Model Output Discussion - Winter arrives

[Blessed Weather]

As we enter a very interesting spell of weather heading into early winter, a new thread to continue with discussions. The thread is now getting busy so it’s important to stay on topic and keep to Model Output discussion in here please.

For “will it snow in my back yard” chat, please head to the Regional threads.

For more general chat and letting off steam, please head to the Moans/Chat thread.

The guidelines for posting anywhere throughout the forum can be found here.

[knocker]

I'll repost here then

The medium term anomalies continue to indicate the pattern change with one tpv lobe setting up over northern Canada whilst the other and ext trough moves towards NE Europe. In between the subtropic  high slowly loses amplification albeit the upper flow still north of west. Temps returning to a tad above average but likely quite a marked N/S variation

[Mapantz]

Repost:

On 25/11/2021 at 20:03, Man With Beard said:

Couple more wind forecasts, and they are not good. The ECM has now upped gusts to 90mph on the North Yorkshire coast, pretty concerning from one of main go-to models, and now at just T24.

Pretty extreme on the UKV as well, MWB.

    

   

 

 

Edited November 25, 2021 by Mapantz

[Lord Grogon]

I love this site, but crickey you get some discrepancies. 
In the space of 30 mins you get a post saying 90mph gusts in Edinburgh, then another saying a downgrade to 40mph! 
By all accounts off the same model run too…
 

[Man With Beard]

1 minute ago, Mapantz said:

Repost:

Pretty extreme on the UKV as well, MWB0.

    

   

 

 

Every model I look at is worse the previous. There are several that get the storm up to 100mph very close to shore, including UKMO! 

I see a separate thread has been set up for the storm, I will try to post some updates in there too.

[Man With Beard]

1 minute ago, Lord Grogon said:

I love this site, but crickey you get some discrepancies. 
In the space of 30 mins you get a post saying 90mph gusts in Edinburgh, then another saying a downgrade to 40mph! 
By all accounts off the same model run too…
 

Not the same run, no. ECM is kinder to Edinburgh, and the consensus is similar to the ECM I think, but a few models push the storm closer. 50 miles is going to make a big difference for places on the edge of the storm.

[MATTWOLVES 3]

Looks like the 46 may be going down a different route tonight...having a go at extending Heights back into Greenland...and not to far away.

Should of held fire for a bit..seems like it was shortlived..I will will wait for the next week or so to run.

Edited November 25, 2021 by MATTWOLVES

[damianslaw]

29 minutes ago, knocker said:

I'll repost here then

The medium term anomalies continue to indicate the pattern change with one tpv lobe setting up over northern Canada whilst the other and ext trough moves towards NE Europe. In between the subtropic  high slowly loses amplification albeit the upper flow still north of west. Temps returning to a tad above average but likely quite a marked N/S variation

No signal of an imminent return to balmy south westerlies - more likely a cool westerly feed as the azores high remains slightly amplified with low pressure systems pulling quite chilly air from the north atlantic.

[Uncertainty]

Things, can only get, better!

I’m at least waiting till the next run to write off winter

Ive looked through the 12z EPS members and a good minority are pretty blocked. Better than the above I would hazard. Nevertheless, a good third are the stuff of nightmares (present company excluded @knocker) and bring a seemingly insurmountable ++NAO that would flatten any hopes of a trop pattern to bring any meaningful strat disruption and would put any hope of cold in December firmly in the can.

I wonder whether this minor Canadian warming is somehow partly behind this (putting a big trough into Asia rather than the ridge we that would promote a future reversal?) and I don’t think it’s helpful for us because it’s not a split and the rebound will be severe and prolonged. Would love to know any one’s thoughts on that…

As for the MJO I get what Tamara’s saying it’s a pointer not a decider but Dan has a point too and if it were to get to P7 at a decent amplitude then it would surprise (but not shock) me to see the flattest, angriest of those EPS members come to pass. You would expect some resistance to the dark side of the force from that…

 

Also the GEFS really aren’t that bad later on, quite interesting in fact

Winter football analogy time:

We’re 1-0 down after 10 minutes, but plenty of time to go. We’ve got some great players (The East brothers: qbo and Nina) on the bench about to come on but Raging Vortex FC have done us in the past and they’re smelling blood. If it were up to me I’d sign that Russian star from the Urals back ASAP as he did a great job for us this time last year! 

