Model output discussion - Christmas approaches

[TSNWK]

21 minutes ago, booferking said:

Posted

Thank you..  p1 or 11 please sub zero Max’s top to bottom.. all have Scotland in the cold air and there some shocker with 13c as max in south..

[swfc]

28 minutes ago, MJB said:

Too many knee jerk reactions of individual frames .....................it's a bit comical .

It's the "Chuckle brothers" influence MJB. Anyway things look great this morning on the 6z. Study the models synoptically then breath. 

[Eagle Eye]

1 minute ago, swfc said:

It's the "Chuckle brothers" influence MJB. Anyway things look great this morning on the 6z. Study the models synoptically then breath. 

The models really are going 

To the coldies

To the mildies 

To the coldies

To the mildies

I think we should call it Chuckle Winter 

[nick sussex]

6 minutes ago, Gypo said:

Save going to Twitter

 

Thanks for posting those. A real mix of solutions on offer . Some very good and some ugly looking ones .

[tight isobar]

A definite shift to cold. And we now start to see a defined clustering  below the drop line.from around 26 onwards-@ boxing day!, it’s all preety positive this morning - enjoy ya day

Edited December 18, 2021 by tight isobar

[Lukesluckybunch]

1 minute ago, nick sussex said:

Thanks for posting those. A real mix of solutions on offer . Some very good and some ugly looking ones .

agree nick i dont think there great tbh.

[Lukesluckybunch]

2 minutes ago, tight isobar said:

A definite shift to cold. And we now start to see a defined clustering  below the drop line.from around 26 onwards-@ boxing day!, it’s all preety positive this morning - enjoy ya day

looks encouraging lets hope there similar or even improved in couple days time.

[Mike Poole]

Well having seen the change in the modelling overall from yesterdays 12z to the morning runs, my feeling is that takes us very slightly away from the knife-edge, to one where one might have more confidence that further upgrades will happen now, as we count this thing down.  Particularly for the GFS, which you might expect will lose the dartboard low at some point along that journey.  

I think we are in a much better place this morning.  

[DOdo]

I think that block will win out at the end, Our own Met Eireann have not ruled out snow for Christmas which is unusual for them. There are many more twists and turns to this exciting saga. I am enjoying the ride

[Anthony Burden]

Stunning GFS fantasy island charts,regardless of what happens over Christmas things beginning to 

point towards some very wintery weather after this debacle with Atlantic lows.Always going to be

northern blocking that will be the answer to our weather,key to every door to open the freezer door.

[Earthshine]

18 minutes ago, Gypo said:

Save going to Twitter

 

Blimey, quite the range of outcomes there!

[Phil Blake]

53 minutes ago, Ed Stone said:

Way out in LaLa Land, I know, but bordering on perfection: -9-10C 850s, low SLP and low heights? What more can one ask for?

    

Oh, I nearly forgot: warm North Sea!

North sea temperatures currently between 9-11c. 850s of -9 -10 would surely see some decent convection going on

[nick sussex]

2 minutes ago, Lukesluckybunch said:

agree nick i dont think there great tbh.

I’d say 10 members  vary from passable to very good . So it could have been worse . 

The GFS 06 hrs run manages to spread the fun around because of its evolution .

It’s all very stressful for coldies in here as the stakes are quite high given the rarity of snow on Christmas /Boxing Day .

One thing to bear in mind if this lands  getting to friends and family could be an issue depending on where you live .

[TSNWK]

Just now, Phil Blake said:

North sea temperatures currently between 9-11c. 850s of -9 -10 would surely see some decent convection going on

For it to 72 hours out not 300: plus

[Lukesluckybunch]

1 minute ago, nick sussex said:

I’d say 10 members  vary from passable to very good . So it could have been worse . 

The GFS 06 hrs run manages to spread the fun around because of its evolution .

It’s all very stressful for coldies in here as the stakes are quite high given the rarity of snow on Christmas /Boxing Day .

One thing to bear in mind if this lands  getting to friends and family could be an issue depending on where you live .

thats true its looking quite severe if it does deliver,whats your bet at the moment on cold for xmas boxing day,50/60% chance of cold and snow.how do you see it

[Kasim Awan]

1 hour ago, Catacol said:

Except there is oodles of scientific evidence for the shift in the sub tropical high pressure belt, and a cupboard full of observational data on UK weather patterns over recent decades. This is not original stuff.

And yet for all the negativity surrounding the pattern there is still considerable potential for wintry conditions - indeed I would say the last week has seen this upgrade significantly in terms of broad pattern. Here is the jet streak starting this weekend, modelled by GFS a week or so ago as a result of +EAMT conditions 

To be honest the broad pattern for the weekend we are in has not changed much at all over the previous 7 days. NWP success story. Then the jet pattern for the key period at Xmas

You can clearly see the jet streak has reached the US and is set to hit the Atlantic. However the modelling here has changed a bit. Charts posted a few days ago showed that streak heading in a NW to SE access. The modelling has flattened that prediction out and so we are looking at a much more marginal setup for the trajectory of low pressure systems into the block that has spawned. Why then is this an upgrade?

