El Nino 2023-2024

[Terpeast]

44 minutes ago, bdgwx said:

The September IRI ensemble forecast is out.

           10    11    12     1     2     3     4     5     6
          SON   OND   NDJ   DJF   JFM   FMA   MAM   AMJ   MJJ
DYN      1.83  2.00  2.07  2.00  1.69  1.33  1.03  0.74  0.45
STAT     1.36  1.41  1.39  1.27  1.05  0.82  0.59  0.38  0.15
ALL      1.67  1.80  1.84  1.75  1.43  1.09  0.81  0.54  0.28
(D+S)/2  1.60  1.71  1.73  1.64  1.37  1.07  0.81  0.56  0.30

Still a large spread only 2 months away from their projected OND/NDJ peak

[40/70 Benchmark]

8 hours ago, snowman19 said:

We couldn’t sustain +PNA back in 15-16, minus that one lone, perfectly timed historic blizzard in January. And we had a raging ++PDO and a super El Niño over +3.0C in region 3.4 at the end of November. Don’t you remember what was happening that winter? Every time a +PNA ridge popped up it got knocked right back down by that raging STJ on roids crashing into the west coast. The models kept pumping +PNAs and huge coastal snowstorms in the long range only to see the STJ beat them right back down as fast as they popped up

Right.....but as we have been discussing, this el nino is going to have some fundamental differences from that one. This is why many of the seasonals look the way thay they do.

[40/70 Benchmark]

4 hours ago, snowman19 said:

I know the Euro showed regions 1+2 and 3 remaining warmer than regions 3.4 and 4 through February

But how did the Euro's h5 pattern look?

[40/70 Benchmark]

8 hours ago, GaWx said:

Thanks.
1. Why don’t you think Pinatubo adds to the strength of 1994-5 as an analog?

2. Since you and I agree on the idea of attempts to overly attribute wx to AGW even though we both fully accept AGW as real, I thought you might find this reply that I just made interesting regarding an article citing an attempt to partially attribute increased Midwest rainfall in recent decades to AGW:

 

https://easternmassweather.blogspot.com/2023/08/preliminary-analysis-of-extratropical.html?m=1

[40/70 Benchmark]

8 hours ago, griteater said:

I think it could.  What I've said is that I want to see how the stratosphere is looking in Oct-Nov.  If it is ice cold, I'd think we'd at least partially have to attribute that to the excess water vapor in the stratosphere from Hunga Tonga.  If it's not ice cold then, I think we'll be fine going into winter.

Well, I think there is a decent shot December is mild, so....not sure why that means that the pattern can't change later on, as is often the case during el nino.

Tell me something...you said the WV hit the N Hemisphere last January.....yet March featured very anomalous high latitude blocking, which I correctly predicted in November btw. But if this December has a strong PV, then it must be due to the water vapor??? Why wasn't March as telling for you as this December apparently will be? I mean, the WV had propagated into the NH by that point, right?? Show me a winter month in the early 90s with that type of blocking on the heels of Pinatubo....

[griteater]

7 minutes ago, 40/70 Benchmark said:

Well, I think there is a decent shot December is mild, so....not sure why that means that pattern can't change later on, as is often the case during el nino.

Tell me something...you said the WV hit the N Hemisphere last January.....yet March featured very anomalous high latitude blocking. But if this December has a strong PV, then it must be due to the water vapor??? Why wasn't March as telling for you as this December apparently will be? I mean, the WV has propagated into the NH by that point, right?? Show me a winter month in the early 90s with that type of blocking on the heels of Pinatubo....

I said if the stratosphere is 'ice cold' in Oct-Nov, "we'd at least partially have to attribute that to the excess water vapor in the stratosphere from Hunga Tonga."  And I wouldn't want to fight that battle as we go thru winter.  Yes, back in March, the water vapor had propagated into the NH polar cap, but the Jan-Mar period is more subject to dynamic strat warming compared to early winter (i.e. dynamic wave driving can overcome other potential hindrances in mid-late winter...applies to this winter as well as Dateline forcing plus the -QBO should help with that).  As far as the early 90's, I feel that, in addition to Pinatubo, you also had the descending solar in some of those years <and> elevated CFCs that favored ++AO.  These are just my thoughts.  Do I have all the answers?  No.

[GaWx]

3 hours ago, bdgwx said:

The September IRI ensemble forecast is out.

