Latest 10 day CFSv2 ensemble mean forecast of RONI: +2.0 peak OND. Note that unlike the BoM’s nearly impossible +0.6 for April, this has a much more sensible -0.3:

 The newest BoM prog (dated April 11th) is unchanged and thus still has a RONI of +0.6 for April averaged out. This is almost certainly going to end up much too warm for April:

 

How do I know it is almost definitely going to bust much too warm for April?

 

Weekly RONI equivalent: 3rd column is 3.4

01APR2026         0.6       -0.3       -0.2        0.3
 08APR2026         1.0       -0.2       -0.3        0.2

https://www.cpc.ncep.noaa.gov/data/indices/rel_wksst9120.txt

 
 So, the weeks centered on April 1/April 8 were -0.2/-0.3.

 Here’s the current OISST, which isn’t relative and thus one needs to subtract ~0.5 from it:

 As the above chart shows, there’s been no net warming for the last 3 weeks and the latest few days of OISST have been only +0.05 to +0.15. Subtracting 0.5 gives ~-0.4 for the RONI equivalent. April 1-11 OISST are likely no warmer than ~-0.3 for RONI equiv. To be conservative in converting from OISST to ERSST, I’ll call it -0.2 for RONI MTD. The weeklies I showed suggest between -0.2 and -0.3. 
 

 How is it even possible for April RONI as a whole to come in anywhere near as warm as +0.6? These daily OISST readings (don’t forget these are not relative) would need to skyrocket to an avg of at least ~+1.5 for Apr 12-30!! And with OISST starting off at <+0.2, there are going to have to be some +2++ dailies starting no later than 2 weeks from now! Nothing even remotely close to that extremely rapid rate of warming has occurred on record. Thus, BoM is looking to bust much too warm for Apr RONI. With Apr being way off, the credibility of the rest of the run is compromised.

QBO (30 mb) still has not updated for March! I don’t recall it ever taking nearly this long for any month, which has me a bit concerned:

https://psl.noaa.gov/data/correlation/qbo.data

Latest OHC:

1 hour ago, snowman19 said:

 

I’ll compare 2026 to others.

 Here’s 2026 with its first strong -SOI period not til days 98-102:

2026  98 1010.27 1010.30  -17.45

2026  99 1009.30 1011.45  -32.74

2026 100 1009.19 1011.45  -33.53

2026 101 1009.56 1011.00  -27.62

2026 102 1010.69 1010.75  -17.67

 

1) 1994: already had strong -SOI days 75-90:

1994  75 1009.95 1009.25  -16.33

1994  76 1011.21 1009.00   -9.08

1994  77 1010.30 1008.65  -11.78

1994  78 1009.25 1009.30  -19.92

1994  79 1009.33 1009.25  -19.32

1994  80 1010.65 1008.60   -9.86

1994  81 1011.61 1009.45   -9.32

1994  82 1012.00 1010.25  -11.30

1994  83 1010.73 1009.80  -15.23

1994  84 1009.74 1010.30  -22.37

1994  85 1011.13 1011.00  -19.08

1994  86 1012.49 1011.90  -16.86

1994  87 1012.66 1011.95  -16.27

1994  88 1012.31 1012.15  -18.90

1994  89 1012.79 1011.85  -15.19

1994  90 1012.12 1011.85  -18.36

2) 1997: already had strong -SOI days 81-90:

1997  81 1011.33 1011.55  -20.69

1997  82 1009.53 1010.25  -23.08

1997  83 1009.46 1010.35  -23.92

1997  84 1009.17 1010.95  -28.17

1997  85 1009.38 1011.65  -30.50

1997  86 1008.01 1011.85  -38.04

1997  87 1007.55 1011.15  -36.91

1997  88 1010.10 1010.60  -22.07

1997  89 1011.92 1011.00  -15.24

1997  90 1011.97 1010.55  -12.85

 

3) 2002: already had strong -SOI days 72-80

2002  72 1010.71 1012.50  -28.24

2002  73 1010.25 1011.40  -25.18

2002  74 1011.11 1011.10  -19.62

2002  75 1010.70 1010.90  -20.63

2002  76 1009.60 1010.35  -23.27

2002  77 1010.04 1010.55  -22.13

2002  78 1012.20 1010.55  -11.78

2002  79 1013.25 1010.20   -5.07

2002  80 1010.45 1008.90  -12.26

 

