Model Output Discussion - mid Autumn

[blizzard81]

4 minutes ago, Downburst said:

What happened to January also. It’s extraordinarily meh. When was the last 4 to 5 day freeze in January. I think once in my 50 years in Ireland anyway. I know eastern England and maybe Scotland get somewhat colder weather sometimes, but settled highs in January are so rare I can’t remember one.

You are right. The deep mid winter month of January has been an abject failure in the most part for the last 30 years plus. Mobile/zonal in the main. Rarely blocked. 

[Rain All Night]

10 hours 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 - 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.

Something has taken a scythe to that Atlantic ridge signal in the past 12 hours. These frames are from the midway point (12z on Friday 10th) of the four sets of frames I posted earlier. It looks like a sorry little feature now:

It's the same on all of the ensembles this evening.

I'll show you something which I'm sure can't be helping...

What is all that warm water doing up there in the Labrador Sea?!

Edited November 2, 2023 by RainAllNight

[Robbie Garrett]

43 minutes ago, blizzard81 said:

I do remember reading years ago that statistically, cool and wet November's gave the best chance of a cold proceeding winter. It was quite specific. Dry November's did not bode well. Wet and warm November's also didn't bode well. Specifically cool and wet were the best harbingers for a cold and blocked winter. 

Considering this is how November 2nd was in 2010

It's not bad 2023

Things can change very dramatically.

End of November 2010

 

[Rain All Night]

3 minutes ago, Robbie Garrett said:

That's the fourth appearance in 36 hours 

[blizzard81]

5 minutes ago, Robbie Garrett said:

Considering this is how November 2nd was in 2010

It's not bad 2023

Things can change very dramatically.

End of November 2010

 

Quite. I happen to think the unsettled and zonal theme will continue into December though. El nino this year as opposed to La Nina in 2010. Hopeful for the back end of Dec though. 

[Rain All Night]

In case anyone is interested, here is the mean 500mb height anomaly chart for the calendar month of October 2023...

Edited November 2, 2023 by RainAllNight

[WYorksWeather]

Ensembles for GFS and ECM 12z show broadly average temperatures, albeit with a bit of variation. Operational runs are largely in line with the mean.

 

The GEFS air pressure ensemble does show some support for a brief ridge early next week, but it's marginal and as I've been saying for ages we keep getting led up the garden path. If the signal is still there by the weekend I'll be more optimistic.

Now onto the operational runs. At T+72, the second low forecast for Saturday has passed over the country, but this is not quite as deep as Storm Ciaran, and there does seem to be increasing confidence that the worst of the winds will miss the UK.

 

At T+120, we start to see some differences between the models. GFS again tries to build up the Greenland high as has been signalled for a while, but again ECM is not really interested.

 

By T+168, we see some more substantial differences as a result. GFS brings a deep low near Northern Scotland, possibly bringing some impacts to Orkney and Shetland depending on track. Again looks like a near miss with the worst of the winds out in the Atlantic. ECM doesn't make as much of the low, and it fills quite quickly on approach to the UK.

 

At T+192, we see signs of a brief ridge developing on the GFS. ECM doesn't really make anything of it.

 

At T+240, both GFS and ECM have us under low pressure. We're on the periphery of a deep area of low pressure centred south of Greenland on the GFS, while ECM has the low much closer to us, so still a very unsettled pattern.

 

Finally, at T+384, after several more areas of low pressure wash over the UK, we are in something of a lull. Pressure rises slightly, but it has to be said that based on the look of that chart, I would assume that the next area of low pressure away to our west has our name on it.

In short, the position today is possibly some hope of a brief lull on the GFS, but nothing much to speak of on the ECM.

I've just checked the GFS 18z as a comparator, and it does seem a bit stronger with the high beyond day 7. For cold fans though, it is a mild ridge. Personally I still appreciate mild spells at this time of year. I don't think there's much point hunting for cold and snow before the end of November. Any below average spells before that will just produce cold rain for most of us, and increase heating bills!

In summary, based on the totality of the model guidance, I'm going to say no relief from the Atlantic onslaught until day 7, beyond day 7 there is at least a possibility of an improvement. Let's see what happens as it starts to come into the reliable.

