ENSO Updates (2007 thru 2023)

[cycloneye]

The Aussies change the ENSO status to Neutral.

Excerpt:

La Niña 2020–21 fades as El Niño–Southern Oscillation returns to neutral.

The Bureau's ENSO Outlook has moved from LA NIÑA to INACTIVE as most El Niño–Southern Oscillation (ENSO) indicators have now returned to neutral levels. Climate model outlooks suggest the Pacific will remain at neutral ENSO levels at least until the winter.

Tropical Pacific Ocean sea surface temperatures have persisted at ENSO-neutral values for several weeks. Below the surface, much of the tropical Pacific is now at near average temperatures. Atmospheric indicators are also generally at neutral ENSO levels. The Southern Oscillation Index (SOI) is close to zero, while trade winds are currently being enhanced by the Madden–Julian Oscillation (MJO). Only cloudiness near the Date Line continues to show a weak La Niña-like signature.

These changes are consistent with climate model outlooks, which have indicated a return to ENSO neutral during the southern hemisphere autumn, with little indication of a return to La Niña patterns in the coming months. A return to ENSO neutral conditions in autumn is also typical of the life cycle of ENSO events. All models indicate ENSO will remain neutral until at least the end of the southern winter.

http://www.bom.gov.au/climate/enso/

[DorkyMcDorkface]

The Aussies change the ENSO status to Neutral.

Excerpt:

La Niña 2020–21 fades as El Niño–Southern Oscillation returns to neutral.

The Bureau's ENSO Outlook has moved from LA NIÑA to INACTIVE as most El Niño–Southern Oscillation (ENSO) indicators have now returned to neutral levels. Climate model outlooks suggest the Pacific will remain at neutral ENSO levels at least until the winter.

Tropical Pacific Ocean sea surface temperatures have persisted at ENSO-neutral values for several weeks. Below the surface, much of the tropical Pacific is now at near average temperatures. Atmospheric indicators are also generally at neutral ENSO levels. The Southern Oscillation Index (SOI) is close to zero, while trade winds are currently being enhanced by the Madden–Julian Oscillation (MJO). Only cloudiness near the Date Line continues to show a weak La Niña-like signature.

These changes are consistent with climate model outlooks, which have indicated a return to ENSO neutral during the southern hemisphere autumn, with little indication of a return to La Niña patterns in the coming months. A return to ENSO neutral conditions in autumn is also typical of the life cycle of ENSO events. All models indicate ENSO will remain neutral until at least the end of the southern winter.

http://www.bom.gov.au/climate/enso/

I always forget that BOM's thresholds for Niña/Niño are different from the CPC's....

Regardless their assessment is reasonable, although I'm not sure I agree with them saying ENSO is resembling neutral atmospherically (walker circulatiion wise). While this look is certainly MJO-enhanced, if the atmosphere weren't Niña coupled trades in the Pacific likely wouldn't be as strong and extensive in coverage and the WWB in the Indian Ocean wouldn't be as potent either. It's a classic case of constructive interference as I mentioned previously.


Even if SSTs briefly rise if a downwelling KW happens to help a portion of the subsurface warm pool to surface I'm still pretty convinced overall that the walker cell will remain atmospherically-coupled with La Niña/-ENSO (which would only help set up the Pacific for another dip by the fall/winter) but I'm waiting to see what this current period of widespread enhanced trades does - could be capable of producing an upwelling KW.

[Kingarabian]

The Aussies change the ENSO status to Neutral.

Excerpt:

La Niña 2020–21 fades as El Niño–Southern Oscillation returns to neutral.

The Bureau's ENSO Outlook has moved from LA NIÑA to INACTIVE as most El Niño–Southern Oscillation (ENSO) indicators have now returned to neutral levels. Climate model outlooks suggest the Pacific will remain at neutral ENSO levels at least until the winter.

Tropical Pacific Ocean sea surface temperatures have persisted at ENSO-neutral values for several weeks. Below the surface, much of the tropical Pacific is now at near average temperatures. Atmospheric indicators are also generally at neutral ENSO levels. The Southern Oscillation Index (SOI) is close to zero, while trade winds are currently being enhanced by the Madden–Julian Oscillation (MJO). Only cloudiness near the Date Line continues to show a weak La Niña-like signature.