           10    11    12     1     2     3     4     5     6
          SON   OND   NDJ   DJF   JFM   FMA   MAM   AMJ   MJJ
DYN      1.83  2.00  2.07  2.00  1.69  1.33  1.03  0.74  0.45
STAT     1.36  1.41  1.39  1.27  1.05  0.82  0.59  0.38  0.15
ALL      1.67  1.80  1.84  1.75  1.43  1.09  0.81  0.54  0.28
(D+S)/2  1.60  1.71  1.73  1.64  1.37  1.07  0.81  0.56  0.30

 Now that Sep exact model numbers are out, I can derive the exact model changes from the prior month’s runs:

Model: new peak/months (change in peak)

BoM: +2.87/DJF (0.00)

Met-France: +2.69/NDJ (+0.03)

Euro: +2.24/NDJ (-0.16)

JMA: +2.06/NDJ (-0.16)

UKMET: +1.96/DJF (-0.04)

CFSv2: +1.83/NDJ (-0.28)

 

AVG: +2.28/between NDJ and DJF (-0.12)

[snowman19]

 Now that Sep exact model numbers are out, I can derive the exact model changes from the prior month’s runs:
Model: new peak/months (change in peak)
BoM: +2.87/DJF (0.00)
Met-France: +2.69/NDJ (+0.03)
Euro: +2.24/NDJ (-0.16)
JMA: +2.06/NDJ (-0.16)
UKMET: +1.96/DJF (-0.04)
CFSv2: +1.83/NDJ (-0.28)
 
AVG: +2.28/between NDJ and DJF (-0.12)

Here is the visual for the IMME (DJF): https://x.com/weather_west/status/1704550674305008106?s=46&t=NChJQK9_PUjA1K7D2SMojw

https://x.com/weather_west/status/1704550676196639178?s=46&t=NChJQK9_PUjA1K7D2SMojw

[GaWx]

1 hour ago, snowman19 said:

Here is the visual for the IMME (DJF): https://x.com/weather_west/status/1704550674305008106?s=46&t=NChJQK9_PUjA1K7D2SMojw

https://x.com/weather_west/status/1704550676196639178?s=46&t=NChJQK9_PUjA1K7D2SMojw

I was last ~+2.20 for the ONI peak, which was a good bit warmer than my prior strong ONI peak prediction. 

 Based on the slight cooling of the model consensus since last month, I’m lowering my prediction to +2.10 (lower end super Nino). I feel being very slightly warmer than the JMA and a little cooler than the Euro is the best place to be right now.

[snowman19]

1 hour ago, GaWx said:

I was last ~+2.20 for the ONI peak, which was a good bit warmer than my prior strong ONI peak prediction. 

 Based on the slight cooling of the model consensus since last month, I’m lowering my prediction to +2.10 (lower end super Nino). I feel being very slightly warmer than the JMA and a little cooler than the Euro is the best place to be right now.

I’m sticking with a trimonthly ONI of +2.2C. I think we hit +2.0C on the weeklies by mid-October, but the real “show” is NDJ. Still thinking +2.2C, +2.3C, +2.2C (NDJ) in that order, also think the Euro is correct in keeping regions 1+2 and 3 warmer than 3.4 and 4 through February. Without getting into semantics, I guess we can call it an ‘east-lean’ El Niño. In addition, I think the +IOD ends up being even stronger than forecast and plays a much bigger role this winter than people think

[bluewave]

11 hours ago, snowman19 said:

Don’t kill the messenger. Extremely good model agreement that we see a super El Niño, they are also still showing it being east-based. Latest guidance from Eric Fisher: https://x.com/ericfisher/status/1704615564163928441?s=20

While the Euro has been running warm, it has Nino 4 as the warmest region near +30C during the winter. That would tilt the forcing further west and negate 1+2. Remember, we have not seen any 1+2 forcing due to the balance of the warmest waters being near 4. Much different from true based east events which weren’t near +30C in Nino 4 allowing 1+2 and 3 to dominate. I think the Euro is overdone since it’s now warmer in 4 than 09-10 and 15-16. 
 

[40/70 Benchmark]

7 hours ago, griteater said:

I said if the stratosphere is 'ice cold' in Oct-Nov, "we'd at least partially have to attribute that to the excess water vapor in the stratosphere from Hunga Tonga."  And I wouldn't want to fight that battle as we go thru winter.  Yes, back in March, the water vapor had propagated into the NH polar cap, but the Jan-Mar period is more subject to dynamic strat warming compared to early winter (i.e. dynamic wave driving can overcome other potential hindrances in mid-late winter...applies to this winter as well as Dateline forcing plus the -QBO should help with that).  As far as the early 90's, I feel that, in addition to Pinatubo, you also had the descending solar in some of those years <and> elevated CFCs that favored ++AO.  These are just my thoughts.  Do I have all the answers?  No.

Fair enough.

Thanks.

[bluewave]

9 minutes ago, 40/70 Benchmark said:

Fair enough.

Thanks.