[Mucka]

Blimey, just checked the output this morning expecting to see some form of blocking set up and...

What happened?

Looks like I jumped the shark on that one.

First false alarm of the season, glad it isn't even Bonfire night.

[blizzard81]

Much better build up of cold to our north east on the ecm run this morning. A better run than last night's generally. Better blocking. 

[ANYWEATHER]

11 minutes ago, blizzard81 said:

Much better build up of cold to our north east on the ecm run this morning. A better run than last night's generally. Better blocking. 

Models are good at predicting zonal weather ,just like it picked up the wind storm days ago, but blocking scenarios, they are useless ,and I have little or no faith in their output ,until it gets to T+0 !

[blizzard81]

14 minutes ago, ANYWEATHER said:

Models are good at predicting zonal weather ,just like it picked up the wind storm days ago, but blocking scenarios, they are useless ,and I have little or no faith in their output ,until it gets to T+0 !

Very wise. 

[IDO]

Looking at the D10 means for ECM and GFS, they both paint a similar picture:

 

It seems like typical autumnal weather as we enter mid-November, changeable, and the Azores high in play, so there is little room for anything too cold unless we get a less flat upstream profile. 

[LRD]

10 hours ago, RainAllNight said:

That's the fourth appearance in 36 hours 

Yep

When we get 1947, 1963, 1979 and 1981 posted we know the models are looking REALLY poor!

GFS 850 ensembles. Nothing cold in sight but nothing especially warm either

ECM - also very average with precipitation spikes featuring right the way through

All very meh. Some rain, some drier days. Temps - nothing unusual.

Are we facing yet another autumn without a significant spell of fog and/or frost in my patch? I think so and I also think that's the new normal now - it's been so long without an autumn like that

Edited November 3, 2023 by LRD

[Cambrian]

A few reasons to be a bit more upbeat about the 0z ECM op:

Despite very little overt difference between day 3 and day 10…

 

… the pocket of heights to the north remains throughout, and is beginning to impose itself, pushing the low a bit further south and separating it from the Atlantic low.

Day 5 itself looks half decent! The day 5-10 animation shows the steady west to east progression of the next low after Ciarán, its remnants and the re-complexing. 

  

The next stage would likely see the low continue east into the Baltic, good potential for pulling us into a northeasterly and a reasonable prospect of some influence from all that cold air over Scandinavia, with the foundations to a Eurasian trough in the making and a useful looking schism in the PV running east-west from Siberia to the North Atlantic. 

Looking west, a bit more of a gap emerging after that as the next seaboard low is dropping south rather than moving east out of Newfoundland, it’s eastward movement being arrested by a combination of the northern wedge and Azores heights. It will be interesting to see how the development after that, pushing south through the Labrador Sea is handled. 

It’s increasingly looking for now like this early part of November is one of those situations when we’re looking for the potential for the gaps between systems to turn into something more substantial. In the meantime, a lot of very cold air lurking not at all too far to our north raises the interest during the gaps themselves.

Have a great day. 

[Rain All Night]

2 hours ago, Cambrian said:

Day 5 itself looks half decent!

Only speaking for IMBY and appreciate there's a fair bit of spread here, but it's looking to be one of the worse days of the week down here...

[Rain All Night]

One popular idea this morning (or yesterday morning for the EC46) was for the Azores high to return in the week beginning Mon 13th Nov, though it doesn't seem evident that this would be a prolonged recovery, and neither does there seem to be any prospect (as had briefly been hinted by the ECM ensemble a few days ago) that it will ridge over the UK:

These charts also suggest there will be a trough downstream of the high, over much of Europe.

Edited November 3, 2023 by RainAllNight

[tight isobar]

24 minutes ago, RainAllNight said:

One popular idea this morning (or yesterday morning for the EC46) was for the Azores high to return in the week beginning Mon 13th Nov, though it doesn't seem evident that this would be a prolonged recovery, and neither does there seem to be any prospect (as had briefly been hinted by the ECM ensemble a few days ago) that it will ridge over the UK:

These charts also suggest there will be a trough downstream of the high, over much of Europe.

