2025 ENSO Updates

[Ntxw]

There is a WWB going on near 120W in the Pac EQ Epac.

[DorkyMcDorkface]

There is a WWB going on near 120W in the Pac EQ Epac.

A strong easterly trade surge in the Equatorial CPAC looks to be manifesting concurrently. We already have somewhat of a Modoki Niña look going on (although current anoms are closer to neutral) so I'd imagine that will be reinforced in the coming weeks.

[Ntxw]

There is a WWB going on near 120W in the Pac EQ Epac.

A strong easterly trade surge in the Equatorial CPAC looks to be manifesting concurrently. We already have somewhat of a Modoki Niña look going on (although current anoms are closer to neutral) so I'd imagine that will be reinforced in the coming weeks.
https://i.ibb.co/TMbvNRWS/20250220232735-04d7bc16c3d6fb3a9aa1eef91d273d86b75dff49.png
https://i.ibb.co/HLPyB6QS/eps-u850-anom-hov-equatorial-2025022100.png
https://i.ibb.co/fV7SPJvc/crw-ssta-enso.png

It's normal for weakening cold ENSO to shift EWBs to the IDL and then further west, progression. What's happening in the EQ Epac isn't, is why 1+2 has warmed so much, these epac wwbs since November have reflected some over the PDO each time/PNA.

[Kingarabian]

There is a WWB going on near 120W in the Pac EQ Epac.

A strong easterly trade surge in the Equatorial CPAC looks to be manifesting concurrently. We already have somewhat of a Modoki Niña look going on (although current anoms are closer to neutral) so I'd imagine that will be reinforced in the coming weeks.
https://i.ibb.co/TMbvNRWS/20250220232735-04d7bc16c3d6fb3a9aa1eef91d273d86b75dff49.png
https://i.ibb.co/HLPyB6QS/eps-u850-anom-hov-equatorial-2025022100.png
https://i.ibb.co/fV7SPJvc/crw-ssta-enso.png

It's normal for weakening cold ENSO to shift EWBs to the IDL and then further west, progression. What's happening in the EQ Epac isn't, is why 1+2 has warmed so much, these epac wwbs since November have reflected some over the PDO each time/PNA.

If memory recalls correct, 2012 and 2017 were good examples on why WWBs in the far eastern Pacific are useless if trades dont slow near the dateline. Without a downwelling KW, WWBs near 120W can cause the Nino regions to warm temporarily only to reverse come July. For warm neutral/El Nino we would need an erupting downwelling KW off of Peru and easterlies between 120W->90W.

[Ntxw]

A strong easterly trade surge in the Equatorial CPAC looks to be manifesting concurrently. We already have somewhat of a Modoki Niña look going on (although current anoms are closer to neutral) so I'd imagine that will be reinforced in the coming weeks.
https://i.ibb.co/TMbvNRWS/20250220232735-04d7bc16c3d6fb3a9aa1eef91d273d86b75dff49.png
https://i.ibb.co/HLPyB6QS/eps-u850-anom-hov-equatorial-2025022100.png
https://i.ibb.co/fV7SPJvc/crw-ssta-enso.png

It's normal for weakening cold ENSO to shift EWBs to the IDL and then further west, progression. What's happening in the EQ Epac isn't, is why 1+2 has warmed so much, these epac wwbs since November have reflected some over the PDO each time/PNA.

If memory recalls correct, 2012 and 2017 were good examples on why WWBs in the far eastern Pacific are useless if trades dont slow near the dateline. Without a downwelling KW, WWBs near 120W can cause the Nino regions to warm temporarily only to reverse come July. For warm neutral/El Nino we would need an erupting downwelling KW off of Peru and easterlies between 120W->90W.

Yeah, to be fair I'm not saying an El Nino initiating wwb is occuring. It's to support the idea of earlier post, there are competing factors against a dominate enso state thus neutral is best bet.

[cycloneye]

CPC weekly update has niño 1+2 warming up to +1.0C and niño 3.4 remains at -0.3C.

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

[cycloneye]

Text of Andy's message:

While we are still not past the "Spring Predictability Barrier" for ENSO, it looks like we'll go into March with enhanced trades along the dateline for a while. Easterly surges around this time of year tend to be an indicator of ENSO remaining on the cooler side, although it wouldn't surprise me if the far East Pacific "El Niño Costero" persists for another month or two with weaker trades there.


 https://x.com/AndyHazelton/status/1894395322392056268

[weeniepatrol]

Despite anemic cool anomalies in Nino 3.4 (ONI will probably only have a single -0.5 trimonthly), the atmosphere response is quite robust. Strong standing wave of suppressed IDL convection.

