Winter 2023/24 - Discussions & Forecasts

[Mike Poole]

38 minutes ago, Don said:

I think it should be peaking now, going by recent forecasts, yes?  However, the concern is that I don't think it's forecast to really weaken until December and taking into account a lag effect and the fact it is now the 4th most positive on record, that can't bode well for winter?

Yes, the +IOD is predicted not to go much higher now, but not to start falling until December:

Latest data has it (on this index) at +1.69, some way short of 2019:

I’d like to see the next data point turn this around though.  At the moment, I am taking comfort from the fact it is probably not the overriding driver this year, as we have El Niño and strong eQBO in play at the same time, but it is squeaky bum time if it gets any higher - just my guess as to where we sit at the moment.

[Don]

39 minutes ago, Mike Poole said:

I’d like to see the next data point turn this around though.  At the moment, I am taking comfort from the fact it is probably not the overriding driver this year, as we have El Niño and strong eQBO in play at the same time, but it is squeaky bum time if it gets any higher - just my guess as to where we sit at the moment.

I think it's squeaky bum time whether it gets any higher or not, as it's not forecast to decline until winter starts and taking the lag effect into account, this is a concern.  I think the main hope currently is the E-QBO!

[Mike Poole]

15 minutes ago, Don said:

I think it's squeaky bum time whether it gets any higher or not, as it's not forecast to decline until winter starts and taking the lag effect into account, this is a concern.  I think the main hope currently is the E-QBO!

Maybe, I’m reserving judgement, largely because of the models.  The same models that are predicting a +IOD peaked about now that doesn’t decline until December are predicting blocking patterns, particularly Jan and Feb.  October updates awaited to see if all that still remains the case, of course…ECM seasonal is out Friday I think…

[Don]

Just now, Mike Poole said:

Maybe, I’m reserving judgement, largely because of the models.  The same models that are predicting a +IOD peaked about now that doesn’t decline until December are predicting blocking patterns, particularly Jan and Feb.  October updates awaited to see if all that still remains the case, of course…ECM seasonal is out Friday I think…

Yes indeed, the latest long rangers (apart from CFSv2) offer hope for winter.  Squeaky bum time for the October updates!!

[Chesil View]

I am less than convinced that the IOD is the Winter wiper outer that some have been suggesting. It is just one of many factors that wax and wane in their influence depending on each individual winter set up of those factors. The cfs has shown a high IOD yet many of its runs on its nine month outlook have been showing some fantastic winter synoptic set ups. Which any winter lover on here would sell their granny for.

[MattStoke]

On 02/10/2023 at 22:08, northwestsnow said:

Yup.

Just checked ,Oct update not available yet.

Any news on October's update?

[bluearmy]

8 minutes ago, MattStoke said:

Any news on October's update?

Hopefully later today 

[MattStoke]

5 minutes ago, bluearmy said:

Hopefully later today 

Don't know why but I had in my mind that yesterday was the 5th. D'oh!

[northwestsnow]

3 minutes ago, MattStoke said:

Don't know why but I had in my mind that yesterday was the 5th. D'oh!

 

I suspect Octobers update will be more revealing as to where we stand and give us a much  better picture of DJF..

Edited October 5, 2023 by northwestsnow

[Addicks Fan 1981]

2 hours ago, Chesil View said:

I am less than convinced that the IOD is the Winter wiper outer that some have been suggesting. It is just one of many factors that wax and wane in their influence depending on each individual winter set up of those factors. The cfs has shown a high IOD yet many of its runs on its nine month outlook have been showing some fantastic winter synoptic set ups. Which any winter lover on here would sell their granny for.

The positive IOD in winter 2019-20 basically ruined the winter.   It was very mild right ️ from the beginning to end.   

[bluearmy]

47 minutes ago, Addicks Fan 1981 said:

The positive IOD in winter 2019-20 basically ruined the winter.   It was very mild right ️ from the beginning to end.   

It can’t be as simple as that 

the atmosphere is way more complex than that. I don’t doubt it was contributory and it may have been the most important factor but there are instances where a positive IOD has not correlated to a mild winter for nw europe 

[Met4Cast]

12 hours ago, Don said:

I think it's squeaky bum time whether it gets any higher or not, as it's not forecast to decline until winter starts and taking the lag effect into account, this is a concern.  I think the main hope currently is the E-QBO!

Agreed. 

