The hunt for cold - Model discussion (late November)

[Seasonality]

1 hour ago, carinthian said:

Morning all , -4C in the village and snow cannons back in operation on the slopes. Due to open runs this weekend. Picture over looking Katschberg village. Another variation on the model runs this morning but the theme towards a rise in pressure over the British Isles likely in the period day 7 to 10. So a fairly short lived spell of unsettled and relatively mild conditions in your part of the world , although not particularly mild so in the north. The model our expert use still indicate a strong developing ridge over the British Isles for the second week of December and pressure falls in Eastern Europe as the trough starts to sharpen against the cold block. The forecast 300mb flow is indictive of this process over Scandinavia and into East Europe in the longer term charts . 

C

 

And just as you say @carinthian the 06z shows this scenario! 

[Yarmy]

1 hour ago, Shaftesbury Snow said:

Hi Karlos, They are but just at differing time scales. Ill post some others now

Hi, Shaftesbury. I'm not sure that 3 snapshots from a single op run of the 4th-best performing model really indicates anything, but for what it's worth I'm not overly optimistic for December either (the first half more so). This is based on all the output out to 12 days or so. Beyond that there's a ton of scatter on the ens, but there are still a significant number showing high lat blocks and a negative AO:

https://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=300

So not an overwhelming signal for anything, but I've looked at hundreds of these GEFS panels over the years when they are showing nothing but 100% zonal out to 16 days. 

 

 

[Methuselah]

An early Christmas present for lovers of anticyclonic gloom?

[Rayth]

This thread is getting perilously close to farce , last nights sniping by grown adults was embarrassing , sadly the theme is continuing today !

[matt111]

14 minutes ago, Raythan said:

This thread is getting perilously close to farce , last nights sniping by grown adults was embarrassing , sadly the theme is continuing today !

Unless the offending posts have vanished in between reading this thread, I haven’t seen any sniping this morning. A bit of constructive debate maybe but no sniping. Maybe overreactions to models being completely different each run? Nothing unusual there... 

Edited November 27, 2018 by matt111

[ItNeverSnowsInWindsor]

It’s bizarre how the overnight GFS runs have been on the mild side compared to the evening runs!

[blizzard81]

The gfs parallel now agrees with the ecm Atlantic spoiler low approaching Ireland. It didn't agree with it at all on the 00z run. 

Edited November 27, 2018 by blizzard81

[Glacier Point]

One further observation. Both EPS and GEFS very keen to dislodge the Siberian lobe of PV into the Pacific sector and nudge the Canadian lobe further west. Net result - the hemispheric wave number becomes much reduced and aggregated. That's a massive signal for high pressure development in the high latitudes across the eastern side of the hemisphere. Not a lot of change is going to happen to that wave pattern so we are lining ourselves up for the winter pattern here. Slowly slowly catchy monkey.

[carinthian]

52 minutes ago, Seasonality said:

And just as you say @carinthian the 06z shows this scenario! 

Hi Seasonality, yes the ops runs will vary from run to run but clearly the trend is there as  @Glacier Point posted earlier this morning. Cheers.

C

[Seasonality]

Question to all, is there anywhere where I could see the GFS Para/FV3 graphed alongside the current op and its suite? Would be interesting for comparative purposes.

[frosty ground]

27 minutes ago, blizzard81 said:

The gfs parallel now agrees with the ecm Atlantic spoiler low approaching Ireland. It didn't agree with it at all on the 00z run. 

They don't make spoiler lows like they did in the past.

[bradymk]

Quite a few eye candy GEFS members appearing now at the end of the 6Z suite.

[carinthian]

2 hours ago, carinthian said:

Morning all , -4C in the village and snow cannons back in operation on the slopes. Due to open runs this weekend. Picture over looking Katschberg village. Another variation on the model runs this morning but the theme towards a rise in pressure over the British Isles likely in the period day 7 to 10. So a fairly short lived spell of unsettled and relatively mild conditions in your part of the world , although not particularly mild so in the north. The model our expert use still indicate a strong developing ridge over the British Isles for the second week of December and pressure falls in Eastern Europe as the trough starts to sharpen against the cold block. The forecast 300mb flow is indictive of this process over Scandinavia and into East Europe in the longer term charts . 

C

 

This latest 300mb wind flow pattern out east would be indictive to sharpen the trough (under cut process) against the cold block to the NE . This split in the main polar jet helps ridging, as in this case over the British Isles. Where we end up from there is another story ? but this set up usually leads to a colder outcome in days 10 -15  Hope this helps.

C

[Methuselah]

11 minutes ago, carinthian said:

This latest 300mb wind flow pattern out east would be indictive to sharpen the trough (under cut process) against the cold block to the NE . This split in the main polar jet helps ridging, as in this case over the British Isles. Where we end up from there is another story ? but this set up usually leads to a colder outcome in days 10 -15  Hope this helps.

C

Just what the 06Z para is threatening, eh? Maybe even a snow-grain or two!

[Man With Beard]

This time yesterday I reported that the ECM ensembles were all at sea from D8 onwards. Have they caught up yet? 

