GaWx

RDU was once again with their 99 THE hottest at 2PM by 2F of ALL major reporting stations in the entire SE! Louisburg, NC, was next at 97.

Semi-fake news RDU sensor was 97 at 1PM and was by 2F the hottest in the entire SE among official reporting stations with Rocky Mount, NC, and Brunswick, GA, next at 95!

The Triangle, Triad, and neighboring S VA was the only area in the entire SE to notably worsen as the rest of the SE either was unchanged or improved vs last week’s map.

As of noon, RDU (and Rocky Mt, NC also) was at 94F, not surprisingly THE hottest in the entire SE. I’m including all SE states including FL. With 94 at noon, RDU has a a good shot at ~101-2 despite the NWS forecast having “only” upper 90s for the Raleigh area. This, of course, is assuming that clouds and convection don’t start to increase there or even in the general vicinity: “TODAY MOSTLY SUNNY. ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON. HOT WITH HIGHS IN THE UPPER 90S. SOUTHWEST WINDS 5 TO 10 MPH. CHANCE OF RAIN 20 PERCENT. HEAT INDEX VALUES UP TO 102.”

Big news in the ENSO monitoring/ranking world: ECMWF yesterday finally followed NOAA’s lead and implemented its own version of a relative Nino 3.4 index! Although the general idea is the same, it is its own unique relative index and thus is calculated somewhat differently. Also, they use different databases to determine SSTs. Here’s ECMWF’s own graph showing both the traditional and the new relative Nino 3.4 SST anomalies going back to 1982: Note the following based on this ECMWF graph: -Most recently relative was ~0.5 cooler, similar to NOAA -It has 2023-4 ~same as NOAA with ~+1.5/+2 (relative ~0.5 cooler) -Like for NOAA, relative has been cooler since ~2014. -Similar to NOAA, the relationship was much more variable prior to 2014 including: -only small differences between relative/non-relative for 1997-8 just like for NOAA -relative being a large ~0.6C warmer in 1991-2 just like NOAA -relative being ~0.35 warmer in 1982-3 similar to NOAA’s ~0.3 warmer and warmest on record like for NOAA -But, ECMWF has bigger variations/extremes than NOAA for both El Niño and La Niña: -The ECMWF’s strongest La Niña since 1982 is just as for NOAA 1988-9, but it’s way down at -2.5 (for both) vs only -1.9 for NOAA (for both) -The ECMWF’s strongest El Niño is 1982-3 for both measures and is significantly stronger than NOAA with +3.1 relative/+2.75 non-relative vs NOAA’s +2.5/+2.2. This probably should be kept in mind when looking at the Euro’s ENSO progs vs history —————————————————— Measuring the strength of El Niño – introducing Relative Niño indices 10 June 2026 However, as the climate warms, interpreting these anomalies becomes more challenging. Rising background temperatures can make recent El Niño events appear stronger, and La Niña events weaker. To address this, with the support of the WMO, ECMWF is introducing an additional measure of El Niño strength, alongside the more traditional Niño 3.4 SST anomalies, in its seasonal forecast from 1 June 2026: the Relative Niño indices. These indices compare the Niño 3.4 region with the rest of the tropics at the same time, offering a perspective that is less sensitive to long-term warming. This will provide an additional tool for describing the likely strength of an upcoming El Niño event. Even with this adjustment, current forecasts suggest that El Niño may be unusually strong later in the year. https://www.ecmwf.int/en/about/media-centre/science-blog/2026/measuring-strength-el-nino @40/70 Benchmark@LakePaste25@bluewave@snowman19@donsutherland1among others

The extreme dry soils in parts of NC are favoring that highs there will be a little hotter and threaten records vs most other areas of the SE. It will be interesting to see what actually happens. Much will depend on the pattern of mid afternoon pop-up thunderstorm activity and how far reaching are the associated outflow boundaries. OTOH, the ATL area, where it has been raining a good bit more, isn’t favored to threaten record highs. Their forecasts have mainly lower 90s.