If we isolate winters with a max IOD of >1.0, we see 2 cold winters and 8 mild ones in a set of 18. If we filter that to only include El Nino events those 2 cold winters disappear and 100% of sampled months were at least 0.5C above average. That's no small signal for mild weather in NW Europe/UK with strong IOD events. 

Stats: James Peacock

P.S: Incidentally 2019 isn't included in the above because the IOD peaked in October and declined into December, so it's likely there's a lag effect. Which again would NOT be in our favour this coming winter.

Edited October 5, 2023 by Met4Cast

[Redbull165]

Here is a composite of different winters with El nino conditions . We have three types.

Winter SST expected over D,J,F 2023/2024 by CANSIPS model. As I am seeing the anomalies are looking the closest to the east-central based el nino. With hopefully modoki coming towards the end of the winter. All to play for.

 

 

And I have some more interesting things to add to my post.

This was posted on World Climate Service some months ago.

"Added the newly-released 1940-1949 data to our ERA5 viewer. The notoriously cold European winter of 1941-1942 (coldest of the 20th century) occurred in tandem with an extreme +PDO phase, following a super-El Niño the prior winter. Extreme climate anomalies!"

 

 

Greetings from Slovenia.

 

[Chesil View]

I fully appreciate that IOD may play a part in general atmospheric winter patterns. But samples sizes of 18 and 1 do not prove a causal link.

[Met4Cast]

Worth noting the IOD was found to be largely responsible for the very mild 2019 winter across Europe.

Just a moment...

RMETS.ONLINELIBRARY.WILEY.COM

"The impact of the IOD on the Atlantic jet stream and associated precipitation anomalies is a northward shift in the jet latitude, a slight increase in the jet strength, and anomalously high precipitation over the UK and northern Europe, as shown in Figure 5. This is consistent with an anomalously positive NAO and agrees well with the features observed in winter 2019/20."

Edited October 5, 2023 by Met4Cast

[Chesil View]

An interesting article from learned people but I'm not sure it proves a causal link rather it says we've observed some outcomes over a small sample size and feel that the iod was probably the major player in 2019/20.

[summer blizzard]

2 hours ago, Addicks Fan 1981 said:

The positive IOD in winter 2019-20 basically ruined the winter.   It was very mild right ️ from the beginning to end.   

1 hour ago, bluearmy said:

It can’t be as simple as that 

the atmosphere is way more complex than that. I don’t doubt it was contributory and it may have been the most important factor but there are instances where a positive IOD has not correlated to a mild winter for nw europe 

While a high amplitude IOD is not good, it's not currently functioning in the same way. 

In 2019 we were basically in a +IOD event that gave the east Pacific enough scraps to be near El Nino, this meant that we saw persistent convection through Autumn in the Indian Ocean. 

(Sadly i only posted one of these charts once in the Nino thread that Autumn)
 

Basically the reality was that waves started strong in the Indian Ocean and then got a bit weaker than that forecast as they progressed. 

Contrast that to this Autumn where even if the Nino is fighting the PDO and Nina legacy (struggling to couple strongly), it is a Nino driven pattern and the Indian Ocean is dead (the IOD is producing convection but well west of 2019, over Africa).

 

Dominant forcing here is over the west Pacific rather than Indian Ocean.

..

We probably still have to worry about the IOD but its clear that the forcing is being driven elsewhere this time.  

Edited October 5, 2023 by summer blizzard

[CoxR]

avert your eyes people, it's not a good one: 

[northwestsnow]

We've lost northern blocking signal on latest update 

[northwestsnow]

EC goes wet and mild..

Dec

jan

feb is similar so one gets the picture 

[Methuselah]

7 minutes ago, northwestsnow said:

EC goes wet and mild..

Dec

jan

feb is similar so one gets the picture 

Nicely primed for some potentially record-breaking warmth, then? 

[northwestsnow]

Sept update for djflooked like this 

 

octobers update for djf is this

 

Any high lat blocking is gone .

Not surprised looking at the el nino tbh.

Edited October 5, 2023 by northwestsnow

[BremX]

If I never hear IOD again it will be too soon . To my untrained eye, there are many factors for winter, not all of them have to be right. Let's enjoy the next few months of model watching, fantasy island outputs and stop trying to pooh pooh winter before it's even begun

[Frigid]

I knew this would happen. 

[northwestsnow]

The ONLY positive I can see is little appetite for a Euro High...