Model Output Discussion - Into 2024

[bluearmy]

34 minutes ago, Allseasons-Si said:

I thought that they form in an arctic airmass ?,that is why i posted it because it looks like one to me

a snippet from John holmes:-

Polar Lows tend to form, in the area of our interest, in a north or north west airflow. It is possible for it to occur in the Norwegian Sea in a north east flow but is less common. One area they seem to favour is just south of Iceland.

 

If you look back through the run then you’ll see a kink in the isobars around day 9. That becomes a shortwave which eventually develops into the system that trundles towards Scotland

it’s not what I would consider a polar low but between us, we’ve managed to derail the thread  

[Dignity]

1 minute ago, bluearmy said:

If you look back through the run then you’ll see a kink in the isobars around day 9. That becomes a shortwave which eventually develops into the system that trundles towards Scotland

it’s not what I would consider a polar low but between us, we’ve managed to derail the thread  

Sub Polar Low?

 

[PsychedelicTony]

6 minutes ago, I remember Atlantic 252 said:

polar low, isn't it like a 'runner' feature, but north to south in the flow, rather than west to east

Yeah but unmodelable, a small but intense feature that crops up hours before impact. 

Is my take. John Holmes is the expert. 

[Allseasons-Si]

13 minutes ago, PsychedelicTony said:

Once again... That is not a polar low

 

9 minutes ago, I remember Atlantic 252 said:

polar low, isn't it like a 'runner' feature, but north to south in the flow, rather than west to east

 

4 minutes ago, bluearmy said:

If you look back through the run then you’ll see a kink in the isobars around day 9. That becomes a shortwave which eventually develops into the system that trundles towards Scotland

it’s not what I would consider a polar low but between us, we’ve managed to derail the thread  

It is embedded in arctic airmass and formed off the south coast of Iceland and pushes S/SE,i would class that as a polar low

anyway,let's move on from this now and i do hope some crop up in the unstable airflow

 

[Battleground Snow]

Shortwave doesn't escape out of the Atlantic at 102 before the high closes it in.

Also the Pacific is punching more into the pole already.

Should be a pub run special from here on in

[Rain All Night]

A summary of the 12z charts.

Day 0 (Sun 7th)

Day 3 (Wed 10th)

Day 7 (Sun 14th)

Day 10 (Wed 17th)

That crazy GEM ensemble...

Machine learning models: AIFS got there once and is about to reload, FourCastNet got there and is now flattening out, FuXi (with the best verification scores ) got there and then stayed cold out to the end, GraphCast brought disappointing uppers which were washed away quite quickly, Pangu-Weather got there and is now being washed away.

Edited January 7 by RainAllNight

[Mike Poole]

Pub run at T120, compared to 12z T126:

Looks cleaner in the region indicated.  I think the trend today is towards cleaner evolution into Greenland, let’s see how this one pans out.

[Catacol]

Bounce back to zero complete. 

Not too much damage done - still significantly "Nino" as an /ocean/atmosphere coupling

and momentum is on the high side still

So. The challenge now is to work out just how significant the lagged impacts of the dip will be, timed for week 3 starting 22 Jan. Anyone looking at the EC weeklies can see the change, BUT we are likely to have embedded cold as this flatter influence returns. If we remember back to December as a case study the westerlies came through as expected, but the timeline was put back and the crash was quite a big one. Not so this time, and cold will be significantly stronger. 

I think the battleground snow scenario for that week will gain traction. Too far out at present to see any evidence in NWP but it will come. Some warming of the overall pattern at that point is inevitable, but I dont think it will last long and we can cross fingers that it may only impact the south. Next rise in frictional/mountain torque will be in the wings and the MJO is forecast to be back in the western pacific soon after 21 Jan by both ECM and BOMM with GFS only a few days behind.

So... no change really to the prognosis laid out before.

1. Cool to cold, sometimes very cold this week, mainly anti cyclonic but some snow showers bound to pop up.

2. Cold to very cold, sometimes severe cold? the week after, snow in the mix from both NE and SW potentially.

3. Cool to cold in final week of Jan with battleground snow potential, low pressures deflected south with luck.

4. Amplified into early February - Greenland again?

 

 

 

[ANYWEATHER]

3 minutes ago, Catacol said:

Bounce back to zero complete. 

