Andrej / severe-weather.eu

Comparing some of the latest forecast runs to past strong El Niño events shows we are in for quite a historic ride, if verified. Both the BOM and CFSv2 use the Relative ENSO index forecast. Interesting to see how close the new BOM forecast is to the ECMWF. @AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh @BenNollWeather

@novasufferer134 @AndyHazelton It would put it 3rd at that October data point, yes. We have yet to see what the full ECMWF RONI peak looks like. But the extended ONI forecast is quite significant.

@Recretos @AndyHazelton I saw the euro roni is 2.2, would that put it at like 3rd all time?

Comparing some of the latest forecast runs to past strong El Niño events shows we are in for quite a historic ride, if verified. Both the BOM and CFSv2 use the Relative ENSO index forecast. Interesting to see how close the new BOM forecast is to the ECMWF. @AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh @BenNollWeather

@novasufferer134 @AndyHazelton This is from the historical file calculated by NOAA/PSL, so its most likely that its ONI

@Recretos @AndyHazelton Also are the previous El Niños on the graph in roni or oni?

@AndyHazelton Also, comparing the latest ECMWF run to the previous run for July and September, we can see a stronger El Niño, but also a bit more intensity in the "+PDO" signature

@tcrawf_nh @AndyHazelton @webberweather @PaulRoundy1 I don't think it should in a grand way, similar to how the stratospheric U10mb winds dont really matter that much if they bottom out at 1m/s or -1m/s during an SSW event. But while small, the 0.3K delta should not be totally insignificant.

Nice analysis! I wonder if we’re needlessly splitting hairs at this point. Model forecasts have been consistent and trending more impressive with time, and recent observations are following along nicely with previous big Nino events. Will it really make significant differences in atmospheric impacts whether Nino 3.4 maxes out with SST anoms or relative SST anoms at 2.5 or 2.8?

Looking at the latest snapshot comparison to the last 2 Super El Niño events, we can see a significant speedup of the subsurface warming evolution in 2026 compared to the start of the month. @AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh

@AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh Last but not least, here is also the comparison graphic, using the May 5-9th forecast data, comparing it to the past 2 Super events. Also adding the CFSv2 Relative Niño index for good measure.

This is now also the revised plot for the older two Super events, comparing the late April 2026 data to April monthly means, and the second graphic is the forecast for May 5-9, 2026, compared to the May monthly mean for past events. The forecast comes from the Mercator Ocean International system, forced by ECMWF IFS.

@WeatherProf Where is this data found now? I have the old link which stoped updating in december

The latest CFS forecasts for El Niño need no hyperbole or exaggeration. The traditional Nino 3.4 region might actually be +3.4°C lol - I can’t tell because some of the members and also the mean are literally off the chart. The RONI.. newer “relative” index - which takes our warmed climate into account - is like 2.7 which would be close to a record (if averaged over 3 months). The current record is +2.5°C in 1982-83. The original index is good to look at for comparison sake. But the Relative index will give us a better idea of the impacts of the event. That’s because El Niño is most impactful when its anomalies are the highest compared to other adjacent regions/ basins. In 2023 there was a strong-ish El Niño but the Atlantic was also warm, diluting the El Niño impacts and allowing major hurricane Idalia to form in the Gulf.

@WeatherProf @AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh Exactly the same yes.

@Recretos @AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh Is the anomaly to the same baseline?

Looking at the month-to-date comparison to the last 2 Super El Niño events, we can see how big the OHC delta is in the western Pacific. Likely a stronger buildup, or perhaps just a time difference in the process evolution? @AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh

I decided to also load the zonal flow data for depth, and overlay the 2026 with the latest mean, and also do a comparison where/how the 2026 shows stronger/weaker zonal flow compared to past events. Will be really interesting to see the 2026 analysis plot in a week or two after the upcoming round of WWBs. But overall, stronger westerlies in the west are evident versus all years.

@AndyHazelton @webberweather @PaulRoundy1 @tcrawf_nh The final comparison is a simple subtraction of anomaly fields, which shows the true delta between the events, with a much stronger western OHC in 2026, and a closer resemblence to 1997 than 2015.

@Francis03915071 @PaulRoundy1 @AndyHazelton @webberweather @tcrawf_nh Check the graphic in the reply that directly compares the thermocline.

@Recretos @PaulRoundy1 @AndyHazelton @webberweather @tcrawf_nh La termociclina es más grande hoy

@webberweather @PaulRoundy1 @AndyHazelton @tcrawf_nh Saw this one earlier, it's a remarkable difference. Also further shows how the subsurface warm maxima this year is not "weaker" per se, but likely just at a certain point in development, and is soon going to be unleashed further.

@Recretos @PaulRoundy1 @AndyHazelton @tcrawf_nh Nice plot. Yeah the meridional width of our wind stress in the west pac is much more like 1982 & 1972 than 1997 so far this year

@webberweather @PaulRoundy1 @AndyHazelton @tcrawf_nh Great find! I also plotted the monthly data for 1982 and 1972 as a comparison, and 1972 does seem to be the closest to 2026 of the bunch in the western regions, but weaker in the east.

@Recretos @PaulRoundy1 @AndyHazelton @tcrawf_nh The meridional width of the westerly wind anomalies in the West Pacific this year thus far has been much greater than either 1997 or 2015. This allows IPWP displacements to hold a charge much longer w/o an upwelling Kelvin Wave response in the West Pac repository.library.noaa.gov/pdfjs/web/view…

@PaulRoundy1 @AndyHazelton @webberweather @tcrawf_nh Yes, the 1997 subsurface maxima was further east, which is why the negative delta between 180-100W. It looks like main difference could be just the time delta between the WWB events and the Kelvin Wave progression. Will revise these graphics weekly to see the progression.

@Recretos @AndyHazelton @webberweather @tcrawf_nh But it's interesting that your figures show so much subsurface warmer water this year than 1997. It was obvious that there was more warm water in the surface maximum of the warm pool.

@PROLIFICSHlTTER @webberweather Yea, ignore the large-scale picture, model bias from 2010's is all you need. 🙏

@Recretos @webberweather But but but models busted in 2017 that means we can ignore the reality in observational data right before us now!!

The sheer amount of blatant wishcasting I’ve seen on this platform lately that ignorantly downplays this El Niño even existing in the first place is honestly alarming. A lot of people are about to find out the hard way.