Model Output Discussion - Christmas week and beyond

[nick sussex]

I’d say the chances of  a White Christmas has improved today for Scotland and the far north of England .

So not a bad start to the day and the ECM is huge relief given its recent op runs .

It is however a very complex set up because of the low heights to the north so the propensity for shortwaves to pop up can’t be ruled out given the timeframes .

Edited December 27, 2022 by Paul
Edited to topic title

[Mike Poole]

ECM clusters T120-T168:

Variations on a theme in the Christmas period, cluster 3 looks the best, clusters 1 and 5 OK for the north.  Cluster 4 has the southwesterly, the one to avoid, seems to be diminishing now run to run.

T192-T240:

Cluster 1, that leave sufficient gap between the low SW and the low heights to our NE for the euro heights to join those over Greenland has grown to 30 members, from 22 yesterday.  Cluster 2 goes a different route, but also cold for the UK.  So these are both good at this range.

Edited December 19, 2022 by Mike Poole

[Chesil View]

An albeit grudging move from ecm towards last nights gfs run but not yet enough to bring most of England into play for xmas. 

However as  Matt Hugo posted last night the situation is very complicated and fluid so a fair way to go until this is resolved even at this seemingly close range

Edited December 19, 2022 by Chesil View

[That ECM]

9 minutes ago, Mike Poole said:

ECM clusters T120-T168:

Variations on a theme in the Christmas period, cluster 3 looks the best, clusters 1 and 5 OK for the north.  Cluster 4 has the southwesterly, the one to avoid, seems to be diminishing now run to run.

T192-T240:

Cluster 1, that leave sufficient gap between the low SW and the low heights to our NE for the euro heights to join those over Greenland has grown to 30 members, from 22 yesterday.  Cluster 2 goes a different route, but also cold for the UK.  So these are both good at this range.

IF we are to go back in the freezer then that’s the best chance imo. 

[geordiekev]

GFS still on the sherry or will it's consistency be a test of it's upgraded mettle?

[ANYWEATHER]

Not posted any charts, but looking good for you cold lovers as this change in the weather looks likely to be a short milder spell. Will be an interesting week coming up. Usual complications and variances in the models but the run up too Christmas and beyond could well see the cold even deeper than this last notable cold spell.......Here we go for the next winter roller coaster ....

[MJB]

Snow opportunities in that lot 

[Anthony Burden]

Morning all,uncertainty in the charts this morning Gem/ICON going for a scorcher ECM/GFS cold with pressure rise to the north all around Christmas period.Interesting weather scenarios although the colder period after Christmas has been shown on and off from the charts for a while especially in the north,need to keep an eye on the fax charts over the next few days.

[bluearmy]

1 hour ago, mulzy said:

Scandi high if FI is probably one of the options on the table (after seeing that ECM run).  Let’s see what the clusters say..

Eps control went that way with cold easterly later on 

the sheer number of eps clusters shows how fluid the next two weeks look at the moment. 

two things that has caught my eye last few runs 

a) is the tpv headed back to Asian for the new year 

b) the downwelling of the strat zonal flow seems to be moving back up once it arrives in the upper reaches of the trop rather than sticking around where it would be v unwelcome 

[minus10]

Better ec ens if it is cold you are after this morning..(wgc)

Admittedly it doesnt get going till after christmas but the descent is supported by a fair few ens.

Pressure ens show the rise in pressure once cold air in place..

 

 

All.in all pattern slowely emerging..not there yet though...

Edited December 19, 2022 by minus10

[Cymro]

An improvement this morning albeit not quite enough yet to bring most of Wales in the game for some festive weather but a few adjustments here and there and both Wales and Ireland should tap in on the action. 

 

Here's hoping for an upbeat positive day of modelling

Edited December 19, 2022 by Cymro

[Mark wheeler]

Plenty of scatter on mogreps still . All up for grabs . 

[BlueHedgehog074]

Just to add to this new thread to try to keep things friendly in here please. (quite the rollercoaster we had yesterday morning, although I’ve felt things usually run quite well on here). Any rude or insulting behaviour won’t be put up with - any harassing or off-topic posts (unless their’s a good amount of model discussion in it) will either be moved to a more suitable thread, or be put through our shiny shredder. 

You can also Private Message one of the moderators/admins if you find unsuitable posts that we’ve either missed (or just weren’t available at the time) to deal with. 

For general Winter chat, please feel free to use this thread: https://community.netweather.tv/topic/98050-winter-2022-moans-ramps-chat/

If you also be naughty, don’t be surprised if we sneak to Santa’s headquarters and tell Father Christmas to give you a lovely Christmas present this year - a lump of coal.

Thanks guys and do continue  

 

[Snowmadsam]

7 minutes ago, DiagonalRedLine said:

If you also be naughty, don’t be surprised if we sneak to Santa’s headquarters and tell Father Christmas to give you a lovely Christmas present this year - a lump of coal.

You wouldn't dare!!!! 