[cycloneye]

https://i.imgur.com/gNAfze0_d.webp?maxwidth=760&fidelity=grand

Despite anemic cool anomalies in Nino 3.4 (ONI will probably only have a single -0.5 trimonthly), the atmosphere response is quite robust. Strong standing wave of suppressed IDL convection.

And is exactly -0.5C for NDJ.

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

[DorkyMcDorkface]

 https://x.com/cyclonicwx/status/1895509860600717686

[Kingarabian]

SPAC is pretty warm as well so its helping to give the look that +ENSO is developing. But the subsurface is the opposite. When Nino 3 and Nino 1+2 warm independently, it's always interesting. But in the grand scheme of the ENSO mechanism, it means nothing. +ENSO doesn't form east to west at the subsurface, rather west to east.

[Hurricane2022]

 https://x.com/dmorris9661/status/1895916224003129446

[cycloneye]

The CPC weekly update of 3/3/25 has niño costero up to +1.1C while Niño 3.4 is at -0.2C.

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

[Kingarabian]

Looking more and more likely that the CFS +ENSO forecast will bust for ASO. Nina forcing will get stronger with westerly wind anomalies over the IO and very strong trades continue over the date line. This looks to continue during the first week of April. We haven't even gotten a WPAC WWB yet much less a dateline event.

Doesn't take much to get La Nina/-ENSO. But it takes a lot to get +ENSO/El Nino.

[Iceresistance]

 https://x.com/cyclonicwx/status/1895509860600717686

What is El Nino costero? I've never heard of that term before

[WeatherBoy2000]

 https://x.com/cyclonicwx/status/1895509860600717686

What is El Nino costero? I've never heard of that term before

El nino costero is a term used to describe the el nino like warming of the waters right off South America. It's still not a proper el nino because the nino 3.4 region remains below 0.5c.

[DorkyMcDorkface]

 https://x.com/cyclonicwx/status/1895509860600717686

What is El Nino costero? I've never heard of that term before

Oh, someone else answered before I could get back to you lol.
The poster above pretty much explained it. Last time we saw something similar was during the spring of 2017 (albeit 3.4 was warmer than this year). I remember when many agencies were expecting El Niño to emerge from that but it was a "head-fake" in a way as -ENSO ended up developing by the fall due to an unimpressive subsurface and lack of strong WWB activity. Here's a snapshot from late March of that year:

[LarryWx]

26FEB2025 27.5 1.1 27.0 0.3 26.7-0.2 27.5-0.6
05MAR2025 28.1 1.6 27.4 0.5 27.0 0.0 27.8-0.3

 So, the latest week being reported (last calendar week) shows all regions warmed with Nino 3.4 up to 0.0 and Nino 1+2 up to a whopping +1.6. But keep in mind that these aren’t taking into account the relatively warm surrounding tropical/global waters like RONI does. So, one may want to subtract ~0.5 to 0.6 to get a better picture of the situation. Regardless, the trends have been clearly warmer and Nino 1+2, itself, would still be in moderate Nino territory and Nino 3 would be up to neutral.

https://www.cpc.ncep.noaa.gov/data/indi ... st9120.for

[cycloneye]

The weekly update from CPC has continued warming of the different areas. Niño 1+2 at +1.6C / Niño 3 at +0.5C / Niño 3.4 at 0.0C

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

[Ntxw]

26FEB2025 27.5 1.1 27.0 0.3 26.7-0.2 27.5-0.6
05MAR2025 28.1 1.6 27.4 0.5 27.0 0.0 27.8-0.3

 So, the latest week being reported (last calendar week) shows all regions warmed with Nino 3.4 up to 0.0 and Nino 1+2 up to a whopping +1.6. But keep in mind that these aren’t taking into account the relatively warm surrounding tropical/global waters like RONI does. So, one may want to subtract ~0.5 to 0.6 to get a better picture of the situation. Regardless, the trends have been clearly warmer and Nino 1+2, itself, would still be in moderate Nino territory and Nino 3 would be up to neutral.

https://www.cpc.ncep.noaa.gov/data/indi ... st9120.for

Question for you Larry, if the RONI is the superior index, how would you grade this past winter noting was showing a better La Nina than ONI based off the PAC teleconnections? My initial guess is that the +PNA and North Pacific Aleutian trough gave some questions as to how reliable it is. Should we not have seen a more robust -PNA/Aleutian ridge combo per RONI?