ENSO Updates (2007 thru 2023)

[cycloneye]

 https://twitter.com/jnmet/status/1236643567222886401

[Kingarabian]

Models have been on and off about the current voyage of the MJO as it passes through the Pacfic. Sometimes showing enough to trigger westerly anomalies and sometimes showing trade winds in control.
CFS and the Euro have the MJO over or near the IO by March 20. If this occurs we'll have continued trade winds over the Nino regions to enforce cooling.

To get a full blown La Nina by summer (as models currently forecast) we need much more cooling beneath the subsurface. There's no way around this. It's evident in any analog SST or subsurface chart. So over the next 6 weeks we'll need to see the cold pool beneath the WPAC expand and move east into the CPAC, and the present warm pool to fizzle out. I think if we get a nice MJO amplification over the IO it is plausible.

[Kingarabian]

March 9 2020 update:
Niño 4: 1.1ºC
Niño 3.4: 0.5ºC
Niño 3: 0.1ºC
Niño 1+2: 1.1ºC

[Kingarabian]

Euro shows solid positives for the next 5 days, followed by 5 days of solid negatives on the SOI.

Also what's weird is that the models on the RMM charts shows the MJO taking its time over the IO (which would mean trades will remain enhanced longer over the Pacific) while their pressure pattern and hovmoller forecasts show the MJO back over the Pacific by March 23.

[cycloneye]

 https://twitter.com/jnmet/status/1237736694759243776

[CyclonicFury]

 https://twitter.com/CyclonicFury/status/1237802846747267077

[cycloneye]

 https://twitter.com/RyanMaue/status/1237854091637714946

[Kingarabian]

Would be a great NCEP win if the CFSV2 verifies -- and it really would be a step in the right direction.

[cycloneye]

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP/NWS
and the International Research Institute for Climate and Society
12 March 2020

ENSO Alert System Status: Not Active


Synopsis: ENSO-neutral is favored for the Northern Hemisphere spring 2020 (~65% chance), continuing through summer 2020 (~55% chance).

During February 2020, above-average sea surface temperatures (SSTs) were evident across the western, central, and far eastern Pacific Ocean [Fig. 1]. The latest weekly Nino-3.4 and Nino-3 indices were near-to-above average (+0.5°C and +0.1°C, respectively), with the Nino-4 and Nino-1+2 indices warmer, at +1.1°C [Fig. 2]. Equatorial subsurface temperatures (averaged across 180°-100°W) remained above average during the month [Fig. 3], with positive anomalies spanning the western to the east-central equatorial Pacific, from the surface to ~150m depth [Fig. 4]. Also during the month, low-level westerly wind anomalies persisted over the western tropical Pacific Ocean, while upper-level wind anomalies were mostly westerly over the eastern half of the basin. Tropical convection remained suppressed over Indonesia and was enhanced near and just west of the Date Line [Fig. 5]. While the equatorial Southern Oscillation index (SOI) was negative, the traditional SOI was near average. Overall, the combined oceanic and atmospheric system remained consistent with ENSO-neutral.

The majority of models in the IRI/CPC plume [Fig. 6] favor ENSO-neutral (Nino-3.4 index between -0.5°C and +0.5°C) through the Northern Hemisphere fall. Despite elevated Nino 3.4 index values in the near-term, the forecaster consensus expects the Nino-3.4 index values will decrease gradually through the spring and summer. In summary, ENSO-neutral is favored for the Northern Hemisphere spring 2020 (~65% chance), continuing through summer 2020 (~55% chance; click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).



https://www.cpc.ncep.noaa.gov/products/ ... odisc.html

[cycloneye]

Here is a great discussion about the March update at their ENSO Blog. They are more on the Neutral side than La Niña. Excerpts below.

Getting into late summer and next fall, though, some models predict that the Niño3.4 index could drop below the La Niña threshold of 0.5°C cooler than the long-term average. So are we gearing up for La Niña next winter? Perhaps, but we’re giving it lower odds. Forecasters are putting the odds of La Niña at around 35-40% by next fall, but there are reasons why we’re not giving La Niña a big edge.

First, check out that Niño3.4 graph a few paragraphs up. The gray lines show every year since 1950 that started from an ENSO-neutral winter like the one we’ve just had. In 22 examples, La Niña has not followed a neutral winter once! Does that mean it’s impossible? Definitely not! But it would be something we haven’t observed before.