Next up, it’s the big one between Analog FC and Seasonal Models United. I’ll be watching, from my favourite seat behind the sofa!

[stripeyfox]

On 25/11/2021 at 21:09, Uncertainy said:

Things, can only get, better!

I’m at least waiting till the next run to write off winter

Ive looked through the 12z EPS members and a good minority are pretty blocked. Better than the above I would hazard. Nevertheless, a good third are the stuff of nightmares (present company excluded @knocker) and bring a seemingly insurmountable ++NAO that would flatten any hopes of a trop pattern to bring any meaningful strat disruption and would put any hope of cold in December firmly in the can.

I wonder whether this minor Canadian warming is somehow partly behind this (putting a big trough into Asia rather than the ridge we that would promote a future reversal?) and I don’t think it’s helpful for us because it’s not a split and the rebound will be severe and prolonged. Would love to know any one’s thoughts on that…

As for the MJO I get what Tamara’s saying it’s a pointer not a decider but Dan has a point too and if it were to get to P7 at a decent amplitude then it would surprise (but not shock) me to see the flattest, angriest of those EPS members come to pass. You would expect some resistance to the dark side of the force from that…

 

Also the GEFS really aren’t that bad later on, quite interesting in fact

Winter football analogy time:

We’re 1-0 down after 10 minutes, but plenty of time to go. We’ve got some great players (The East brothers: qbo and Nina) on the bench about to come on but Raging Vortex FC have done us in the past and they’re smelling blood. If it were up to me I’d sign that Russian star from the Urals back ASAP as he did a great job for us this time last year! 

Next up, it’s the big one between Analog FC and Seasonal Models United. I’ll be watching, from my favourite seat behind the sofa!

Are you the Jonathan Van Tam of meteorology?

 

 

[damianslaw]

9 minutes ago, MATTWOLVES said:

Looks like the 46 may be going down a different route tonight...having a go at extending Heights back into Greenland...and not to far away.

Backs up my assertion and hunch that mid atlantic heights will never be too far away, as the base La Nina state isn't going to change in December. 

[Mike Poole]

EURO4 has this at T54 for cumulative snow and max wind:

As others have posted, the wind potential for the northeast is modelled stronger.  

HARMONIE 12z less with the snow, but backs the wind - this just to T48 though on the 12z:

[MATTWOLVES 3]

10 minutes ago, damianslaw said:

Backs up my assertion and hunch that mid atlantic heights will never be too far away, as the base La Nina state isn't going to change in December. 

We still appear to have that mid Atlantic ridge in evidence...this run is way different to the last run,when it hinted at an extension of those Heights into scandy...not sure I'm liking the Arctic profile at this juncture either...all be it,a very long way off.

Edited November 25, 2021 by MATTWOLVES

[Man With Beard]

3 minutes ago, Mike Poole said:

EURO4 has this at T54 for cumulative snow and max wind:

As others have posted, the wind potential for the northeast is modelled stronger.  

HARMONIE 12z less with the snow, but backs the wind - this just to T48 though on the 12z:

EURO4 has lost its way with snowfall predictions the last two years ... Harmonie looks like a higher ground affair for major settling, which may prove right

[knocker]

12 minutes ago, damianslaw said:

Backs up my assertion and hunch that mid atlantic heights will never be too far away, as the base La Nina state isn't going to change in December. 

