ENSO Updates (2007 thru 2023)

[LarryWx]

So, the April 1st Euro ensemble mean 3.4 plume for ASO is ~+1.7. How does this compare to some past actual El Niño ASOs?

2015: +2.2

1997: +2.1

1965: +1.9

1972, 1982: +1.6

1957: +1.3

1963: +1.2

 For these 7, the average increase from ASO to peak was 0.4 with a range of 0.1 to 0.6. So, that would imply based on the April 1st Euro ASO forecast of +1.7 a later peak between +1.8 and +2.3 (mean of +2.1).

https://origin.cpc.ncep.noaa.gov/produc ... ONI_v5.php

 Keep in mind though that none of this takes into account whatever forecast bias the Euro may or may not have (see below). And of course even if the bias is negligible, there is mean forecast error to keep in mind when looking ahead that far (as much as 6 months).

 How does the April 1st Euro plume mean of +1.7 for ASO compare to some past April 1st Euro progs for ASO?

- 2017: +1.1 (the year of worst forecast) vs -0.4 actual

- 2015: +2.0 vs +2.2 actual

- 2014: +1.5 vs +0.2 actual

- 2012: +1.0 vs +0.4 actual

- 2009: +0.8 based on May 1st forecast vs +0.7 actual

 So, for these 5 years, the April 1st forecast mean for ASO ended up too warm 4 times and too cool once. On average for these five years, the April forecast for ASO was 0.6 too warm. Even if I were to throw out the 2017 forecast debacle, the April forecast for ASO for the remaining four years was still 0.45 too warm. So, perhaps the April 1st forecast for ASO has a too warm bias. If so, the odds would favor the actual ASO end up lower than +1.7.


 But regardless, the +1.7 ASO prediction being the 2nd warmest for the Euro in April is a significant indicator that a pretty robust El Niño is probably on the way. Even if I were to reduce the +1.7 ASO forecast to +1.2 or +1.3 to account for Euro warm bias, that would still imply that the later peak would most likely end up in the strong (+1.5 to +1.9) category though most likely not super-strong and with high end moderate also in the mix. Then again, the trend from last month's Euro forecast is significantly warmer.
 
 So, we'll see! Lots of uncertainty but the chance for a robust El Niño has increased significantly from last month based on the Euro.

[dexterlabio]

Niño 3 temp has been dropping like a rock BUT Niño 4 is warming up fast. Could this be due to the WPAC MJO?

[dexterlabio]

I'm very interested to see the stats for the years when El Niños of at least moderate strength had formed with -PDO in place. What's making me think that 2023 might end up as weak +ENSO is the -PDO. Before the 2014-2016 El Niño, the PDO was negative but it quickly got to positive territory as the El Niño developed. This year though, I don't think we're seeing clear signs of the PDO turning positive, it actually appears to be going more negative.

[Kingarabian]

Niño 3 temp has been dropping like a rock BUT Niño 4 is warming up fast. Could this be due to the WPAC MJO?

That's fine, the Nino regions will fluctuate. Right now I would watch the subsurface warm pool and see if it can redevelop those +4C/+5C anomalies. Could be the difference between a warm neutral or an El Nino event.

[Kingarabian]

I'm very interested to see the stats for the years when El Niños of at least moderate strength had formed with -PDO in place. What's making me think that 2023 might end up as weak +ENSO is the -PDO. Before the 2014-2016 El Niño, the PDO was negative but it quickly got to positive territory as the El Niño developed. This year though, I don't think we're seeing clear signs of the PDO turning positive, it actually appears to be going more negative.

2009 didn't develop a +PDO until August. However this is a telling sign thst a multi year +PDO regime is not in the cards.

[cycloneye]

 https://twitter.com/AndyHazelton/status/1644315055381532677

[cycloneye]

Will the cyclone that forms north and NW of Australia affect the SOI? Is already climbing.

