Model Output Discussion - the cold has arrived

[Jimmyh]

I love this forum and have been on it for a long time..... what never fails to amaze me is the search for a breakdown when we are at 48 hours into the cold spell. In the last 3 winters we would have given our right and left arms to be in this position. I can't remember a time probably since the forever mentioned 2010 when there wasn't any purples over ne us or Canada. Our little island is always going to br on the edge of the breakdown. But just let's enjoy this. It mat not be record breaking in terms of temps. I can't remember a single frost last year. What do the perturbations have in store for us who knows... i know for one I am going to enjoy this and hope to get a taste of narnia. But I wouldn't ever usher this away for screaming sw winds and dross. Hopefully we can catch a couple of cheeky streamers. But enjoy the ride.

[mb018538]

1 minute ago, Jimmyh said:

I love this forum and have been on it for a long time..... what never fails to amaze me is the search for a breakdown when we are at 48 hours into the cold spell. In the last 3 winters we would have given our right and left arms to be in this position. I can't remember a time probably since the forever mentioned 2010 when there wasn't any purples over ne us or Canada. Our little island is always going to br on the edge of the breakdown. But just let's enjoy this. It mat not be record breaking in terms of temps. I can't remember a single frost last year. What do the perturbations have in store for us who knows... i know for one I am going to enjoy this and hope to get a taste of narnia. But I wouldn't ever usher this away for screaming sw winds and dross. Hopefully we can catch a couple of cheeky streamers. But enjoy the ride.

Trouble is.....if it's just dry and cold (which this spell looks like being for the overwhelming majority), then it's not particularly exciting. Nice to have some colder weather, but without the snow to go with it, it's just a bit meh.

[mountain shadow]

8 minutes ago, sheikhy said:

Its hilarious!!some of us are so desperate for mild we start mentioning charts at 240 hours!!!

I would say most are desperate for snow, and regrettably we need the mild air to come in and provide the necessary moisture.

For most, this cold spell looks like being snowless unfortunately. 

[Downburst]

On the ecm. There’s still a lot of ensemble spread on the two lows for this time next week. The brighter pink the colour the wider the spread. Heights to the north more certain. So a lot of details to nail down yet for next weekend. Although direction of travel may well be well advertised there. 

[alexisj9]

2 hours ago, Mike Poole said:

UKMO very good and consistent again this morning.  T168 chart out now:

Deals with the ‘tropical storm’ low with the minimum of fuss, keeping UK cold for the foreseeable.  

It never developed into a tropical storm, just extraa tropical like our own types. So I don't expect it to be a problem guess we'll find out when it gets here though, most models take it way south now though.

[IDO]

So the GFS has followed what the GEM was showing yesterday, a wedge of heights ejected from the GH to the UK to cut off the trough:

GFS 0z:  GEM yesterday:  

This mornings GEM is similar again, but faster with this scenario, so the surface cold mixes out earlier. ECM keeps with the phasing of the low, preventing that wedge escaping. But with all the lows incoming, and outgoing meeting traffic as they try to undercut the UK, it has an inevitable roadblock, with the pattern breaking down around D9-10:

Obviously we are still low-confidence in post D6 so how the cold loosens its grip and where we end up, remains just conjecture.

Still a long cold spell, and we wait and see how much snow we get as we progress.

 

Edited December 9, 2022 by IDO
missed image

[Guest]

 Well sadly less than a week to go on this chart its looking like we'll  still be dreaming of a white Xmas for another year! Unless your a hobnail goat on a mountain somewhere!

 

[Eagle Eye]

1 hour ago, CreweCold said:

UKMO and ECM almost perfectly aligned at 120 hrs. Hard to see how GFS and GEM trump those two models.

Exactly, both are ran at a much higher resolution than the GFS and GEM

I'm not sure of ECM upgrades since then but the integrated forecasting system...

"For high-resolution forecasts (HRES) and ensemble forecasts (ENS) the grid-point resolution is roughly doubled to 9 km and 18 km, respectively"

UKMO is around 10KM but I think it depends on the area like the GFS.

GEM is 25 KM according to the TWO, 22KM according to Meteologix

The GFS I couldn't find much for that's accurate but we know it's a low resolution model and Meteologix says 23KM.

Extra resolution according to Meteologix

ICON - Roughly 13KM.

ARPEGE - roughly 46KM.

 

Edited December 9, 2022 by Eagle Eye

[blizzard81]

Ecm day 10 mean looks much more favourable than the op. No big chunk of vortex on the mean over northern Greenland and northern Canada. 

[booferking]

Ecm similar to the op losing our heights towards Greenland compared to last night. Hence break down

Edited December 9, 2022 by booferking

[bluearmy]

8 minutes ago, Eagle Eye said:

Exactly, both are ran at a much higher resolution than the GFS and GEM

I'm not sure of ECM upgrades since then but the integrated forecasting system...

"For high-resolution forecasts (HRES) and ensemble forecasts (ENS) the grid-point resolution is roughly doubled to 9 km and 18 km, respectively"

UKMO is around 10KM but I think it depends on the area like the GFS.

GEM is 25 KM according to the TWO, 22KM according to Meteologix

The GFS I couldn't find much for that's accurate but we know it's a low resolution model and Meteologix says 23KM.

Extra resolution according to Meteologix

ICON - Roughly 13KM.

ARPEGE - roughly 46KM.

