Model Output Discussion Autumn 2024

[Jacob]

ECM mean is a downgrade

[Brad in Kent]

Morning all,

My first comment on this thread since the summer hope finds you all well.

Definitely agree with Carinthian above on the issues with disturbances preventing a northward movement of heights into Greenland. 

We've already achieved the 'get the heights in' so it's now down to how HP retrogresses. We need to keep an eye on the Eastern Seaboard of course.

Even if this ends up being the first goose chase, it's better to have one this stage of the season than not at all!

EDIT: I'd definitely take a chilly NW'ly right now anyway

Edited November 10, 2024 by Bradley in Kent
Extra point

[Met4Cast]

On 08/11/2024 at 18:38, Met4Cast said:

This fall in AAM is the trigger (perhaps also helped by lagged MJO phase 7-8) for our high pressure to retrogress & build into the Atlantic hence the cooler suggestion during the 2nd half of November.

The returning jet stream runs into this road block (the high pressure) and buckles, this causes an anticyclonic wave breaking event potentially up into Greenland leading to a temporary high latitude block, my current thinking though is that a mid latitude block, i.e Atlantic high is the most likely outcome but exact timing will be critical on this, in any case, cooler across the UK during the 2nd half of November is favoured

We’re seeing the above becoming increasingly advertised within NWP output this morning. 

The critical timing of the wave breaking is key but we’re certainly seeing a trend more towards the mid Atlantic high vs high latitude blocking, there just isn’t enough forcing to produce high latitude blocking at the moment & relying on a well timed anti-cyclonic wave break often doesn’t go the way we’d like it to!

[Geordiesnow]

 Chesil View I think that is the issue here, most runs don't go for a Greenland high, a few runs here and there have but I say it every year, I am constantly skeptical when I see the odd run go for a true Greenland high because I have seen it  time and time again of attempted ridging which does not make it and the whole thing collapses as quickly as it forms.

All that said, there is a definite pattern change on the way with low pressure and threat of a polar airmass looking likely, I suspect for most the airmass won't be cold enough for snow but I still won't rule out that it could be. If the models do go for true ridging into Greenland then of course that increases the chances. Still time for changes that is for sure.

[Sceptical]

Colder temperatures with rain for some would be my guess..

[blizzard81]

 Mcconnor8 Things delayed a little but I thought it turned into quite a decent run for those in the north especially.

[Dennis]

around 20th still my fokus 

 

[bluearmy]

 blizzard81 because the AI uses previous actual sypnotic evolutions rather than just modelling parcels of air and their interactions over the next number of days. 

Edited November 10, 2024 by bluearmy

[blizzard81]

 bluearmy That's interesting to know. Thank you.

[Lukesluckybunch]

Key timeframe is around 168.ECM wasnt really interested in bringing the trough south into the uk and left it north of Scotland.at the same time however the UKMO made a far better job of it!

[Mcconnor8]

Blocking looking poor on the 6z compared to the 0z even early on in the run, struggling to get any oomph into Greenland at all.

[Dennis]

icon6z 15th 

[HarvSlugger]

Definitely not getting snow from this spell here,just give me some windstorms and I'll be happy

[Lukesluckybunch]

6 minutes ago, Mcconnor8 said:

Blocking looking poor on the 6z compared to the 0z even early on in the run, struggling to get any oomph into Greenland at all.

We could be alright..look for a renewed push of heights into Greenland,around 8/9 not certain but possible

Edited November 10, 2024 by Lukesluckybunch
Adding

[CoventryWeather]

Noticing modelling are all over the place regarding where the cut off near Newfoundland heads. GFS as an example. 

The GFS is significantly larger and deeper, and it enters onto the Jet Stream quicker, overall leading to a collapse in the pattern. 

The GEM and ECM very similar - they both have it weaker and don't collapse the pattern. Instead they have the low keeping WAA into Greenland supporting the high. The GEM has this significantly stronger than the EC. 

Considering the EC has been very strong in this region, I'd suspect the GFS to back down, and likely see a more resilient high just south of Greenland. Of course, there are likely more differences in modelling but this shortwave crucial on how much amplification we achieved. 

GFS probably underdoing it, GEM overdoing it, EC somewhere in the middle. 

[That ECM]

 Lukesluckybunch not over yet.

[northwestsnow]

 Lukesluckybunch

Nope.

Game over at 168 IMHO.

6z v 0z 168

think that says it all..

[AO-]

Good Morning, 

Despite the operationals being les favourable, the plume for here hasn't downgraded at all. Still a decrease in temperatures compared to yesterday albeit little.

Yesterday 12

Today 00

So now it is interesting to see whether the decrease is due to colder uppers or a favourable wind direction (green, blue and purple). Here is the wind direction probability:

Yesterday 12

Today 00

Not a significant increase in Northerlies, Easterlies and Northeasterlies

Edited November 10, 2024 by AO-

[Lukesluckybunch]

5 minutes ago, northwestsnow said:

Game over at 168 IMHO.

Problem is it missed the initial northerly at 168 like the ECM did,average run it make take the long route also let’s see

[CoventryWeather]

Shortwave after shortwave on this run. 

Horrific.. the cut off makes the pattern into a mess. Suggests the model is struggling a lot. 

[TSNWK]

Giving it another go at 198. Better into Greenland 

Thing is.. those of certain vintage in this place are all too familiar with the jam tomorrow issues..

[northwestsnow]

 Lukesluckybunch

It ain't cold enough out to day 9 .

As per usual its all getting watered down as we count down ...

Maybe we'll see a swing back, well one day it will happen

 

[Lukesluckybunch]

2 minutes ago, northwestsnow said:

ain't cold enough out to day 9 .

Lack of cold air over scandi this run,I’m watching the high get squashed now at day 9..day 10 to the rescue finally some influence from the east/northeast

Edited November 10, 2024 by Lukesluckybunch
Adding

[Mcconnor8]

 TSNWK Far too West based into Greenland at that point, we need the initial push of heights at Day 6 to be much more robust as otherwise we won't get any of the deeper cold near our shores

Edited November 10, 2024 by Mcconnor8

[northwestsnow]

Better.

BUT it's FI ..