GaWx

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

Note that Nino 3 anomalies are stronger than Nino 1+2. So, this prog isn’t severely E based as of 2/1/27.

1877-8 followed by cold neutral and then weak La Nina 1888-9 followed by strong La Niña and then weak La Niña But in neither of these cases were they immediately preceded by La Niña like ‘26.

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.

Nino 3.4 warmed only 0.2 in today’s release for last week averaged out vs the prior week from 0.5 to 0.7 vs my guess based on daily OISST levels/changes of it warming 0.3 (from 0.5 to 0.8). But this difference could possibly be mainly due to rounding. For example, perhaps the prior week was, say, +0.46 vs last week being, say, +0.74 or whatever. It has gotten more E based the last 5 weeks but (as per what I recently posted) the Euro doesn’t have it getting more E based overall from this point forward and thus keeps it from getting anywhere near as E based as 1997-8: 1+2 3 3.4 4 29APR2026 0.6 0.4 0.4 0.5 06MAY2026 1.0 0.5 0.4 0.5 13MAY2026 1.3 0.6 0.4 0.6 20MAY2026 1.6 0.7 0.5 0.6 27MAY2026 1.7 0.8 0.5 0.7 03JUN2026 2.1 1.0 0.7 0.7

Thanks. I realize that the RDU sensor is often a hot spot under sunshine in the warm season per past discussions I’ve read here and elsewhere. Do you know if your house had temps that jumped around ~6 F within just a few minutes of 3 PM? That seems very high with little change in sky condition (mostly sunny as opposed to large amounts of cloud cover suddenly moving in or out) and no big wind direction shift!

Fake news from RDU??TODAY MAXIMUM 99 259 PM CLI from KRAH ——————-NORTH CAROLINA WEATHER ROUNDUP NATIONAL WEATHER SERVICE RALEIGH NC 300 PM EDT SUN JUN 07 2026 RALEIGH-DURHAM MOSUNNY 93 57 29 VRB3 29.93F RWR from KRAH ——————-So, the 99 high was recorded at 2:59PM whereas the 3PM hourly reading was only 93. Sure, yeah right. This is truly bizarre! And the 99 seemed too high when considering surrounding stations!

Are we headed for another 2023-4 where SSTs are warm around Australia? Per JB, the models that showed for winter 2023-4 at H5 the mean E US trough/Aleutian low (most of them) didn’t have it that warm there and thus he blamed the unforecasted warmth around Australia.

After a very strong warming the prior 5 days averaging a very impressive 0.1C/day, the latest OISST 3.4 finally slowed its warming although it still warmed slightly (.014). Now that the full week’s data is in, I’m guessing 3.4 will be warmed by 0.3C to +0.8C in tomorrow’s release:

The MJO ended up going strongly into phase 8 (see image below) after all despite models a couple of weeks ago going only modestly into it and extended ensembles a month ago turning left in 7 toward the circle/missing 8. Bastardi back in April predicted W Car/Gulf TCG in June based on his expectation the MJO would go into 8 despite the extended ensembles not showing that. He more often than not predicts early activity. So, that’s not unusual. But he was right about the MJO. Will he be right about the Atlantic basin June TCG? Models/ensembles are hinting at the chance for this late this week:

Thanks, snowman. A key will be to see whether or not 3.4/4 fall severely behind regions 3/1+2 to determine whether or not this will be a very strong form of E based. For those who prefer it be/not be overly E based like ‘97, you’ll want 3.4 to not warm too steadily/keep warming steadily through the summer/early fall overall.