4) 2004: already had strong -SOI days 87-97

2004  87 1010.56 1010.65  -20.11

2004  88 1009.84 1011.25  -26.42

2004  89 1009.20 1011.25  -29.49

2004  90 1008.64 1011.75  -34.56

2004  91 1007.47 1011.75  -40.16

2004  92 1006.10 1012.30  -61.94

2004  93 1005.85 1012.25  -63.38

2004  94 1006.74 1011.55  -51.92

2004  95 1005.93 1011.20  -55.23

2004  96 1007.71 1011.00  -40.96

2004  97 1008.59 1010.60  -31.73

5) 2014: already had strong -SOI days 73-80

2014  73 1010.53 1009.55  -14.98

2014  74 1009.38 1010.70  -25.99

2014  75 1008.55 1009.75  -25.42

2014  76 1009.09 1010.40  -25.94

2014  77 1009.21 1009.75  -22.26

2014  78 1007.89 1010.20  -30.73

2014  79 1007.49 1009.30  -28.34

2014  80 1009.69 1008.25  -12.78

6) 2015: already had strong -SOI days 67-79:

2015  67 1007.50 1008.10  -22.55

2015  68 1008.11 1008.65  -22.26

2015  69 1008.73 1008.20  -17.14

2015  70 1009.33 1008.65  -16.42

2015  71 1009.24 1008.45  -15.89

2015  72 1009.91 1007.55   -8.38

2015  73 1010.42 1007.65   -6.42

2015  74 1010.41 1008.90  -12.45

2015  75 1006.90 1010.15  -35.23

2015  76 1005.66 1009.05  -35.90

2015  77 1008.13 1008.65  -22.16

2015  78 1010.35 1009.55  -15.84

2015  79 1008.79 1011.20  -31.21

7) Even the non-Nino 2012, which psyched out the Euro, had an earlier strong negative period:

2012  90 1011.39 1009.80  -12.06

2012  91 1009.90 1010.70  -23.50

2012  92 1010.45 1011.70  -26.25

2012  93 1012.60 1012.20  -14.35

2012  94 1012.53 1013.55  -24.59

2012  95 1011.19 1013.45  -33.53

2012  96 1010.10 1012.15  -32.01

2012  97 1009.94 1011.85  -31.01

2012  98 1009.98 1011.60  -28.91

2012  99 1010.16 1011.65  -27.98

2012 100 1011.50 1011.45  -16.87

 

 OTOH, 2026’s strong -SOI is ahead of 2006, 2009, 2018, and 2023.

3 hours ago, bluewave said:

Great write up from ECMWF on how to interpret the recent El Nino forecast so early in the development process.

https://www.ecmwf.int/en/about/media-centre/science-blog/2026/el-nino-2026

Chris,

 1. The writeup you linked us to specifies what we already knew: the U.S. now incorporates RONI for its official ENSO updates vs the Euro still not doing so. So, to approximate RONI based on the current difference, ~0.5C should be subtracted from the Euro progs since they are still predicting a straight ONI.

2. The following shows that although the Euro’s too warm ASO ONI prog was highest for April progs in 2017 (+1.4), it was also significantly too warm in 2025 (+0.8), 2022 (+0.7), 2021 (+0.6), 2020 (+0.8), 2014 (+1.2), and 2012 (+0.6). Moreover, misses to the cold side were much less frequent and smaller. So, based on averaging out the misses, a notable warm bias is evident although it isn’t as large when El Niño actually verifies. None of this means ONI will definitely verify colder than the April Euro prog, but rather to not be surprised if it verifies several tenths colder based on a bias corrected ONI prog:

 

 Today from JB: any comments? Is he making sense saying that in the cold season it’s harder to get record cold further N?? That doesn’t sound right. What am I missing? Aren’t SDs/variances larger at higher latitudes? See what I bolded below.

 OTOH, due to GW, if he had said it’s harder to get record cold than record heat, I’d agree. So, in that regard, much of AK/Canada having its coldest March on record in this 2-3F warmer world certainly is quite remarkable.