Not  if you look at the Xmas week

 

[snowsummer]

38 minutes ago, Man With Beard said:

Every model I look at is worse the previous. There are several that get the storm up to 100mph very close to shore, including UKMO! 

I see a separate thread has been set up for the storm, I will try to post some updates in there too.

Can you put a link up for this thread please as i cannot find it. Thank you

[Man With Beard]

2 minutes ago, snowsummer said:

Can you put a link up for this thread please as i cannot find it. Thank you

https://www.netweather.tv/forum/topic/96411-storm-arwen/#comment-4583776

[Tim Bland]

Can we just pin to the top of the thread that the ECM accumulates all falling snow and the Euro 4 exaggerates snow depth. Otherwise we will end up 1000 posts by April saying the same thing… just like last year

[blizzard81]

3 minutes ago, knocker said:

Not  if you look at the Xmas week

 

Quite a switch from the EC46 from the previous runs. Is the EC46 run based on the 00z run from the same morning? So tonight's update is based on the 00z run from this morning but run on for 5 to 6 weeks? If so, is it based purely on the operational or is it based on the ensembles? Sorry for all the questions. 

[Uncertainty]

1 minute ago, blizzard81 said:

Quite a switch from the EC46 from the previous runs. Is the EC46 run based on the 00z run from the same morning? So tonight's update is based on the 00z run from this morning but run on for 5 to 6 weeks? If so, is it based purely on the operational or is it based on the ensembles? Sorry for all the questions. 

It is a big switch so I suggest waiting till next Monday’s run before becoming too swayed by it.

Yes

Yes

Ensembles, there are clusters too.

Hope that helps

[knocker]

11 minutes ago, blizzard81 said:

Quite a switch from the EC46 from the previous runs. Is the EC46 run based on the 00z run from the same morning? So tonight's update is based on the 00z run from this morning but run on for 5 to 6 weeks? If so, is it based purely on the operational or is it based on the ensembles? Sorry for all the questions. 

It actually is not that different to the two previous runs for this period. It is an Ensemble Prediction System

Edited November 25, 2021 by knocker

[knocker]

12 minutes ago, Uncertainy said:

It is a big switch so I suggest waiting till next Monday’s run before becoming too swayed by it.

 

Not that big and I humbly suggest down to the tpv lobe flexing it's muscles northern Canada

And I mioght add that the ext anomalies this evening are flat which I will not botherr to post

Edited November 25, 2021 by knocker

[Ice Day]

So the pub run has pushed the strongest winds slightly east and are now showing inland gusts of up to 100mph for the south east coast of Scotland and north east of England.  Yikes!!!

[Uncertainty]

13 minutes ago, knocker said:

Not that big and I humbly suggest down to tpv lobe flexing it's muscles northern Canada

Surface weather difference will be highly significant.

The regimes have shifted heavily from blocked to +NAO, I agree the more aggressive trop vortex lobe the culprit.

Monday run = dry and calm for majority, drier than average (esp In NW)  with frost and fog 

todays run: Wetter than average in NW, cloudy and bleak.

However on reflection many of the forecast elements are similar between the runs and thus I would amend my wording to ‘quite’ big

PS the mean would be flat as two big clusters of members are very flat / downright stormy but a significant minority are anomalously blocked and thus it’s a watching brief…

Edited November 25, 2021 by Uncertainy

[Eagle Eye]

I am now going to attempt to write a post briefly about Saturday on an IPhone 5C, wish me good luck 

Originally we see the potential for snow definitely not widespread (never was really though) with it more conductive for those convective like showers initiating just in from the coast especially around the frontal rain, potential for showers to initiate further inland over west U.K but weak moisture potential unfortunately for those over in the west of Britain.

You can see the cold around ground level in Britain. 

Looks like it'll initiate east of the red line mainly (click on image if you can't see it it's small for some reason), I suspect there could be a small easterly shift later.

That's about as much as I could write up to now

Xander

Edited November 25, 2021 by Eagle Eye