Model Output Discussion Autumn 2024

[Lukesluckybunch]

1 hour ago, TSNWK said:

what sense Matey?

What do you mean?TSNWK

[Don]

55 minutes ago, northwestsnow said:

I'm all for a wintry blast but at this juncture it looks very brief and I'd say its 50/50 south of the Midlands sees even a frost.

Knowing how northerlies are typically modelled in recent years, the Shetlands might feel cold in the wind with perhaps a few wintry showers!

[northwestsnow]

 Don

There's a range of outcomes reg the depth of cold 

In theory we could get something fairly tame but we could also get something decent.

It's pretty cool to be getting any kind of chase in November !

 

[blizzard81]

 Don  Cmon man, where's your fighting spirit? I suppose you are being realistic though 

[happyfoxyboy]

Good afternoon fellows! Good start of the weekend with the GEFS 06z mean . OP is okay-ish but ends with a more zonal flow with the PV heading towards Greenland and thus no long lasting cold. Ensemble looking awesome with more than half of members going for a longer period of relatively cold weather. A few members show a good blocked overall pattern but details not in our favour. And then there's the few going for a zonal flow. Anything can be possible at this point, but as how it looks like right now, cold weather has the winning hand. Onto the 12z!

Edited November 8 by happyfoxyboy

[blizzard81]

Nice update from Exeter today. Mentions the increased chances of northerly winds and subsequent colder weather

[Don]

1 hour ago, blizzard81 said:

Cmon man, where's your fighting spirit? I suppose you are being realistic though 

It's been quashed by our a***hole climate!  

[Mcconnor8]

 Don Already pretty sure this 12z suite will begin the downgrades lol

[CoventryWeather]

 Mcconnor8 doubt it, likely to see modelling switching solutions over the coming days.

That shortwave/cold pool early next week still troubling models, as well as that one developing way in the Atlantic. That one is the one I'm worried about - how will that impact retrogression, we'll see in coming days. 

[happyfoxyboy]

GFS 12z // Overall pattern looking amazing, but the details.. those might break everything down. This run looks risky at day 9 but if it remains blocked, then it is a  huge reward situation.

 

[happyfoxyboy]

Cold air flowing over the Atlantic at day 10, hope the high is strong enough to block the flow. If not, then the low east of Canada might massively strengthen. Though, the low west of the UK might prevent it from happening since it will pull the cold air further southwards and possibly keeping the block alive.

 

This idea mentioned above is also nicely seen on the 500 hPa temp. chart, its a very small ridge against the force of the cold air. As long as the wall doesn't break it should be fine for an prolonged period of chilly/cold weather.

Edited November 8 by happyfoxyboy

[CoventryWeather]

 happyfoxyboy exactly how I thought it would go. The Atlantic low and earlier cold pool over Spain merge together, causing a mess over the UK. 

Never easy, and when these runs start happening, it makes us nervous. 

Albeit if the cold air arrives earlier there is a chance we get a decent slider from it. 

Edited November 8 by CoventryWeather

[That ECM]

That general pattern and we can improve the detail.

[blizzard81]

WHAT A MESS GFS! Lol. Plus Gem has vomited too!

[happyfoxyboy]

The wall is breaking, cold air flows through towards Canada. Meanwhile the low that was west of the UK earlier didn't exactly help us out, because of the cold air it didn't go further south anymore but instead strengthen at a insanely fast speed. I'm expecting a not so wintry last third of the run. But two positives though; the general pattern as  That ECM showed above, remains very good. And Scandinavia is going to see some serious cold in this 12z GFS run.

   

Edited November 8 by happyfoxyboy

[blizzard81]

 CoventryWeather Yep, the problem is that all important explosion of cold air to the east of Greenland is bottled up incredibly tight which makes it an eternity to be ejected south. Which in turn gives more time for gremlins in the Atlantic to intervene. 

[blizzard81]

 Mcconnor8 Prophetic!

[Jacob]

I know the chances of this are virtually 0 but if everything goes perfectly, is it possible for the PV to end up on the UK? Has it ever happened and what would conditions be like

[Mike Poole]

 blizzard81 Happy that the GFS shows a decent Greenland block - the details at that range can and will change, so it lends support to the general trend towards a blocked pattern.  

GEM is more of a worry because it develops no block at all, at least within T240, speculate one might develop not long after, though.

[northwestsnow]

GEM similar to ukmo 144..

 

[Mike Poole]

 Jacob A lobe of it can end up over the UK, for example this from December 2010 would count, I think:

Pretty rare, it has to be as far as it can possibly get (in a clockwise direction) from its usual location over Canada.

Edited November 8 by Mike Poole

[Met4Cast]

The last three runs from the GFS show why attempting to pick out detail re: the potential northerly is futile. 

The bold green line (the deterministic run) is jumping between various solutions, essentially modelling is in "feeler mode", trying to pick out the dominant signal & subsequent impacts on pressure patterns. 

Anticyclonic wave breaking into Greenland is an absolute nightmare to forecast, as seasoned model watchers will attest to!

[northwestsnow]

168 UKMO V GFS

[TSNWK]

Thanks.  I prefer ukm looks cleaner towards Greenland.

Lower pressure and more spread out over Europe.. don't need those bowling balls to southwest

[happyfoxyboy]

GEFS member 4.. that's a close one, the high is just a tad too far south.

      

 

The overall ensemble mean is again, very great!

   

Edited November 8 by happyfoxyboy