Sure, I can help with that.

Here's a more detailed paraphrasing of the text:NOAA's National Centers for Environmental Information were impacted by Hurricane Helene in late September.

While products and services are now available, many data products are still being updated.

We apologize for any inconvenience.

The ENSO blog, which discusses monitoring and forecasting El Niño, La Niña, and their regional and global impacts, is written, edited, and moderated by Michelle L’Heureux (NOAA), Emily Becker, Nat Johnson (NOAA), Tom DiLiberto (NOAA Office of Communications), and Rebecca Lindsey (contractor to NOAA), with occasional guest contributors.

The ideas and explanations in these posts should be attributed to the ENSO blog team, not to NOAA as an agency.

These are blog posts, not official agency communications.

If you quote from these posts or the comments section, you should attribute the quoted material to the blogger or commenter, not to NOAA, CPC, or Climate.

gov.

In September, the tropical Pacific Ocean reflected neutral conditions—neither El Niño nor La Niña.

Forecasters continue to favor La Niña later this year, with an approximate probability of it developing in September–November.

The probability of La Niña is a bit lower than last month, though, and it’s likely to be a weak event.

La Niña is the cool phase of the ENSO cycle, a pattern of alternating warmer (El Niño) and cooler surface waters in the tropical Pacific.

Rising warm air in the tropics drives global atmospheric circulation, influencing storm tracks and resulting weather patterns.

ENSO’s varying sea surface temperature changes affect where this occurs.

ENSO is predictable several months in advance, and when combined with our knowledge of how it changes global patterns, it provides an early picture of potential upcoming weather and climate patterns.

Let’s review recent conditions in the tropical Pacific.

The threshold for La Niña is a sea surface temperature in the central equatorial Pacific that is equal to or more than 0.

5°C below the long-term average (currently, 1991–2020).

The most recent temperature difference from average in the Niño-3.

4 region was -0.

3°C, and the September average was also -0.

3°C.

Hurricane Helene’s devastating impacts on the Asheville, NC, region affected data sources this month.

Michelle and CPC’s Caihong Wen did extensive testing and determined that the temporary replacements have historically been very close to the ones we usually use, so we’re confident that ENSO-neutral conditions are still in place.

An animation shows weekly sea surface temperatures in the Pacific Ocean compared to average from July 1–September 29, 2024.

Orange and red areas were warmer than average; blue areas were cooler than average.

Warmer-than-average sea surface temperatures in the key ENSO-monitoring region of the tropical Pacific (outlined with a black box) have started to be replaced by cooler-than-average waters—a sign that La Niña may be brewing.

There has been a region of cooler-than-average water in the central-eastern tropical Pacific in recent weeks, but it’s not quite crossing the threshold.

Some aspects of the tropical atmosphere are still reflecting neutral conditions.

There was a region of stronger-than-average trade winds in the east-central tropical Pacific and a little bit of reduced rainfall over the central Pacific, but overall, no strong, distinct pattern of stronger-than-average trade winds or increased rainfall over Indonesia as we’d expect during an established La Niña.

In fact, a couple of weeks of average to weaker-than-average trade winds during September allowed the surface to warm a bit.

If it seems like we’ve been stuck in neutral for longer than expected—we have! Last winter, models were predicting that La Niña would develop rapidly after the end of El Niño 2023–24.

So what happened? Why are we still waiting? Didn’t I just say ENSO is predictable? ENSO is predictable, but only in the big picture, meaning seasonal averages or longer.

The signals that tell us that El Niño or La Niña are on the way, such as a large amount of cooler or warmer water under the ocean surface, or a particularly strong, long-lasting shift in the trade winds, are reliable indicators.

Also, our computer climate models, which look at current conditions and make predictions based on mathematical and physical equations, are pretty good, especially after the spring predictability barrier (a time of year when predictions are especially difficult).

However, small fluctuations, such as the weaker equatorial trade winds that occurred during September, can’t be predicted more than a couple of weeks (at best) in advance.

They tend to have a disproportionate impact during borderline, more marginal situations when we are hovering near our ENSO thresholds.

These small fluctuations can tip the scales one way or the other.

