ENSO Updates (2007 thru 2023)

[cycloneye]

Do you have the link? I have this one but stopped at 2018.

Hello Luis, right here.

https://oceanview.pfeg.noaa.gov/erddap/tabledap/cciea_OC_PDO.htmlTable?time,PDO

Thank you. Added to the first post of thread. (Hyperlink to PDO Data)

[Kingarabian]

Tonight's 00z Euro has the next 10 days on the SOI mainly negative, with some big negatives towards the middle of the month. And that's despite the MJO being over the IO next week.

This Euro forecast is busting pretty badly.

+15 today on the daily SOI.

We can clearly see the subsurface shifting towards cool-neutral. But the atmosphere has been lagging. But in the past week, the atmosphere's progression towards cool-ENSO appears to be in the works. See how the fragmented weak El Nino low pressure bias over 180 stops by early June (solid black contour). And see how a low pressure bias starts (tries?) to situate over the MC as we enter July. Also see how the easterlies start dominating the Pacific, and see how the westerly anomalies shift over to the MC. This is aided by the MJO remaining prolonged suppressed over the CPAC/EPAC (dashed red contours) and prolonged active over the MC (solid red contours).

[cycloneye]

Tonight's 00z Euro has the next 10 days on the SOI mainly negative, with some big negatives towards the middle of the month. And that's despite the MJO being over the IO next week.

This Euro forecast is busting pretty badly.

+15 today on the daily SOI.

We can clearly see the subsurface shifting towards cool-neutral. But the atmosphere has been lagging. But in the past week, the atmosphere's progression towards cool-ENSO appears to be in the works. See how the fragmented weak El Nino low pressure bias over 180 stops by early June (solid black contour). And see how a low pressure bias starts (tries?) to situate over the MC as we enter July. Also see how the easterlies start dominating the Pacific, and see how the westerly anomalies shift over to the MC. This is aided by the MJO remaining prolonged suppressed over the CPAC/EPAC (dashed red contours) and prolonged active over the MC (solid red contours).

https://i.imgur.com/W42m8q9.png

It seems that all the ingredients torwards cool neutral are starting and will come together from now thru the next few weeks.

[cycloneye]

Kingarabian I see +0.4 for Mondays update.

[StruThiO]

Oceanic subsurface heat content anomalies are negative for the first time in seven months.

[Kingarabian]

Kingarabian I see +0.4 for Mondays update.

Yeah it'll probably be either +0.4C or +0.5C.

[cycloneye]

JMA going La Niña by late 2020.

 https://twitter.com/jnmet/status/1249497200318713857

[Kingarabian]

Cycloneye BOM came in at +0.54C for this week.

[cycloneye]

CPC update is at +0.6C.

[cycloneye]

JFM trimonthly came in at +0.5°C. That's the fourth such trimonthly that meets the El Niño threshold in a row. Yet, the CPC or BOM has never declared an El Niño, and the atmospheric response has been weak.

It's going to be interesting to see what CPC ends up classifying 2019-20 as. If FMA comes in at +0.5°C (which is a possibility), 2019-20 could be retroactively classified as a weak El Niño year by ONI - which would technically make 2018-19 and 2019-20 back to back El Niños. This is hard to consider a "two year Niño" considering the brief dip into cool neutral territory last fall. For most of 2019, the tropics did not behave like a typical El Niño either.

If 2019-20 does get classified as a weak El Niño, the prospects of La Niña for 2020-21 make more sense. It would also mean we would not have had a true ENSO neutral year since 2013-14.

CPC says besides the +0.5 threshold,they look at other factors like atmosferic features to persist to then decide to declare officially.

CPC considers El Niño or La Niña conditions to occur when the monthly Niño3.4 OISST
departures meet or exceed +/- 0.5ºC along with consistent atmospheric features. These
anomalies must also be forecasted to persist for 3 consecutive months.

[hurricanes1234]

https://www.nasa.gov/feature/goddard/2020/nasa-study-adds-a-pinch-of-salt-to-el-ni-o-models

An interesting study which suggests that measuring sea surface salinity could further improve the accuracy of ENSO forecasts.

