GaWx

Sep OHC (keep in mind these aren’t relative) continues the record shattering of the prior 2 months with it at 3.38. The 2nd highest Sep is 2.38 (1997). Even if there were a relative version, it would still be a record.

11 minutes ago, EasternLI said:

Luckily there are some other ways to view the strength of enso besides SST related metrics and those are pointing at a record event as well. Record WWB's, record shear for the Atlantic hurricane season, VP anomalies that make all the other years pale in comparison. The MEI could be another and I'll be curious to see that once it updates with Sept included plus future updates. RONI vs ONI is an interesting conversation but I think both are likely useful in their own ways. 

Also the record summer -SOI 

 The NOAA ERSSTv6 Sep PDO was -0.74:

-As expected based on WCS, this was less negative than Aug’s -1.12

-This is the least neg Sep since 2019’s +0.44.

-2023 Sep was way down at -2.52!

-This is the 3rd month in a row that NOAA came in less negative than avg of WCS dailies, which was ~-1.0 in Sep

- The NOAA August PDO had come in at -1.12 vs the WCS avg of ~-1.55.

https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/v6/index/ersst.v6.pdo.dat

  Here I got rain since 12:45PM-1:30 moving NE with some of it very heavy. This is in addition to a quick shower this morning and moderate rain (few tenths) late yest. afternoon from popups. It appears I’dreceived 1.5”+ from all of this with most of it just since 12:45PM. This compares to ~2.55” for all of Sep!

 Update at 5: been getting additional mod to heavy rain since 4:45. I’m now likely at 2”+ since yest.

 Edit: Final total for Fri-Sat 10/2-3 was ~2.1”.

1 hour ago, LakePaste25 said:

RONI vs ONI are not important to me this year because both are well above the threshold for super on the daily index, and will be for the 3 month index eventually. 

for records, I only care about absolute SSTs. similar to how we measure record heatwaves based on setting the absolute temperature of say, 105 degrees, not the “record anomaly.” We are currently above record SSTs in the 3.4 region. 

 

 We agree that the absolute 3.4 temp has been blowing away its record since summer on OISST. But a portion of that difference from prior records is obviously due to the globe being near its warmest on record:

-Avg trop ocean warming since 1997 is ~0.6C. So, without any of that warming, 2026 OISST would still be warmer going back to Sep 1st. But the diff would be ~0.6 smaller.

-Avg warming since 1982 ~~0.8C. So, it would still be warmer than 82 w/o the GW since then but would be ~0.8 smaller diff.

-It has warmed ~0.3C since ‘15. So, even after taking into acct GW, it would still be blowing away ‘15.

-It is pulverizing ‘23 as that was a much weaker Nino at this point vs the other 3 and there’s been some GW since then.

-Also, keep in mind that cyclonicwx’s OISST graph has been ~0.4 warmer than NOAA’s OISST the last 2 months. They used to be within ~0.1 apart on avg. I don’t know why, but it’s possible Alex’s OISST has been skewed a few tenths higher due to a bug for all I know.

-Even after taking into account both a possible bug in Alex’s graph and GW, ‘26 looks like it would still be at a record in 3.4.

1 hour ago, bluewave said:

The original paper that RONI is based on discusses it mostly being developed to prevent weak La Nina’s from getting lost in the mix rather than some deficiency in measuring super El Niño events.

Plus the weaker El Niños not being able to fully couple. Both instances were also a function of the record WPAC warm pool. 

So the ONI and the absolute SSTs are a good measure of how intense this event is becoming.

My original ONI post was correct as the original ONIs we relied on for many years into the 2010s had the ONI with the 1972-1973 event peaking at the +2.0 to +2.1 range. So a lower end super El Niño event. 

 

1. The concept of RONI applies to all ENSO.

2. ONI is a good measure of the combo of GW and ENSO. RONI is a good measure of ENSO, alone.

3. NOAA officially currently has 1972-3 at +2.0.

30 minutes ago, JLPhill said:

 

How much is this complicated by the fact that some of the feedbacks reinforcing El Niño depend on absolute SST ? Convection becomes much more favorable once SSTs reach roughly 27–28C, and when that convection shifts eastward it can weaken the trade winds and reinforce El Niño.