 From JB:

However, later he says this, which I agree with since variances in summer are not as large as March:

“Now lets look at the March map again off the PSL site. you have got areas 12 above normal in the time of the year when its much easier to get that warm, then when you are at the hottest time of the year, pulling this off like 1934,1936 is much harder to do.”

———————

 PHX was 6.5 warmer than any other Mar on record whereas Fairbanks was only 2.4 colder than any other Mar on record. But, 2.4 colder in a warmer world might be about as impressive.

 Opinions?

 

40 minutes ago, suzook said:

November? We all will be burned down to nothingness by then. This is beyond ridiculous.

 My water bills are looking to be outrageously high, but I have no choice if I want to keep the grass healthy.

21 minutes ago, snowman19 said:

If (IF) this is correct, that is insane for a 13 models/637 member ensemble mean for September, at +2.2C, since the El Niño will still be strengthening at that point. They normally peak in November or December….
 

UKMET has been one of the better models in recent years. It’s going ~+2.05 for Sep ONI and would likely rise a few more tenths from there. Then take off ~0.5 to convert to RONI. So, ~+1.5-1.6 C RONI in Sept and rising per UKMET.

 Euro ONI is just over +2.2 in Sept and rising, but it has tended to verify too warm although not as much warm bias verified on average in actual El Niños.

 This all suggests to me a mid to high grade strong RONI peak as of now. I’ll continue to update.

5 hours ago, Typhoon Tip said:

Welp ... I was wrong about March when it comes to predicting the product result, below.  I had presumed recently that we'd result a more obvious local geographic ( 'local' relative to the entire world) cool zone/island anomaly relative to the whole "inferno" that is clearly and coherently, unarguably the product's character below... eh hm.  Said island had been a persistent leitmotif since late last autumn... 

Still, you know, it really didn't sensibly come off that way?  I recall seeing March colder locally comparing to the whole country on a lot of days... In fairness I think what is actually going on is that this product below is the "anomaly".  What we experienced may have technically been a warm anomaly, just not as demonstrative or obviously so as everywhere else... SO, in that vein and sense it might still qualify.  

Also, having that impressively deep cold garland lording over top the Canadian Shield while there's a quasar spanning the conterminous U.S., definitely helps explain why we've been getting these wild 40 to as much as 50+ F air mass whiplashes, too.

Anyway, here is the tabulation and mean for March provided by https://data.giss.nasa.gov/gistemp/maps/

 

•  

• Quote

That’s the coldest March for Canada, overall, since 2002, which is below:

 

57 minutes ago, BooneWX said:

The forests in the western half of NC are littered with dried debris from Helene. It’s a powder keg and I’m afraid one cigarette flung out of a window could cause a disaster. 

 I’ve been sprinkling the yards recently. The drought in this area and especially to the SW is about the most severe in the entire SE with widespread D3 (extreme) here to D4 (exceptional) in SC GA to NC FL. See map below.

 Although it’s unpredictable, the good news is that a strong El Niño appears to be on the way. If that verifies, much of the SE should see wet relief by November based on history and long range models:

 

1 hour ago, michsnowfreak said:

Thanks. So we can realistically say super nino winters were: 1877-78, 1888-89, 1957-58, 1965-66, 1972-73, 1982-83, 1991-92, 1997-98, 2015-16.

 Yeah, that’s what I have. I find it amazing that there were none for the 68 winters between 1888-9 and 1957-8. I wonder whether or not this is random, especially considering there were 7 over the subsequent 68 winters 1957-8 through 2024-5!

7 hours ago, michsnowfreak said:

Are the only super events 1877-78, 1982-83, 1997-98, & 2015-16?

 

 

Add to those using a peak of 2+ RONI for 1950+: 1888-9, 1957-8, 1965-6, 1972-3, 1991-2

Nov: NMME is warmer than its prior run and much more E based than Cansips Modoki:

Nov SSTa NMME latest run:

 

Nov SSTa NMME prior run:

 

Nov SSTa Cansips

42 minutes ago, bluewave said:

We have plenty of time to watch this one develop. Remember, these ENSO plume forecasts are just basically repeater models. They extrapolate the current conditions going forward. They are correct when the actual conditions repeat. When changes occur they exhibit errors.