For coldies it will be a relief this morning to see the ECM (hopefully) begin to be dragged kicking and screaming in its glass slippers to the cold aisle.

As for how quick or how cold it comes, well I'm sure this detail will be worked on as days go by....

 

[NewEra21]

If you are in Scotland in particular, it's looking quite promising to say the least for a cold Christmas. Same for Northern England, just with less confidence.

But overall things look more promising on the whole this morning for a cold spell of sorts over the Christmas period for most of the country. Nothing nailed as of yet though, lots of runs and hurdles to get through.

[Mucka]

A couple of comments directed toward my posts from the last thread I can no longer directly respond to.

In response to a comment I made alluding to ECM moving toward GFS this with below charts was posted as a repost.

@Weathizard

"Unless I’m missing something, these charts look majorly different to me, aside from the push of heights towards scandi, Maybe the ECM needs to go to specsavers because it’s copying is sub standard"

 

Well frankly, I think you may well be missing something. A few somethings perhaps?

And those somethings are.

How output progresses with each new run and how no two runs are ever the same in FI even using the same model let alone comparing different models.

Not understanding that deviations do not mean they are not synoptically doing similar things and that any deviations increase the further out we go.

That different models are not always in sync when feeling out pattern changes but ,ore often out of sync.

 

Here are comparisons between Todays ECM and yesterdays GFS but also the same comparison between ECM itself with yesterdays output and see if you can figure out which model is following the other in exploring a pattern change.

The fact that GFS has progressed that exploration while ECM is only just starting to explore it doesn't mean they are going in different directions, the exact opposite in fact. Just that they are out of sync for now.

Hope this helps.

 

And  @Paul_1978 in response to my saying Icon and GEM are cannon fodder and anyone else who thinks GEM and ICON are comparable with GFS

"No they are not. Don’t forget Ian Fergusson’s recent tweet which suggested he rated ICON and GEM more than the GFS!"

Well okay, if it is just a matter of opinion you follow Icon and GEM ahead of GFS and good luck.

 

 

 

 

[DanStormUK]

54 minutes ago, Cymro said:

An improvement this morning albeit not quite enough yet to bring most of Wales in the game for some festive weather but a few adjustments here and there and both Wales and Ireland should tap in on the action. 

 

Here's hoping for an upbeat positive day of modelling

It's close,   Wales has the advantage of the hills/black mountains/beacons which will drop the temperatures higher up. 
13C at the moment here in Mid Wales though.

Edited December 19, 2022 by DanStormUK

[TEITS]

Yesterday was a small step in the right direction and today its a much larger step.

What is happening on the model output is the low pressure you see at +72 in the Atlantic is now being modelled to track further S due to the forcing from the blocking to our NW. What the models are struggling with isn't just the exact track but also what happens to it. For example some models do not even have this travelling E across the country and instead takes the low S. This in turn allows the blowtorch S,lys.

However the step in the right direction is intially we thought Scotland was in the perfect position and then yesterday I thought it was N England. Today even the S could get to see some snow over xmas day. Note the ensembles for Cambs and how some members are bringing the much colder air S a few days ahead of the mean!

This happens simple because the low pressure swiftly tracks much further S and brings in the colder air. The ensemble below is a great example.

So in summary the chances of turning colder have increased and no location can be ruled out for this to occur on xmas day or before.

[mushymanrob]

IMHO these charts support the North South divide on Christmas day, as most of the North has contours from Greenland whilst the South from the mid Atlantic.

A White Christmas for Northern areas is a strong possibility, with many of us being so close... just where the boundary between cold and mild sits is unlikely to be resolved until nearer the time.

[bluearmy]

3 minutes ago, Mucka said:

 

 

And  @Paul_1978 in response to my saying Icon and GEM are cannon fodder and anyone else who thinks GEM and ICON are comparable with GFS

"No they are not. Don’t forget Ian Fergusson’s recent tweet which suggested he rated ICON and GEM more than the GFS!"

Well okay, if it is just a matter of opinion you follow Icon and GEM ahead of GFS and good luck.

 

I do find the dissing etc of models quite odd. They are all processing billions of calculations to produce a representation of the atmosphere over a period of time in the future. No model can actually predict the future.  We have to use our experience and intuition to sort the wheat from the chaff but never throw out the chaff unless it’s absolutely minging !  And that doesn’t mean not showing what you would like it to! 

we don’t have the met office stuff which enables them to do that sorting (not models such as glosea) but even then, I wouldn’t say we’re in a much worse place to make judgments than they are - but only if we take off our blue tinted specs and stop over reacting to a couple, runs/suites which may not go where we expected. 
 

we have enough decent models without needing to be looking at navgem or the Indian/Chinese models.  The amount of data we now have access to compared to only half a dozen years ago is brilliant.  Not that it seems to make this thread any easier to get through! 
 

anyway, ec/Ukmo/icon/gfs and gem are all pretty excellent at day 5 in predicting where we will be once the more uncertain period begins - that’s when the human side gets involved.  Nwp charts behind that are simply guesses - some are going to be closer to what happens that others. the modelling is definitely improving - when was the last time we saw an ‘ian brown wtf moment’ when Ukmo diverged completely from what was cross model agreement at day 5 and proved to be correct ? 

we can only dismiss a model run if we have very good reason to do so. 
 