 As the globe warms, the threshold for the SST becoming much more favorable for convection warms:

Significant Increase in Sea Surface Temperature at the Genesis of Tropical Mesoscale Convective Systems

“We show that this threshold (SSTG) has undergone a significant warming trend at a rate of ∼0.2°C per decade. The SSTG shows a remarkable correspondence with the tropical mean SST and upper-tropospheric temperature on interannual and longer timescales.”

“The development of tropical ocean showers and thunderstorms requires a warm ocean surface as an energy source fueling the storm.”

”Using satellite observations and a high-resolution global climate model, we show that this threshold has undergone a significant warming trend during the past several decades and will continue to increase in the future. This warming trend is closely related to the changes in the tropical mean SST. A constant relationship between the SST threshold and upper-tropospheric temperature is found in both the current climate and a warming climate, which corroborates the argument that tropospheric temperatures in the tropics approximately follow a moist adiabatic adjustment.”

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101950

58 minutes ago, bluewave said:

The old ONI that we used before the recent updates was also +2.1. It’s perfectly fine to use the ONI as a measurement of the actual intensity of the event. With an event as extreme as this RONI can make the event seem weaker than it actually is.

https://x.com/BenNollWeather/status/2105084471750037987

From a scientific perspective, part of the challenge is that weather patterns in different parts of the world are not equally sensitive to the same El Niño index. In South America, for example, Niño 1+2 is particularly important, while patterns across the U.S., Australia, Singapore and many other regions are more closely associated with conditions in Niño 3.4. Some rely on a blend of ocean-atmosphere indicators (e.g., ONI, RONI, SOI, EQSOI, OLR, MEI, etc.) to capture coupling. For the public, the minutiae of those indices matter much less. What's record-breaking in one index may not be record-breaking in another, and I think it's incumbent on the communicator to make that clear. At the very least, if a record is being claimed, then a reference to the index/data set being used is essential (see attached). Not everyone will read the fine print, but it's duty of care. I think there's an opportunity for a larger body to step in (e.g., WMO) to classify a record El Niño event, if there's sufficient evidence, like they would a global temperature record. Lastly, I think the RONI-ONI debate will go on for years. RONI is more closely tied to atmospheric responses. ONI informs absolute extremes. In the ONI space, every tenth of a degree matters to global water vapor levels and temperatures, and therefore, the weather. The best approach is up for debate, but I think showing both is a fair balance. One El Niño, many ways to measure it!

https://x.com/WeatherProf/status/2105064342441939064

On the other hand, if you are trying to communicate the absolute strength of this El Niño vs other historic El Nino’s, how global warming has impacted it, or how it may impact global temperatures in the coming months - then use the traditional ONI or raw sea surface temperature anomalies. Certainly it can be confusing to the public, but I’d argue the relative index inadvertently obscures the larger climate signal - it can be misleading because it basically subtracts the warming that has occurred in recent decades. So it’s unintentionally deceptive.

You said in your earlier post that I responded to:

“It was a+2.1 event up until a few years ago before the CPC dropped it to +1.8. So until very recently it was rated as a lower end super.”

1. The CPC officially now has 72-3 at +2.0, not +1.8, as I showed, because ONI hasn’t been official since Feb.

2. You said,

“With an event as extreme as this RONI can make the event seem weaker than it actually is.”

 No, it’s not RONI making the event seem weaker. It’s ONI making the current Nino seem stronger than it really is due to GW. That’s the reason the RONI exists.
 
 ONI isn’t per NOAA and BoM the absolute strength of the 26 Nino, itself, because that exaggerates the strength due to adding the increasing warming from GW to the warming from El Niño, itself. The warming from El Niño, itself, is what RONI measures.

