Model Output Discussion - mid Autumn

[damianslaw]

Looking further into November.. conflicting signals from the models at present, atlantic high, scandi high, azores high influence, take your pick.

I suspect mid atlantic heights of some sort will eventually come into play, but whether they build north and hold the atlantic trough and energy from the canadian lobe of the PV at bay.. or topple quick, or even advect NE to scandi with a euro trough scenario who knows. All to play for.

In the meantime, it stays wet, windy with temps not far off average, typical early November fayre. We may next week see some clearer brief colder incursions meaning some chillier but not frosty nights away from sheltered northern spots.

Edited November 1, 2023 by damianslaw

[Frosty.]

4 minutes ago, northwestsnow said:

Less said about EC46 the better...

 

Let me guess, wet wet wet? ….not funny I know! ️ 

[northwestsnow]

6 minutes ago, Allseasons-si said:

Doesn't it come out tomorrow

 Updates Every night Si

Edited November 1, 2023 by northwestsnow

[Rain All Night]

40 minutes ago, northwestsnow said:

Less said about EC46 the better...

 

Are you sure? 

[Rain All Night]

1 hour ago, Allseasons-si said:

Doesn't it come out tomorrow

Winter-only posters may not yet be aware that the ECM ensembles got a big upgrade in June: the 15-day ensemble now has all 51 members running at the same high resolution as the deterministic run, and the 46-day ensemble now runs at 0z every day and has been doubled to 101 members (with a lower resolution than the shorter-range ensemble).

Edited November 1, 2023 by RainAllNight

[blizzard81]

10 hours ago, LRD said:

The ECM does turn out to be a very mild run at the end compared to its ensembles, though. Could be a trendsetter, of course

The proper cold can wait another 6 weeks but it'd be nice to have a cold, frosty high sat over us for a change in November. +5 by day, -5 by night. The days of those conditions in November appear to, largely, be a thing of the past in my neck of the woods, however

Same up here unfortunately. I remember as a kid in the late 70's and early 80's wading through piles of dried up leaves through many autumns. No chance these days. Anyway, at least the gfs and ecm 12z runs trended away from the awful flat 00z runs. Much more meridonal which is always good news going forwards. 

1 hour ago, Don said:

Will you ever learn?!  

In a word.....  

[Don]

1 hour ago, northwestsnow said:

Less said about EC46 the better...

 

You've already said too much.....

[Mike Poole]

8 minutes ago, blizzard81 said:

Same up here unfortunately. I remember as a kid in the late 70's and early 80's wading through piles of dried up leaves through many autumns. No chance these days. Anyway, at least the gfs and ecm 12z runs trended away from the awful flat 00z runs. Much more meridonal which is always good news going forwards. 

In a word.....  

The flat runs on the 0z were in the smallest cluster in the ECM ensembles at the day 10 timescale, and looked unsupported.  I agree we wish to see the generally meridional pattern persist for the next month, when it becomes cold enough to get some advantage from it.

29 minutes ago, RainAllNight said:

Are you sure? 

This is starting to look a very strong signal now, never mind the handful showing the reversal, by the end of the run, the mean is some 15m/s below climatology (green arrow), and so many members in free fall (yellow arrows), there would be a good chance of a SSW by end December, and, maybe more importantly, even if there is no SSW, nothing to speak of to drive the trop vortex to develop into a bad thing going into winter.

[blizzard81]

Just now, Don said:

You've already said too much.....

Doesn't look too much different to me. The early December warming up top looks to be as strong as ever anyway. 

[Don]

Just now, blizzard81 said:

Doesn't look too much different to me. The early December warming up top looks to be as strong as ever anyway. 

Indeed, I was referring to the weekly anomaly charts.

[blizzard81]

1 minute ago, Don said:

Indeed, I was referring to the weekly anomaly charts.

I looked at them earlier and didn't see much of a downgrade. I will have another look. 

[blizzard81]

4 minutes ago, Don said:

Indeed, I was referring to the weekly anomaly charts.