[cycloneye]

UKMET says hello to Weak La Niña.

 https://twitter.com/jnmet/status/1249755631097188354

[Kingarabian]

CPC update is at +0.6C.

[url]https://i.imgur.com/3EOsdME.jpg[url]

With this update keeping Nino 3.4 @ +0.6C, this week will probably determine whether April will average out over +0.5C. If we get +0.5C for the 3rd week of April I think we have a very good chance of meeting the 5 tri-monthly requirement.

[Kingarabian]

CPC says besides the +0.5 threshold,they look at other factors like atmosferic features to persist to then decide to declare officially.

CPC considers El Niño or La Niña conditions to occur when the monthly Niño3.4 OISST
departures meet or exceed +/- 0.5ºC along with consistent atmospheric features. These
anomalies must also be forecasted to persist for 3 consecutive months.

Yeah. That's why they took so long in 2019 to call the 2018-2019 El Nino. But weak El Nino's are weak for a reason. There isn't enough atmospheric momentum and so the atmosphere acts more noisy. You also get fluctuation in appearence with the event sometimes looking traditional and sometimes looking like a modoki. But to get 5 tri-monthlies means something and does not happen by accident. There is evidence of an El Nino like response in the atmosphere with the successive strong WWB's over the dateline between late Fall and March, and the standing wave that ended in March. Per the ONI table, there was never a case where 5 straight tri-monthlies did not end up in an El Nino declaration. Last time we came close was in 1993 but even that year did not have 5 straight months.

[Kingarabian]

CPC is doing a survey if you folks have time. They want the public's input on possible changes to the ENSO alert system.

[Shell Mound]

The low amplitude of the MJO is arguably a net positive for a transition to La Niña by early fall, since it allows the thermocline to gradually flatten and then upwell over time, especially as enhanced easterlies start to become entrenched near the IDL (180°W). This enables a cold pool to expand at the subsurface in this area. Additionally, the low amplitude of the MJO allows seasonal effects to assert themselves and exert more influence than would be the case otherwise. This alone favours a faster transition from weak El Niño to weak La Niña conditions, particularly once the feedback loops set in. Therefore, even if the models have shown a cool SSTA bias vs. trends in the short term thus far, we could still see a faster-than-expected transition to weak La Niña conditions by ASO.

[cycloneye]

I guess is comming down from here right?

[cycloneye]

The BoM latest update has Neutral to La Niña by the fall.

While most of the eight international climate models surveyed by the Bureau indicate central tropical Pacific sea surface temperatures in the NINO3.4 region will remain at ENSO-neutral levels through the southern hemisphere winter, one model exceeds the La Niña threshold during June, and another two models have reached or approached the threshold by September.

http://www.bom.gov.au/climate/enso/#tabs=Outlooks

[Kingarabian]

The low amplitude of the MJO is arguably a net positive for a transition to La Niña by early fall, since it allows the thermocline to gradually flatten and then upwell over time, especially as enhanced easterlies start to become entrenched near the IDL (180°W). This enables a cold pool to expand at the subsurface in this area. Additionally, the low amplitude of the MJO allows seasonal effects to assert themselves and exert more influence than would be the case otherwise. This alone favours a faster transition from weak El Niño to weak La Niña conditions, particularly once the feedback loops set in. Therefore, even if the models have shown a cool SSTA bias vs. trends in the short term thus far, we could still see a faster-than-expected transition to weak La Niña conditions by ASO.

Comes down to that feedback loop and when it can take off. GFS has it robust by day 10 while the Euro is taking its time.

[Kingarabian]

I guess is comming down from here right?

[url]https://i.imgur.com/fawW1ls.png[url]

Tough to say. The WWB in the EPAC could keep it above +0.4C until May. Then after that a gradual drop down. Though like in 2017 and even briefly last season, I would fully expect Nino 3.4 to dip into negative territory by July as soon as the June trades take hold.