Model Output Discussion - Deeper into Autumn

[CoventryWeather]

Don't know why everyone is stressing with the GFS output. Models will flip and change per run - they aren't going to get the pattern right first time. 

Like above, it struggles with trough disruption.. so don't worry, we would expect these runs to come at times.

[Kasim Awan]

4 minutes ago, Ali1977 said:

The para is epic and is a more powerful and updated Op. if the Op is also an outlier within the ENS then everything is still very much heading towards the freezer.

The difference in accuracy between them is negligable, that doesnt mean the op is likely to verify mind.

Edited November 25, 2022 by Kasim Awan

[LRD]

6 minutes ago, Nick F said:

If we just pretend the 06z GFS PARA is OP, then all is fine, no panic 

Ha ha! Indeed

But even with the op, it isn't a disaster when you look at the NH view (granted it's a single FI frame). At this point in time it does feel that all roads may lead to short, medium or long term cold... or even all three. To contradict myself, I am still not completely convinced but that's what is trending

[joggs]

Regarding my earlier post,this is an example of the lower heights eroding the higher heights from the west

that I was talking about. Not good if you're of a cold persuasion. 

Edited November 25, 2022 by joggs

[BlueHedgehog074]

Some rocking times ahead! 

In the closer range (I guess someone has to do it ), and it looks like some further disturbed weather to come before the likelyhood of UK/Northern-Eastern UK blocking ganging up on the Atlantic Lows.

Using the 00Z GFS as an example, today looks like a bright and fairly dry day for most places as a transient ridge of High Pressure to the South of the UK provides some less unsettled conditions. Could still be breezy in the Westerly flow and some showers are likely over Western areas of the UK. More frequent over Western Scotland. Fairly mild in the South (temperatures in low double digits towards the far(ish) South), but cooler further North. 

Tomorrow sees that ridge transfer towards the East of the UK with a deep Atlantic Low out West bringing a disturbance Eastwards through the UK with outbreaks of rain spreading Eastwards. South-Eastern areas holding onto the driest, brightest conditions ahead of the rain out West. Quite mild again in the South and a little cooler further North. But a bit milder overall than today (although could feel cooler for the areas under the rain). Windy at times, especially over North-Western areas. 

 

Rain reaching most areas (while having cleared Ireland) heading early into Sunday. 

 

The rain making its escape Eastwards through Sunday (probably clearing Eastern areas early to mid afternoon). A brighter day for most to follow, but still with a keen South-Westerly flow over the UK. Some showers likely over Western and Northern areas. Southern/South-Eastern areas holding on to the mildest temperatures, but quite cool or chilly everywhere else. 
 

 

The Low Pressure that was over the Iceland area on Sunday will head North-East through Monday across the North of Scotland weakening as it does so, and becoming pinched and squashed against the Scandinavian block over North-Eastern UK. There is also a ridge of High Pressure from the Azores trying to build in from the South-West. Flow becomes North-Westerly over the UK. And, apart from a few showers over Western and North-Western parts, it should be a mostly dry and bright day. Eastern and South-Eastern areas probably escaping without any showers (except perhaps the odd isolated one). Chilly in the North, and quite cool further South. A little cooler overall compared to last few days, but still could be pleasant where the sun peeps through. Plus, temperatures probably for a time in low double digits in the far South.
 

While the details could still change a bit, the Azores ridge should start extending some of its upper and surface heights North/North-East through the UK on Tuesday bringing a still and dry for many. Quite cold across Northern areas (temperatures in fairly low(ish) single figures) and fairly chilly across the South. 

 

Although has been covered by many others, by 144 hours (Thursday morning from the 00Z runs), some of the Azores/UK ridging will have merged with the Scandinavian blocking bringing the possibility of a chilly flow from the East, (more so for Eastern and South-Eastern UK parts).