These changes are consistent with climate model outlooks, which have indicated a return to ENSO neutral during the southern hemisphere autumn, with little indication of a return to La Niña patterns in the coming months. A return to ENSO neutral conditions in autumn is also typical of the life cycle of ENSO events. All models indicate ENSO will remain neutral until at least the end of the southern winter.

http://www.bom.gov.au/climate/enso/

I always forget that BOM's thresholds for Niña/Niño are different from the CPC's....

Regardless their assessment is reasonable, although I'm not sure I agree with them saying ENSO is resembling neutral atmospherically (walker circulatiion wise). While this look is certainly MJO-enhanced, if the atmosphere weren't Niña coupled trades in the Pacific likely wouldn't be as strong and extensive in coverage and the WWB in the Indian Ocean wouldn't be as potent either. It's a classic case of constructive interference as I mentioned previously.
[url]https://i.ibb.co/6XRYsdC/u-anom-30-5-S-5-N-1.gif[url]

Even if SSTs briefly rise if a downwelling KW happens to help a portion of the subsurface warm pool to surface I'm still pretty convinced overall that the walker cell will remain atmospherically-coupled with La Niña/-ENSO (which would only help set up the Pacific for another dip by the fall/winter) but I'm waiting to see what this current period of widespread enhanced trades does - could be capable of producing an upwelling KW.

It does look like La Nina is in complete control just from looking at this 7 day GFS 850mb wind forecast graphic. But I think it'll change up soon. The Euro and CFS 850mb wind forecasts show the 850mb wind pattern substantially changing over the WPAC in a week from now.

Climo simply says that an El Nino or even warm-neutral this year is very unlikely. It's the best bet, and hard to go against it.

On the other hand, the Euro and CFS say that the sinking branch over the dateline is breaking apart (significantly by May) due to successive strong MJO passages over the WPAC.




This could largely be due to the SPB and the biases from both models. But we'll see what happens in the next 2 weeks.

[DorkyMcDorkface]

The Aussies change the ENSO status to Neutral.

Excerpt:

La Niña 2020–21 fades as El Niño–Southern Oscillation returns to neutral.

The Bureau's ENSO Outlook has moved from LA NIÑA to INACTIVE as most El Niño–Southern Oscillation (ENSO) indicators have now returned to neutral levels. Climate model outlooks suggest the Pacific will remain at neutral ENSO levels at least until the winter.

Tropical Pacific Ocean sea surface temperatures have persisted at ENSO-neutral values for several weeks. Below the surface, much of the tropical Pacific is now at near average temperatures. Atmospheric indicators are also generally at neutral ENSO levels. The Southern Oscillation Index (SOI) is close to zero, while trade winds are currently being enhanced by the Madden–Julian Oscillation (MJO). Only cloudiness near the Date Line continues to show a weak La Niña-like signature.

These changes are consistent with climate model outlooks, which have indicated a return to ENSO neutral during the southern hemisphere autumn, with little indication of a return to La Niña patterns in the coming months. A return to ENSO neutral conditions in autumn is also typical of the life cycle of ENSO events. All models indicate ENSO will remain neutral until at least the end of the southern winter.

http://www.bom.gov.au/climate/enso/

I always forget that BOM's thresholds for Niña/Niño are different from the CPC's....

Regardless their assessment is reasonable, although I'm not sure I agree with them saying ENSO is resembling neutral atmospherically (walker circulatiion wise). While this look is certainly MJO-enhanced, if the atmosphere weren't Niña coupled trades in the Pacific likely wouldn't be as strong and extensive in coverage and the WWB in the Indian Ocean wouldn't be as potent either. It's a classic case of constructive interference as I mentioned previously.
[url]https://i.ibb.co/6XRYsdC/u-anom-30-5-S-5-N-1.gif[url]

Even if SSTs briefly rise if a downwelling KW happens to help a portion of the subsurface warm pool to surface I'm still pretty convinced overall that the walker cell will remain atmospherically-coupled with La Niña/-ENSO (which would only help set up the Pacific for another dip by the fall/winter) but I'm waiting to see what this current period of widespread enhanced trades does - could be capable of producing an upwelling KW.