So if these record WWBs continue, then we have a shot at what they are showing. All I can say is that the models did a great job on the plumes from April of 2023.

We would probably need a wind reversal on the order of June 2014 to avoid a +2.0 or greater ONI outcome. Once we verify the June conditions then things will come into better focus.

The big story in 2023-2024 was the models underestimating the Nino ridge and warmth along the Northern Tier and overestimating the Aleutian low and troughing in the South and East. So it will be interesting to see how things go with this event.

The 4/23 ONI fcasts: BoM much too warm and Euro/CFS/UK somewhat too warm. Actual JAS +1.37

1. BoM: +2.17 for JAS or 0.80 too warm

2. Euro: +1.57 for JAS or 0.20 too warm

3. CFSv2: +1.56 for JAS or 0.19 too warm

4. UKMET: +1.58 for JAS or 0.21 too warm

 OTOH, the avg of all 17 dynamicals was +1.33, which was almost perfect.

ONI history:

https://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt

 

4/23 ONI forecasts: 

https://iri.columbia.edu/our-expertise/climate/forecasts/enso/2023-April-quick-look/?enso_tab=enso-sst_table

4 hours ago, snowman19 said:

 

 This tweet is deceptive. I’m surprised the smart pro met. Ethan said this. Of course the SSTs are significantly warmer than 29 years ago due to GW. But you know that the measure of Nino strength isn’t SST but rather SSTa.

 Relative SSTa:

02APR1997         1.1       -0.3        0.1        1.1

01APR2026         0.6       -0.3       -0.2        0.3
 

 So, per relative anomalies, not only is 2026 not warmer than 1997, it is 0.5 cooler in 1+2, 0.3 cooler in 3.4, and 0.8 cooler in 4! 

https://www.cpc.ncep.noaa.gov/data/indices/rel_wksst9120.txt

 

 @mitchnick

45 minutes ago, wncsnow said:

Super Nino is not ideal for snow lovers but if you can get just enough cold to go with the hyperactive STJ you can get massive snows like Jan 22, 2016. 

Also, there was 2/9-10/1973 and 3/24/1983 in large parts of the SE.

 Regardless of snow or not, the relatively predictable thing about strong El Niños is their tendency to be wet Nov-Mar in most of the SE.

12 minutes ago, snowman19 said:

 

Webb exhibits at times a tone that borders on being over the top to get attention. “Hilariously strong”?

1 hour ago, bluewave said:

They have done detailed reanalysis from that era. That may be the earliest case of a a El Niño above +2.0 C that we have. Notice the record warmth that winter in the Upper Midwest.

Time Series Summary for Minneapolis-St Paul Area, MN (ThreadEx) Warmest Winters with ONI  above +2.0 C bolded 
Click column heading to sort ascending, click again to sort descending.

1	2023-2024	29.9	0
2	1877-1878	29.0	0
3	1930-1931	26.9	0
4	2001-2002	26.8	0
5	2011-2012	26.3	0
6	1881-1882	26.1	0
7	1997-1998	25.9	0
8	1986-1987	25.8	0
9	2016-2017	24.3	0
10	2015-2016	24.2	0
11	1982-1983	24.0	0
12	1991-1992	23.7	0
13	1943-1944	23.5	0
14	1920-1921	23.2	0
15	1999-2000	23.1	0

https://psl.noaa.gov/data/20thC_Rean/

20th Century Reanalysis and PSL

Four-dimensional historic weather reconstructions, or reanalyses, provide a crucial instrument-based link between long paleoclimate reconstructions and climate model forecasts. But until recently, the earliest reanalyses began with the year 1948, leaving out many important 20th century climate events, such as the 1930’s Dust Bowl. 

To expand the coverage of global gridded reanalyses, the 20th Century Reanalysis Project is an effort led by NOAA's Physical Sciences Laboratory (PSL) and  CIRES at the University of Colorado, supported by the Department of Energy, to produce reanalysis datasets spanning the entire 20th century and much of the 19th century. These reanalyses assimilate only surface observations of synoptic pressure into NOAA's Global Forecast System and prescribe sea surface temperature and sea ice distribution in order to estimate e.g., temperature, pressure, winds, moisture, solar radiation and clouds, from the surface to the top of the atmosphere throughout the 19th and 20th centuries.