Not too much damage done - still significantly "Nino" as an /ocean/atmosphere coupling

and momentum is on the high side still

So. The challenge now is to work out just how significant the lagged impacts of the dip will be, timed for week 3 starting 22 Jan. Anyone looking at the EC weeklies can see the change, BUT we are likely to have embedded cold as this flatter influence returns. If we remember back to December as a case study the westerlies came through as expected, but the timeline was put back and the crash was quite a big one. Not so this time, and cold will be significantly stronger. 

I think the battleground snow scenario for that week will gain traction. Too far out at present to see any evidence in NWP but it will come. Some warming of the overall pattern at that point is inevitable, but I dont think it will last long and we can cross fingers that it may only impact the south. Next rise in frictional/mountain torque will be in the wings and the MJO is forecast to be back in the western pacific soon after 21 Jan by both ECM and BOMM with GFS only a few days behind.

So... no change really to the prognosis laid out before.

1. Cool to cold, sometimes very cold this week, mainly anti cyclonic but some snow showers bound to pop up.

2. Cold to very cold, sometimes severe cold? the week after, snow in the mix from both NE and SW potentially.

3. Cool to cold in final week of Jan with battleground snow potential, low pressures deflected south with luck.

4. Amplified into early February - Greenland again?

 

 

 

I don’t think the word cool should be used in Winter. Wrong terminology. Sorry to be critical.

[Ali1977]

Another slight upgrade, I imagine we’ll all be in -8c uppers by T180 this run - note some heights being recorded West of Greenland 

Edited January 7 by Ali1977

[TSNWK]

Just now, Ali1977 said:

Another slight upgrade, I imagine we’ll all be in -8c uppers by T180 this run 

It’s an upgrade so far on 12z that was a slight downgrade on 06z… but holistically it’s all good and variations on potentially interesting scene next week

[Ali1977]

2 minutes ago, TSNWK said:

It’s an upgrade so far on 12z that was a slight downgrade on 06z… but holistically it’s all good and variations on potentially interesting scene next week

Cold by 180, but not sure what happening around Greenland - a little messy - but the last few runs messy has always worked out ok!! Polar low maybe

Edited January 7 by Ali1977

[TSNWK]

Just now, Ali1977 said:

Cold by 180, but not sure what happening around Greenland - a little messy - but the last few runs messy has always worked out ok!! 

Agreed got messy south of Greenland 168 and 174 and went nice and clean at 180

[January Snowstorm]

Better heights again from the pub run. Expect a very good run from here!!

Edited January 7 by January Snowstorm

[frosty ground]

energy still sneaking across the north of Greenland which the GFS has picked up since Friday.

could do with the pattern backing west a little bit snow will come eventually on this run.

[Allseasons-Si]

This is nice if i am honest

[BLAST FROM THE PAST]

 

liking this a lot.  -8 down eastern side and spreading with a potential NNW/SSE diving low/trough…..and much less influence from  SW so should be a better/cleaner N’ly shot…..prolonged cold, deeper cold from north

 

BFTP 

Edited January 7 by BLAST FROM THE PAST

[IDO]

There is much more WAA pumping to Greenland on this run:

Energy from the ESB and the Iberian wave.Cold by D8:

 

[Ali1977]

Can this end up epic 

[frosty ground]

here comes that energy as a developing low sinks south, mild export to the west of where it runs maybe a bit like the ECM 

pattern backs up west a little and low stays shallow should make a good snow maker 

[feb1991blizzard]

Belter inbound! - should just make it - somewhere should get a hiding.

[The Enforcer]

Come in GEFS12z P01, your time is up:

Could GEFS18z finally be a set devoid of 'stinkers'?

[Polar Maritime]

3 minutes ago, Allseasons-Si said:

This is nice if i am honest

It would be even if you wasn't

[Weathizard]

Hells bells the 18z has been in the pub all night

[Met4Cast]

Let the upgrades flow.