The brief pressure rise over southern Europe looks to be transient. Plus, the run is off the back of the crud, flat 00z run which has been binned by the 12z runs..... For now anyway lol. 

[near northampton]

3 hours ago, Allseasons-si said:

The 12z EC has a Scandi high in the making at day 10...

totally different to  this mornings run,...a trend?

It's the hope that will kill you, when was the last time  the models showed a Scandinavian hiigh at 10 days and it happens? rare as hen's teeth. I do think that NWP has not adjusted to our warming climate in Winter

Edited November 1, 2023 by near northampton

[Allseasons-Si]

1 minute ago, near northampton said:

It's the hope that will kill you, when was the last time  the models showed a Scandinavian hiigh at 10 days and it happens? rare as hen's teeth. I do think that NWP has not adjudicated to our warming climate in Winter

I think that the NWP'S will have factored in to this and besides that,the warming climate takes decades to effect the global skale of things ,...another thread for that!

no hope will kill me and perseverance and stamina keeps me going till the end my friend when it comes to winter,it's like watching your footy team when you are 2-0 down in the 80th minute but only for your team to bounce back 3-2 full time,things can change very quickly in the models i can assure you

still early days yet but we are in a better position than previous years with an el nino and an EQBO

the teleconnect signs are there in place as far as i can tell.

[Rain All Night]

9 hours ago, RainAllNight said:

ECM 0z and GEFS 6z at day 10 (Sat 11):

...

ECM 0z and GEFS 6z at day 13 (Tue 14):

...

The GEFS had been weakening its support for an Atlantic ridge leading into the second weekend of November, but its 6z run this morning pivots back the other way and offers much strengthened support - and this run also shows an Azores high ridge early the following week, which is also favoured by the ECM 0z ensemble.

The ECM ensemble cluster analysis shows the Atlantic ridge towards the end of next week as featuring in the largest cluster of member runs, although it is not quite a majority.

Here are the individual members from those two ensemble runs, at day 10. The members which show an Atlantic ridge don't show it to be particularly robust-looking - but at least it's not a trough!

The Atlantic ridge anomaly at the end of next week is now showing consistently on all runs of all three ensembles with long enough range, so I would be surprised now if something of that nature does not verify, even if it is only a transient interlude between Atlantic lows.

The ECM follows this up a few days later (approaching mid-month) with a decent Azores high ridge anomaly - as it had also done on its two previous runs - but it is still awaiting consistent support from either the GEFS or GEM.

Edited November 1, 2023 by RainAllNight

[Mucka]

I see some posters have mentioned the potential for blocking toward mid month and I would go with that.

This mornings runs seem to affirm the suggestion we  have seen in various runs prior  for blocking to the N and/or E take hold 2nd week of Nov.

As always though it is very difficult know exactly what that will mean for the UK if it does set up in any meaningful way.

An Easterly flow of some form, at least for a while seems most likely but often the models put out Easterlies when they first sniff out blocking but ultimately have the blocking further W and more Northerly component. 

And of course wherever any blocking sets up just the orientation can make  the difference between cold or relatively mild.

 

GFS mean picking up potential Atlantic ridge day 7

UKMO day 7

 

So it looks as though a Sceuro ridge of some form will  stall the Atlantic trough and force it to dig S with the potential ridging behind.

It takes something exceptional to get proper Arctic cold to our shores in November so a long way to go, but of course we can dream of that record breaking late November cold spell.

 

[blizzard81]

Very decent ecm this morning. All about the building blocks. Coming together nicely. 

[Cambrian]

0z GFS op yet another run that is feeling around for ways of bringing in properly cold air from the north or northeast for the middle of the month.

Day 12 / 13

  

This would be firmly in the “coincidence category”, if it wasn’t for the ECM op (again) working towards a similar setup at day 10 -

 

heights to the northeast over the Norwegian Sea and to the southwest towards the Azores, framing low pressure over Denmark and northern Germany - a Euro low, which has been a much repeated feature in the models recently, the same pattern creeping into the ensemble means:

0z GFS mean day 10

 

0z ECM mean day 9

 

The Atlantic trough is still there but being held at bay, giving the UK and Ireland a well-deserved break, something a good deal quieter and very probably a good deal colder if this pattern establishes towards mid-month. 