20CR uses an ensemble filter data assimilation method which directly estimates the most likely state of the global atmosphere for each three-hour period, and also estimates uncertainty in that analysis. The most recent version of this reanalysis, V3, provides 8-times daily estimates of global tropospheric variability across 75 km grids, spanning 1836 to 2015 (with an experimental extension from 1806 to 1835.) There are three previous versions of the reanalysis: V1, V2, and V2c.

The project has greatly benefited from international cooperation under the Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative, which undertakes and facilitates the recovery of historical instrumental surface terrestrial and marine global weather observations to underpin 4D weather reconstructions spanning the last 200 to 250 years. Additional support has been provided by the Global Climate Observing System and the World Climate Research Programme.

https://journals.ametsoc.org/view/journals/clim/33/11/jcli-d-19-0650.1.xml

 

How Significant Was the 1877/78 El Niño?

 

5. Conclusions

The ERSSTv5 analysis clearly shows a strong El Niño during 1877/78. The ranking of El Niño strength will vary depending on the SST dataset, the Niño regions examined, and the climatology that is used. Here, we attempt to quantify how strong it was in the SST record using the monthly 2° × 2° ERSSTv5 (Huang et al. 2017). To compare the strength of El Niño events, the uncertainty of the Niño indices should be taken into account (Huang et al. 2016a). To date, the uncertainty has rarely been considered in comparing the strength of El Niño events. In ERSST, the SST uncertainty consists of parametric and reconstruction uncertainties (Huang et al. 2016b, 2020). For a regionally averaged SST such as Niño indices, the parametric uncertainty dominates over the reconstruction uncertainty. A 1000-member ensemble analysis of ERSSTv5 (Huang et al. 2020) is used to quantify the parametric uncertainty of Niño indices, which depends on the 2–7 selections of 28 parameters. Our initial analysis of the 1000-member ensemble shows that the ensemble averaged Niño-3 over 1877/78 is lower (1.8°C) than the value from ERSSTv5 standard run while the uncertainty is large (2.8°C). In contrast, the uncertainty range in the Niño-3 and Niño-3.4 indices during 1982/83, 1997/98, and 2015/16 is much smaller (0.1°–0.2°C).

The reasons for the small Niño-3 index value and large uncertainty among the ensemble members over 1877/78 has been investigated using factor analysis here among the 28 ERSSTv5 parameters. We find two of the 28 parameters are especially critical in representing El Niño events when observational data are sparse. In particular, the selections of 1-month high-frequency filter and 20% EOT acceptance criterion appear to reduce the Niño indices by 0.6°–0.8°C and increase the uncertainty by approximately 1.1°C. By removing these members within the 1000-member ensemble, a reassessment of the data confirms a strong El Niño during 1877/78 (with averaged Niño-3 value of 2.8°C and reduced uncertainty of 0.5°C). However, with these adjustments, the Niño indices and their uncertainty do not change much during 1982/83, 1997/98, and 2015/16, suggesting that the selections of those two parameters do not exert a large influence on the SST reconstruction across the tropical Pacific in the modern era. The reason for a more stable SST reconstruction in the modern era is due to the better observational coverage after the 1960s (80%) than during the 1870s (10%).

The strong 1877/78 El Niño in ERSSTv5 is consistent with independent SOI index derived from sea level pressure measurements in Darwin and Tahiti (Trenberth 1984). This El Niño event in ERSSTv5 is also consistent with the precipitation and temperature proxy data derived from tree rings and coral reefs and from the great famine record in southeastern Asia and Africa (Kiladis and Diaz 1986; Allan et al. 1991; D’Arrigo et al. 2008; Garden 2008; Hao et al. 2010; Räsänen et al. 2016; Singh et al. 2018; Lough et al. 2018). For example, Singh et al. (2018) used the Palmer drought severity index (PDSI) in Asia and demonstrated a record-breaking El Niño during 1877/78. D’Arrigo et al. (2008) used the PDSI in Australia and Lough et al. (2018) used the degree heating month index (DHMI) derived from coral reef in the tropical oceans; both showed a strong El Niño event during 1877/78.