 I’ll use a hypothetical example to illustrate better:

-Say that the avg worldwide tropical ocean 30 year SSTa is at +1.0 vs its prior 30 year avg. Now say that 3.4 is also at +1.0 vs its own 30 yr avg. Per ONI it’s a +1.0 Nino. But per RONI it’s at 0.0/neutral because it’s measuring the contrast of the 3.4 anom vs the anomaly of the tropical waters. NOAA and BoM at the least have determined that +1.0 is deceptively high in this example because 3.4 is up to +1.0 due to GW, not because of El Niño. 

 Measuring the true strength of ENSO means measuring the contrast with surrounding tropical waters. If 3.4 and avg tropical waters are both at +1.0c there’s essentially no contrast (no relatively warm tongue in 3.4) and thus no Nino. A contrast is needed to have a Nino (or a Niña) per the official RONI. With no contrast like in this example it is neutral.

@mitchnick

2 hours ago, chubbs said:

https://bsky.app/profile/khaustein.bsky.social/post/3mwqu6hrps22s

 

26 is also notably colder than 23 in the Arctic.

1 hour ago, MJO812 said:

People throwing in the towel in October make me laugh. Same people do this every winter.  There are so many factors to consider during the winter.  Its not just enso.

Even throwing in the towel just based on ENSO, alone, would seem to be awfully bold.

I know it is hard to accept because of Fay’s tenacity, but the 0Z UKMET actually dropped her coming back to being a TC. Poor Fay 

4 hours ago, bluewave said:

It was a+2.1 event up until a few years ago before the CPC dropped it to +1.8. So until very recently it was rated as a lower end super. 

In any event, it’s rare to get a +AO +EPO +WPO pattern in October regardless of the ENSO. We haven’t since this October combination since the 2011 La Niña. 

But this time around we are getting a stronger mid-latitude ridge across the CONUS than 2011 had. Unusual to get such a strong TPV this early in the season.

 The CPC has 1972-3 peaking at +2.0 in its most up to date RONI table linked just below. Since RONI is the official way of classifying (and has been since Feb), that’s the current CPC official peak for 1972-3 rather than +1.8:

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/

 More on the transition of CPC from ONI to RONI for official classification of ENSO (this was released in Feb 2026):

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/announcement.php

 From the link above:

“The Climate Prediction Center is making the shift to use the Relative Oceanic Niño Index (RONI) to better designate past events and predict future ENSO.”

———————

 The table at the link below, which is to the most up to date ONI, has 1972-3 peaking at +1.8. But ONI hasn’t been the official way for CPC to classify since Feb. At the top it says this:

This page will continue to be updated by the 5th of each month, but per NWS Public Information Statement 26-05, the Relative Oceanic Niño index (RONI) is used for official monitoring and prediction of the El Niño-Southern Oscillation (ENSO) phenomenon.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/oni/v6/

@Maestrobjwa

40 minutes ago, olafminesaw said:

Womp womp

 This like another map I saw this morning shows that I’d get within just the next few days at least as much as I got in all of pretty dry Sept., which was ~2.55”. So, I hope it verifies pretty closely for MBY. In reality due to the showery nature of some of this producing isolated heavy amounts, I realize there will likely be significant variations in totals within pretty short distances though.

15 hours ago, LakePaste25 said:

Beautiful! going to be a crappy winter regardless so might as well root for the highest possible 

I agree with most that a record strong RONI is likely at this point. But NOAA is ~0.4 cooler than this fwiw (low +2s). So, it very likely won’t get nearly as warm as some models, like the BoA (still way up near +3.8) are showing.

 Regardless, the strongest anomalies are going to continue to be in 1+2 and 3. This is now the most E based on record by a good margin over 1997, and that’s looking to continue down the road.

1 hour ago, Maestrobjwa said:

Now hang on...I was told in another thread that 72-73 didn't technically classify as a super. But was it?

1. Technically FYI, “super” is not an official category for NOAA. I think they call those with RONI max of +2.0+ “very strong” or something similar. But here we including myself usually call them “super”.

2. 72-3 barely qualifies as “super” or “very strong” per the RONI table:

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/

20 minutes ago, MANDA said:

I know 1914 has lowest ACE on record.  I consider anything not in the satellite era questionable.

In the satellite era what season has lowest ACE?  