It does look like La Nina is in complete control just from looking at this 7 day GFS 850mb wind forecast graphic. But I think it'll change up soon. The Euro and CFS 850mb wind forecasts show the 850mb wind pattern substantially changing over the WPAC in a week from now.

Climo simply says that an El Nino or even warm-neutral this year is very unlikely. It's the best bet, and hard to go against it.

On the other hand, the Euro and CFS say that the sinking branch over the dateline is breaking apart (significantly by May) due to successive strong MJO passages over the WPAC.

https://i.imgur.com/r5d6EhV.png
https://i.imgur.com/sBv46Vw.png

This could largely be due to the SPB and the biases from both models. But we'll see what happens in the next 2 weeks.

Yeah I do think the Nina signal overall, despite still being firmly in place, definitely isn't as strong as it was over the winter. Idk it's best just to wait and see what this spell of enhanced trades does over the next week or so, especially with the warm pool trying to grow in extent and surface - I think any lapse of slackened trades that lasts for a week or so could help that subsfc warmth bubble up eventually. As you said, Spring Predictability Barrier things I guess.

We do get the new CanSIPS run tomorrow evening so maybe that''ll be worth a look.

[Kingarabian]

Warm subsurface's and even successive downwelling Kelvin wave's don't always result in substantial ENSO changes. The current subsurface snapshot is warmer than 2017 and 2012. But it's practically the same as 2011 which was a second year La Nina:



Through Jan-March, In terms of the atmosphere, the La Nina base state was stronger in 2011 and 2017, compared to 2006 and 2021.

[cycloneye]

Interesting info here.

 https://twitter.com/_WxPhil_/status/1378109907019370498

[Kingarabian]

Interesting info here.

[url]https://twitter.com/_WxPhil_/status/1378109907019370498[url]

Yeah a very complicated setup which only means a complicated hurricane season forecast. Slightly above average trades over the CPAC/EPAC should stop the SST's in the Nino 3 and Nino 1+2 regions from raising too much. Maybe even create some shallow upwelling. But this upcoming WWB will surely trigger another downwelling Kelvin wave and maybe eventually fliping the SST's over Nino 4 and Nino 3.4 to positive territory.



Also it's odd that there's another active MJO(maybe it's a strong CCKW?) so soon after this current one passes. But the CFS and Euro are in good agreement about this scenario.

[TROPICALCYCLONEALERT]

Interesting info here.

[url]https://twitter.com/_WxPhil_/status/1378109907019370498[url]

Yeah a very complicated setup which only means a complicated hurricane season forecast. Slightly above average trades over the CPAC/EPAC should stop the SST's in the Nino 3 and Nino 1+2 regions from raising too much. Maybe even create some shallow upwelling. But this upcoming WWB will surely trigger another downwelling Kelvin wave and maybe eventually fliping the SST's over Nino 4 and Nino 3.4 to positive territory.

https://i.imgur.com/vuM6ukB.png

Also it's odd that there's another active MJO(maybe it's a strong CCKW?) so soon after this current one passes. But the CFS and Euro are in good agreement about this scenario.

I’m personally banking on the combination of the African Standing Wave and a warm Atlantic/IO to eventually play into -ENSO forcing worldwide, but even then it may become a question of how much damage is dealt to the Niña before that activates, so to speak.

[ClarCari]

How much difference does a Neutral ENSO play compared to a La Niña. My assumption is that a La Niña only minimally decreases wind shear across the Atlantic compared to a Neutral ENSO.
Do we maybe put too much stock into La Niña vs Neutral when maybe both contribute to the same
favorable conditions in the Atlantic and other conditions can play an equally or more important factor?

[cycloneye]

CFS no longer dips back to La Niña in ASO as it stays Neutral thru the rest of the year, however is close to the Neutral / La Niña line of -0.5C.

[DorkyMcDorkface]

 https://twitter.com/webberweather/status/1378361091000918018

[TROPICALCYCLONEALERT]

https://twitter.com/webberweather/status/1378361091000918018

Also relevant follow up tweet

 https://twitter.com/webberweather/status/1378370678336856064

[cycloneye]

Another one.

 https://twitter.com/webberweather/status/1378386845948506117

[DorkyMcDorkface]

Another one.

https://twitter.com/webberweather/status/1378386845948506117

Yeah that was a good thread by Eric. Signs further pointing towards a transition away from La Nina of some sort. Still think a Nino is highly unlikely at the moment though, which is why it's safe to go with neutral at the moment.

