ENSO Updates (2007 thru 2023)

[cycloneye]

Here is the ENSO Blog where the CPC folks explain in more detail about the November advisory.

https://www.climate.gov/news-features/b ... rt-options

First stop—this El Niño has now met the threshold for a “strong” event! The August–October Oceanic Niño Index, which measures the three-month-average sea surface temperature in the east-central tropical Pacific (the so-called Niño-3.4 region), was 1.5 °C above the long-term average (long-term is currently 1991–2020). The Oceanic Niño Index is our primary metric for ENSO (El Niño/Southern Oscillation, the entire El Niño and La Niña system). The monthly Niño-3.4 Index was 1.7 °C above average.[/size]

[size=150]“Strong” here is in quotation marks because we don’t have an official definition of ENSO strength. Our unofficial thresholds for the strength of an El Niño event are an Oceanic Niño Index of 0.5–0.9 °C for weak, 1.0–1.4 °C for moderate, and above 1.5 °C for strong. Over 2.0 °C is considered “very strong,” or “historically strong.” I’m going to drop the quotation marks going forward, because they slow us down, and we’re motoring here!

We started noting the potential for a strong El Niño way back in April 2023, before El Niño had even arrived (that happened in June). Currently, forecasters estimate a greater than 55% chance that El Niño will remain above that threshold for strong through January–March 2024. There’s about a 1-in-3 chance that the Oceanic Niño Index will reach 2.0 °C, which has happened four times before in our 73-year record: 1972-73, 1982–83, 1997–98, and 2015–16.

[cycloneye]

We'll see over the next 3 months what effect this lack of cohesive coupling, between the ocean and atmosphere, has on the NHEM winter season.

SOI 30 day is barely in El Nino territory at -7, while the 90 day is at weak El Nino levels at -9.

But CPC declared it a strong one.

[cycloneye]

 https://twitter.com/webberweather/status/1723093371936186774

[Kingarabian]

Latest model runs continue the current theme with this event and show the WWB sticking over 140E-160E.

[Dean_175]

Latest model runs continue the current theme with this event and show the WWB sticking over 140E-160E.

Followed by a trade burst though. That will help attenuate the effect and possibly reduce the relatively near-term intensification of El Nino that some models such as CFS suggest. We are getting into the last inning, so to speak, with regards to ENSO strengthening.

[cycloneye]

 https://twitter.com/BenNollWeather/status/1726601288572363162

[cycloneye]

CPC weekly update has Niño 3.4 up to +1.9C.

https://www.cpc.ncep.noaa.gov/products/ ... ts-web.pdf

[Ntxw]

Looks like the warmest values are now in the central Pacific after the recent ongoing WWB. Warm water sloshing to the west to the east from IDL. Despite actual SSTs being cooler than May/June in the CP-EP regions, however it's all about relative to the climatology of the current period.

[Ntxw]

In terms of comparison this is less than 1982, 1997, and 2015 so far. But a little stronger than 1957 and 2009. Likely closer to 1965 and 1972.

[cycloneye]

Niño 3.4 reaches +2.0C, but still has to pass three consecutive monthly periods to equal 82/83, 97/98, 15/16.

[Kingarabian]

Warm PDO horseshoe is back off the NWCONUS. Waters east of Japan are still stubbornly warm which will probably mean a negative PDO.

PMM is starting off cool again.

[zzzh]

MJO will go back to the Pacific in the second week of December and induce another wave of strong WWB.

[dexterlabio]

Warm PDO horseshoe is back off the NWCONUS. Waters east of Japan are still stubbornly warm which will probably mean a negative PDO.

PMM is starting off cool again.

The anomalously warm subtropical waters east of Japan seems to be detrimental to having a classic El Nino-induced typhoon season in the Pacific. While this year is indeed more active than your typical La Nina years, it could have been a lot more active and become both a quantity and quality type of season. It clearly did not happen despite the strong El Nino present.

[Iceresistance]

Warm PDO horseshoe is back off the NWCONUS. Waters east of Japan are still stubbornly warm which will probably mean a negative PDO.

PMM is starting off cool again.

The anomalously warm subtropical waters east of Japan seems to be detrimental to having a classic El Nino-induced typhoon season in the Pacific. While this year is indeed more active than your typical La Nina years, it could have been a lot more active and become both a quantity and quality type of season. It clearly did not happen despite the strong El Nino present.

The waters are starting to cool down
Coral Reef Watch

https://s5.gifyu.com/images/SR8Xm.png
OISST

https://s5.gifyu.com/images/SR8Xm.png

[cycloneye]

The CPC weekly update has Niño 3.4 going up to +2.1C.





https://www.cpc.ncep.noaa.gov/products/ ... ts-web.pdf

[Ntxw]

We should have peaked or within peak for this event. Weeklies might see a reading higher or two and then hold a steady state with the new sub-surface warmth in the CPAC below. Mid December WWB should keep the western basin warm. 1.9C to 2.1C ONI range for peak seems reasonable.

[Dean_175]

This isn't exactly ENSO but: the Atlantic El Nino is now weakly but firmly positive (atl nino3 is around +1C) and should remain such for the next few months at least.

[cycloneye]

The ONI is up for SON to +1.8C.



https://www.cpc.ncep.noaa.gov/products/ ... ts-web.pdf

[hurricanes1234]

In terms of ONI, at +1.8°C, this now means that the 2023-2024 event has the second highest ONI of any 21st century El Niño, surpassed only by the mighty 2014-2016 event. The last ONI above +1.8°C was Jan/Feb/Mar 2016.

[Dean_175]

One more WWB about to start before climatology makes it less likely for El Nino to intensify further. This will more or less keep the temperatures warmer for longer rather than lead to much warming. Maybe we will see an ONI of 1.9, but I think we will be just shy of 2.0C for a trimonthly.