Winter 2023/24 - Discussions & Forecasts

[Summer8906]

On 29/09/2023 at 10:42, Dorsetbred said:

Give it a few more years, and cricket will be on the TV Christmas Day, (from Edgebaston)

Knowing what mild weather in December is typically like, it would be continually stopped by rain, drizzle and bad light though.

Edited September 30, 2023 by Summer8906

[Summer8906]

On 26/09/2023 at 11:42, Catacol said:

Same basic thoughts here. I think we are in for a stormy autumn, perhaps very stormy indeed, and then an SSW to provide a back loaded winter. Nature of the SSW (split or displaced) will clearly affect things and no way at all of knowing this until much nearer the time. A very different feel to things compared to the last two I think.

Though mid-October 2022 to mid-January 2023 was predominantly wet (sometimes very wet), sometimes windy, very unsettled and Atlantic-dominated; I certainly don't consider it a benign period at all. It only really relented for three weeks for that December cold spell.

Edited September 30, 2023 by Summer8906

[Summer Sun]

Beast from the East stories are underway

 

Forecasters warn Beast from the East could return bringing months of snow to UK - Birmingham Live

WWW.BIRMINGHAMMAIL.CO.UK

---

Temperatures could drop significantly

 

[raz.org.rain]

1 hour ago, Summer8906 said:

Though mid-October 2022 to mid-January 2023 was predominantly wet (sometimes very wet), sometimes windy, very unsettled and Atlantic-dominated; I certainly don't consider it a benign period at all. It only really relented for three weeks for that December cold spell.

I'm certain we had a cold snap last winter. I remember I had to walk down the road near midnight and it was absolutely freezing cold with a thick layer of frost everywhere. The kind of cold you struggle to dress for.

 

edit apologies I thought this was the autumn thread for some reason 

Edited September 30, 2023 by razorgrain

[Bristawl Si]

4 minutes ago, Summer Sun said:

Beast from the East stories are underway

 

 

Forecasters warn Beast from the East could return bringing months of snow to UK - Birmingham Live

WWW.BIRMINGHAMMAIL.CO.UK

---

Temperatures could drop significantly

 

Ha!Ha! 

Madden's 'out of the blocks' early

Same pony every year

[S Bragg]

31 minutes ago, Summer Sun said:

Beast from the East stories are underway

 

 

Forecasters warn Beast from the East could return bringing months of snow to UK - Birmingham Live

WWW.BIRMINGHAMMAIL.CO.UK

---

Temperatures could drop significantly

 

I'll get my shorts ready then! 

[Weather Enthusiast91]

59 minutes ago, Summer Sun said:

Beast from the East stories are underway

 

 

Forecasters warn Beast from the East could return bringing months of snow to UK - Birmingham Live

WWW.BIRMINGHAMMAIL.CO.UK

---

Temperatures could drop significantly

 

Their favourite words: 'could' and 'may'.

 

[Methuselah]

But better than the more realistic 'almost certainly won't'! 

[Chesil View]

Madden up to his usual tricks again.

I particularly loved his classic '100 days of Ice and Snow' forecast prior to the extremely mild and stormy winter of 2013/14.   Vintage b******s that one.  

[RJBingham]

2 hours ago, Summer Sun said:

Beast from the East stories are underway

 

 

Forecasters warn Beast from the East could return bringing months of snow to UK - Birmingham Live

WWW.BIRMINGHAMMAIL.CO.UK

---

Temperatures could drop significantly

 

James Madden, nothing else needs to be said.

[Summer8906]

3 hours ago, razorgrain said:

I'm certain we had a cold snap last winter. I remember I had to walk down the road near midnight and it was absolutely freezing cold with a thick layer of frost everywhere. The kind of cold you struggle to dress for.

edit apologies I thought this was the autumn thread for some reason 

We did, the three week spell in early December. However the prevailing theme of mid-Oct to mid-Jan was mild and wet with southwesterlies and frequent Atlantic lows; aside from that three week spell, it was almost constantly that for the entire three months.

[summer blizzard]

Just playing around to look forward and the signal i see is for a milder than average Oct-Nov, Average Dec and Feb, Cold January and March (need 3.0 and 4.9 for the coldest since 2010 and 2013 respectively). SSW likely between Jan 2nd and Feb 9th. 

My pre-winter excitement level has risen a notch. 

[Uncertainty]

To add to the excitement generated by @summer blizzard above, the latest Cansips is out (eg first October seasonal)

- Keeps the huge blocking signal for Jan/Feb. 

- Mutes the December signal compared to its last update but no where near a raging +nao, still a weak euro trough in fact. Other models have already backed off December blocking so actually better alignment.

- The DJF mean would be an amazing pattern for coldies 

Can’t post the charts just yet but all you need to do is look at SB’s analogue above and that’s it!

Ive followed cansips for years it usually goes +nao it has never been consistent on blocking like this - apart from last year’s December - which was correct.

[blizzard81]

Great vibes! We are certainly over due a good old fashioned wintry January. I'm still hopeful it starts /kicks in around Christmas time which would be the icing on the cake. 