Put simply because of this. The UK high has managed to achieve Greenland status before we even get to Xmas, something I was personally not expecting but the result surely of the MJO and supportive tropical typhoon engineering the long wave amplification signature required. I would have bet a fair bit on the high sitting over the UK for longer - but instead we appear to be about to cash in on swifter developments. Rarely do high pressure cells move faster than originally forecast.

What this in turn means is that the colder air from the NE is being sucked in that bit more quickly, and the Scandy trough has more room to breath as the broadly meridional pattern forced out of the tropics encourages it southwards. Nothing whatsoever to be gloomy about here.

This in turn is bringing snow opportunities forward to Xmas itself. Remember that this wasn’t really on the cards a week ago. People were focusing on individual runs, seeking the grail of a white Christmas - but the charts were not really showing it. Now we have an accelerated and improved context, and this very marginal but potentially high reward scenario is a possibility.

What is not to like? Answer = nothing.

And what of the period just after Xmas, the period that realistically was the beginning of cold opportunity prior to the upgraded pattern? It’s gone from good to very good. We now have an Arctic High being modelled as the seasonal forecasts are sent scuttling for cover with their tails between their legs, and the optimistic background drivers dig in.

And if you go back to that jet forecast for Xmas above - notice anything? Another pacific jet streak waiting in the wings, helping to maintain the amplified pattern. The MJO remains favourable for a bit longer at least too. The ONLY small negative in all this is that the Greenland block is nudging a bit further west than we would like, as retrogression occurs at serious speed, but with this kind of signal this is not as bad as it sounds. Cold air in place over Scandy and Europe, wedges of heights remaining to the north as a result, overall amplified and meridional pattern - of course there remains the risk of us catching the mild edge of this at times….but there is also the significant opportunity to hit the boundaries between Atlantic moisture and Arctic cold. Is this not what we crave every year?

The current pattern sits in the top 3 for wintry potential from the last 20 years. 2010, 2018 and now 2021. 

 

 

Yes, but I would like to see more concrete research on the causal relationship between hadley cell expansion and uk winter synoptics such as the rate of failed initiation of cold with varying intensities of Hadley cell.

Edited December 18, 2021 by Kasim Awan

[Phil Blake]

1 minute ago, TSNWK said:

For it to 72 hours out not 300: plus

Exactly. Watch it countdown like clockwork . If we can get the pattern locked in then it would not take long to draw in the cold air from the north east. Dew points would be lower too than the failed attempt (last year or the year before I think it was, had 850s of -7 -8 and only sleet due to high dew points) 

[nick sussex]

It might be an idea if you’re going to family on the big day to get one of those bung in the oven Xmas dinners just in case ! 

Of course not forgetting your bobble hat, ear muffs and gloves and sledge just in case your in the higher risk areas !

 

[Mark wheeler]

Hello , Hello , Hello . What do we have here then !!! 

Loving the JMA 

Edited December 18, 2021 by Mark wheeler

[TSNWK]

1 minute ago, nick sussex said:

It might be an idea if you’re going to family on the big day to get one of those bung in the oven Xmas dinners just in case ! 

Of course not forgetting your bobble hat, ear muffs and gloves and sledge just in case your in the higher risk areas !

 

And there be the point... Where be higher risk areas... Im saying the whole lot ends up in the channel and northern France and we are in a cold slack airmass with little features popping up... 

[Summer Snow]

Great to see the models trending colder again today....I think the models will resolve the overall pattern in next few days , but even then the front arriving from the west will be hard to pin down right up to the day....in the run up to the December 2017 slider here in Ireland , Met Eireann issued a warning for Northern areas 2 days out, then moved the warning area to the North midlands / east 24 hours before event. The outcome was the South midlands / south-east ended up in the sweet spot and I ended up with a dumping of snow which stayed around for a few days. Therefore I wouldn't be getting too caught up on exact placement until much closer to the event....the overall pattern shifting south though is pleasing to see and long may it continue...my own personal view is that the low arriving from the west will be much further south than currently modelled ......the longer term also promises much winter goodies based on the latest NOAA charts, ensembles etc......

What a great time of the year to be seeing these synoptics play out....Best since 2010 - but in 2010 that brilliant cold spell was coming to an end, where as this looks like it's only just the beginning..... fascinating to see it all play out and hopefully we will all see snow at some point to bring some seasonal cheer to all in the UK and Ireland .....

[Lukesluckybunch]

4 minutes ago, Mark wheeler said:

Hello , Hello , Hello . What do we have here then !!! 

Loving the JMA 

does this JMA run go all the way?

[bluearmy]

1 minute ago, TSNWK said:

And there be the point... Where be higher risk areas... Im saying the whole lot ends up in the channel and northern France and we are in a cold slack airmass with little features popping up... 

Would Be Excellent !

[nick sussex]

4 minutes ago, Lukesluckybunch said:

thats true its looking quite severe if it does deliver,whats your bet at the moment on cold for xmas boxing day,50/60% chance of cold and snow.how do you see it

I think it’s too early to say in all honesty .

The morning trends have been encouraging though. 

[mushymanrob]

Some very strange comments regarding the GFS 06z....

Id suggest the GFS at day 8, boxing day (mid point of the 6-10 day anomaly) is pretty much bang on! as it corresponds very closely to the Anomaly chart..  of course they could be wrong... but i dont think theyll be far out.