Maybe just maybe - but also maybe not. Here's D11 clusters for last night and this morning:

  

Still rather split but slightly more emphasis on ridging trying to get north from the Azores (so back to the position the EC clusters held a couple of days ago on the 6th-9th December period)

By D15 though

  

60% of runs have fair height anomalies to our north around 11th-12th December. This opens up several possibilities, but none likely to be particularly mild; 1. if heights get far north, southerly tracking jet firing lows directly through the UK  2. if heights can't get too far north UK high  3. middle ground option, heights to our north but not so far to allow Atlantic lows access to the UK, resultant easterly flow. 

[Tim Bland]

More eye candy from the GFs(p) in FI with a huge scandi high delivering a cold easterly flow and snow showers in the East 

[ArHu3]

1 hour ago, sebastiaan1973 said:

You speak of 'record week'. You mean 'weak'. The graph shows clearly this is not true.

I suppose "week" was my autocorrect maar je begrijpt dat ook wel 

[mountain shadow]

5 minutes ago, Tim Bland said:

More eye candy from the GFs(p) in FI with a huge scandi high delivering a cold easterly flow and snow showers in the East 

Unfortunately given the updated Met Office long ranger we now know we can treat these spectacular runs as nothing more than randomness from the logarithms for the next month or so.

I think we're more likely to see a northerly toppler than full blown easterly over the next few weeks.

 

[karlos1983]

The mean slowly heading down in the extended ENS.. nothing dramatically cold, but certainly not much screaming mild there! December certainly holds interest as it stands, in my mind at least. 

Operationals seem to have a decent grip on the D5/6 period, but other than that they are clearly struggling. So looking to far ahead using the Ops is futile in my opinion, especially as they are flip flopping between solutions regularly at the moment particularly in the low res. But will that stop me having a peak, or raising an eyebrow when I see a cold run.....? Not a chance

PS MetO 15-30D outlook is just short of useless in these situations. They have a responsibility to the public, so aren’t going to jump off the fence at that range unless it’s utterly inconceivable that anything else might happen. So the 15-30D forecast will generally follow climate norm for our island on the edge of the Atlantic! Note they use the word “Should” several times... that’s not definitive!

Edited November 27, 2018 by karlos1983

[Tim Bland]

6 minutes ago, mountain shadow said:

Unfortunately given the updated Met Office long ranger we now know we can treat these spectacular runs as nothing more than randomness from the logarithms for the next month or so.

I think we're more likely to see a northerly toppler than full blown easterly over the next few weeks.

 

Not necessarily IMO. I’ve seen the meto outlook flip very quickly. They are using mostly the same models as us. If this signal continues they will change that outlook 

[Yarmy]

15 minutes ago, mountain shadow said:

Unfortunately given the updated Met Office long ranger we now know we can treat these spectacular runs as nothing more than randomness from the logarithms for the next month or so.

I think we're more likely to see a northerly toppler than full blown easterly over the next few weeks.

 

Presumably this is driven largely by MOGREPS. It's a shame that Ian F got chased from here, as he used to have good insider knowledge on confidence and the rest.

There's actually some archive data for MOGREPS now publicly available at the following link, albeit in netCDF format so you'd have to write some code to read it and render it.

https://aws.amazon.com/public-datasets/mogreps/

I don't know how up to date it is, but it does say this 'Data is currently updated infrequently with regular updates coming soon'.

 

Edit: Just googling around and found the following tool called Panopoly. Anyone used it?

https://www.giss.nasa.gov/tools/panoply/

 

Edited November 27, 2018 by Yarmy

[Norrance]

1 hour ago, Raythan said:

This thread is getting perilously close to farce , last nights sniping by grown adults was embarrassing , sadly the theme is continuing today !

Looking back last nights sniping was out of order andif repeated posts will be removed and if necessary warnings given. Nothing of that scale noted this morning though.

[Ali1977]

7 minutes ago, Tim Bland said:

Not necessarily IMO. I’ve seen the meto outlook flip very quickly. They are using mostly the same models as us. If this signal continues they will change that outlook 

Agree, the 16-30 dayer is put together using a variety of long range models , some that we see for free, although the likes of MOGREPS clearly add value - however I’m sure even that computer flips at that range from day to day. What they don’t seem to do is change wording with every run which makes sense, so don’t be surprised if in 2 days time the words snow/frost start appearing (hopefully) 

[mb018538]

15 minutes ago, Ali1977 said:

Agree, the 16-30 dayer is put together using a variety of long range models , some that we see for free, although the likes of MOGREPS clearly add value - however I’m sure even that computer flips at that range from day to day. What they don’t seem to do is change wording with every run which makes sense, so don’t be surprised if in 2 days time the words snow/frost start appearing (hopefully) 

They could, but they consistently mentioned a return to colder more settled conditions through December....then a day ago changed it to say milder weather was more likely. If you pin your hopes on these prepare to be disappointed, they change frequently.

[northwestsnow]

17 minutes ago, Norrance said:

Looking back last nights sniping was out of order andif repeated posts will be removed and if necessary warnings given. Nothing of that scale noted this morning though.

I went to bed early so missed all that but i feel like yourself there has been little or no sniping today whatsoever.