El Nino Watch

NASA GMAO GEOS-S2S forecast plumes

NASA's own seasonal model forecast of the Nino regions and the Indian Ocean Dipole.

Data and trust

NASA's Global Modeling and Assimilation Office runs the GEOS-S2S-3 coupled model several times a month and publishes plume charts once a month: Nino 3.4, 3, 4, 1+2 and the Indian Ocean Dipole for the next 9 months.

Limits. Images only: NASA does not publish the numbers in a machine-readable form, so none are extracted. Released early each month (September 2026 posted on 2 Sep).

How to read it

Each dashed line is one model start date, the thick red line their average. Values are degC from normal. The September 2026 release keeps Nino 3.4 near +3.5 to +3.8 through December before a slow decline.

Why it matters for Koh Samui

A third independent forecast next to NOAA/IRI and ECMWF. The Indian Ocean Dipole chart matters too: a positive IOD together with El Nino deepens drought over Southeast Asia.

Sources

ENSO status now

ONI (NOAA CPC)
+1.80 °C, JJA 2026 (previous +1.39 °C)
RONI (NOAA CPC)
+1.36 °C, JJA 2026
Nino 3.4 weekly (NOAA CPC / OISST)
+3.0 °C anomaly, week of 16 Sep 2026 (SST 29.6 °C)