Forecast Forum

The canonical correlation analysis (CCA) forecast of SST in the central Pacific (Barnett et al. 1988, Science, 241, 192‑196; Barnston and Ropelewski 1992, J. Climate, 5, 1316‑1345), is shown in Figs. F1 and F2. This forecast is produced routinely by the Prediction Branch of the Climate Prediction Center. The predictions from the National Centers for Environmental Prediction (NCEP) Coupled Forecast System Model (CFSv2) are presented in Figs. F3 and F4a, F4b.  Predictions from the Markov model (Xue, et al. 2000: J. Climate, 13, 849‑871) are shown in Figs. F5 and F6.   Predictions from the latest version of the LDEO model (Chen et al. 2000: Geophys. Res. Let., 27, 2585‑2587) are shown in Figs. F7 and F8.  Predictions from the ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633‑652) are shown in Fig. F9.  Niño 3.4 predictions are summarized in Fig. F10, provided by the Forecasting and Prediction Research Group of the IRI.

The CPC and the contributors to the Forecast Forum caution potential users of this predictive information that they can expect only modest skill.

 

ENSO Alert System Status: El Niño Advisory

 

Outlook:

 

El Niño conditions are present and are expected to gradually strengthen into the Northern Hemisphere winter 2023-24.

 

Discussion:

 

In May, weak El Niño conditions emerged as above-average sea surface temperatures (SSTs) strengthened across the equatorial Pacific Ocean (Fig. T18). Three of the Niño indices were more than +0.5C: Niño-3.4 was +0.5C, Niño-3 was +0.9C, and Niño1+2 was +2.0C (Table T2). Area-averaged subsurface temperatures anomalies remained positive, reflecting the continuation of widespread anomalous warmth below the surface of the equatorial Pacific Ocean (Fig. T17). For the May average, low-level wind anomalies were westerly over the western equatorial Pacific Ocean (Fig. T20), while upper-level wind anomalies were westerly over the eastern Pacific Ocean (Fig. T21). Convection was enhanced along the equator and was suppressed over Indonesia (Fig. T25). Both the equatorial SOI and traditional SOI were significantly negative. Collectively, the coupled ocean-atmosphere system reflected the emergence of El Niño conditions.

The most recent IRI plume indicates the continuation of El Niño through the Northern Hemisphere winter 2023-24 (Figs. F1-F12). Confidence in the occurrence of El Niño increases into the fall, reflecting the expectation that seasonally averaged Niño-3.4 index values will continue to increase.  Another downwelling Kelvin wave is emerging in the western Pacific Ocean, and westerly wind anomalies are forecasted to recur over the western Pacific. At its peak, the chance of a strong El Niño is nearly the same as it was last month (56% chance of November-January Niño-3.4 >= 1.5C), with an 84% chance of exceeding moderate strength (Niño-3.4 >= 1.0C).  In summary, El Niño conditions are present and are expected to gradually strengthen into the Northern Hemisphere winter 2023-24.

Weekly updates of oceanic and atmospheric conditions are available on the Climate Prediction Center homepage (El Niño/La Niña Current Conditions and Expert Discussions).