Winter Approaching: Forecast and Model Discussion Commentary

[Legend.Ice]

 Gregulator

very nice Question , Geopotential heights determine the jet streams, and jet streams contribute to the formation of surface pressure areas, all of them interact with each other, of course we cannot just say jet streams about “winds”, for example the interaction of the 150-350 hpa region and the wind interaction of the 500-700 hpa region contain different components. It is impossible not to be amazed by the miraculous beauty and complexity of the atmosphere.

[northwestsnow]

EC chilly very HP dominated with a brief cold shot days 8 + 9..

Hard to tell if there's a signal for retrogression at day 11

HP to the west / south west day 12

From the limited view it looks like the cold is heading Into C Europe..

Edited November 30, 2024 by northwestsnow

[Mike Poole]

It’s easy to forget with this thread having been in full swing for ages now, that the first day of winter was…tomorrow!

[minus10]

Icon looks interesting...

 

[northwestsnow]

Brutal cold for @jules216

That chart is basically day 11-15 on EC..

Edited November 30, 2024 by northwestsnow

[Lukesluckybunch]

12 minutes ago, northwestsnow said:

That chart is basically day 11-15 on EC..

Ecm is cold run especially for the south and east

[northwestsnow]

 Lukesluckybunch yep very chilly at the surface..

I can live with that

Day 15 perhaps suggesting another attempt at retrogression

too much energy towards Greenland on EC but we'll take dry and cold im sure..

defo seasonal..

[northwestsnow]

 Lukesluckybunch

Days 8/9/10 are actually colder in the West ...

ice day in Ireland day 10!

 

 

[WYorksWeather]

 Mike Poole Thinking that the clusters in half an hour or so could be very interesting.

[northwestsnow]

 WYorksWeather

For the fanciful gfs runs i'll stick with Exeter who suggest high pressure to the west and no mention of retrogression as of yet ..

That's not to say its bad news, EC, as I've posted is dry cold,and seasonal.

I despise wind and rain in Dec so I'm very satisfied right now..

Edited November 30, 2024 by northwestsnow

[Mike Poole]

 WYorksWeather Indeed.  I’ve just been looking at the GEFS and if that’s anything to go by I’d expect the clusters to be an improvement in the extended timeframe.  I was struck by the split vortex on the mean day 16, I don’t think we’ve seen it as clear, with heights holding in Greenland:

Note also, I don’t think the Asian lobe will prevent a Scandi high from there.

Just to note re the strat - all the GEFS show the warming at the end of the run, so there’s clearly something going on there.  P29 is stronger than the op:

Edited November 30, 2024 by Mike Poole

[LRD]

A better day today. Definitely a step or 2 forward again. GFS ensembles are good if it's cold you want

Even the end-of-run warm (850s-wise) op involves a Scandi high of sorts

Edited November 30, 2024 by LRD

[Anthony Burden]

Evening all,Geffs ensembles firming up nicely from 7th December onwards on a cold period with both GFS and ECM on the 12z showing pressure rise in the Atlantic and low pressure to the east bringing colder northerly air flow to the UK. Positioning of the high always crucial regarding wind direction and temperatures,but beginning to look positive for a colder December than we normally get depending on a continuous positive high pressure orientation.

[Johnp]

 Jacob that will quickly become very cold at the surface in mid December. 

[damianslaw]

 northwestsnow Not hearing much about the atlantic SST pattern.. interesting, might end up an underplayed factor this winter.

The 12z runs are showing much more amplification, signficantly so. 

[Dennis]

GEM ENS LT

 

[northwestsnow]

 damianslaw

Yeah Im on twitter as @Met4Cast says,there is some decent stuff on there I'll post stuff relevant to the thread..

( mainly if it's good news only )

[northwestsnow]

Others can add I'm not always sure of what is being implied for our little part of the world..

Edited November 30, 2024 by northwestsnow

[Bricriu]

From an imby perspective I am just hoping we can get a mid Atlantic high that allows a cold northerly or north westerly  airstream to affect us just in time for Christmas eve or Christmas  day.  By the way how well rated is that model you posted,  Dennis?

Edited November 30, 2024 by Bricriu

[Mike Poole]

ECM clusters in the key T192-T240 timeframe, upgrade:

Cluster 1 (17) has gone full Iceland Scandi block, well propped up by low heights southern Europe.  Cluster 3 (14) is similar, maybe more Iceland.  

Cluster 2 (15) has weaker high running through the UK.  Cluster 4 (5) has stronger UK high, ripe for retrogression.

The extended clusters have not yet updated. 

[Bats32]

 northwestsnow  I just read your post as “I’m on Twitter as Met4Cast” lol,I  thought you were Met4Cast for a few mins!

[northwestsnow]

 Mike Poole thanks Mike 

Cluster 1 though

[northwestsnow]

Currently waiting for EC 46 to update

[Mcconnor8]

 northwestsnow If only EC46 was based on the 12z runs and not the 0z runs lol

[northwestsnow]

Its going in the right direction..