 

[Battleground Snow]

11 minutes ago, Mucka said:

A couple of comments directed toward my posts from the last thread I can no longer directly respond to.

In response to a comment I made alluding to ECM moving toward GFS this with below charts was posted as a repost.

@Weathizard

"Unless I’m missing something, these charts look majorly different to me, aside from the push of heights towards scandi, Maybe the ECM needs to go to specsavers because it’s copying is sub standard"

 

Well frankly, I think you may well be missing something. A few somethings perhaps?

And those somethings are.

How output progresses with each new run and how no two runs are ever the same in FI even using the same model let alone comparing different models.

Not understanding that deviations do not mean they are not synoptically doing similar things and that any deviations increase the further out we go.

That different models are not always in sync when feeling out pattern changes but ,ore often out of sync.

 

Here are comparisons between Todays ECM and yesterdays GFS but also the same comparison between ECM itself with yesterdays output and see if you can figure out which model is following the other in exploring a pattern change.

The fact that GFS has progressed that exploration while ECM is only just starting to explore it doesn't mean they are going in different directions, the exact opposite in fact. Just that they are out of sync for now.

Hope this helps.

 

And  @Paul_1978 in response to my saying Icon and GEM are cannon fodder and anyone else who thinks GEM and ICON are comparable with GFS

"No they are not. Don’t forget Ian Fergusson’s recent tweet which suggested he rated ICON and GEM more than the GFS!"

Well okay, if it is just a matter of opinion you follow Icon and GEM ahead of GFS and good luck.

 

 

 

 

Pulled this from twitter regarding model performances, it always surprises me how the ecm is always so far ahead. It must model the North Pacific bang on or something.

It would be interesting if there was UK or Europe performance graph rather than just Northern hemisphere

[tight isobar]

The direction of travel today = the Iberian high becomes an North African one.. and the 12z start walking into   what the gfs- has shut the door on already and possible further general upgrades croosboard.

Edited December 19, 2022 by tight isobar

[Mucka]

16 minutes ago, bluearmy said:

I do find the dissing etc of models quite odd. They are all processing billions of calculations to produce a representation of the atmosphere over a period of time in the future. No model can actually predict the future.  We have to use our experience and intuition to sort the wheat from the chaff but never throw out the chaff unless it’s absolutely minging !  And that doesn’t mean not showing what you would like it to! 

we don’t have the met office stuff which enables them to do that sorting (not models such as glosea) but even then, I wouldn’t say we’re in a much worse place to make judgments than they are - but only if we take off our blue tinted specs and stop over reacting to a couple, runs/suites which may not go where we expected. 
 

we have enough decent models without needing to be looking at navgem or the Indian/Chinese models.  The amount of data we now have access to compared to only half a dozen years ago is brilliant.  Not that it seems to make this thread any easier to get through! 
 

anyway, ec/Ukmo/icon/gfs and gem are all pretty excellent at day 5 in predicting where we will be once the more uncertain period begins - that’s when the human side gets involved.  Nwp charts behind that are simply guesses - some are going to be closer to what happens that others. the modelling is definitely improving - when was the last time we saw an ‘ian brown wtf moment’ when Ukmo diverged completely from what was cross model agreement at day 5 and proved to be correct ? 

we can only dismiss a model run if we have very good reason to do so. 
 

 

 

Obviously all output should be taken into consideration and if I hurt the feels of GEM or Icon I am profoundly sorry, there is no room for hate speech.

 

Edited December 19, 2022 by Paul
Removed un-needed comments.

[Rain All Night]

6 minutes ago, bluearmy said:

we don’t have the met office stuff which enables them to do that sorting (not models such as glosea)
 

 

What does GLOSEA actually do?

[johnholmes]

Very brief from me using the ECMWF chiefly, for a peek as possible temperature levels over the festive season.

Rather cold as opposed to our recent cold/very cold for most.

Scotland colder than south of the Border or N Ireland  to some extent with the -5 C 850 mb temperature getting as far south as N Ireland and the Borders by the 27 th but back just north of Scotland by the 29 th.

At 500 mb the trough SW from SW England on the 25 th ‘warms’ out through 25-29 th as the flow veers to north of west bringing less cold air into most of the UK

The 6-10 NOAA has a risge over southern Greenland giving a north of west flow just west of the UK into a fairly shallow trough for the UK. This becomes a mainly westerly flow during the 8-14 period. The initial pattern gives slightly higher 500 mb heights over the UK. But detail for the early period 24-27 th will be given by synoptic charts. Quite probably more like the ECMWF than the NOAA charts suggest.

You never know the above might be near what actually happens!

Happy Christmas to one and all

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

  

 

Edited December 19, 2022 by johnholmes