I’ll use simple hypothetical examples to illustrate why I think RONI is a better way to measure ENSO for both historical classification purposes and relevant effects: -assume worldwide ocean anomalies are in 2026 all +1C vs 1996-2025 climo due to GW and assume it’s uniform across all of the oceans -thus ONI would also be +1C/El Nino since it doesn’t separate out the 1C warming from GW -but there’s no El Nino signature as it’s +1C everywhere in the oceans -per RONI it’s perfectly neutral (0C) ENSO -classifying it as neutral makes more sense to me -now change it to +3C in 3.4 but keep a uniform +1C in all other oceans -now there’s a clear El Niño signature, but how strong is it? -ONI would classify it as +3C Nino -RONI would classify it as close to +2C Nino, which makes more sense to me @LakePaste25@bluewave

For the first time in awhile, Nino 3.4 didn’t warm per OISST. Instead, there was a notable cooling of 0.065C (see image below). After such an impressively strong warming since May 31st, this isn’t surprising. To me it is just El Niño taking a temporary breather of sorts. Ups and downs always happen. It’s still up at ~+1.0 RONI/+1.5 ONI equivalent snapshot. I expect the next round of notable warming to be later this month or in early July at the latest, especially if the -SOI persists, as that’s what ENSO models are suggesting.

I obviously agree with your last sentence as that’s essentially what my quoted 2026 sources said and it’s logical to me, regardless. Regarding the first part, I don’t see why RONI shouldn’t be the preferred way for historical rankings. As far as heat being released into the atmosphere: we know that heat released into atmosphere increases as SSTs rise from El Niño. But we know that the atmosphere also directly warms up from AGW, which adds to SST warming by what essentially is the equivalent of ONI less RONI more or less. In the upcoming case, a huge amount will be imparted by what has a good chance to be a record breaking RONI or at least close to a record. All ENSO regions are looking to be quite warm and thus will contribute a large amount of heat. That’s different from a severely E based that may not contribute as much heat because of the other ENSO regions not being as warm. *Edited to improve my wording about portion of SST increases due to AGW.

Thanks, Chris. The following two sources are very recent (2026) and are in support of RONI over ONI: New NOAA El Niño-Southern Oscillation Index Supports Drought Early Warning RONI accounts for the long-term ocean temperature trends in a way that the traditional ONI does not, thus providing a better representation of the seasonal climate variability. Not accounting for the warming oceans means recent El Niño temperature anomalies look bigger than they really are, and La Niña anomalies look smaller. Consider the last six winters: Five of the last six winters saw a La Niña pattern, which is one of the reasons much of the southern half of the Nation experienced persistent and recurring drought throughout the first half of this decade. Using the traditional ONI, 2020-2023 experienced a “triple-dip” La Niña, but RONI classified this as one continuous, unbroken La Niña event that lasted three years. These years were also very dry across the Southwest and Southern Plains. The 2024-2025 and 2025-2026 winters were ENSO-neutral using the traditional ONI. Using RONI, these events would instead be classified as definitive La Niñas. Winter 2025-2026 brought Moderate to Severe Drought (D1-D2) or worse for a broad swath of the Southern U.S. from Arizona to Florida. The La Niña pattern in place since around August 2025 is a primary driver of this drought. This season mostly followed the traditional La Niña response, with a few exceptions https://www.drought.gov/news/new-noaa-el-nino-southern-oscillation-index-supports-drought-early-warning-2026-03-11 ———————————————— Relative Oceanic Niño Index (RONI) A clearer, more reliable way to track El Niño and La Niña More reliable in real-time: ONI depends heavily on the choice of a 30‑year average. As tropical ocean temperatures shift over time, that reference can lag behind current conditions. RONI reduces this sensitivity, leading to more consistent classifications. More stable ENSO classifications RONI is less sensitive to which 30‑year reference period is used, meaning that the classification of past El Niño, Neutral, and La Niña events is more stable. Clearer connection to impacts RONI better reflects when ENSO‑related atmospheric patterns are actually present, improving alignment with seasonal temperature and precipitation outlooks. How is this change to RONI going to benefit decision makers who rely on an accurate ENSO forecast? RONI is better able to capture the expected changes in the atmosphere inherent to ENSO, and El Niño/La Niña categorization is more stable even as the climatology changes. Because RONI is more accurately reflecting the ENSO state, users will be able to more accurately make decisions that rely on associated seasonal forecasts and risk assessments. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/pdf/roni-info-may-2026.pdf