17.4 (1983)

 Going back all the way to 1851, only 3 had lower ACE than 1983 and all of them could have been higher in reality due to being way before the satellite era: 1914, 1925, 1907

https://en.wikipedia.org/wiki/Accumulated_cyclone_energy

 I ended up getting only ~2.55” of rainfall in Sept, which is well below the longterm average of >4.5”. The upcoming progged significant rainfall in early Oct here would be most welcomed!

Tulsa, OK, was 84.3 F in Sep ‘26, which was in addition to being 10.1 warmer than the longterm Sep mean:

- 2.4 warmer than its 2nd warmest Sep

- 1.4 warmer than its longterm mean for July

- warmer than 69% of Julys, 74% of Augusts, and 98% of Junes on record (records back to 1905)

@donsutherland1

16 hours ago, GaWx said:

 As I said, I’ve been following model initializations of 2m at 80+ N. They were colder than climo most of late May-early Aug.

 Check out those of the Euro for yesterday: clearly solidly BN vs 1981-2010 for 80N+ on Sep 29th (associated with a storm)(they were also quite cold going back to Sep 23rd by the way), which may actually be cold enough to support the ~2C colder than the 1958-2002 mean shown on the newest DMI graph:

 

 Here’s the Euro forecast for Oct 2nd, which shows notable warming as the storm moves S into Siberia. This is why I’m expecting warming on the DMI graphs by then:

@so_whats_happening@OSUmetstud

Follow-up: As expected based on the model consensus having significantly warmer 2m maps on Sep 30th vs Sep 29th at 80N+, the DMI warmed notably yesterday (>1C) vs Sep 29th as it rose to the blue line (mean for 1958-2002). It should warm further tomorrow:

12Z UKMET: Fay starts off deceased but she gets revived once again (on Friday) and like 2 runs ago later becomes a TS: 

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 60 HOURS
FORECAST POSITION AT T+ 60 : 27.3N 60.5W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 03.10.2026 60 27.3N 60.5W 1014 27
1200UTC 03.10.2026 72 29.3N 60.6W 1013 28
0000UTC 04.10.2026 84 31.8N 60.1W 1012 30
1200UTC 04.10.2026 96 34.0N 58.9W 1012 30
0000UTC 05.10.2026 108 35.6N 57.1W 1011 29
1200UTC 05.10.2026 120 37.5N 55.3W 1009 30
0000UTC 06.10.2026 132 40.2N 53.3W 1004 33
1200UTC 06.10.2026 144 44.7N 49.2W 996 41
0000UTC 07.10.2026 156 51.2N 44.3W 992 43
1200UTC 07.10.2026 168 CEASED TRACKING

@jconsor

 As I said, I’ve been following model initializations of 2m at 80+ N. They were colder than climo most of late May-early Aug.

 Check out those of the Euro for yesterday: clearly solidly BN vs 1981-2010 for 80N+ on Sep 29th (associated with a storm)(they were also quite cold going back to Sep 23rd by the way), which may actually be cold enough to support the ~2C colder than the 1958-2002 mean shown on the newest DMI graph:

 Here’s the Euro forecast for Oct 2nd, which shows notable warming as the storm moves S into Siberia. This is why I’m expecting warming on the DMI graphs by then:

@so_whats_happening@OSUmetstud

3 hours ago, OSUmetstud said:

The ecmwf was upgraded on May 12, 2026. What do you notice?

IFS users will also see the introduction of the new NEMO4-SI³ ocean and sea-ice model, bringing substantial improvements in forecasts and analysis over the marine areas, as well as over 40 new ocean and sea ice-related variables. Key improvements include a more accurate representation of how sea ice affects the power of waves and the interactions between waves and ocean currents, often at play in rougher seas. Other improvements for IFS include improved tropical upper-air temperature and wind forecasts, and improvements to temperature and humidity forecasts around the tropopause.

 

https://www.ecmwf.int/en/about/media-centre/news/2026/ifs-cycle-50r1-aifsv2-live

What's likely happening here is actually the new ecmwf 2 m temperatures over the Arctic are more accurate as the near surface inversion is more properly coupled to the ice and the cold ocean. The old 2 m ERA40 climatology is what's too warm. 