[RJBingham]

https://twitter.com/WorldClimateSvc/status/1708214486182592584

[Mike Poole]

CANSIPS!!

BANK!!

Very interesting indeed, in fact looks like December chart is a ‘work-in-progress’ of the later developments re the low anomalies, and the very clear pattern (not necessarily correct, of course, but it does look like a clear pattern) just strengthens into February.

Just reading between the lines, thinking about how an SSW would fit into that - given the charts are an average of ensemble members I expect we are seeing an increasing chance of the SSW having happened as the months progress, but that does mean some at least small chance of quite an early one for a hint at the pattern to show in December. 

Edited October 1, 2023 by Mike Poole

[Uncertainty]

30 minutes ago, Mike Poole said:

CANSIPS!!

BANK!!

Very interesting indeed, in fact looks like December chart is a ‘work-in-progress’ of the later developments re the low anomalies, and the very clear pattern (not necessarily correct, of course, but it does look like a clear pattern) just strengthens into February.

Just reading between the lines, thinking about how an SSW would fit into that - given the charts are an average of ensemble members I expect we are seeing an increasing chance of the SSW having happened as the months progress, but that does mean some at least small chance of quite an early one for a hint at the pattern to show in December. 

The amazing thing Mike, is the extraordinary consistency of the forecast. Take Cansips for instance, it has been forecasting the above for Jan and Feb for nearly a year.

All the below are for this coming DJF 

Mar 23

 

May 23

Aug 23

 

Oct 23

 

Other models have the same theme. An extraordinarily consistent and unusual forecast for mid winter northern blocking. 

[MattH]

15 minutes ago, Uncertainty said:

The amazing thing Mike, is the extraordinary consistency of the forecast. Take Cansips for instance, it has been forecasting the above for Jan and Feb for nearly a year.

All the below are for this coming DJF 

Mar 23

 

May 23

Aug 23

 

Oct 23

 

Other models have the same theme. An extraordinarily consistent and unusual forecast for mid winter northern blocking. 

The consistency within the seasonal models is most certainly something that remains of significant interest in terms of long-range seasonal forecasts this year, we can often see variability from one month to the next, sometimes losing a signal that many of the seasonal models have one month, for it then to be weaker or gone completely. As you highlight the consistency is quite impressive and not just from individual seasonal models, but across the board and particularly so from the more important seasonal models, like the ECMWF and GloSea and if you put any credit to it, CANSIPs as well, which many do over in the US/Canada.

When you throw into the mix the eQBO and Nino combination as well, as I mentioned in a post the other day we have, generally speaking, teleconnection and seasonal models signing from the same hymn sheet which also helps the cause, when there is a clear divide that also reduces confidence markedly, of course. This combination also brings into play the scientific studies done over the years on the risk of a mid-winter SSW as well, clearly, numerous papers highlight a marked increase in the risk of a wintertime SSW with the eQBO and Nino combination, something we've not had for a good few years either.

The Oct and Nov updates of the seasonals will be crucial, if we can maintain this signal then it will provide great interest and also a test of the seasonal models as well. It seems to have been a long time since I've seen such cross-model agreement on an overall evolution over a number of months. Granted we can always talk about the so-called "curve balls" that come into play, AGW, H20 content from the Hunga Tunga volcano, the final type (E-based, Modoki etc) and strength of Nino and whether the IOD event will eventually die off by Dec as currently expected.

Fascinating outlook and I still stick with my own thoughts that this winter seems to be providing the best footing and foundations for colder winter synoptics than for a good few years...

Cheers, Matt.

[Met4Cast]

20 minutes ago, MattH said:

The consistency within the seasonal models is most certainly something that remains of significant interest in terms of long-range seasonal forecasts this year, we can often see variability from one month to the next, sometimes losing a signal that many of the seasonal models have one month, for it then to be weaker or gone completely. As you highlight the consistency is quite impressive and not just from individual seasonal models, but across the board and particularly so from the more important seasonal models, like the ECMWF and GloSea and if you put any credit to it, CANSIPs as well, which many do over in the US/Canada.

When you throw into the mix the eQBO and Nino combination as well, as I mentioned in a post the other day we have, generally speaking, teleconnection and seasonal models signing from the same hymn sheet which also helps the cause, when there is a clear divide that also reduces confidence markedly, of course. This combination also brings into play the scientific studies done over the years on the risk of a mid-winter SSW as well, clearly, numerous papers highlight a marked increase in the risk of a wintertime SSW with the eQBO and Nino combination, something we've not had for a good few years either.

The Oct and Nov updates of the seasonals will be crucial, if we can maintain this signal then it will provide great interest and also a test of the seasonal models as well. It seems to have been a long time since I've seen such cross-model agreement on an overall evolution over a number of months. Granted we can always talk about the so-called "curve balls" that come into play, AGW, H20 content from the Hunga Tunga volcano, the final type (E-based, Modoki etc) and strength of Nino and whether the IOD event will eventually die off by Dec as currently expected.

Fascinating outlook and I still stick with my own thoughts that this winter seems to be providing the best footing and foundations for colder winter synoptics than for a good few years...