Thanks. Some of us have already been discussing ‘26-7 vs ‘97-8. On Saturday I posted that per the Euro progs, ‘26-7 is looking to evolve into a much less E based Nino than ‘97-8, which became the most E based Nino on record (back to 1951-2). When I refer to E based, I’m referring to the differences between 1+2 and 3 vs 3.4 and 4. This is what I posted: More on 97. Here were the monthlies: 1+2 3 4 3.4 1997 6 26.12 3.00 28.13 1.51 29.23 0.26 28.82 1.09 1997 7 25.59 3.63 27.90 2.09 29.37 0.47 28.86 1.56 1997 8 24.96 3.96 27.71 2.59 29.29 0.50 28.75 1.89 1997 9 24.69 3.96 27.74 2.84 29.44 0.68 28.85 2.13 1997 10 24.69 3.67 28.06 3.08 29.34 0.58 29.08 2.36 1997 11 26.12 4.47 28.37 3.27 29.39 0.69 29.12 2.41 1997 12 27.06 4.25 28.53 3.30 29.11 0.57 28.89 2.29 1998 1 28.12 3.55 28.74 3.08 28.95 0.64 28.93 2.38 1998 2 28.74 2.64 28.90 2.49 28.79 0.59 28.78 2.03 1+2 (peak 4.47) and 3 (peak 3.3) were way, way stronger than 4, which remained just wk (peak 0.69) and even way stronger than 3.4 (peak 2.41)! The forecast for ‘26 is much stronger in 3.4/4 and stronger in 3, but not as strong in 1+2: Per latest Euro, here are peak non-rel. monthlies: 1+2: 3.9 3: 3.9 3.4: 3.7 4: 2.4 That’s only a contrast of 1.5 from E to W compared to 3.8 in ‘97! And contrast from 1+2 to 3.4 is a mere 0.2 vs 2.1 in ‘97!! So, the prog is for ‘26 to be E based but way more balanced and thus not nearly as E based as the extremely E based ‘97.

Since yesterday, the non-AI ensemble progged Gulf tropical activity has diminished other than for perhaps the Bay of Campeche, which would be favored to landfall in MX. (The AI never picked up on anything much.)

Do you have this map for other states in the SE? TIA

Thanks, Chris -Long range model winter forecasts have, indeed, tended to be too cold on average based on my recollection although the Euro has missed on both sides. So, I wouldn’t be shocked if 25-6 also comes in warmer than today’s forecast, but that remains to be seen. -But keep in mind that you essentially are showing a super Nino sample size of just one (2015-6 done in August) since 2023-4 wasn’t a true super (RONI peaked at only +1.49). ONI had ~0.5C excess due to very warm surrounding tropical waters from GW inflating the ONI. -Also, other super Ninos had a fairly similar temp. pattern to what the NMME shows overall.

-Unlike Cansips, these NMME maps look typical/more believable for a strong Nino. -The strong Nino very typical wetness (starting as early as Oct on this run but I usually bank on the start in Nov) gives a lot of hope that the bad but somewhat improved drought in the SE will be mainly history by mid to late winter. - These maps are consistent with the El Niño winters that had one major to possibly historic SE US snowstorm like has occurred in many El Niños.