GFS 00Z

 

ECMWF 00Z

 

UKMO 00Z 

Both the ECMWF and UKMO look to be the cleanest regarding the evolutions leading to the light Easterly over Eastern parts of the UK. I suspect details will continue to change at that range and while there is good support for a strengthening North-Eastern UK block through next week, am going to leave the sledge locked away for now. (The GFS 06Z for example ending up showing a different variation on a similar theme for Thursday morning):

Might look quite iffy and reminds us of the fact that things just may not go as how most of us wants with regards to cold and the white stuff. But the most important thing really is the final platform the weather pattern train ends up getting to. (PS: don’t actually have a sledge… yet )

[LRD]

1 minute ago, joggs said:

Regarding my earlier post,this is an example of the lower heights eroding the higher heights that I was talking about. Not good if you're of a cold persuasion. 

Even with that disappointing chart, while it's a short/mid-term defeat it could be a long-term win. A split PV, cold polar heights looking as though they want to support the flagging and failing Scandi heights (or former Scandi heights). Doesn't quite turn into Jan 1987 this time but it's possible

Like Sheiky says, it's probably an outlier too

[Yarmy]

11 minutes ago, Kasim Awan said:

The difference in accuracy between them is negligable, that doesnt mean the op is likely to verify mind.

Yeah, it's interesting that despite a decade or more of upgrades, the GFS really hasn't improved all that much:

 

[Kirkcaldy Weather]

13 minutes ago, Mike Poole said:

GFS // at T294:

Another worth chucking in with the rest in the stunner collection Mike ...  

AWESOME run that is 

12 minutes ago, CoventryWeather said:

Don't know why everyone is stressing with the GFS output

Is this your first winter viewing the model thread if so buckle up  

[Ali1977]

Day 9 mean, that’s not too bad

[Downburst]

couple of questions to help through the winter: I have looked myself, but too much waffle out there.

 

1. Does anyone have the latest info on the 4 daily GFS runs input information, I recall the 06z had the least data input, then 12z etc. perhaps this has changed and although I can find info from 10 years ago, I am sure that has changed. I'd like to so if this can be analysed for skill.
2. Are there any verification stats for the GFS Parallel run? Does it have its own lower resolution ensembles? What are the hopes they have for improvement, expected tweak or major upgrade?

In saying all this, good old Americans for producing all this for "free" to us.

 

 

[feb1991blizzard]

Near perfect Ssw precursor trop pattern.

[Eagle Eye]

25 minutes ago, CoventryWeather said:

Don't know why everyone is stressing with the GFS output. Models will flip and change per run - they aren't going to get the pattern right first time. 

Like above, it struggles with trough disruption.. so don't worry, we would expect these runs to come at times.

Welcome to Netweather.

I think there should be a sign on this thread every Winter saying "Please do not take every GFS run as gospel"

[LRD]

8 minutes ago, Ali1977 said:

Day 9 mean, that’s not too bad

Yep, 850s ensembles (not full set) highlight the op as being among the warmest if not THE warmest member from next weekend. Some minority support but not a lot

Edited November 25, 2022 by LRD

[SLEETY]

Stop hanging off every gfs run, basically. 

It's known for its wide inconsistencies every 6 hours, bit people still follow it like gospel. 

[joggs]

24 minutes ago, LRD said:

Even with that disappointing chart, while it's a short/mid-term defeat it could be a long-term win. A split PV, cold polar heights looking as though they want to support the flagging and failing Scandi heights (or former Scandi heights). Doesn't quite turn into Jan 1987 this time but it's possible

Like Sheiky says, it's probably an outlier too

Oh yes. Agree. Just trying to keep a little balance on here for newbies.

[LRD]

12 minutes ago, SLEETY said:

Stop hanging off every gfs run, basically. 

It's known for its wide inconsistencies every 6 hours, bit people still follow it like gospel. 

Yep, basically.

But, having said that, I get why people are drawn in. It's a long time since we had a nationwide classic cold, snowy spell and next month MIGHT produce so I get the anxiety. Guess I've just got more philosophical down the years. Disappointment with winter weather just washes over me now, like mild UK winter rain, cos I'm so used to it!

Edited November 25, 2022 by LRD

[geordiekev]

1 hour ago, LRD said:

If significant cold emerges next month it will be a slow burner. Proper cold won't arrive until the week of the 5th at the earliest. There will be variations on a theme in the build up to the cold arriving (if it does happen and I'm still not totally convinced but I think the odds favour it).

