                       5.96                     5.09

Anom        +1.52                     -1.24                  +0.14                 Anom        +2.12                     -1.07                    +0.53

Week 3 came out like this                                                         Week 4 came out like this

                Average Min    Average Max    Average Mean                     Average Min       Average Max      Average Mean

Temp           2.71                      5.43                     4.07                Temp          3.96                       6.36                     5.16

Anom          +0.62                   -1.60                    -0.49                Anom        +1.87                     -0.67                   +0.60

Week 5 summary

How does week 5 compare with weeks 1 to 4 and will we be milder or colder than last week or maybe even milder or colder than weeks 1 to 4. Included is the change from week 4 as well

                    Average Min                Average Max            Average Mean

Temp          4.00 (up +0.04)           6.57 (up +0.21)        5.29 (up +0.13)

Anom        +1.91                             -0.46                         +0.73

When we averaged out all of the max, min and mean data for week 1 it wasn't a great start for cold fans with the overall +0.14C milder anomaly. The coldies misery continued in week 2 when we shifted more into the direction of a milder Christmas overall and stood at a weekly average of 5.09C which was +0.53C above the 1991-2020 25th December mean. Week 3 was good news for coldies as we came back with an overall Christmas Day mean of 4.07C which is -0.49C below the 1991-2020 25th December mean. Update 4 came out as the mildest one so far last week with a Christmas Day mean anomaly of +0.60C. 

The bad news for coldies is that week 5 has pushed even further in the direction of milder conditions for Christmas Day as we have set a new averaged out mean of 5.29C which is +0.73C above the 1991-2020 Christmas Day mean and this is an increase of the anomaly by 0.13C. This puts us at 4 milder updates and just 1 colder update so far so chances of cold if CFS is to be believed are reducing every week I do these updates.