The strong 1877/78 El Niño in ERSSTv5 is consistent with that in HadSST1 (Fig. 2c; dotted blue) (Rayner et al. 2003). The Niño-3 index is approximately 0.5°C lower in HadISST1 than in ERSSTv5 from January 1877 to February 1878, which is in the range of the uncertainty of ERSSTv5 as indicated in Fig. 5d and Table 1. The temporal correlation between ERSSTv5 and HadISST1 Niño-3 indices between January 1877 and January 1879 is high (approximately 0.94). The consistency between the 1997/98 El Niño events in ERSSTv5 and HadSST1 is very good with strong correlations (0.99) between January 1997 and January 1999 (Fig. 2f).

In conclusion, the strength (2.8°–3.5°C) and uncertainty (0.5°C) of the 1877/78 El Niño event are quantified by evaluating the selection of certain parameters in the ERSSTv5 ensemble. The strength of the 1877/78 El Niño appears approximately equal to those during 1982/83, 1997/98, and 2015/16.

 I fully get that 1877-8 is as strong as any El Niño on record based on Nino 3.4 as Eric Webb’s and other tables show. But it’s the H5 maps that were shocking to see since I had never seen any H5 maps before the late 1940s. Now after reading what you posted above, I realize this 1877-8 H5 is no more than the equivalent of a wild educated guess as all it is based on is surface data as that’s all the only data they have.

13 hours ago, snowman19 said:

 

Being that the current OISST dailies suggest that RONI is likely ~-0.3 to -0.4, it is a very tall order to get the full April averaged RONI to rise all of the way to  +0.6, which is what this BoM run has. We’ll see what the very strong WWB/TC triplets are able to do. The rate of April warming would probably have to be well beyond record highs to get April RONI up to +0.6. The daily RONIs may have to approach +1.5 by April 30th!! I don’t see that being realistic at all.

On 3/31/2026 at 12:28 PM, GaWx said:

JB is going to bring his numbers way down per what he recently said. He said 2015 may be a good analog.

Makes perfect sense to me.

From JB:

April 5, 2026

The forecast numbers have been taken way down.
The Canadian model has been thrown out.
The European indicates a powerful El Niño and a negative AMO "look".
The closest analog is 2015.
The impact forecast is a roll of the dice.
Impacts will likely be below normal and scattered.
There is always the threat of one (un)lucky punch.
Early season Gulf or SE system a concern
The Western Pacific will take up the Global slack.
Eastern Pacific Mexican higher impact season possible
The forecast numbers for the 2026 season

Total storms: 9-13
Hurricanes: 3-5
Major Hurricanes: 1-2
Landfalling U.S. hurricanes: 1-2
Impact storms on the U.S. when at least a warning is issued: 3
ACE Index: 85-105

The closest analog is 2015

9 hours ago, snowman19 said:

 

 In 2023, the same BoM model also had it getting to +2.4 at the same time (Sept) as per snowman’s post at the bottom of this post. Here was that 4/8/23 run:

 

 But “it” back then was ONI, which like now was then ~0.5 higher than RONI. So, it implicitly was predicting RONI only at +1.9. Thus, the current BoM prog on an apples to apples basis is progging 0.5 warmer than what it had 3 years ago.

 But also keep in mind that the ‘23 BoM turned out to be significantly too warm for the ONI. In Sept, ONI verified to be only +1.64 meaning a large bust of +0.76! RONI was only +1.15. If this BoM run were to bust as badly to the top warm side, the Sept RONI would be at +1.64.

 

 

13 minutes ago, FPizz said:

It is largely a huge guess and mostly filled in using a handful of data.  If it was a science paper for college using that, you'd probably fail. 

Thanks. Do you have a link to the source for the map Chris posted?

37 minutes ago, bluewave said:

1877-1878 super El Niño more traditional like 1997-1998.

 

Chris, I’m curious. How is it possible to come up with even approximate geopotential hts for way back in 1877-8?

 I ended up getting the better part of 1/2” of much needed rain from thunderstorms late this afternoon. That was the best rain in quite awhile!