In this case, they’ve added up to a slower and weaker La Niña development.

That said, many of our models are holding steady for La Niña to develop shortly.

A line graph shows observed and predicted temperatures (black line) in the key ENSO-monitoring region of the tropical Pacific from early 2024 through spring 2025.

The gray shading shows the range of temperatures predicted by individual models that are part of the North American Multi-Model Ensemble (NMME).

Most of the shading appears below the dashed blue line by the fall, meaning most models predict that temperature in the Niño-3.

4 region of the tropical Pacific will be cooler than average by at least 0.

5 degrees Celsius (0.

9 degrees Fahrenheit)—the La Niña threshold.

Forecasters have nudged the overall chance that La Niña will develop down a bit from last month, though.

That means that, while La Niña is still favored, we’re less confident in La Niña emerging.

Out of the three climate possibilities—La Niña, El Niño, and neutral—forecasts say that La Niña conditions are the most likely for the September–November season (blue bar over the SON label, 60% chance).

Also, if La Niña forms, it’s very likely this will be a weak event, with a maximum between -0.

9 and -0.

5°C, in line with model predictions.

In the historical record, which starts in 1950, only four La Niña events have formed this late in the year, with two forming in September–November and two in October–December.

These were all either weak or on the border between weak and moderate.

ENSO events are strongest in the winter, so there’s less time for this La Niña to grow from where we are now.

The strength of an ENSO event, as gauged by its sea surface temperature departures, matters because stronger events change the atmospheric circulation more consistently, leading to more consistent impacts on temperature, rainfall, and other patterns.

A weaker event makes it more likely that other weather and climate phenomena could play the role of spoiler.

However, even a weak La Niña can factor into seasonal outlooks because it can still nudge the global atmosphere.

Next month, Nat will review what the models have to say about winter conditions, including how much they reflect La Niña’s expected impacts.

Stay tuned here at the ENSO Blog—we’re all treat, not trick!A spike that lasts a year or more is not consistent with the secular, monotonic rise in temperature predicted by a GHG model.

It could be a tipping point perhaps, but if the spike disappears, that does not make sense.

So that leaves an El Niño or ocean-cycle cause, Hunga-Tonga response, or an aerosol change as has been suggested.

No way is it a sunspot-related event in my opinion.

As Gavin said, it's somewhat embarrassing not understanding the cause, but that's really in the context of not having a consensus to the cause of El Niño events in the first place.

Or having an agreement on whether the AMO is an oscillation or not.

Nature certainly can humble us in many ways, and the climate system often throws us curveballs (so it's not just for us ENSO forecasters and researchers).

I agree that the magnitude of recent heat is still a mystery, but I disagree with the statement that 'a spike that lasts a year or more is not consistent with the secular, monotonic rise in temperature predicted by a GHG model.

' The rise of global mean temperatures in response to GHG forcing does not preclude the competing or reinforcing effects of internal variability or other radiative forcing agents, which could last days or decades.

So, I agree that it's unsettling that we don't have a definitive answer for this spike, but that shortcoming doesn't necessarily say anything about consistency or inconsistency with the influence of GHG forcing on global mean temperature.

I noticed that in the interview article, there was not one mention of the words CO2, GHG, greenhouse gas, climate change, or global warming as a mechanism for the conspicuous heat spike of the last 2 years.

This could be overlooked by the author of the article, but the implication conveyed by Gavin Schmidt is that they're looking at something else, including ENSO.

Yet it's not ENSO alone as observed with the large spikes in the AMO for the Atlantic and the IOD for the Indian Ocean.

I've read in the past that central-based La Niña events are more common with weak events.

At least currently looking at the SST maps, the coldest SST locations are in the central Pacific.

At least following SST graphs and the maps, not much cold SSTs in the Niño 3 region.

What do you think the odds are of a Central-Based Modoki type La Niña?I cannot speak for Emily, but I can respond anyway.

The relationship between ENSO strength and east versus central/Modoki is stronger for El Niño than for La Niña.

La Niña tends to be centered farther west than El Niño in general, so most La Niñas are 'Modoki-like' to some extent.

That said, it's still possible this event could be centered farther east or west than normal.