889 

FXUS24 KWNC 111329

PMDENS

El Nino/Southern Oscillation (ENSO) Diagnostic Discussion

NWS Climate Prediction Center College Park MD

900 AM EDT Thu 11 Sep 2025



NOTE: figures mentioned in the discussion are available on

the internet at HTTP://WWW.CPC.NCEP.NOAA.GOV



ENSO Alert System Status: La Nina Watch



Synopsis: A transition from ENSO-neutral to La Nina is likely

in the next couple of months, with a 71percent chance of La

Nina during October - December 2025. Thereafter, La Nina is

favored but chances decrease to 54percent in December 2025 -

February 2026.



ENSO-neutral continued in August 2025, with near-to-below

average sea surface temperatures (SSTs) observed across the

central and eastern equatorial Pacific Ocean (Fig. 1). The

latest weekly Nino SST index values ranged from -0.4degC to

-0.2degC (Fig. 2). Negative subsurface temperature anomalies

(averaged from 180deg-100degW) strengthened (Fig. 3), with

below-average temperatures prevailing from the surface to 200m

depth in the central and eastern Pacific (Fig. 4). Low-level

wind anomalies were easterly across most of the equatorial

Pacific, while upper-level wind anomalies were westerly over

the western and eastern equatorial Pacific. Convection was

enhanced over Indonesia and was suppressed near the Date Line

(Fig. 5). Collectively, the coupled ocean-atmosphere system

reflected the continuation of ENSO-neutral.



The IRI multi-model predictions slightly favor

ENSO-neutral through the Northern Hemisphere winter 2025-26

(Fig. 6). However, all available models from the North American

Multi-Model Ensemble favor La Nina to emerge and persist through

the winter. Based on this guidance and recently observed trends

across the surface and subsurface equatorial Pacific, the team

also favors La Nina to develop. In summary, a transition from

ENSO-neutral to La Nina is likely in the next couple of months,

with a 71percent chance of La Nina during October - December

2025. Thereafter, La Nina is favored but chances decrease to

54percent in December 2025 - February 2026 (Fig. 7).



This discussion is a consolidated effort of the National Oceanic

and Atmospheric Administration (NOAA), NOAA's National Weather

Service, and their funded institutions. Oceanic and atmospheric

conditions are updated weekly on the Climate Prediction

Center website (El Nino/La Nina Current Conditions and Expert

Discussions). A probabilistic strength forecast is available

here. The next ENSO Diagnostics Discussion is scheduled for

9 October 2025. To receive an e-mail notification when the

monthly ENSO Diagnostic Discussions are released, please send

an e-mail message to: ncep.list.enso-update@noaa.gov.







$$