ENSO Blog

Last November, I wrote about how a strong El Niño might shape precipitation over the U.S. this winter (December – February). So, what happened? With crocuses now starting to bloom and the chirps of spring peepers in full chorus, we’re ready to investigate! An El Niño-ish big picture First, let’s acknowledge that a strong El Niño occurred this winter, as NOAA had been forecasting since issuing an El Niño Watch in April 2023. (If we couldn’t check that box, this would be a very short post!) We unofficially consider El Niño to be “strong” when the Oceanic Niño Index (ONI) exceeds 1.5 °C (2.7 °F), and the ONI value for this past December – February w…   Read article

El Niño—the warm phase of ENSO, which is short for El Niño-Southern Oscillation—is still hanging on in the tropical Pacific, but signs are pointing to a quick transition to neutral conditions by the April–June period. There’s a 62% chance of La Niña getting the golden ticket by June–August. Stay tuned, because La Niña affects global climate patterns, including the Atlantic hurricane season and North American winter. Red carpet The sea surface temperature in the Niño-3.4 region of the tropical Pacific (our primary ENSO-monitoring region) was 1.6 °C (2.9 °F) above the long-term average (long-term = 1991–2020) in February, according to our most reliable dataset, ERSSTv5. This is still com…   Read article

On a brisk early February morning, all of us El Niño-Southern Oscillation (ENSO) forecasters emerged from our burrows and saw our shadows. That can mean only one thing: conditions are favorable for the development of La Niña within the next six months. Yes, the February ENSO Outlook officially announces that we are in a La Niña Watch, even while, at the current moment, the Pacific Ocean remains in an El Niño (this is simultaneous to the ongoing El Niño Advisory—here is an explainer to help sort it out). The outlook gives a 79% chance that El Niño will transition to ENSO-Neutral by the April–June period, and then a 55% chance the Pacific transitions into La Niña in June–August. Confused? I’ll…   Read article

Find your favorites! Here's an index of ENSO blog posts grouped a bit differently than what you get from the Climate.gov search function or what a simple listing page produces. The categories are simply the main ways that the ENSO blogging team tends to remember and talk about previous posts. Please keep in mind that everything about this index list is manual, from remembering/finding articles to include to the alphabetization of the guest authors section. I will almost certainly have missed some posts or made other mistakes. If you see a problem, feel free to point it out in the comments. I update this page a few times per year, so it will eventually get corrected.     …   Read article

Happy New Year from the ENSO Blog! With the arrival of the new year and an ongoing strong El Niño, many folks are already asking us, why isn’t the current El Niño bringing the expected wetter/drier/warmer/cooler conditions over my house yet?!  First, we’ve already seen impacts consistent with El Niño across much of the globe and those impacts have been occurring for some time now. A quick look around the world indicates some very El Niño-like impacts over the past half year (footnote #1). Second, we’re two-thirds through January as of this writing, which means we’re barely past the midway point in the December-February season. We’ve basically just entered the January-March seaso…   Read article