2026-2027 Record-breaking El Nino

[GaWx]

1 hour ago, 40/70 Benchmark said:

I was never wishing for a lower RONI because given how warm the Pacific basin is, I think that could predispose the hemisphere to residual MC influence in the mid latitudes, as we are still seeing signs of those competing forces despite the magnitude of El Nino. 

 
 The ONI peak in OND fell by the same 0.5 over the same period:

Aug 1-10: ONI peak +4.15

Aug 30-Sep 8: ONI peak +3.65 and likely to fall further just like RONI as per the location of the blue lines

 So, the difference between the peaks of ONI and RONI didn’t widen.

[40/70 Benchmark]

10 minutes ago, GaWx said:

 
 The ONI peak in OND fell by the same 0.5 over the same period:

Aug 1-10: ONI peak +4.15

Aug 30-Sep 8: ONI peak +3.65 and likely to fall further just like RONI as per the location of the blue lines

 So, the difference between the peaks of ONI and RONI didn’t widen.

Makes sense since the drop is due to the El Nino being focused east of 3.4 right now, rather then any type of reduced expression of El Nino across the hemisphere

[LakePaste25]

17 minutes ago, 40/70 Benchmark said:

Makes sense since the drop is due to the El Nino being focused east of 3.4 right now, rather then any type of reduced expression of El Nino across the hemisphere

Yup. It’s consistent with it undershooting 1+2 

[mitchnick]

Meanwhile, for those planning on a fishing trip off Japan, PDO up to -.73 as of yesterday. 

[GaWx]

The MEI v2 was just released for JA: +2.5 vs +2.4 for JJ. That’s the 2nd bimonthly in a row at a record high for the bimonth (back to 1979). The record high for any bimonth is +2.9.

 Here’s the rundown for JAs of +0.5+:

2026: +2.5

1997: +2.3

2015: +2.0

1982: +1.9

1987: +1.5

2002: +1.0

1986: +1.0

1994: +0.9

2004: +0.8

2009: +0.6

2006: +0.6

1993: +0.6

2023: +0.5

2018: +0.5

1979: +0.5

 

 

[OSUmetstud]

1 hour ago, 40/70 Benchmark said:

Makes sense since the drop is due to the El Nino being focused east of 3.4 right now, rather then any type of reduced expression of El Nino across the hemisphere

Its also mostly just the cfs. The 3.4 ONI on the ecmwf plumes is very similar from August to September with a peak around 4C. The CCSC/IRI plumes average went up from the July 20 to the August 19 forecast. The early September BOM forecast had a similar peak to the early August one. 

[OSUmetstud]

Bom weekly data runs hotter than other agencies so you gotta compare apples to apples. The latest forecast compared to the one from just under a month ago:

 

 

[40/70 Benchmark]

25 minutes ago, OSUmetstud said:

Its also mostly just the cfs. The 3.4 ONI on the ecmwf plumes is very similar from August to September with a peak around 4C. The CCSC/IRI plumes average went up from the July 20 to the August 19 forecast. The early September BOM forecast had a similar peak to the early August one. 

Yea, the EURO was better...but I'm willing to bet that the CANSIPS and JAMSTEC have missed by more than the CFS.

[GaWx]

32 minutes ago, OSUmetstud said:

Bom weekly data runs hotter than other agencies so you gotta compare apples to apples. The latest forecast compared to the one from just under a month ago:

 

 

 Yep, the BoM monthly relative peak actually rose ~0.1 over the last month to ~+3.7, very much unlike the drop of 0.5 of the CFSv2 RONI trimonthly peak. Also, it unlike most others keeps it almost that high in Dec.

 I expect BoM will bust significantly too warm for this progged relative monthly peak of +3.7 like it did in 2023, when it was the warmest and verified way too warm. Also, note that every month since April has busted significantly too warm. One can even see that for Aug by comparing your two graphs: the Aug 8th run had Aug way up at +2.7. The Sep 5th run lowered it down to +2.35. (I believe that the BoM uses a different dataset anomaly that makes it warmer than NOAA as you probably realize. I think it uses the warmer CRW as a base at least to an extent. That only adds to confusion.)

The BoM had a whopping +2.9 for its peak forecast in its Sept run!