Cheers, Matt.

Are there any concerns with seasonal model performance going into this season given the unprecented warmth we’re seeing across the planet? 

I’m not 100% clued up on how these models predict things but given we have seen things not “working” as they should, is this potentially the case for whatever the seasonals are picking up on? 

I.E are they going on what would be the “normal” most likely outcome based on the variables you highlighted above, when actually we’ve got this wildcard of very warm sea & air temperatures which could perhaps “skew” things? Another concern of mine is the developing +IOD, I wonder how much of that the models are factoring in given we’re still early on in that development. 

[Mike Poole]

1 hour ago, Met4Cast said:

Are there any concerns with seasonal model performance going into this season given the unprecented warmth we’re seeing across the planet? 

I’m not 100% clued up on how these models predict things but given we have seen things not “working” as they should, is this potentially the case for whatever the seasonals are picking up on? 

I.E are they going on what would be the “normal” most likely outcome based on the variables you highlighted above, when actually we’ve got this wildcard of very warm sea & air temperatures which could perhaps “skew” things? Another concern of mine is the developing +IOD, I wonder how much of that the models are factoring in given we’re still early on in that development. 

The dynamic simulation models just simulate the physics from their best interpretation of the starting conditions at T0 - out for as many days, weeks or months as necessary.  They don’t have any additional knowledge that the IOD is this, or the QBO is that etc.  So they are likely to perform as well, or as poorly, as they usually do.  

In my opinion, it is forecasts based on analogues or pattern matching with previous years that will prove less reliable because this year’s SSTs are unprecedented.  The models should take it in their stride, but they will only be as good as they ever are at this kind of range, which as we know is far from infallible!

It will certainly be interesting to see how well they predict the eventual outcome…

Edited October 1, 2023 by Mike Poole

[sundog]

If we get a decent winter this year I will be stunned. I'm just  not buying into the seasonal models.  Also very warm Septembers in recent yrs being followed by poor winters is the hill I will die on........

Edited October 1, 2023 by sundog

[Uncertainty]

The models know how hot the seas are. I believe it is the SSTs that are driving the forecast, as well as the EQBO. Not sure they (or any forecaster) are able to comprehend the influence of Hunga Tonga though. That and the solar are the big unknowns the models don’t take into account enough. (I might be wrong about them not taking hunga Tonga into account - would love to be corrected on that).

Peitao Pengs SST analogues are as serious about the blocking as the dynamical models are!

 

Again, I’ve followed these for years - never seen anything like it! 
 

It’s a shame the ecm AI forecasts aren’t available for seasonal output yet, would love to know their view on it.

 

 

[summer blizzard]

4 minutes ago, Uncertainty said:

The models know how hot the seas are. I believe it is the SSTs that are driving the forecast, as well as the EQBO. Not sure they (or any forecaster) are able to comprehend the influence of Hunga Tonga though. That and the solar are the big unknowns the models don’t take into account enough. (I might be wrong about them not taking hunga Tonga into account - would love to be corrected on that).

Peitao Pengs SST analogues are as serious about the blocking as the dynamical models are!

 

Again, I’ve followed these for years - never seen anything like it! 
 

It’s a shame the ecm AI forecasts aren’t available for seasonal output yet, would love to know their view on it.

 

 

Models should take the eruption into account since they will record the water vapour level even if they don't know where it came from. 

[Beanz]

2 hours ago, sundog said:

If we get a decent winter this year I will be stunned. I'm just  not buying into the seasonal models.  Also very warm Septembers in recent yrs being followed by poor winters is the hill I will die on........

Well if you’re up a hill, they’ll be more chance of snow  

[Mike Poole]

52 minutes ago, Uncertainty said:

The models know how hot the seas are. I believe it is the SSTs that are driving the forecast, as well as the EQBO. Not sure they (or any forecaster) are able to comprehend the influence of Hunga Tonga though. That and the solar are the big unknowns the models don’t take into account enough. (I might be wrong about them not taking hunga Tonga into account - would love to be corrected on that).

Peitao Pengs SST analogues are as serious about the blocking as the dynamical models are!

 

Again, I’ve followed these for years - never seen anything like it! 
 

It’s a shame the ecm AI forecasts aren’t available for seasonal output yet, would love to know their view on it.

 

 

Yes, the models will fully factor in anything that is in the starting conditions, so the current SST pattern, extra water vapour in the strat due to the Hunga Tonga volcano, winds in the strat etc.  But that’s the totality of the extent to which these things are factored in - only in the starting conditions - from T0 onwards, they just simulate the physics.

I’m not sure how Peitao Peng’s model works to be honest, but if it is based on SST analogues, then it must involve extrapolation rather than interpolation this year because the current SST pattern is way out of recent precedent, and extrapolation adds big uncertainty, so I’m cautious of that one.

Agree that AI would be interesting re seasonal prediction - one would think that AI-based seasonal models could take the pattern matching we humans can do to another level, given the masses of data available, possibly coming up with weird teleconnections humans have never noticed or dreamed of.  But - again - they might struggle this year because lack of precedence.

Edited October 1, 2023 by Mike Poole