[TROPICALCYCLONEALERT]

Guess this is pertinent now. Would be a excellent way to obliterate the existing Niña, given verification of course. Some sort of weakened trade winds in that time period wouldn’t really surprise me, given the passage of MJO as KingArabian has alluded to earlier in this thread. PDO/PMM/WAM combination still isn’t incredibly favorable to the development of a niño, but I’d have to wonder how close we get.

[Kingarabian]

Guess this is pertinent now. Would be a excellent way to obliterate the existing Niña, given verification of course. Some sort of weakened trade winds in that time period wouldn’t really surprise me, given the passage of MJO as KingArabian has alluded to earlier in this thread. PDO/PMM/WAM combination still isn’t incredibly favorable to the development of a niño, but I’d have to wonder how close we get.

[url]https://media.discordapp.net/attachments/662133337120571405/827998162131615744/image0.gif[url]

Yeah that would be a classic case of a robust MJO passage -> generating a WWB -> increased convergence that enhances TC genesis. If a strong TC (TC's?) is actually spawned, it would validate the concerns for the current -ENSO phase. Super Typhoon spawning as a result of a strong WWB is typically something we see when ENSO is shifting towards warm-neutral or some sort of El Nino. But still, it's really hard to go against Climo here which strongly supports continuation of -ENSO into hurricane season. I think many of us won't believe it till we see it.

[JetFuel_SE]

Guess this is pertinent now. Would be a excellent way to obliterate the existing Niña, given verification of course. Some sort of weakened trade winds in that time period wouldn’t really surprise me, given the passage of MJO as KingArabian has alluded to earlier in this thread. PDO/PMM/WAM combination still isn’t incredibly favorable to the development of a niño, but I’d have to wonder how close we get.

https://media.discordapp.net/attachments/662133337120571405/827998162131615744/image0.gif

Fun fact! The southern storm actually crosses the equator in the 318th forecast hour in that run!

[Category5Kaiju]

So is there really a major difference between Neutral and La Nina favorability for the Atlantic? Because while I understand La Nina tend to lower shear in the Atlantic, does neutral (especially cool neutral) do the same or is it much less? Most of 2005's activity if I am not wrong took place during cool neutral, and from what I have heard major US hurricane strikes actually tend to occur more often during neutral episodes than La Nina.

[DorkyMcDorkface]

So is there really a major difference between Neutral and La Nina favorability for the Atlantic? Because while I understand La Nina tend to lower shear in the Atlantic, does neutral (especially cool neutral) do the same or is it much less? Most of 2005's activity if I am not wrong took place during cool neutral, and from what I have heard major US hurricane strikes actually tend to occur more often during neutral episodes than La Nina.

Really as long as ENSO isn't El Niño the prospects of an active Atlantic season are pretty decent (particularly with cool neutral, warm neutral a little less so). Obviously there are other factors that come into play such as SSTs in the Atlantic itself and such but that I suppose that's a discussion more suited for the indicators thread.

[Kingarabian]

It's time to monitor the SOI and see if it can dip further south, and the actual surface temperatures over the Nino regions -- see if they actually warm up.

The subsurface snapshot for AMJ 2011 was just as warm if not warmer than 2021's:


But despite all the subsurface warm anomalies in AMJ 2011, most of these anomalies did not make it to the surface or were blown off due strong easterlies across the entire Pacific. The subsurface in 2011 was the warmest in May and June. Naturally trade winds dominate and it takes WWB's to slow them down or reverse them to create warming. For pretty much the entirety of AMJ, the MEAN easterly wind speed was strong over the CPAC (much stronger than it is now in fact). You can see this with the plethora of long arrows pointing from east to west. Longer means stronger.



That was largely due to a strong La Nina atmosphere which was evident in the SOI:

Code: Select all

2011  1   18.06
2011  2   22.62
2011  3   17.45
2011  4   23.86

So far this year:

Code: Select all

2021  1   15.85
2021  2   11.32
2021  3   -0.46

https://data.longpaddock.qld.gov.au/Sea ... 89Base.txt

Here's a CFS graphic from 2011 showing how quickly things changed back to La Nina after the failed ENSO warming attempt:



So there's a long way to go.