Another consideration is the spring predictability barrier. Forecasts made in March, April, and May tend to be less reliable than forecasts made during the rest of the year. This is partly because spring is often a transition time between El Niño, La Niña, and neutral. Also, the tropical Pacific has a particularly narrow temperature range in the spring, with only about 2°C separating the warmest spring Niño3.4 and the coolest. For comparison, the range in winter is more than 5.5°C. Predicting a small change is tougher than predicting a larger one, contributing to the spring barrier.

[Kingarabian]

Upwelling Kelvin wave expanding but slowly moving eastward:


CFS has a large scale trade surge that should promote further upwelling. Also it and the Euro show westerly anomalies in association with a CCKW building back over the dateline by the end of March, but they don't look impressive.

[Kingarabian]

CDAS picking up on some warming over Nino 3.4 and Nino 3 this past week:


CDAS has been running much cooler than the CPC's Nino values for the most part. Also interesting to see tomorrow's OHC update with the CPC graphics showing less warm anomalies and stronger cooler anomalies compared to the TAO buoys.

[Kingarabian]

Today's update keeps Nino 3.4 @ +0.5C:

Niño 4: 1.2ºC
Niño 3.4: 0.5ºC
Niño 3: 0.5ºC
Niño 1+2: 0.3ºC

The warm pool is erupting with little resistance in the past 2 weeks, probably due to trades actually verifying normal rather than above normal.


GFS has a strong trade burst over the dateline on the way which in theory should promote further upwelling and a reduction of OHC.

[TROPICALCYCLONEALERT]

Things seem to be pointing towards a La Niña, though I'm personally refraining from calling it one this early. IMO, there may be a slow degeneration of the dateline warmpool, and an eventual transition to a cool neutral by ASO. The pattern in the IO also resembled that of a -IOD event for a few days, though that has appeared to recede recently (has been replaced by anomalous warmth).

For a while, we saw a nearly uninterrupted stretch of +PMM and +PDO. As a result of a strong ridge developing over the Northeast Pacific, this regime has weakened its grip over the region. The ridge favors easterlies at about 20-30 degrees north (+NPO), which ends up cooling the waters in the ridge’s periphery. The latest wind PMM value (Feb) was -6.370, while the SST index shows 0.470. The latter might've declined even further based on SST maps.

Because of the SPV breaking down, the upper atmosphere at the North Pole is warming while the tropical atmosphere is cooling leading to convection and a strengthened MJO. This explains the EWB (being pushed to it's position because of the warm IO).

Anyways, I’m starting to pre-emptively favor a cool neutral event based on all of this, obviously things can still fluctuate. First post ¯\_(ツ)_/¯

[Kingarabian]

Need to see an extended period of above average trades over or near the dateline for there to be a La Nina by ASO.

Nino regions seem to be peaking and there is enough negative anomalies to wipe them out once the warm pool fizzles out. But then you need another upwelling Kelvin wave to develop and push east by summer time to ensure there's sufficient cool anomalies. All in all I think cool-neutral is a pretty good bet. If I'm not mistaken I think the hardest hitting Atlantic hurricane seasons are cool neutral ENSO years.

[Shell Mound]

Today's update keeps Nino 3.4 @ +0.5C:

Niño 4: 1.2ºC
Niño 3.4: 0.5ºC
Niño 3: 0.5ºC
Niño 1+2: 0.3ºC

The warm pool is erupting with little resistance in the past 2 weeks, probably due to trades actually verifying normal rather than above normal.
https://i.imgur.com/3nsJBor.png

GFS has a strong trade burst over the dateline on the way which in theory should promote further upwelling and a reduction of OHC.
https://i.imgur.com/Sb1svni.png

Given the respective biases of the GFS- and EC-based guidance, the actual trades will probably verify somewhere in between both models.

[StruThiO]

 https://twitter.com/MJVentrice/status/1239871449185345538




 https://twitter.com/PaulRoundy1/status/1239872743773999105

[cycloneye]

 https://twitter.com/TylerJStanfield/status/1239965152402800642

[Kingarabian]

[url]https://twitter.com/TylerJStanfield/status/[url]

Having the MJO over the MC during the winter months is different than it is over the summer. During the winter it can open the door to WWB's and since late fall till the end of February that's all we've seen and it reflected well on the ONI. During the summer, if the MJO persists over the MC during JASO it helps La Nina/cool-neutral odds a lot more. So I'm not sure if there's La Nina atmospheric coupling just yet. I think it's easier to go into cool-neutral first and then possibly over the summer months it should trigger La Nina in the atmosphere.

[Kingarabian]

https://twitter.com/MJVentrice/status/1239871449185345538

https://twitter.com/PaulRoundy1/status/1239872743773999105

Is Ventrice saying that enhanced trades simply warm the WPAC or they could trigger downwelling Kelvin waves @ the subsurface?