I also ready a study that the persistent +AO +NAO during those years was related to the IO forcing near India. 
 

[40/70 Benchmark]

13 hours ago, mitchnick said:

Here you go 40/70 Benchmark.  Stolen from Phillywx.

Thanks.

Aligns pretty well with my thoughts.

[40/70 Benchmark]

9 hours ago, bdgwx said:

The September IRI ensemble forecast is out.

           10    11    12     1     2     3     4     5     6
          SON   OND   NDJ   DJF   JFM   FMA   MAM   AMJ   MJJ
DYN      1.83  2.00  2.07  2.00  1.69  1.33  1.03  0.74  0.45
STAT     1.36  1.41  1.39  1.27  1.05  0.82  0.59  0.38  0.15
ALL      1.67  1.80  1.84  1.75  1.43  1.09  0.81  0.54  0.28
(D+S)/2  1.60  1.71  1.73  1.64  1.37  1.07  0.81  0.56  0.30

At this point, I think a blend of the statistical and dynamic works.

[40/70 Benchmark]

19 hours ago, bluewave said:

The -PDO isn’t responding int the canonical way. Notice that the warm pool east of Japan extends all the way to California and the Baja.  Then we have the issue of how much coupling we get. The -PDO was strongly coupled last winter but not so much in 20-21. Also we had the coupling interruption in January 2022. Plus the El Niño is only weakly coupled now as per MEI and 500 mb composites. So no telling what the winter pattern will look like with so many mixed  influences during the winter.

 

Do you have the warm phase version of that graphic?

TIA...

[bluewave]

5 minutes ago, 40/70 Benchmark said:

Do you have the warm phase version of that graphic?

TIA...

Sure. The PDO is essentially an Aleutian low index. +PDO has a giant cold pool and low pressure north of a Hawaii. Strong ridge and warmer waters underneath in -PDO. Read studies that the PDO and Aleutian low are regulated through SST changes in the WPAC. But sometimes the PDO isn’t very well coupled to the actual pattern like in 20-21 and Jan 22. So sometimes just using a persistence forecast based on the PDO SST signature doesn’t work. Plus now we have these non-canonical expressions with distortions to the original composites. 

 

[40/70 Benchmark]

3 minutes ago, bluewave said:

Sure. The PDO is essentially an Aleutian low index. +PDO has a giant cold pool and low pressure north of a Hawaii. Strong ridge and warmer waters underneath in -PDO. Read studies that the PDO and Aleutian low are regulated through SST changes in the WPAC. But sometimes the PDO isn’t very well coupled to the actual pattern like in 20-21 and Jan 22. So sometimes just using a persistence forecast based on the PDO SST signature doesn’t work. Plus now we have these non-canonical expressions with distortions to the original composites. 

 

I Like those graphics.

Thanks.

[40/70 Benchmark]

Negative IOD years

 

1. 1960
2.  
3. 1964
4.  
5. 1974
6.  
7. 1981
8.  
9. 1989
10.  
11. 1992
12.  
13. 1996
14.  
15. 1998
16.  
17. 2010
18.  
19. 2014
20.  
21. 2016
22.  
23. 2021

 

Positive IOD years

 

1. 1961
2.  
3. 1963
4.  
5. 1972
6.  
7. 1982
8.  
9. 1983
10.  
11. 1994
12.  
13. 1997
14.  
15. 2006
16.  
17. 2012
18.  
19. 2015
20.  
21. 2019

[40/70 Benchmark]

1963-1964 is an interesting case....basin-wide, moderate el nino with +IOD and descending solar.....I never would have guessed it would have been a cooler, blockier winter. My guess is descending solar maybe less of a detriment when near minimum, like Larry was saying. Maybe a volcanic influence (Agung)?

[40/70 Benchmark]

1 hour ago, 40/70 Benchmark said:

Negative IOD years

 

1. 1960
2.  
3. 1964
4.  
5. 1974
6.  
7. 1981
8.  
9. 1989
10.  
11. 1992
12.  
13. 1996
14.  
15. 1998
16.  
17. 2010
18.  
19. 2014
20.  
21. 2016
22.  
23. 2021

 

Positive IOD years

 

1. 1961
2.  
3. 1963
4.  
5. 1972
6.  
7. 1982
8.  
9. 1983
10.  
11. 1994
12.  
13. 1997
14.  
15. 2006
16.  
17. 2012
18.  
19. 2015
20.  
21. 2019

Hilighted years are la nina/el nino.

[Terpeast]

1 hour ago, 40/70 Benchmark said:

1963-1964 is an interesting case....basin-wide, moderate el nino with +IOD and descending solar.....I never would have guessed it would have been a cooler, blockier winter. My guess is descending solar maybe less of a detriment when near minimum, like Larry was saying. Maybe a volcanic influence (Agung)?