 Due to the timing of the upgrade, I’m also quite suspicious that this Euro 5/12/26 upgrade MAY have contributed to the colder 2026 vs previous summers. So, I do see what you’re saying. Thats why I went to that other forum and spent a couple of hours to see if anyone pointed to that. But nobody did in those hundreds of posts from very knowledgeable folks, including very experienced pro-mets. If this Euro upgrade is really a contributor or possibly even the main cause, don’t you think at least one person there would have mentioned that?

 That’s why I’d prefer to keep an open mind until there’s decent agreement among the met. community. Do you see anything wrong with that? You may be right and you’d then deserve major kudos, but I’d first Iike to see some consensus. But even if you’re right, can’t 2026 still be a cold outlier but to a lesser extent?

4 hours ago, OSUmetstud said:

This plot is not consistent with 2 m temperature being 2 C below the much older 1958 to 2002 climatology all summer. This area is all ocean/ice. 

 Because the plot he posted was for May-Aug, I’ll analyze that period. Looking at the image below, May-Aug averaged ~1.3C, not ~2C, below the much older 1958-2002 climo: May was ~-2C, June was ~-2C, July was ~-1C, and Aug was ~-0.1C. This means ~-1.3C for the avg of May-Aug rather than -2C. However, I do realize that -1.3C vs 1958-2002 would be a good bit more negative vs 1991-2020….perhaps as much as ~-3C?? So, that would be colder than what that 925 mb anomaly map suggests for 80N+, which I roughly estimate to be -1.25C:

 However, that image is for 925 mb, not 2m. Isn’t it possible that the 2m anom was colder than the 925 mb anom?

4 hours ago, jconsor said:

Larry,
I think that UKMET forecast showing Fay coming back this weekend is likely not a total outlier.

Moreover, seems Fay may have been deactivated too fast; it's almost like she's taunting NHC - every time they try to deactivate her, convection increases and she refuses to die!

https://x.com/yconsor/status/2105201133736415667

Yaakov,

 So, the Energizer Bunny may really come back for a 3rd time? Holy cow!

 Here’s the 0Z UKMET, which suggests that:

0Z UKMET actually has it as a non-TC tomorrow:

GLOBAL MODEL DATA TIME 0000UTC 30.09.2026

TROPICAL DEPRESSION FAY ANALYSED POSITION : 23.4N 48.7W

ATCF IDENTIFIER : AL062026

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 30.09.2026 0 23.4N 48.7W 1013 21
1200UTC 30.09.2026 12 23.3N 50.8W 1014 22
0000UTC 01.10.2026 24 CEASED TRACKING


 When I first saw this part of the 0Z textual output, I thought that even the UKMET had finally given up on it. But as I looked further down to look at other TCs, what did I see? Fay came back 36 hours later!

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 60 HOURS
FORECAST POSITION AT T+ 60 : 25.4N 58.6W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 02.10.2026 60 25.4N 58.6W 1015 25
0000UTC 03.10.2026 72 26.8N 59.6W 1014 27
1200UTC 03.10.2026 84 28.3N 60.5W 1014 26
0000UTC 04.10.2026 96 30.3N 60.5W 1014 26
1200UTC 04.10.2026 108 32.2N 59.4W 1014 27
0000UTC 05.10.2026 120 33.6N 58.4W 1013 26
1200UTC 05.10.2026 132 34.6N 56.7W 1011 25
0000UTC 06.10.2026 144 35.4N 55.1W 1009 24
1200UTC 06.10.2026 156 CEASED TRACKING

16 minutes ago, so_whats_happening said:

This is something you certainly do not see very often in this warmer world, especially in the confines of the Arctic. It was a solid retention year to say the least. Whether the temps are representative or not the overall pattern would suggest things didn't go haywire. 

It was a shame we started at such a low point from the previous winter which is weird coming out of La Nina to see such low volumes for sea ice.

Will be interesting to see how this plays out going into winter.

I started following the model consensus of 2m temps for the high Arctic regularly since May. The majority of the time through early August they initialized with a mean of BN fwiw.