I fear for people's sanity if they're going to agonise over every single run between now and next weekend

Having said that, I'll treat you all. Have a GFS 6z para chart on me:

Snow showers in the SE, south and maybe even central areas I'd have thought

GFS 6z op is not great though. A mild Easterly a la 2020-21

Thought you'd posted the 62/63 pattern there for a moment

[LRD]

2 minutes ago, geordiekev said:

Thought you'd posted the 62/63 pattern there for a moment

Ha! Isn't too far off, is it?!

Ahem, in no way am I predicting 62-63 here. Just to clear that up!

[Cold Winter Night]

30 minutes ago, Downburst said:

couple of questions to help through the winter: I have looked myself, but too much waffle out there.

 

1. Does anyone have the latest info on the 4 daily GFS runs input information, I recall the 06z had the least data input, then 12z etc. perhaps this has changed and although I can find info from 10 years ago, I am sure that has changed. I'd like to so if this can be analysed for skill.
2. Are there any verification stats for the GFS Parallel run? Does it have its own lower resolution ensembles? What are the hopes they have for improvement, expected tweak or major upgrade?

In saying all this, good old Americans for producing all this for "free" to us.

 

 

From NOAA NCEP themselves:

GFS

WWW.EMC.NCEP.NOAA.GOV

EMC Verification: Global Models

WWW.EMC.NCEP.NOAA.GOV

It should be noted that the ECMWF IFS is more integrated with their HRES Operational, the EPS ensemble, and the extended range output than the GFS and GEFS products are.

Hope this helps!

[seb]

Looks like some exciting times ahead

As always, it is good to remember not take individual runs in isolation, not to take the Ops as gospel and to look at the overall patterns. Anything 8+ days is FI but if Models overall are close with their solutions then that is good guidance. 

[feb1991blizzard]

@bluearmy could you post the T324 Gefs run to run variation chart up please - it will be a stonker - Gefs 6z - corker!

[Cold Winter Night]

4 hours ago, Johnp said:

And I always argue against this. Doing this means the run you are looking at is 24hrs out of date. A lot can change in that time!

That's not really how it works though.

Our society has been conditioned to think that Newer = Better, plus the speed of these model threads, and the amount of models and the 3/6/12 hour cycle output they generate make us easily forget the runs that have gone before, but, to quote the ECMWF Forecast User Guide:

"Just because the most recent forecast is, on average, better than the previous one, it does not mean that it is always better.  A more recent forecast can be worse than a previous one, and often with increasing forecast range it becomes increasingly likely that the 12 or 24 hours older forecast is the better one."

I highly encourage all to read this user guide, in this case the chapter on uncertainty.

7 ENS Products - Dealing with Uncertainty - Forecast User Guide - ECMWF Confluence Wiki

CONFLUENCE.ECMWF.INT

[Methuselah]

Given that a new GFS run comes along every 6 hours, it's hardly surprising (IMO) that not every run will comply with our wishes for a repeat of 1962-63 -- even back then, arguably before AGW really set in, that was a once-in-three-hundred-year event... But, in any case, today's 06Z hardly speels disaster!

    

    

IMO, the models are all a wee bit nonplussed just now -- even the ones encouraging folks to predict Snowmageddon. The models do not control the weather!

[MATTWOLVES 3]

How many times have I and others said on this Forum regarding getting hung up over each and every operational run! 

If you get the runs 4 times a day your gonna end up with something hurting

Seriously if your gonna compare,go like for like (ie) 6z runs with 6z runs and 12s with 12s...thats the best way to spot any trends or if the model and run is going off on one.

There's a huge amount of support for cold and blocked sypnotics down the line within these ensembles and the prognosis I feel still looks pretty solid.

Keep a cool head boys and gals it's gonna be a very long road before we hit the next service station.

[bluearmy]

9 minutes ago, feb1991blizzard said:

@bluearmy could you post the T324 Gefs run to run variation chart up please - it will be a stonker - Gefs 6z - corker!

Yes, the greeny heights on the increase 

   

comparing T324 06z with T372 from two days ago. Iberian low will obvs show as a big anom if it’s got mean strength but best if it has the jet running into it to push lower heights further east too. We don’t want a stuck Iberian trough driving a se euro ridge with flow source Mediterranean 

remaining more than interesting