May have been something else that caused it to be blocky. I’m not sold on the IOD effect on the polar domain, I tried to find the correlations and they just aren’t there, even with lag.  

Also the 60s were cold. Probably the coldest decade in the last century to date. 
 

[40/70 Benchmark]

7 minutes ago, Terpeast said:

May have been something else that caused it to be blocky. I’m not sold on the IOD effect on the polar domain, I tried to find the correlations and they just aren’t there, even with lag.  

Also the 60s were cold. Probably the coldest decade in the last century to date. 
 

Me neither....most of those +IOD/el nino seasons had other prominent factors that contributed to the ++AO/NAO IMHO. 

[Volcanic Winter]

Regarding Gunung Agung and the 1960’s:

https://acp.copernicus.org/articles/19/10379/2019/

“We followed the estimated emission profiles and assumed for the first eruption on 17 March an injection rate of 4.7 Tg SO₂ and 2.3 Tg SO₂ for the second eruption on 16 May. ”

https://en.m.wikipedia.org/wiki/List_of_volcanic_eruptions_1500–1999

The 1960’s had a tight clustering of VEI 4 level events, though not traditionally capable of a climate impact individually, this temporal clustering around Agung almost certainly added to the overall SO2 / volcanic forcing for this decade. 
 

The 20/21 eruption of Soufriere at VEI 4 level ejected about .4Tg/Mt of SO2. Replicate that a few more times and add on the end of a significant VEI 5 (Agung) and it sounds to me like the 60’s had considerable volcanic forcing in the mix. 

[40/70 Benchmark]

9 minutes ago, Volcanic Winter said:

Regarding Gunung Agung:

https://acp.copernicus.org/articles/19/10379/2019/

“We followed the estimated emission profiles and assumed for the first eruption on 17 March an injection rate of 4.7 Tg SO₂ and 2.3 Tg SO₂ for the second eruption on 16 May. ”

https://en.m.wikipedia.org/wiki/List_of_volcanic_eruptions_1500–1999

The 1960’s had a tight clustering of VEI 4 level events, though not traditionally capable of a climate impact individually, this temporal clustering around Agung almost certainly added to the overall SO2 forcing for this decade. 
 

The 20/21 eruption of Soufriere at VEI 4 level ejected about .4Tg/Mt of SO2. Replicate that a few more times and add on the end of a significant VEI 5 (Agung) and it sounds to me like the 60’s had considerable volcanic forcing in the mix. 

Considering the 60's featured a predominately very weak PV, this underscores the importance of refraining from the generalization of events, much like we have learned to do with respect to ENSO.

[40/70 Benchmark]

One thing to keep an eye on is that it looks as though guidance has continued to rush the progression of warmer waters to the west throughout the summer and into the fall....IE a positive bias with respect to the EMI.

[bluewave]

The stronger trades not letting 3.4 get much higher than the 1.6 peak around a month ago. I think the weaker EQSOI isn’t letting the SOI couple preventing the stronger WWBs we would usually get.
 

[40/70 Benchmark]

High Confidence in Evolution of ENSO Allows for Shift of Focus to Concurrent Sensible Weather | Eastern Mass Weather

[snowman19]

The stronger trades not letting 3.4 get much higher than the 1.6 peak around a month ago. I think the weaker EQSOI isn’t letting the SOI couple preventing the stronger WWBs we would usually get.
 

The funny part is, while 3.4 has remained steady at over +1.6C, regions 1+2 and 3 are both warming. 1+2 is back up to over +2.8C and 3 is up to almost +2.2C, so the east-based nature of this event continues. 3.4 is extremely likely to warm shortly, as the eastern region warming has lead the way and preceded it so far in this event and there is and has been strong -SOI. I’m still expecting region 3.4 to hit +2.0C on the weeklies next month

[bluewave]

1 hour ago, snowman19 said:

The funny part is, while 3.4 has remained steady at over +1.6C, regions 1+2 and 3 are both warming. 1+2 is back up to over +2.8C and 3 is up to almost +2.2C, so the east-based nature of this event continues. 3.4 is extremely likely to warm shortly, as the eastern region warming has lead the way and preceded it so far in this event and there is and has been strong -SOI. I’m still expecting region 3.4 to hit +2.0C on the weeklies next month

This  is the 1st time that Nino 4 made it to nearly +30 C during the month of September since 2015. The 1.2, 3, and 3.4 regions have all been higher during this time of year. So as long as Nino 4 remains this warm relative to the other regions, the forcing will continue to lean west. +30C SSTs are essentially a forcing magnet.