A good starting point at this stage is/would be… as the models pyramid drop into seasonal deciphering, To take longer range modeling as a mere opening tool “ as per “! And await swirl and update until axis deep -ie, lowering of geomagnetic or influence…. To add the spoon stirring in the mid - upper latitudes of late- Are will be short - mid term wanting of rectification…. Any modeled short range blocking needs taking lightly .     

[Rain All Night]

24 minutes ago, tight isobar said:

A good starting point at this stage is/would be… as the models pyramid drop into seasonal deciphering, To take longer range modeling as a mere opening tool “ as per “! And await swirl and update until axis deep -ie, lowering of geomagnetic or influence…. To add the spoon stirring in the mid - upper latitudes of late- Are will be short - mid term wanting of rectification…. Any modeled short range blocking needs taking lightly .     

I have been stung quite a few times recently by the empty promises of the ensembles (particularly those of the ECM) at days 8-15, but at the moment they are all we have to go on if we're looking for a pattern change...

Here are some day 10 ECM ensemble members I posted on 23rd October while there seemed to be some prospect of heights building in the opening days of November:

What actually verified on the date shown was... Storm Ciarán 

Edited November 3, 2023 by RainAllNight

[Bats32]

Looks like any blocking is being pushed back on Cansips. Can see a wet/windy and mild winter to be honest. https://twitter.com/WorldClimateSvc/status/1720449365158817990?s=19

Edited November 3, 2023 by Bats32

[mathematician]

41 minutes ago, Bats32 said:

Looks like any blocking is being pushed back on Cansips. Can see a wet/windy and mild winter to be honest. https://twitter.com/WorldClimateSvc/status/1720449365158817990?s=19

These long term predictions are absolutely useless most of the time. Flipping a coin would give you more accurate results...

[damianslaw]

1 hour ago, RainAllNight said:

One popular idea this morning (or yesterday morning for the EC46) was for the Azores high to return in the week beginning Mon 13th Nov, though it doesn't seem evident that this would be a prolonged recovery, and neither does there seem to be any prospect (as had briefly been hinted by the ECM ensemble a few days ago) that it will ridge over the UK:

These charts also suggest there will be a trough downstream of the high, over much of Europe.

If the above verifies, it appears to be more of the same in the next 2 to 3 weeks. Atlantic dominating, very brief settled incursions. Often wet, with temps at or a bit above average. All quite standard for November. 

Awaiting more concerted indications for a pattern change away from the trough sitting on top of the UK for an eternity!

[LRD]

8 minutes ago, mathematician said:

These long term predictions are absolutely useless most of the time. Flipping a coin would give you more accurate results...

Disagree. Thing is people misinterpret them, especially pressure anomaly modelling. But the seasonal models aren't useless

They aren't going to be massively accurate as the science is still developing. It's just a guide. But, what do we do if they're not accurate? Just give up on them? Surely it's better to try and improve them and our knowledge? But, as I say, sometimes they do get it right

Edited November 3, 2023 by LRD

[CoventryWeather]

54 minutes ago, Bats32 said:

Looks like any blocking is being pushed back on Cansips. Can see a wet/windy and mild winter to be honest. https://twitter.com/WorldClimateSvc/status/1720449365158817990?s=19

Don't particularly agree with that post. Jan/Fab look pretty decent, with a mean easterly there. Like discussed on other threads, it seems December could be a background between cold to our NE and Atlantic lows, as there are still strong suggestions of highs over Scandi and Greenland. Think this winter could potentially be one to remember, but one little thing could change it dramatically.

[tight isobar]

On a basic vanilla slant- this lrfm is worth a view on its update- however as  with ANY lrf mod…  jigsaw it with an open mind.   And my advice would be at sea and head level at this range.   Anyway polar forces are not yet absorbing critical top hemisphere forwarding- …. Exiting- or garden path walking again??!  We’ll see - the array of probabilities/ non fruitions are what keep the juices going 

Edited November 3, 2023 by tight isobar

[carinthian]

A bit of a difference emerging today between The American and  European models. The latest UKMO keeps the European trough in place with unsettled weather continuation with seasonal temps for many . Our local forecast is for another Italian Low in place for Wed/ Thursday next week  with snow in the Alps and plenty of more rainfall in the valleys. Will be interesting to see what ECM comes up with at 144t compared to GFS run.

C