[captaincroc]

10 hours ago, RainAllNight said:

Winter-only posters may not yet be aware that the ECM ensembles got a big upgrade in June: the 15-day ensemble now has all 51 members running at the same high resolution as the deterministic run, and the 46-day ensemble now runs at 0z every day and has been doubled to 101 members (with a lower resolution than the shorter-range ensemble).

Thanks for this. Good to know, cheers for thinking of us part-timers! 

[Jeremy Shockey]

t300 GFS0z

After these storms have passed i wouldn't be surprised to see a few colder shots from the North ( or even the North East ) as we approach mid month. Some evidence of potential blocking from both GFS and ECM today

[Rain All Night]

Thought I would use ECM and the machine learning models to illustrate the possible evolutions of the little ridge coming in from the Atlantic at the end of next week. Note that these charts are showing MSLP + 200hPa wind (jet stream), not the more familiar MSLP + 500hPa geopotential height, as the ECMWF website does not offer that combination.

All agree that it will begin on Thursday with a northwesterly/northerly for us from the previous trough departing to the east.

That's still ongoing on Friday, and by then you can see disagreement developing over exactly how much of a gap there will be between the trough existing eastwards and the next one coming in from the west; Pangu-Weather is the most pessimistic here.

By Saturday, we've got either a thin wedge of high pressure over the UK - meaning this could be a usable dry Saturday for us all - or one of two alternatives: Pangu-Weather has a little low sliding over us underneath some cut-off HP over Iceland, and FourCastNet is building a little Scandi high which looks like it would keep further Atlantic lows away from us for longer.

Sunday, day 10 and thus the end of these 0z runs, just showing a continuation of the above; on the AIFS, the Atlantic has broken back through.

For balance, I should mention that there has not been consistent support for any of the more positive outcomes suggested above on recent deterministic runs of the GFS, GEM or JMA models.

Edited November 2, 2023 by RainAllNight

[Downburst]

6 minutes ago, RainAllNight said:

Thought I would use ECM and the machine learning models to illustrate the possible evolutions of the little ridge coming in from the Atlantic at the end of next week. Note that these charts are showing MSLP + 200hPa wind (jet stream), not the more familiar MSLP + 500hPa geopotential height, as the ECMWF website does not offer that combination.

All agree that it will begin on Thursday with a northwesterly/northerly for us from the previous trough departing to the east.

That's still ongoing on Friday, and by then you can see disagreement developing over exactly how much of a gap there will be between the trough existing eastwards and the next one coming in from the west; Pangu-Weather is the most pessimistic here.

By Saturday, we've got either a thin wedge of high pressure over the UK, or one of two alternatives: Pangu-Weather has a little low sliding over us underneath some cut-off HP over Iceland, and FourCastNet is building a little Scandi high which looks like it would keep further Atlantic lows away from us for longer.

Sunday, day 10 and thus the end of these 0z runs, just showing the continuation of the above:

 

Yes, looking at the ECM Operational for Saturday next, talk about a thin end of the wedge. The oddest looking surface Azores high ridge up into the arctic. Naturally this doesn't inspire me as a likely outcome, but at least it's trying and something may be afoot.

[Rain All Night]

3 minutes ago, Downburst said:

Yes, looking at the ECM Operational for Saturday next, talk about a thin end of the wedge. The oddest looking surface Azores high ridge up into the arctic. Naturally this doesn't inspire me as a likely outcome, but at least it's trying and something may be afoot.

A weird ridge from the Azores up to the Arctic... time to post this again, think it's been posted in this thread three times in the past 24 hours now 

[Downburst]

4 hours ago, RainAllNight said:

A weird ridge from the Azores up to the Arctic... time to post this again, think it's been posted in this thread three times in the past 24 hours now 

Cry havoc and let slip the dogs of war!

[ANYWEATHER]

2 hours ago, Downburst said:

Cry havoc and let slip the dogs of war!

Its gone