[Iceresistance]

Will the cyclone that forms north and NW of Australia affect the SOI? Is already climbing.

https://i.imgur.com/h117xFe.jpg

https://i.imgur.com/SySCVlt.jpg

Yeah, I am already thinking it's messing up the SOI index, it will come back down with a crash when the storm leaves.

[cycloneye]

 https://twitter.com/BenNollWeather/status/1644443278807564289

[Kingarabian]

Will the cyclone that forms north and NW of Australia affect the SOI? Is already climbing.

https://i.imgur.com/h117xFe.jpg

https://i.imgur.com/SySCVlt.jpg

SOI will climb regardless because rising motion will be favored over the MC thus favoring lower than normal pressures near Darwin.

[Kingarabian]

https://twitter.com/AndyHazelton/status/1644315055381532677

EPS has been more conservative compared to the GFS in regards to this WWB moving east.

CFS is hinting that sometime in May we will see a dateline WWB.

[cycloneye]

NMME April forecast.

 https://twitter.com/TylerJStanfield/status/1644756747339415552

[JetFuel_SE]

NMME April forecast.

https://twitter.com/TylerJStanfield/status/1644756747339415552

"Strongest El Niño since 2015" isn't really a very high bar tbh.

[Kingarabian]

I think we have to drop the use of the NMME. Its either too cold or too warm during the SPB.

[Category5Kaiju]

Here's a quote from University of Arizona's annual April hurricane season prediction for the Atlantic, at least in the context of ENSO:

For our April forecast, we expect an active season over the North Atlantic. Tropical Atlantic SSTs are forecast to be the highest since 2010 and even hotter than 2020, and for the Nino 3.4 region, forecast SSTs are among the highest. The high Nino SSTs should help bring down hurricane activities; it will be an interesting battle between the two sides this summer.

So let's say we do indeed end up with at least a moderate strength El Nino but with Atlantic warmth on the levels of 2005/2010/2020. Would this cause "competition" between the EPAC and Atlantic and cause the EPAC to end up less active than expected given the El Nino strength? What would really happen in a case where both the equatorial EPAC and the Atlantic are very warm?

[Astromanía]

Systems on ATL basin before August are mostly weak and short lived even in La Niña years, if we are going to end up with a moderate to strong el Niño by peak season I don't see the ATL really competing in activity to EPAC. In 2016 and 2018 seasons both basins almost end up hyperactive but I don't think the pattern is the same in this case, we need to see what actually happens, I just don't expect great activity for ATL this year but that's just me

[NotSparta]

NMME April forecast.

https://twitter.com/TylerJStanfield/status/1644756747339415552

"Strongest El Niño since 2015" isn't really a very high bar tbh.

Almost any El Niño would qualify

[dexterlabio]

NMME April forecast.

https://twitter.com/TylerJStanfield/status/1644756747339415552

"Strongest El Niño since 2015" isn't really a very high bar tbh.

Almost any El Niño would qualify

If 2015 wasn't a crazy super one, that forecast could easily say "strongest since 2009," which would have made more impact. And I also just realized that 2015 wasn't really that long ago, if this year's El Nino indeed goes super then that might be telling something about the world's current climate state?

[JetFuel_SE]

Systems on ATL basin before August are mostly weak and short lived even in La Niña years, if we are going to end up with a moderate to strong el Niño by peak season I don't see the ATL really competing in activity to EPAC. In 2016 and 2018 seasons both basins almost end up hyperactive but I don't think the pattern is the same in this case, we need to see what actually happens, I just don't expect great activity for ATL this year but that's just me

The Atlantic had absolutely no right to be active in 2018.
A clear -AMO signature combined with a looming El Niño isn't exactly a good recipe for Atlantic activity.

[Kingarabian]

Atlantic has been more and more active despite above average EPAC activity is due to the ASW.

Generally, if there's going to be a super El Nino there has to be some type of +ENSO conditions in the prior year, especially during OND. Plus, per Climo super El Nino's typically happen every 15-20 years or so.

El Nino's usually keep the Atlantic slow. But if the ASW is active this season, the Atlantic should still see some solid activity.