Some of those numbers are a bit off EE 

trawling the internet is often a waste of time as it throws up out of date info 

Gfs isn’t that far behind ec in horizontal resolution. Also take vertical levels into account where ec also out scores it. 

the years and years of model watching have taught us that resolution isn’t the be all and end all. Ec is generally more right than gfs but it’s higher resolution also sends it down rabbit holes - basically the ops are not to be relied upon beyond day 5 to 7, depending on the situation. 

 

[IDO]

The ECM mean mirrors the op in 850's for this morning run, suggesting good support for the op within the ens.

London 850s: 

So a cold 9-10 days to come according to ECM.

[Mike Poole]

8 minutes ago, Eagle Eye said:

Exactly, both are ran at a much higher resolution than the GFS and GEM

I'm not sure of ECM upgrades since then but the integrated forecasting system...

"For high-resolution forecasts (HRES) and ensemble forecasts (ENS) the grid-point resolution is roughly doubled to 9 km and 18 km, respectively"

UKMO is around 10KM but I think it depends on the area like the GFS.

GEM is 25 KM according to the TWO, 22KM according to Meteologix

The GFS I couldn't find much for that's accurate but we know it's a low resolution model and Meteologix says 23KM.

Extra resolution according to Meteologix

ICON - Roughly 13KM.

ARPEGE - roughly 46KM.

 

Need to be careful here, there’s a lot of out of date nonsense on the internet.

GFS has a resolution of 13km right through to the 16 days, it no longer drops resolution half way through the run as some like to claim (since the FV3 update).

GEM looks wrong, it had an upgrade 2 or 3 years ago.  ARPEGE also looks wrong.  But I can’t find a definitive source on those two.

 

[bluearmy]

Just now, IDO said:

The ECM mean mirrors the op in 850's for this morning run, suggesting good support for the op within the ens.

London 850s: 

So a cold 9-10 days to come according to ECM.

Does the Icelandic site still do eps clusters ?  Ec website not updating 

[Eagle Eye]

2 minutes ago, Mike Poole said:

ARPEGE also looks wrong.  But I can’t find a definitive source on those two.

 

Yes, I got that 46 number a couple times but I don't know how because others are saying 7KM, what I don't understand is how there isn't a definitive source somewhere on the Internet, surely someone has done that. I mean, even the sites that are supposed to be government ran talking about the models are out of date, there's not much I could find for every model away from the years 2012 and 2016 for whatever reason.

[IDO]

7 minutes ago, bluearmy said:

Does the Icelandic site still do eps clusters ?  Ec website not updating 

My bookmark for that no longer connects, so not sure it is available. The Icelandic Met website is basic, here.

[Ali1977]

Well a surprise snow event last night, best get my sledge out

[alexisj9]

41 minutes ago, mb018538 said:

Trouble is.....if it's just dry and cold (which this spell looks like being for the overwhelming majority), then it's not particularly exciting. Nice to have some colder weather, but without the snow to go with it, it's just a bit meh.

I can't agree, we have a lovely hoar frost this morning, freezing fog to go with it, looks nice too. There is far more to cold conditions than just snow. Plus anything can still happen while we have the cold, and where the warm up is, even in those models that bring it in sooner is still fl, so things can still change. Let's see what happens.

[Theresnoway]

Morning All,

Quick question, is the data that sits behind the operational runs for any of the charts available?

I was thinking about plotting a single variable (eg 850’s) from each run from the same model (offset for time difference), to see where they diverge.

So essentially I’m just looking for 850’s data for a single location for each run, from any model.

Thanks

David

 

[cold snap]

Let's be real here  

When it's 10 days away and cold is predicted it want happen.

But if Mild air is predicted it will 

[ICE COLD]

This is what we want to see . P19 on the GEFS reinforces the greenie block and we stay cold out to day 16

[sheikhy]

Very good support it seems for milder weather from day 10!lets hope we get snow before that lol!!

[Stuie]

The jet in 7 days is still pretty non existent. Looking forward to the weekends model runs, nothing is going to breakdown in a hurry.

 

[E17boy]

3 minutes ago, cold snap said:

Let's be real here  

When it's 10 days away and cold is predicted it want happen.

But if Mild air is predicted it will 

Yes indeed but the frustration is there already. The reason we want cold is so that eventually we get some snow. This was my exact point in my post a couple of days ago. Whilst I agree with many on here that yes we are in a good place than what we have been for years this early in December, however it seems such a waste to have the cold and then not to see any snow .

Yes the models are showing cold for several days but to me the lack of snow is a big concern. Also with hints of milder weather trying to break through later we don’t know how this will end up. However it will be a real shame if this cold spell passes and us starved coldies still waiting to see a single flake. 
 

Anyway still a lot to be resolved yet the situation is changing day by day so who knows some lucky ones will see their winter wonderland. I am not convinced yet. For me down here in London it’s the  conventional easterly that will deliver the goods. Have a lovely Friday all.

regards

[Penrith Snow]

15 minutes ago, cold snap said:

Let's be real here  

When it's 10 days away and cold is predicted it want happen.

But if Mild air is predicted it will 

Unfortunately, that's correct and ECM ensembles spread are remarkably tight in the 8 to10 day period, we are going to need something special to prevent a slow warm up next weekend.

For the moment I will ignore GEM that has sent Uncle Barty an invitation for Christmas.

Andy

Edited December 9, 2022 by Penrith Snow